Decitabine combined with chemotherapy in treatment of relapsed T lymphoblastic lymphoma/leukemia with TP53 mutation after allogeneic hematopoietic stem cell transplantation: report of 1 case and review of literature / 白血病·淋巴瘤

Objective:To observe the efficacy and safety of decitabine combined with chemotherapy in treatment of relapsed/refractory T lymphoblastic lymphoma/leukemia (T-LBL/ALL) with TP53 mutation.Methods:The clinical data of a T-LBL/ALL patient with TP53 mutation who had recurrence after allogeneic hematopoietic stem cell transplantation (allo-HSCT) treated with decitabine combined with chemotherapy in the First Affiliated Hospital of Soochow University in June 2018 were retrospectively analyzed and the relevant literature was reviewed.Results:The patient, a 42-year-old male, diagnosed as T-LBL/ALL with TP53 mutation by comprehensive examination underwent sibling-matched donor allo-HSCT after a second complete remission. The patient relapsed 8 months later and was treated with decitabine combined with CLAG regimen to achieve complete remission again. And then, he had leukemia-free survival until now through maintenance treatment with decitabine.Conclusion:Decitabine combined with chemotherapy may be a safe and effective treatment option for relapsed T-LBL/ALL patients with TP53 mutation after allo-HSCT.

Importancia del síndrome de Li-Fraumeni, un síndrome genético de predisposición al cáncer / The importance of Li-Fraumeni syndrome, a hereditary cancer predisposition disorder

El cáncer en pediatría es una entidad infrecuente. Se estima que más de un 10-15 % de los tumores son secundarios a una variante patogénica en un gen de predisposición al cáncer.Se conocen más de 100 genes de predisposición al cáncer y su asociación con síndromes o tumores aislados. Uno de los más descritos es el síndrome de Li-Fraumeni.Los pacientes con este síndrome tienen alto riesgo de desarrollar uno o más tumores. Su conocimiento permite realizar un protocolo de seguimiento del paciente y de sus familiares afectos, con el que detectar precozmente nuevos tumores y disminuir la morbimortalidad del tumor y de su tratamiento.Esta revisión pretende ser una guía útil para el pediatra. Utilizando como caso guía a una familia, se revisarán los motivos de sospecha de un síndrome de Li-Fraumeni, su diagnóstico clínico y genético, y el protocolo de seguimiento de los familiares portadores de la misma mutación

Pediatric cancer is rare. It is estimated that more than 10-15 % of tumors are secondary to a pathogenic variant in a cancer predisposition gene.More than 100 cancer predisposition genes and their association with syndromes or isolated tumors have been identified. Li-Fraumeni syndrome is one of those who have been most widely described.Patients with this syndrome present a high risk of developing one or more tumors. Its knowledge allows to establish a follow-up protocol for the patient and affected family members, so as to detect new tumors in an early manner and reduce tumor- and treatment-related morbidity and mortality.The objective of this review is to offer useful guidelines for pediatricians. Based on a family case, reasons for Li-Fraumeni syndrome suspicion, clinical and genetic diagnosis, and the follow-up protocol of family members who carry the same mutation will be reviewed.

Survival analysis of 118 chronic lymphocytic leukemia patients with abnormal TP53 gene in the era of traditional immunochemotherapy / 中华血液学杂志

Objective: To analyze the survival and first-line immune-chemotherapy (CIT) of chronic lymphocytic leukemia (CLL) with abnormal TP53 gene in the era of traditional CIT. Methods: The clinical data of 118 CLL patients diagnosed from January 2003 to August 2017 were collected. Survival was analyzed according to indicators including sex, age, Binet risk stratification, B symptoms, β(2)-microglobulin (β(2)-MG) , immunoglobulin heavy chain variable region gene (IGHV) mutation status, chromosome karyotype and TP53 gene deletion/mutation. The efficacy of first-line CIT of 101 CLL patients was further analyzed. Results: Among 118 patients, median progression-free survival (PFS) was 12 (95%CI 10.148-13.852) months and median overall survival (OS) was 53 (95%CI 41.822-64.178) months, only 30.5% patients survived over 5 years. Low β(2)-MG<3.5 mg/L indicated longer PFS (P=0.027) , female and Binet A patients had longer OS (P=0.011 and 0.013, respectively) . Of 118 patients, 17 (14.4%) didn't receive any therapy until follow-up time or the dead time. Among the 101 patients who received ≥1 CIT, median time to first treatment (TTFT) was 1 (0-62) months, patients in Binet A had longer TTFT (P<0.001) compared to the patients in Binet B/C. According to statistical needs, we divided those first-line CIT into four groups: there were 30 cases (29.7%) in mild chemotherapy group (mainly treated with nitrogen mustard phenylbutyrate or rituximab alone) , 32 cases (31.7%) in the fludarabine-containing group, 23 cases (22.8%) in high-dose methyprednisolone (HDMP) containing group and 16 cases (15.8%) in the other chemotherapy group. The first regimen contained HDMP can bring longer PFS (P<0.001) , however the OS between four groups had no statistical differences. Conclusion: CLL patients with abnormal TP53 gene had poor response to immunotherapy, rapid clinical progressing, first-line immunotherapy containing HDMP can prolong PFS and will create an opportunity for patients to participate in clinical trials of novel drugs.

