Expression and clinical significance of DNA mismatch repair proteins in sporadic colorectal carcinoma / 上海交通大学学报（医学版）

Objective: To investigate the expressions of mismatch repair (MMR) proteins, i.e. MLH1 (mutL homolog 1), MSH2 (mutS homolog 2), MSH6 (mutS homolog 6) and PMS2 (postmeiotic segregation increased 2) in sporadic colorectal carcinoma (SCRC) and their correlation with clinicopathological characteristics. Methods: Cancer tissue samples of the SCRC patients who underwent radical resection of colorectal cancer at Tongren Hospital, Shanghai Jiao Tong University School of Medicine from April 2014 to August 2018 were collected. MLH1, MSH2, MSH6, PMS2 and p53 proteins in colorectal cancer tissue samples from 209 patients who met the criteria were detected by immunohistochemistry, and 67 samples were detected by real-time PCR for KRAS oncogene mutation. Results: In 209 cases of cancer tissues, MLH1, MSH2, MSH6 and PMS2 deficiency rates were 17.2% (36/209), 2.4% (5/209), 12.9% (27/209), and 16.7% (35/209), respectively. The total deficiency rate of MMR system proteins was 30.1% (63/209), which was higher in the patients under 55 years old, with tumor at the right colon, with tumor bigger than 6 cm or with mucinous adenocarcinoma (all P<0.05). MLH1 deficiency rate of the patients with p53 mutation was significantly higher than that of unmutated patients (P=0.012); MLH1 deficiency rate of the patients with KRAS mutation was significantly lower than that of unmutant patients (P=0.044). There was no significant difference in the positive expression rates of MLH1 and PMS2 in these SCRC patients (P=1.000). Conclusion: MMR systemic protein deletion may be associated with patient age, tumor location, tumor size, and histopathological typing; MLH1 protein deletion may be associated with mutations of p53 and KRAS genes.

Alterações germinativas em pacientes com câncer de reto em idade jovem / Germline alterations in patients with rectal cancer at a young age

O câncer colorretal (CCR) é o terceiro tipo de câncer mais comum no mundo e a segunda causa de morte por câncer. Dados atuais apontam que o câncer de reto (CaRe) contribui para a maior incidência de CCR observada em pacientes jovens e é responsável por um aumento destes tumores em cerca de 75% nos últimos 40 anos. As variantes germinativas são reportadas em 14 a 16% dos indivíduos jovens com CCR, independente de história familiar de câncer. Ainda assim, a causa do desenvolvimento de CCR na maioria dos casos de indivíduos jovens ou famílias com múltiplos indivíduos afetados permanece desconhecida. Neste estudo, foram investigadas variantes germinativas em 76 pacientes com CaRe incluindo 29 classificados pelos critérios de Amsterdam I/II para a Síndrome de Lynch (Grupo 1) e 47 pacientes com idade igual ou inferior 40 anos (Grupo 2). O objetivo principal foi identificar variantes em 93 genes relacionados ao câncer que possam contribuir para o risco de desenvolvimento da doença usando sequenciamento de alto desempenho. Quinze variantes foram selecionadas e avaliadas em membros de oito famílias. Foram identificadas 153 variantes envolvendo 65 genes. Pacientes com câncer de reto apresentaram alta frequência de variantes germinativas em ATM (19%), APC (10%) e BRCA2 (9%). Variantes patogênicas ou likely-patogênicas foram identificadas em genes de alta (MSH2, MSH6, MLH1, MUTYH e BRCA2), moderada (ATM) e baixa (MTHFR e NOTCH1) penetrância, em 18% (14/76) dos pacientes, concordante com dados da literatura. Variantes características da Síndrome de Lynch foram identificadas em seis pacientes (6/76) e variantes associadas à polipose no gene MUTYH, em dois pacientes (2/76). Variantes patogênicas ou likely-patogênicas foram identificadas em 17% (8/47) dos pacientes jovens, especialmente em MUTYH (3/47), MTHFR (2/47), ATM, MSH6 e MLH1 (1/47 cada). Dentre estes, dois de 14 pacientes não reportaram câncer na família e seis tiveram pelo menos um caso de câncer na família, mas não preencheram os critérios clínicos para síndrome de predisposição hereditária ao câncer. Este estudo revelou 25 variantes novas (não identificadas em bancos de dados públicos ou reportadas em literatura). Em adição, foram observadas variantes germinativas em diferentes genes das vias MMR e de recombinação homóloga, incluindo ATM, BRCA2 e POLD1. Foram identificadas 15 variantes candidatas e ou associadas ao fenótipo nos genes ATM, APC, MSH2, MTHFR, CDKN2A, MUTYH e POLD1. Essas variantes foram avaliadas em 20 indivíduos de 8 famílias, sendo confirmadas nos probandos e identificadas em mais de um membro das famílias investigadas. A identificação de genes associados à predisposição ao CaRe tem potencial importância para o delineamento de estratégias mais eficientes de diagnóstico e aconselhamento genético em famílias com um alto risco de desenvolver este tumor (AU)

Colorectal cancer (CRC) is the third most common cancer worldwide and the second leading cause of cancer-related death. Recent studies suggest that rectal cancer (ReCa) contributes to the higher CRC incidence observed in young patients, and it is responsible for 75% of the increased incidence in colorectal tumors over the last 40 years. Germline variants have been reported in 14-16% of patients with early-onset CRC, regardless of family history of cancer. Nonetheless, the causes of CRC onset in most young patients or families with multiple affected cases remain unknown. We investigated germline variants in 76 ReCa patients, including 29 cases classified by the Amsterdam I/II criteria for Lynch Syndrome (Group 1) and 47 early-onset ReCa patients (≤40 years old, Group 2). The main objective was to identify variants in 93 cancer-related genes that can contribute to increased risk of the disease development using next-generation sequencing. Fifteen candidate variants were evaluated in eight selected families. Next-generation sequencing revealed 153 variants involving 65 genes. ReCa patients showed high frequency of germline variants in ATM (19%), APC (10%) and BRCA2 (9%). Pathogenic or likely-pathogenic variants were observed in high (MSH2, MSH6, MLH1, MUTYH, and BRCA2), moderate (ATM) and low (MTHFR and NOTCH1) penetrance genes, in 18% (14/76) of the patients, consistent with the literature data. Variants associated with Lynch Syndrome were identified in six patients (6/76), and variants involved in MUTYH-associated polyposis in two patients (2/76). Pathogenic or likely-pathogenic variants were identified in 17% (8/47) of early-onset patients, especially in the MUTYH (3/47), MTHFR (2/47), ATM, MSH6, and MLH1 (1/47 each) genes. Among these, two of fourteen patients had no family history of cancer and six reported at least one case of cancer in the family, but none of them met clinical criteria for the hereditary cancer syndrome. This study revealed 25 new variants (not reported in public databases or previous studies). In addition, germline variants were observed in several genes involved in MMR and homologous recombination (HR) pathways, including ATM, BRCA2 and POLD1. Fifteen candidates and associated to the phenotype variants were identified in the ATM, APC, MSH2, MTHFR, CDKN2A, MUTYH, and POLD1 genes. These variants were evaluated in 20 individuals (8 families), being confirmed in the index cases and identified in more than one relative of the evaluated families. The identification of genes associated with ReCa predisposition is crucial for outlining more efficient diagnostic strategies and for improving genetic counseling for families with high risk to develop this tumor type (AU)

Relationship between MLH1/MSH2 expression and prognosis of patients with sporadic colorectal cancer / 肿瘤