Clinical implications and prognostic value of TP53 gene mutation and deletion in patients with myelodysplastic syndromes / 中华血液学杂志

Objective: To explore the clinical implications and prognostic value of TP53 gene mutation and deletion in patients with myelodysplastic syndromes (MDS) . Methods: 112-gene targeted sequencing and interphase fluorescence in situ hybridization (FISH) were used to detect TP53 mutation and deletion in 584 patients with newly diagnosed primary MDS who were admitted from October 2009 to December 2017. The association of TP53 mutation and deletion with several clinical features and their prognostic significance were analyzed. Results: Alterations in TP53 were found in 42 (7.2%) cases. Of these, 31 (5.3%) cases showed TP53 mutation only, 8 (1.4%) cases in TP53 deletion only, 3 (0.5%) cases harboring both mutation and deletion. A total of 37 mutations were detected in 34 patients, most of them (94.6%) were located in the DNA binding domain (exon5-8) , the remaining 2 were located in exon 10 and splice site respectively. Patients with TP53 alterations harbored significantly more mutations than whom without alterations (z=-2.418, P=0.016) . The median age of patients with TP53 alterations was higher than their counterparts[60 (21-78) years old vs 52 (14-83) years old, z=-2.188, P=0.029]. TP53 alterations correlated with complex karyotype and International prognostic scoring system intermediate-2/high significantly (P<0.001) . Median overall survival of patients with TP53 alterations was shorter than the others[13 (95%CI 7.57-18.43) months vs not reached, χ(2)=12.342, P<0.001], while the significance was lost during complex karyotype adjusted analysis in multivariable model. Conclusion: TP53 mutation was more common than deletion in MDS patients. The majority of mutations were located in the DNA binding domain. TP53 alterations were strongly associated with complex karyotype and always coexisted with other gene mutations. TP53 alteration was no longer an independent prognostic factor when complex karyotype were occurred in MDS.

Survival analysis of 118 chronic lymphocytic leukemia patients with abnormal TP53 gene in the era of traditional immunochemotherapy / 中华血液学杂志

Objective@#To analyze the survival and first-line immune-chemotherapy (CIT) of chronic lymphocytic leukemia (CLL) with abnormal TP53 gene in the era of traditional CIT.@*Methods@#The clinical data of 118 CLL patients diagnosed from January 2003 to August 2017 were collected. Survival was analyzed according to indicators including sex, age, Binet risk stratification, B symptoms, β2-microglobulin (β2-MG) , immunoglobulin heavy chain variable region gene (IGHV) mutation status, chromosome karyotype and TP53 gene deletion/mutation. The efficacy of first-line CIT of 101 CLL patients was further analyzed.@*Results@#Among 118 patients, median progression-free survival (PFS) was 12 (95%CI 10.148-13.852) months and median overall survival (OS) was 53 (95%CI 41.822-64.178) months, only 30.5% patients survived over 5 years. Low β2-MG<3.5 mg/L indicated longer PFS (P=0.027) , female and Binet A patients had longer OS (P=0.011 and 0.013, respectively) . Of 118 patients, 17 (14.4%) didn’t receive any therapy until follow-up time or the dead time. Among the 101 patients who received ≥1 CIT, median time to first treatment (TTFT) was 1 (0-62) months, patients in Binet A had longer TTFT (P<0.001) compared to the patients in Binet B/C. According to statistical needs, we divided those first-line CIT into four groups: there were 30 cases (29.7%) in mild chemotherapy group (mainly treated with nitrogen mustard phenylbutyrate or rituximab alone) , 32 cases (31.7%) in the fludarabine-containing group, 23 cases (22.8%) in high-dose methyprednisolone (HDMP) containing group and 16 cases (15.8%) in the other chemotherapy group. The first regimen contained HDMP can bring longer PFS (P<0.001) , however the OS between four groups had no statistical differences.@*Conclusion@#CLL patients with abnormal TP53 gene had poor response to immunotherapy, rapid clinical progressing, first-line immunotherapy containing HDMP can prolong PFS and will create an opportunity for patients to participate in clinical trials of novel drugs.

Clinical implications and prognostic value of TP53 gene mutation and deletion in patients with myelodysplastic syndromes / 中华血液学杂志