Objective: To investigate the expressions of mismatch repair gene MutL homolog 1 (MLH1) and MutS homolog 2 (MSH2) in stage II-III sporadic colorectal adenocarcinoma tissues and their clinical signifiance. Methods: The specimens and follow-up data of 490 patients with sporadic colorectal cancer were collected after surgery from January 2014 to April 2016 in Nanjing Hospital of Chinese Medicine. The expressions of MLH1 and MSH2 in colorectal cancer were detected by immunohistochemistry. The relationships of MLH1 and MSH2 expressions with the clinical characteristics and prognosis of patients with colorectal cancer were analyzed. Results: The deletion rate of MLH1/MSH2 expression in colorectal cancer tissues was 20.41% (100/490). The MLH1/MSH2 deletion was correlated with tumor differentiation, location, mucus and lymph node metastasis (all P < 0.05). MLH1/MSH2 deletion mainly occurred in the patients with poorly differentiation, right colon, mucus, and 1-3 lymph nodes metastasis. The disease-free survival (DFS) time of patients with MLH1/MSH2 deletion was longer than that of patients with MLH1/MSH2 normal expression (33.9 months vs 30.4 months, P < 0.001). The prognosis of patients with right colon tumor, poor differentiation, TNM stage III, metastatic lymph nodes more than four, mucus, positive margin and MLH1/MSH2 normal expression was poor (all P < 0.05). The tumor differentiation, tumor location, mucus, surgical margin and expression of MLH1/MSH2 were independent prognostic factors for the patients with stage II - III sporadic colorectal cancer. Conclusion: There is MLH1/MSH2 deletion in stage II - III sporadic colorectal cancer tissues, and it is an independent prognostic factor in patients with colorectal cancer.

Mutación fundadora en síndrome de Lynch tipo II / Founder mutation in Lynch syndrome

El síndrome de Lynch es la más frecuente de las neoplasias colorrectales hereditarias. Se origina por mutaciones germinales deletéreas familia-específicas en los genes que codifican proteínas de reparación del ADN: MLH1 (homólogo humano de mutL), MSH2 y MSH6 (homólogo humano de mutS 2 y 6, respectivamente), PMS2 (homólogo humano de PMS1 2) y MUTYH (homólogo humano de la ADN-glycosilasa mutY). La mutación c.2252_2253delAA, p.Lys751Serfs*3 en el exón 19 del gen MLH1 segrega con un haplotipo descripto en la región norte de Italia y cuyo origen fue atribuido a un efecto fundador. Esta mutación co-segrega con características típicas del síndrome de Lynch, incluyendo afectación temprana y múltiples tumores primarios en el mismo individuo, una alta frecuencia de cáncer pancreático, elevada inestabilidad microsatelital y falta de expresión de PMS2. En el presente trabajo se comunica dicha mutación en una paciente argentina con adenocarcinoma endometroide de útero en cuya historia familiar existen antecedentes de cáncer de colon diagnosticado antes de los 50 años en familiares de primer grado, reuniendo los criterios de Ámsterdam I y síndrome de Lynch II. Los polimorfismos presentes en la paciente coinciden con el haplotipo descripto en una región del norte de Italia. El alto grado de patogenicidad asociada a esta mutación hace imprescindible el estudio de todos los integrantes de las familias con cáncer hereditario permitiendo el diagnóstico genético pre-sintomático, la instauración de tratamientos o conductas preventivas y su seguimiento.

Lynch syndrome is the most frequent syndrome in hereditary colorectal cancer, a family-specific deleterious mutations in genes encoding DNA reparation proteins: MLH1 (mutL homolog 1), MSH2, MSH6 (mutS homolog 2 y 6, respectively), PMS2 (PMS1 homolog 2, mismatch repair system component) y MUTYH (mutY DNA glycosylase).The c.2252_2253delAA, p.Lys751Serfs*3 mutation in MLH1 gene segregates with a haplotype reported in the northern region of Italy and whose origin was attributed to a founder effect. This mutation co-segregates with typical characteristics of Lynch syndrome, including early age at onset and multiple primary tumors in the same individual, a high frequency of pancreatic cancer, high microsatellite instability and lack of PMS2 expression. This report describes a mutation in an Argentinian patient with endometrioid adenocarcinoma of uterus. Her first-degree relatives had a history of colon cancer diagnosed before 50 years, fulfilling the Amsterdam Criteria I and Lynch syndrome II. The high pathogenicity associated to this mutation makes necessary the study of all members from families with hereditary cancer, allowing pre-symptomatic genetic diagnosis, early assessment and the instauration of preventive treatments.