Objective@#To explore the clinical implications and prognostic value of TP53 gene mutation and deletion in patients with myelodysplastic syndromes (MDS) .@*Methods@#112-gene targeted sequencing and interphase fluorescence in situ hybridization (FISH) were used to detect TP53 mutation and deletion in 584 patients with newly diagnosed primary MDS who were admitted from October 2009 to December 2017. The association of TP53 mutation and deletion with several clinical features and their prognostic significance were analyzed.@*Results@#Alterations in TP53 were found in 42 (7.2%) cases. Of these, 31 (5.3%) cases showed TP53 mutation only, 8 (1.4%) cases in TP53 deletion only, 3 (0.5%) cases harboring both mutation and deletion. A total of 37 mutations were detected in 34 patients, most of them (94.6%) were located in the DNA binding domain (exon5-8) , the remaining 2 were located in exon 10 and splice site respectively. Patients with TP53 alterations harbored significantly more mutations than whom without alterations (z=-2.418, P=0.016) . The median age of patients with TP53 alterations was higher than their counterparts[60 (21-78) years old vs 52 (14-83) years old, z=-2.188, P=0.029]. TP53 alterations correlated with complex karyotype and International prognostic scoring system intermediate-2/high significantly (P<0.001) . Median overall survival of patients with TP53 alterations was shorter than the others[13 (95%CI 7.57-18.43) months vs not reached, χ2=12.342, P<0.001], while the significance was lost during complex karyotype adjusted analysis in multivariable model.@*Conclusion@#TP53 mutation was more common than deletion in MDS patients. The majority of mutations were located in the DNA binding domain. TP53 alterations were strongly associated with complex karyotype and always coexisted with other gene mutations. TP53 alteration was no longer an independent prognostic factor when complex karyotype were occurred in MDS.

Síndrome de Li Fraumeni: análisis clínico de un caso y revisión de la literatura / Li-Fraumeni syndrome: clinical case study and literature survey / Síndrome de Li Fraumeni: análise clínica de um caso e uma revisão da literatura

Resumen: El síndrome de Li-Fraumeni (SLF) es una enfermedad hereditaria autosómica dominante con elevada penetrancia, que se caracteriza por la aparición precoz de múltiples tumores en un individuo y una marcada agregación familiar. Aproximadamente el 70% de los pacientes que cumplen criterios clínicos para su diagnóstico son portadores de la mutación germinal del gen TP53 localizado en el cromosoma 17p13. El gen TP53 es un supresor tumoral que cumple una importante función en el control de la estabilidad genómica. Se estima que el riesgo de desarrollar cáncer es del 50 % para las mujeres a los 31 años de edad y para los hombres a los 46 años y cerca del 100 % para ambos sexos a los 70 años. El curso clínico de la enfermedad es similar que en pacientes sin SLF a excepción de la edad más temprana al diagnóstico. Presentamos el caso de una paciente de 31 años a la que se diagnostica un condrosarcoma pelviano tratado con cirugía y al momento de la recidiva, aproximadamente 8 meses después, un cáncer de mama localizado. En otro miembro de su familia se había identificado la mutación 375G>C en el gen TP53 mediante secuenciación Sanger, la cual fue detectada posteriormente en nuestra paciente. Se discuten aspectos particulares del manejo como la minimización de la exposición a la radioterapia (por reportes de tumores malignos en zonas irradiadas) y el especial manejo de la repercusión del diagnóstico a nivel de los otros integrantes de la familia.

Abstract: The Li-Fraumeni syndrome (SLF) is a highly penetrant condition with an autosomal dominant inheritance pattern, characterized by an early onset of multiple tumors in a subject and a marked familial occurrence. About 70 % of patients meeting clinical criteria for diagnosis of the disease carry the germline mutation of TP53 gene located in chromosome 17p13. TP53 is a tumor suppressor gene known for its major role in genome stability control. It has been estimated that risk of cancer development is 50 % for women at the age of 31 and for men at the age of 46 and nearly 100 % for both men and women at 70 years of age. Except at earlier ages of diagnosis, the clinical course of the disease for healthy patients and for patients suffering SLF shows similarities. We present the case of a 31-year-old patient diagnosed both with pelvic chondrosarcoma treated surgically and localized breast cancer during relapse, about 8 months later. By Sanger sequencing, mutation 375G>C had been identified in TP53 gene in another family member, and said mutation was later detected in our patient. We discuss particular aspects of treatment procedures, such as minimizing radiotherapy exposure (due to reports of malignancies in radiated areas) and the special management of diagnosis implications for other family members.

Resumo: A síndrome de Li-Fraumeni (SLF) é uma doença hereditária autorexistente dominante com pena de penetração, que caracteriza a aparição precoz de múltiplos tumores em um indivíduo e uma coletânea familiar. Aproximadamente o 70% dos pacientes com critérios clínicos para o diagnóstico em crianças portadores da mutação germinal do gen TP53 localizado no cromosoma 17p13. El gen TP53 é um tumor tumoral que cumple uma função importante no controle da estabilização genómica. Se estima que o riesgo do desengate faz dos 50% para as mulheres aos 31 anos de idade e para os 40 anos e cerca de 100% para ambos os sexos aos 70 anos. O curso clínico da doença é semelhante ao que ocorre com a SLF a exceção da doença mais tem sido diagnosticada. Presentamos o caso de um paciente de 31 años que diagnostica um paciente de pélvico com relato ao momento da recidiva, aproximadamente 8 meses depois, em um lugar de mama próximo. En otio miembro de la familia se habiocuident to the mutación 375G> C en el gen TP53 por secuenciación Sanger, a cual fue detectada em recente paciente. A discussão foi feita sobre os aspectos do tratamento com a minimização da exposição à radioterapia (por tumores malignos em zonas irradiadas) e o especial manejo da repercussão do diagnóstico a nível dos otros integrantes da familia

Single nucleotide polymorphism of the TP53 gene is not correlated with male infertility / 中华男科学杂志

Objective@#To investigate the correlation of the single nucleotide polymorphism (SNP) rs1042522 of the tumor protein p53 (TP53) gene with the risk of male infertility.@*METHODS@#This casecontrol study included 380 male patients with idiopathic infertility and 398 normal fertile men as controls from the Nanjing area. We genotyped the SNP rs1042522 of the TP53 gene by Sequence Mass Array and analyzed the correlation of the SNP with male infertility using the logistic regression model.@*RESULTS@#Compared with the normal controls, the patients with idiopathic infertility showed significantly decreased sperm concentration (［77.34±49.24］ vs ［13.13±24.96］ ×106/ml), percentage of progressively motile sperm (［42.55±9.57］ vs ［10.38±5.57］%), serum testosterone level (［14.07±5.36］ vs ［11.89±4.50］ nmol/L), and folliclestimulating hormone level (［16.80±18.20］ vs ［4.55±7.17］ U/L) (P < 0.05) but no statistically significant differences in other parameters. No correlation was observed between the SNP frequencies and male infertility and similar results were found in the subgroups of the cases.@*CONCLUSIONS@#SNP rs1042522 of the TP53 gene is not significantly correlated with the risk of male infertility.

DNA methylation patterns of candidate genes regulated by thymine DNA glycosylase in patients with TP53 germline mutations

Li-Fraumeni syndrome (LFS) is a rare, autosomal dominant, hereditary cancer predisposition disorder. In Brazil, the p.R337H TP53 founder mutation causes the variant form of LFS, Li-Fraumeni-like syndrome. The occurrence of cancer and age of disease onset are known to vary, even in patients carrying the same mutation, and several mechanisms such as genetic and epigenetic alterations may be involved in this variability. However, the extent of involvement of such events has not been clarified. It is well established that p53 regulates several pathways, including the thymine DNA glycosylase (TDG) pathway, which regulates the DNA methylation of several genes. This study aimed to identify the DNA methylation pattern of genes potentially related to the TDG pathway (CDKN2A, FOXA1, HOXD8, OCT4, SOX2, and SOX17) in 30 patients with germline TP53 mutations, 10 patients with wild-type TP53, and 10 healthy individuals. We also evaluated TDG expression in patients with adrenocortical tumors (ADR) with and without the p.R337H TP53 mutation. Gene methylation patterns of peripheral blood DNA samples assessed by pyrosequencing revealed no significant differences between the three groups. However, increased TDG expression was observed by quantitative reverse transcription PCR in p.R337H carriers with ADR. Considering the rarity of this phenotype and the relevance of these findings, further studies using a larger sample set are necessary to confirm our results.

Association of BRCA1/2 Mutation and TP53 Over-Expression with Sporadic vs. Hereditary Iraqi Ovarian Cancer Patients.

Aims: In Iraq, ovarian cancer is the fifth most common cause of death, and the 6th in the list of most common cancers. While TP53 is the most common tumor suppressor gene involved with human malignancies, ovarian cancer is already known to be linked to the variations in the breast cancer genes, BRCA1 and BRCA2. Herein we aim to estimate the rate of BRCA1, BRCA2 gene mutation and TP53 immuno-expression in patients with hereditary vs. sporadic ovarian cancer and to show the correlation of these biomarkers to some clinicopathological parameters. Study Design: This is a correlational case-control study design. Place and Duration of Study: The present study was performed in the Department of microbiology; Genetic section, College of Medicine, Babylon University. Samples taken from patients referred to general teaching hospitals and some of the private laboratories in Al-Hilla and Al-Najaf governorate, in the middle of Iraq, over a period from January 2013 to November 2013. Methodology: Fifty-eight patients with ovarian carcinoma (30 sporadic and 28 hereditary), their ages ranging between 28-77 years, and thirty healthy women as control were included in this study. Genetic study using PCR technique was employed for BRCA1/2 gene mutation detection. Avidin-Biotin Complex (ABC) method was employed for immune-histochemical detection of Tp53 gene over-expression. Results: BRCA1l2 gene mutation was found in 21 and 13 cases out of 28 hereditary and 30 sporadic ovarian cancer cases respectively. TP53 over-expression was detected in 18 and 17 cases out of 28 hereditary and 30 sporadic ovarian cancer cases. BRCA1l2 gene mutation and TP53 over-expression was reported more frequently in higher stage of tumor (P=0.05). The large majority of cases were diagnosed in later ages, patients with sporadic cancer got the disease later than hereditary ones. Conclusion: BRCA1/2 and Tp53 genes alterations appears to be more important in hereditary than in sporadic ovarian cancer pathogenesis and evolution, as they are frequently associated with biologically aggressive tumors (high stages). Furthermore, TP53 gene over-expression was found to be more correlated with the cancer occurrence than BRCA1/2 mutation.