Establishing and identification of an immortal cell line of familial papillary thyroid carcinoma with MLH1 R217C/BRAF V600E mutations / 天津医药

Objective To establishing an immortal cell line of familial papillary thyroid carcinoma (FPTC), and explore a new approach for studying familial non-medullary thyroid carcinoma (FNMTC). Methods The specimen from a patient with FPTC was selected, separated, and the primary cells were cultured using DMEM/F12 medium (with TSH, T3, EGF and hydrocortisone). To inducing cell immortalization, the exogenous genes SV40T/TERT were transfected into cells by two ways. RT-PCR was used to detect the expressions of thyroid peroxidase (TPO), thyroid globulin (TG), thyroid stimulating hormone receptor (TSHR) and sodium/iodide co-transporter (NIS). Immunofluorescence method was used to detect the expressions of TPO and GPC3. In order to detect the genomic mutations, the peripheral blood DNA of the patient was extracted. The cell genome was detected. Results The FPTC cells adhered to the plate and showed an irregular polygon shape. The cells can stably grow for six months, FPTC-S (with SV40T transfected) passaged to p26, FPTC cells passaged to p23 and FPTC-ST (with SV40T/TERT transfected) passaged to p19. Both FPTC-S and FPTC-ST can stably express TPO, TG and TSHR in mRNA level. MLH1 R217C mutation existed in the peripheral blood of the patient, and BRAF V600E mutation existed in the primary cultured cells. Either the primary or the immortal cells showed MLH1 R217C mutation. Conclusion This study preliminarily established an immortal cell line of familial papillary thyroid carcinoma with MLH 1 R217C and BRAF V600E mutations. This cell line provides a research model for studying these mutations in FPTC.

Mismatch repair protein deficient endometrioid adenocarcinomas, metastasizing to adrenal gland and lymph nodes: Unusual cases with diagnostic implications.

Recently, certain endometrial carcinomas have been found to be associated with mismatch repair (MMR) protein defects/deficiency. A 39-year-old female presented with cough, decreased appetite and significant weight loss since 2 months. Earlier, she had undergone total abdominal hysterectomy with bilateral salpingo-oophorectomy (TAH-BSO) for endometrioid adenocarcinoma. Imaging disclosed an 8 cm-sized adrenal mass that was surgically excised. Histopathology of the adrenal tumor, endocervical tumor, and endometrial biopsy revealed Federation of Gynecology and Obstetrics (FIGO) Grade II to III endometrioid adenocarcinoma. By immunohistochemistry, tumor cells were positive for cytokeratin 7, epithelial membrane antigen, PAX8, MLH1 and PMS2 while negative for estrogen receptor (ER), progesterone receptor (PR), MSH2 and MSH6. She underwent adjuvant radiotherapy and chemotherapy. A 34-year-old lady presented with vaginal bleeding since 9 months. She underwent TAH-BSO, reported as FIGO Grade III endometrioid adenocarcinoma. By immunohistochemistry, tumor cells were negative for ER, PR, MLH1, and PMS2 while positive for MSH2 and MSH6. She underwent adjuvant radiotherapy and chemotherapy. However, she developed multiple nodal and pericardial metastases and succumbed to the disease within a year post-diagnosis. Certain high-grade endometrioid adenocarcinomas occurring in younger women are MMR protein deficient and display an aggressive clinical course. Adrenal metastasis in endometrial carcinomas is rare.

Characteristics of hereditary nonpolyposis colorectal cancer patients with double primary cancers in endometrium and colorectum

OBJECTIVE: The hereditary nonpolyposis colorectal cancer is inherited syndrome characterized by the development of cancers in various organ system; these includes colorectum, endometrium, and less frequently, small bowel, stomach, urinary tract, ovaries, and brain. We aimed to investigate the clinicopathologic characteristics of hereditary nonpolyposis colorectal cancer patients who had both endometrial and colorectal cancers. METHODS: Between January 2004 and December 2013, 12 women diagnosed with endometrial and colorectal cancers in a single institution were included in this analysis. For these patients, clinical and molecular findings were analyzed retrospectively. RESULTS: All 12 women undertook microsatellite instability analysis, and 9 (75%) were confirmed of having microsatellite instability-high. Among 9 cases with immunohistochemical staining for MLH1 and MSH2, 6 were positive for the loss of mismatch repair protein. Mutational analyses for MLH1 and MSH2 were performed in 3 out of 12 patients; all of them showed germline mutation. CONCLUSION: This study suggests that there is a genetic background in patients with double primary malignancies in their endometrium and colorectum when analyzed with microsatellite instability studies, immunohistochemistry staining, and mutation studies. This finding supports the necessity of re-defining the high-risk groups in endometrial cancers clinically. This will also help diagnose malignancies in such patients in early stages, as well as counsel other family members.

Mismatch Repair Gene MLH1 Involved in Estrogen-induced Apoptosis of Colonic Cancer Cells by Activating p53 Signaling and Mitochondrial Apoptotic Pathway / 胃肠病学

Background:Clinical and epidemiological studies revealed that estrogen replacement therapy was associated with a significant reduction in risk of colorectal cancer in postmenopausal women.In our previous studies,estrogen increased the expression of mismatch repair (MMR)gene MLH1 in colonic cancer cells,and re-expression of MLH1 in MLH-deficient colonic cancer cells significantly increased the estrogen-induced apoptosis.Aims:To investigate the signaling pathway implicated in the MLH1-mediated apoptosis in colonic cancer cells induced by estrogen and the roles of p53 and its related genes in this apoptotic pathway.Methods:Plasmid containing wild type human MLH1 (hMLH1)full length cDNA was transfected into MLH1-deficient human colonic cancer cell line HCT116.By using HCT116 cells transfected with empty plasmid as controls,the apoptotic DNA ladder was determined by electrophoresis and the expressions of p53 and other apoptosis-related proteins were assessed by Western blotting under the condition with or without estrogen stimulation. Results:17β-estradiol (E2 )at the concentration of 10 -8 mol/L induced significant apoptosis in HCT116 cells transfected with hMLH1.In HCT116 cells transfected with hMLH1 and stimulated with E2 (group D),the protein expressions of caspase-3,caspase-9,p53,Bax and cytoplasmic cytochrome C increased significantly when compared with HCT116 cells stimulated with E2 only (group B);expressions of the abovementioned proteins were also higher in group D than in group C (transfected with hMLH1 only).Conclusions:MMR gene MLH1 is involved in estrogen-induced apoptosis of human colonic cancer cell line HCT116 by activating p53 signaling and mitochondrial apoptotic pathway.

Investigação de mutações nos genes MLH1 e MSH2 em portadores de câncer colorretal hereditário sem polipose (HNPCC) / Investigation of mutations in MLH1 and MSH2 genes in carriers with Hereditary Nonpolyposis Colorectal Cancer (HNPCC)

O câncer colorretal tem importância elevada frente a sua incidência e morbidade. Dentre os casos hereditários, o câncer colorretal hereditário sem polipose (HNPCC), ou Síndrome de Lynch, é responsável por cerca de 5% do total de casos. No HNPCC, a alteração genética herdada é a inativação de um dos alelos dos genes envolvidos em reparo do DNA, sendo os principais os genes hMLH1 e hMSH2. O objetivo deste trabalho foi investigar, em indivíduos com diagnóstico clínico de HNPCC, a presença de mutações nos genes MLH1 e MSH2, associar as variáveis clínicas com o gene mutado e investigar os familiares de portadores de HNPCC aos quais tivemos acesso, com relação a mutações germinativas. A investigação das mutações foi realizada por meio de sequenciamento direto dos éxons, região promotora e regiões de junção. Foram analisados 65 indivíduos divididos em três grupos, sendo (I) 46 pacientes portadores de câncer colorretal inclusos nos Critérios de Amsterdã, (II) dois familiares portadores de câncer colorretal e (III) 17 familiares sem câncer, todos da região metropolitana de Campinas, atendidos no Hospital de Clínicas da UNICAMP. Em 21 (45,65%) dos pacientes foram encontradas mutações deletérias. As mutações deletérias nos genes MLH1 e MSH2 estavam na proporção de 34,78% (16 pacientes) e 10,86% (5 pacientes), respectivamente. As mutações não deletérias nos genes MLH1 e MSH2 estavam na proporção de 65,22% dos pacientes (30 alterações) e 50% dos pacientes (23 alterações), respectivamente...