Padronização da análise de mutações no gene TP53 em carcinomas de células escamosas de boca em material parafinado / Standardization of TP53 gene mutations analysis on oral squamous cell carcinoma from paraffin-embedded tissues

Introduction: The tumor protein p53 gene (TP53) is a constant target of investigation in cancer pathogenesis. Analysis by immunohistochemistry provides limited data about p53 in oral carcinogenesis, and TP53 sequencing can contribute to this analysis. However, obtaining high-quality and contamination-free deoxyribonucleic acid (DNA) for a proper amplification can be a difficult task when using paraffin-embedded tissues. Objective: Standardize DNA extraction, polymerase chain reaction (PCR) amplification and DNA sequencing techniques for TP53 mutation analysis. Material and methods: Thirty-nine cases of oral squamous cell carcinoma (OSCC) were selected from the Pathology Division of Instituto Nacional de Câncer (Inca). The DNA extraction method used was the QIAamp® DNA minikit® system. After DNA quantification by spectrophotometry, 250 ng of genetic material obtained from TP53 gene were amplified by PCR for exon 2 and by nested PCR for exon 6. Out of the total sample, 11 cases were selected for exon 2 sequencing. Results: The DNA samples presented mean concentration of 119.74 ± 88.86 ng/µl (28.9-556.4) and purity of 1.69 ± 0.18 (1-1.9). Thirty-three (84.6%) samples were amplified for exon 2, and all samples for exon 6 (39/100%). Readable sequencing data were obtained in 10 (90.9%) cases. Conclusion: Optimization of conditions for TP53 sequencing was obtained, and this will facilitate the analysis of mutations in paraffin-embedded tissues, allowing molecular retrospective studies...

Introdução: O gene TP53 (proteína tumoral p53) é alvo constante de investigação na patogênese do câncer. A imuno-histoquímica fornece dados limitados na análise de p53 no processo da carcinogênese bucal e o sequenciamento de TP53 pode contribuir nessa investigação. Contudo, a obtenção de ácido desoxirribonucleico (DNA) com qualidade para amplificação e livre de contaminação pode constituir uma tarefa difícil na utilização de material parafinado. Objetivo: Padronizar as técnicas de extração de DNA, amplificação por reação em cadeia da polimerase (PCR) e sequenciamento para a análise de mutações em TP53. Material e métodos: Foram selecionados 39 casos de carcinomas de células escamosas bucal da Divisão de Patologia do Instituto Nacional de Câncer (Inca). O DNA foi extraído utilizando o sistema comercial QIAamp® DNA minikit®. Após quantificação do DNA por espectrofotometria, 250 ng de amostra foram amplificados pela técnica de PCR para o éxon 2 e por nested PCR para o éxon 6 do gene TP53. Da amostra total, 11 casos foram selecionados para a padronização da reação de sequenciamento do éxon 2. Resultados: As amostras de DNA apresentaram concentração média de 119,74 ng/µl ± 88,86 (28,9-556,4 ng/µl) e pureza de 1,69 ± 0,18 (1-1,9). Do total das amostras analisadas, 33 (84,6%) foram amplificadas para o éxon 2, e todas (39/100%), para o éxon 6. No sequenciamento do éxon 2 obtiveram-se sequências passíveis de leitura em 10 (90,9%) casos. Conclusão: A otimização das condições para o sequenciamento de TP53 foi obtida, o que facilitará a análise de mutações em tecidos parafinados, permitindo...

Caracterización molecular del gen supresor de tumores TP53 en el cáncer colorrectal / Molecular characterization of TP53 tumor suppressor gene in colorectal cancer

Introducción: El cáncer colorrectal (CCR) es una de las neoplasias más comunes en el mundo; especialmente,en los países desarrollados. En Colombia, la incidencia del CCR ocupa el cuarto lugar en hombres ymujeres; el CCR tiene una gran heterogeneidad genética. Objetivo: Determinar la presencia de mutacionesen los exones 5-8 del gen TP53 en tumores colorrectales, mediante el secuenciamiento directo. Métodos:Muestras con diagnóstico histopatológico de CCR esporádico se dividieron en dos grupos. El Grupo I fue de 30 muestras de tumores a partir de biopsias frescas, y el Grupo II, de 46 muestras de tejidos tumorales embebidos en bloques de parafi na. El análisis de mutaciones se realizó en los exones 5-8 del gen TP53,empleando las técnicas de PCR y de secuenciamiento directo. Resultados: Se encontró una baja frecuenciade mutaciones en el gen TP53, del 4,4%; las mutaciones detectadas fueron sin sentido; además, fueronidentifi cados dos polimorfi smos que segregan juntos. Todas las mutaciones y los polimorfi smos se detectaron en las muestras del grupo I. La mayoría de las muestras analizadas se hallaban en un estado avanzado del cáncer. Conclusiones: La baja frecuencia obtenida de mutaciones en TP53 permite sugerir la existencia de alteraciones en otras vías genéticas, relacionadas con la carcinogénesis colorrectal, como las vías de MSI y de CIN, así como la epigenética; dichas alteraciones no podrían excluirse en las muestras evaluadas. Los estudios moleculares en muestras de tejidos embebidos en parafi na presentan difi cultades para los análisis genéticos. La caracterización molecular del CCR es importante para conocer el espectro de mutaciones y de variantes moleculares presentes en la población observada.

Introduction: Colorectal cancer (CRC) is one of the most common malignancies in the world, especially indeveloped countries. In Colombia, the incidence of CRC ranks fourth in men and women. CRC has greatgenetic heterogeneity. Purpose: The purpose of this study was to determine the presence of mutations inexons 5 to 8 of the TP53 gene in colorectal tumors by direct sequencing. Patients and Methods: Samples with histopathological diagnoses of sporadic CRC were divided into two groups. Group I included 30 tumor samples from fresh biopsies and Group II included 46 tumor tissue samples embedded in paraffi n blocks. Mutational analysis was performed for exons 5 through 8 of the TP53 gene using PCR and direct sequencing.Results: The frequency of TP53 mutations was only 4.4%, and mutations that were detected were nonsense mutations. In addition, two polymorphisms that segregate together were identifi ed. All mutations and polymorphismswere detected in samples from Group I. Most of the samples were in advanced stages of cancer.Conclusions: The low frequency of mutations in TP53 suggests the existence of alterations on other related genetic pathways in colorectal carcinogenesis. These could include MSI pathways, CIN and epigenetics. Such alterations could not be excluded in the samples tested. Molecular studies of tissue samples embedded inparaffi n are diffi cult to analyze genetically. Molecular characterization of CRC is important for determining the spectrum of mutations and molecular variants present in our population.

Analysis of TP53 Gene Mutations in the Korean Patients with Lung Cancer

BACKGROUND: Lung cancer is one of the leading causes of cancer-related deaths throughout the world. The gene tumor protein 53 (TP53) is frequently mutated in cases of lung cancer. This study was performed to investigate the frequencies and types of mutations in the TP53 gene in Korean patients with lung cancer. METHODS: We obtained tissue samples from 80 lung cancer patients and synthesized TP53 cDNA by using RNA isolated from these tissues by performing reverse transcriptase polymerase chain reaction. Hybridization and denaturing high-performance liquid chromatography were performed to identify the TP53 gene mutations, and then, the mutations were validated by direct sequencing. RESULTS: Forty mutations out of the 80 patients (50.0%) were noted in the TP53 gene. The frequencies of TP53 gene mutation for different cancer types, namely, squamous cell carcinoma, adenocarcinoma, and small cell carcinoma were 61.1%, 27.3%, and 26.7%, respectively. The mutation frequencies in the different regions of the gene were 10.0% for exon 4, 35.0% for exon 5, 12.5% for exon 6, 22.5% for exon 7, 17.5% for exon 8, and 2.5% for exon 9. The frequently mutated positions were codon 179 in exon 5, codons 202 and 220 in exon 6, and codons 266 and 273 in exon 8. CONCLUSIONS: Exon 5 was the most frequently mutated region in the TP53 gene. Compared to the patients with the other types of cancers, patients with squamous cell carcinoma showed a higher frequency of TP53 mutation. Codon 179 was the most frequently mutated codon in the TP53 gene.

Análisis de las aneuploidías del cromosoma 17 y deleción del gen TP53 en tumores gastrointestinales por FISH-bicolor / Analyses of numerical aberrations of chromosome 17 And TP53 gene deletion in gastrointestinal tumors by dual-color fluorescence in situ hybridization (FISH)

Introducción. Las alteraciones cromosómicas numéricas y estructurales son comunes en las neoplasias gastrointestinales; estas alteraciones se originan por la inestabilidad cromosómica que ocurre durante el desarrollo del cáncer, afectando la expresión de diversos genes como protooncógenes, genes supresores de tumores y genes de reparación.Objetivo. Evaluar las aneuploidías del cromosoma 17 y deleción del gen TP53 en tumores gastrointestinales primarios, mediante la técnica del FISH bicolor. Muestras y métodos. Se analizaron 15 muestras de tumores gastrointestinales primarios, se disociaron mecánica y enzimáticamente con colagenasa para obtener núcleos interfásicos. El FISH bicolor se realizó con sondas marcadas con fluorocromos para el centrómero del cromosoma 17 y para el locus 17p13.1 del gen TP53. Se analizaron 100 núcleos por cada muestra.Resultados. Se encontró que el 33,3% (5/15) de las muestras tenía aneuploidías para el cromosoma 17; la monosomía fue detectada en todos los casos (5/5). La mayoría de las muestras tenía subpoblaciones de núcleos heterogéneos (mosómicos, disómicos, trisómicos y tetrasómicos). El 93,3% (14/15) de los tumores tenían deleción del gen TP53. El estudio histopatológico mostró que 14 de las 15 muestras presentaban un estado avanzado del cáncer.Conclusiones. Se demostró un imbalance entre las señales del centrómero del cromosoma 17 y del gen TP53 por núcleo mediante el FISH bicolor. Aneuploidías del cromosoma 17 y deleciones en el locus 17p13.1 del gen TP53 son alteraciones muy frecuentes en tumores gastrointestinales. El FISH bicolor permite evidenciar la heterogeneidad genética intratumoral que se presenta en el desarrollo del cáncer.