Colorectal cancer has high importance because of its incidence and morbidity. Among the hereditary cases, the hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome, accounts for about 5% of cases. In HNPCC, the genetic alteration inherited is the inactivation of one of the alleles of genes involved in the DNA repair, being hMSH2 and hMLH1 the main genes. The objective of this study is to investigate the presence of mutations in MLH1 and MSH2 in patients with clinical diagnosis of HNPCC, correlate clinical variables with the mutated gene, and investigate the relatives of patients with HNPCC who we had access to, in relation to germline mutations. Investigation of the mutations was performed by éxons direct sequencing, the promoter and junction regions. Sixty-five individuals, divided into three groups, were studied: (I) 46 patients with colorectal cancer included in the Amsterdam Criteria, (II) two family members of colorectal cancer patients and (III) 17 relatives without cancer, all of them treated at Hospital das Clínicas at UNICAMP and living in the Campinas metropolitan area. Deleterious mutations were found in 21 patients (45.65%). The ratio of deleterious mutations in MLH1 and MSH2 was 34.78% (16 patients) and 10.86% (5 patients) respectively. The ratio of non deleterious mutations in genes MLH1 and MSH2 was 65.22% of patients (30 alterations) and 50% of patients (23 alterations) respectively. Among patients with HNPCC, 23 potentially deleterious mutations were identified, via sequences of MLH1 and MSH2 with a 50% detection rate. It doesn't seem to appear variations in the clinical characteristics of the tumor when a germline mutation occurs in MLH1 or MSH2, with the exception of the relationship between the presence of mutation in the MLH1 gene and age of disease onset. As it occurs throughout the world, the disease present a his molecular extremely heterogeneoty, where only two mutations were repeated in two patients...

Clinico-pathologic Parameters for Prediction of Microsatellite Instability in Colorectal Cancer / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Although the incidence of microsatellite instability (MSI) accounts for 10-15% of cases of colorectal cancer, its clinical application for all colorectal cancers has widened. We attempted to identify clinical and pathological parameters that may be helpful in selection of patients with MSI-high (MSI-H). MATERIALS AND METHODS: A total of 120 resected colorectal cancers were enrolled retrospectively for this MSI study. Polymerase chain reaction (PCR) and denaturing high performance liquid chromatography and/or real time PCR methods with five markers and immunohistochemistry (IHC) for MLH1 and MSH2 were performed for analysis of cancer and blood specimens. Clinico-pathologic parameters, including IHC, were investigated in order to determine their usefulness as predictive factors of MSI. RESULTS: Among 120 cases of colorectal cancer, MSI was observed in 15 cases (12.5%), including 11 cases of MSI-H and four cases of MSI-low. Patients with MSI were younger, less than 50 years old, had a family history of cancer, Rt. sided colon cancer and/or synchronous multiple colorectal cancer, mucinous histologic type, and serum carcinoembryonic antigen group in the normal range. Results of multivariate analysis showed Bethesda guidelines, Rt. sided and/or synchronous multiple colorectal cancer, and negative expression of IHC for MLH1, which was consistently associated with MSI-H. MSI-H colorectal tumors have met at least one of these three parameters and their sensitivity and specificity were 100% and 72.5%, respectively. CONCLUSION: Bethesda guidelines, tumor location, and negative expression of MLH1 protein are important parameters for selection of patients with colorectal cancers for MSI testing. MSI testing is recommended for patients showing any of these three parameters.