Introduction. Numerical and structural chromosome aberrations are common in gastrointestinal cancers; these are originated by chromosomal Instability that happens during development of cancer. Thus, the expression of many genes is affected, such as protooncogene, tumor suppressor genes and repair genes. Aims. To evaluate aneuploidy of chromosome 17 and TP53 gene deletions in primary gastrointestinal tumors by dual- color fluorescence in situ hybridization (FISH).Samples and methods. 15 primary gastrointestinal tumor samples were analyzed, which were mechanically and enzimatically disaggregated with 0.2% collagenase in order to obtain interphase nuclei. Dual-color FISH assays was performed using direct fluorescent labeling probes for the chromosome 17 centromere and TP53 gene (17p13.1). Hybridized signals were counted in 100 interphase nuclei by each case.Results. Aneuploidy of chromosome 17 was found in 33.3% (5/15) of the samples. Monosomy was detected in 100% (5/5) of cases with aneuploidies. Most of tumor samples exhibited heterogeneous clones that were monosomic, disomic, trisomic and occasionally tetrasomic. The TP53 deletion was found in 93.3% (14/15) of the analyzed samples. The histopathological study showed that 14 out of 15 tumors samples displayed an advance stage of tumorigenesis.Conclusions. We found an imbalance of signals for chromosome 17 and TP53 per nucleus. Aneuploidy of chromosome 17 and TP53 gene deletion are very frequent aberrations in gastrointestinal tumors. Dual-color FISH analysis allow detect intratumoral genetic heterogeneity that had occurred in development of cancer.

Resistência ao tratamento no linfoma de Burkitt: associação com mutações específicas no gene TP53?: [revisão] / Treatment resistance in Burkitt's lymphoma: is it associated with specific mutations of the TP53 gene?: [review]

O linfoma de Burkitt (LB) surge a partir de uma célula do centro germinativo que perde o controle da proliferação devido à ativação do gene c-myc. A resistência à apoptose é uma causa importante da falha à quimioterapia na maioria dos cânceres e também no LB. A taxa alta de apoptose observada no LB em fases iniciais da gênese do tumor é seguida pelo desenvolvimento subseqüente de inativação de vias que levam à apoptose da célula. Uma importante via que se encontra alterada no LB é a via mediada pela proteína p53. Essa via é importante para o controle da proliferação celular em resposta ao dano no DNA. Dados da literatura mostram uma correlação entre mutações do gene TP53 com resistência ao tratamento. No entanto, alguns estudos têm demonstrado que diferentes tipos de mutações podem conferir respostas diferentes das células à quimioterapia. Isso tem sido observado em nossos estudos que mostram que linhagens celulares do LB com mutações diferentes da p53 apresentam uma resposta diferenciada à apoptose induzida por drogas que atuam por essa via, como, por exemplo, a doxorrubicina. Diferentes tipos de mutações conferem fenótipos funcionais distintos, embora nem sempre ocorra uma perda da função, o que pode ser um importante componente da resistência à quimioterapia no LB. Nesse artigo revisamos a literatura com relação à resposta ao tratamento no LB e discutimos o papel das mutações do gene TP53 na resistência à quimioterapia nesses tumores.

Burkitt's lymphoma (BL) originates from a germinative centre cell that loses proliferation control due to activation of the c-myc gene. Apoptosis resistance is a major cause of chemotherapy failure in most kinds of cancers, including BL. The high rate of apoptosis seen in the early steps of genesis of BL is followed by a subsequent development of inactivation of pathways leading to cell death by apoptosis. A major pathway known to be altered in BL is the one mediated by the p53 protein. This pathway is important to control cell proliferation in response to DNA damage. Data from the literature show a correlation between TP53 gene mutations and treatment resistance. However, some studies have demonstrated that distinct types of mutations have the ability to confer different cell responses to chemotherapy. We found that BL cell lines bearing distinct mutations of p53 also present different responses to drug-induced apoptosis, when using drugs that act through this pathway, such as doxorubicin. Different types of mutations might confer distinct functional phenotypes. Loss of function does not always occur which may be considered an important component of chemotherapy resistance in BL. In this article we review publications regarding the response to treatment in BL while we discuss the role of TP53 gene mutations in chemotherapy resistance of these tumors.

Genetic Counseling Can Influence the Course of a Suspected Familial Cancer Syndrome Patient: From a Case of Li-Fraumeni Like Syndrome with a Germline Mutation in the TP53 Gene / 대한진단검사의학회지

We report a 26-yr-old female patient with bilateral breast cancer who was clinically diagnosed with Li-Fraumeni like syndrome (LFL) and subsequently found to have a germline mutation of the TP53 gene. The patient was initially diagnosed with right breast cancer at age 24 yr and then with left breast cancer at age 25 yr. Surgery and radiotherapy were performed accordingly. The patient had a family history of various types of early onset cancers and was referred to a genetic counseling clinic. She was clinically diagnosed with LFL. Genetic analysis of the TP53 tumor suppressor gene was performed with the patient's consent. Direct sequencing of TP53 gene exons 5, 6, 8, 9, and 11 revealed a ermline missense mutation, resulting in an amino acid change from an arginine to a histidine (g.13203G>A, p.R175H). Considering the family history, individualized cancer surveillance was performed including a gastroscopy and a brain MRI. Even though the patient had not shown any neurological symptoms, a huge mass on the temporal lobe was incidentally found and the patient received surgery and radiotherapy. Although the residual mass required further treatment, the patient decided on supportive care alone and was discharged. We report a case of LFL, with a germline TP53 mutation, which was confirmed by gene sequencing in Korea. This case shows how genetic predisposition screening and counseling in patients, suspected of having a familial cancer syndrome, can influence the course of the patient.

Análise Multifatorial dos Mecanismos de Resistência ao Tratamento em Linhagens Celulares Derivadas do Linfoma de Burkitt

O Linfoma de Burkitt (LB) é o linfoma maligno mais comum da infância. Embora o regime de tratamento utilizado atualmente seja bem sucedido em grande parte dos casos, há uma constante busca por regimes menos tóxicos, e terapêutica de resgate para os pacientes refratários ao tratamento inicial, ou que apresentam recidiva. Nesse sentido, o entendimento dos mecanismos moleculares de resistência e refratariedade ao tratamento podem auxiliar na obtenção de um modelo de terapia eficaz no caso de falha ao tratamento inicial. Uma importante via de atuação de diversos agentes quimioterápicos, incluindo aqueles usados no tratamento do LB, é a de indução de apoptose mediada pela proteína p53. O gene TP53 encontra-se mutado em uma grande proporção de tumores humanos, e já foi mostrado que suas mutações correlacionam-se com a resposta ao tratamento em diversos tipos tumorais. No entanto, alguns estudos têm demonstrado que diferentes tipos de mutações podem conferir respostas diferentes das células à quimioterapia. Nesse estudo utilizamos duas linhagens celulares tumorais derivadas do Linfoma de Burkitt – Daudi e Raji – que apresentam mutações distintas do gene TP53 e correlacionamos a resposta dessas células à indução de morte pela exposição aos agentes citotóxicos doxorrubicina, etoposídeo, cisplatina e radiação gama. Avaliamos também a capacidade desses agentes induzirem aumento de expressão da proteína p53 nessas linhagens, assim como, a funcionalidade das diferentes mutantes da p53 em relação à indução de apoptose, parada do ciclo celular e habilidade de transativação do gene p21. Os níveis de survivina, uma importante proteína envolvida no processo apoptótico que está sob regulação direta da p53, e da proteína pró-apoptótica SMAC/Diablo também foram avaliados antes e após a exposição das linhagens aos agentes citotóxicos. Como resultados observamos variação no percentual de apoptose, que atingiu 60-80% na Raji e 20-30% na Daudi em 48 horas com a mesma concentração de radiação ionizante. Além disso, a DL50 para os quimioterápicos foi diferente entre as duas linhagens, sendo consideravelmente maior na Daudi do que na Raji. A resistência das linhagens aos variados agentes dependeu em grande parte do tipo de mutação do gene TP53 e do agente utilizado. Observamos ainda diferenças no status funcional da proteína p53, em relação a indução de apoptose e transativação de genes alvo, como o gene p21, mostrando que diferentes mutações podem levar a conseqüências funcionais diversas. A expressão da survivina foi regulada positivamente pela p53 mutada após a exposição às drogas e à radiação gama, mostrando um papel para essa proteína na apoptose dependente de p53 e resistência...

Burkitt’s Lymphoma (BL) is the most common malignant lymphoma in children. Although the currently used treatment regimens are successful in most cases, new less toxic regimens and rescue therapeutics for patients with refractory disease, or who presented relapse are still in continuous search. In this context, understanding the molecular mechanisms related to chemotherapy resistance and lack of treatment response may help to design new treatment approaches, which could be effective in this clinical setting. An important mechanism of action of several chemotherapeutic agents, including those used in BL treatment, is the p53-mediated apoptosis induction pathway. TP53 gene is mutated in a large number of human tumors, and a relationship between p53 mutations and treatment response in many kinds of tumors has been shown. In addition, some studies have reported that different types of TP53 mutations confer different cell responses to chemotherapy. In this study we analysed two Burkitt’s Lymphoma cell lines – Daudi and Raji – in which distinct mutations of TP53 gene were previously described. Cell lines response to doxorubicin, etoposide, cisplatin, and gamma radiation-induced cell death were correlated to TP53 mutations. We also evaluated the ability of these agents to induce overexpression of p53 protein, as well as the functionality of different p53 mutants in relation to apoptosis induction, cell cycle arrest, and capacity to transactivate p21WAF1/Cip1gene. The levels of expression of survivin, an important protein (under direct regulation by p53) involved in the apoptotic process and the expression of SMAC/Diablo (a pro-apoptotic protein) were evaluated before and after cell lines exposure to the cytotoxic agents. As result, we observed differences in the apoptosis index, which reached approximately 60-80% in Raji and 20-30% in Daudi cells, 48 hours after exposure to the same concentration of gamma radiation. Besides, the chemotherapeutic LD50 (lethal dose, 50%) was different between the cell lines, being higher in Daudi when compared to Raji cell line. The resistance to varying types agents in those cell lines depended largely on the type of TP53 gene mutation and the agent used. We also observed dissimilarities in the functional status of p53 protein, regarding apoptosis induction and transactivation of target genes, such as p21, suggesting that those mutations are able to lead to distinct functional consequences. Survivin expression was upregulated by mutated p53 after exposure to drugs and gamma radiation suggesting a possible role played by this protein in p53-dependent apoptosis pathway and resistance...