Cáncer hereditario de colon: Aportes del diagnóstico genético molecular / Molecular and genetic studies for hereditary colon cancer in two patients and their families

Background: About 30 percent of cases of colon cancer (CC) have a family history of CC, and only 5 percent are hereditary forms. Hereditary forms have an increased risk of CC and other tumors. Aim: To report the molecular and genetic study in two families with hereditary CC. Material and Methods: Molecular analysis of the adenomatous polyposis coli (APC) gene of familial adenomatous polyposis (FAP), was done in a patient with multiple benign polyps and his children. Molecular analysis was performed for MLH1 gene mutation of hereditary non-polyposis colon cancer (HNPCC) in an asymptomatic patient with family history of multiple cancers and his mother with a confrmed mutation in the MLH1 gene. Results: The patient with FAP had an insertion of 17 base pairs in exon 9 of the APC gene and two of his children had the same mutation. The patient with history of HNPCC did not have the family mutation on MLH1. Conclusions: In the case of FAP, molecular study was performed in his children since manifestations in carriers of the mutation may begin in childhood. If the second patient would have had the mutation, the study of his children could have been postponed until the age of 18, when the risk for CC is increased.

Colorectal cancer among young native Indonesians: A clinicopathological and molecular assessment on microsatellite instability.

Aim: To obtain clinicopathological characteristics of colorectal cancer among young native Indonesians and to assess MLH1, MSH2, and SMAD4 protein expressions, comparing them with a matched population of colorectal cancer patients aged 60 years old and older. Methods: Medical records of colorectal cancer patients aged 40 years or younger and 60 years or older from several hospitals in three Indonesian cities – Jakarta, Makassar, and Bandung - were reviewed. The “native” ethnic groups were selected from those originating from Java, Makassar (South Celebes), Miinangkabau (West Sumatra). Ethnicity of 121 colorectal carcinoma patients was confirmed by fulfilling requirements in a questionnaire. Tumor specimens of those patients underwent evaluation for histopathology, tumor grading as well as immunohistochemical analysis to assess MLH1, MSH2 protein expressions to detect microsatellite instability mutation pathway and SMAD4 protein expression to reconfirm that the specimens were not microsatellite instability origin. Results: There were 121 colorectal carcinoma cases of Sundanese, Javanese, Macassarese and Minangkabau ethnic group. This study indicated that colorectal cancer has statistically different grade (p = 0.001) between the young and the older patients. Immunohistochemical staining for MSH2 protein and MLH1 were done for 92 and 97 specimens respectively. There was no significant difference between the expressions of MLH1 and MSH2 on tumor grading, indicated there was no correlation between microsatellite instability and tumor grading in this study. Conclusion: Colorectal cancer in young native Indonesian patients (40 years old or less) was not different in clinicopathological characteristics compared to older patients (60 years old or more) in similar ethnic groups. There was also no difference in MSH2 and MLH1 protein expressions, important indicators of microsatellite instability and.

R659X mutation in the MLH1 gene in hereditary non-polyposis colorectal cancer (HNPCC) in an Indian extended family.

Background & objective: Hereditary non-polyposis colorectal cancer (HNPCC or Lynch syndrome), is a genetically heterogeneous disorder that is believed to account for 2–10 per cent of all the colorectal cancer cases. The disease follows autosomal dominant inheritance pattern with high penetrance (85%) and younger age of onset when compared to patients with sporadic tumours. HNPCC is associated with germ-line mutations in the DNA mismatch repair (MMR) genes namely MLH1, MSH2, MSH6, and PMS2. The present study was aimed at analyzing mismatch repair gene(s) in an extended Indian family satisfying the Amsterdam criteria, and extending the analysis to general population to estimate frequency of the mutations/polymorphisms observed. Methods: A total 12 members of the HNPCC family were studied for genetic investigation. Ethnically matched 250 normal individuals were also included as controls to study the observed mutations/ polymorphisms at population level. Results: The analysis resulted in identification of a 1975C>T mutation in exon 17, resulting in substitution of arginine residue with stop codon at codon 659. 655A>G substitution was also observed, resulting in replacement of isoleucine with valine at codon 219. Similar analysis on 250 ethnically matched control subjects revealed complete absence of R659X mutation, while I219V variant was found in 9.8 per cent of the controls. Interpretation & conclusion: R659X mutation correlates with disease phenotype, and 655A>G locus is highly polymorphic. Our study suggested that R659X substitution was prime cause for the disease phenotype in this family. I219V substitution is a polymorphism having no association with the disease onset or segregation. The family members harbouring this mutation were advised to be under regular medical surveillance.

Síndrome de Lynch: Caracterización genético clínica. Caso clínico / Hereditary non-polyposis colorectal cancer: Report of four siblings

Hereditary non-polyposis colorectal cancer (HNPCC) or Lynch Syndrome is an autosomic dominant syndrome involving 596-1096 of colorectal cancer patients. Mutations in MLH1 and MSH2 genes account for most cases. These two genes particípate in the DNA mismatch repair pathway. Therefore mutation carriers show microsatellite instability (MSI) in tumors. This syndrome is characterized by the early development of colorectal cancer (before 50 years) and an increased incidence of cancer in other organs. We report four siblings from a family diagnosed with HNPCC. All of them were subjected to colonic surgery for colorectal cancer Moreover, one patient developed an ampulloma after her colon surgery. The molecular-genetic analysis revealed three brothers with microsatellite instability in the tumor tissue, the absence of the MLH1 protein, and the presence of a germ Une mutation localized in introm 15 ofthe MLH1 gene.

DNA Hypermethylation of Tumor-Related Genes in Gastric Carcinoma

The hypermethylation of the CpG islands is a common mechanism for the inactivation of tumor-related genes. In the present study, we analyzed the methylation status of genes for cell repair such as hMLH1, MGMT, and GSTP1, and a gastric cancer-specifically methylated DNA fragment, MINT 25 in gastric cancer cases and control groups. The study population consisted of 100 gastric cancer patients (50 distal and 50 proximal carcinomas), and 238 healthy controls. All genes showed more frequent hypermethylation in the cases than in the control group (p<0.0001). We investigated the association between promoter hypermethylation and relevant parameters including age, gender, alcohol consumption, smoking, and family history. There was a common hypermethylation of hMLH1 (p=0.008), MGMT (p= 0.0001), and GSTP1 (p=0.0003) in females. This study also demonstrates that hypermethylation was strongly associated with non-drinkers (MGMT, p=0.046 and MINT 25, p=0.049) and non-smokers (hMLH1, p=0.044; MGMT, p=0.0003; MINT 25, p=0.029). Moreover, the frequency of MINT 25 hypermethylation increased with age (p=0.037), and MGMT methylation was frequently detected in distal gastric cancer than in proximal type (p=0.038). Our study suggested that promoter hypermethylation of the genes involved in cell repair system and MINT 25 is associated strongly with some subgroups of primary gastric carcinoma.

Methylation of DNA mismatch repair gene MLH1 and MSH2 in acquired multidrug-resistance of human small cell lung cells H446 / 第三军医大学学报

Objective To investigate the role of methylated DNA mismatch repair gene MLH1 and MSH2 in the acquired multidrug-resistance of human small cell lung cancer cells H446.Methods The reverse transcription polymerase chain reaction(RT-PCR)and Western blot were applied to measure MLH1 and MSH2 mRNA and protein expressions of the multidrug-resistant cells H446/DDP and its parental cells H446.The promoter methylation status of the genes was assessed by methylation-specific PCR(MSP).Results The expressions of MLH1 and MSH2 significantly decreased both in mRNA level and protein level.Promoter methylation of MLH1 was observed in H446/DDP cells but not in H446 cells.Promoter semi-methylation of MSH2 in H446 cells was transformed to methylation in H446/DDP cells.Conclusion The downregulation of DNA mismatch repair gene MLH1 and MSH2 induced by its promoter methylation may play an important role in the acquired multidrug resistance of human small cell lung cancer.