Do alterations in gene expressions influence tumorigenesis in the transmissible venereal tumor in dogs? / Alterações nas expressões gênicas influenciam na tumorigênese no tumor venéreo transmissível em cães?

ABSTRACT: Canine transmissible venereal tumor (CTVT) is a transmissible neoplasm, which spreads naturally between dogs through the halogenic transfer of tumor cells, mainly during coitus. It is the oldest known tumoral lineage in nature and reports on gene mutations have been extended. Also, this tumor shares several genetic mutations with some cancers in humans, among them lung carcinomas, melanoma, prostate, breast, among other cancers. Thus, expression of tumor suppressor genes such as TP53, P21, and apoptosis-related genes such as BAX, BCL-2, and BCL-xL, both in vivo and in vitro (primary cell culture) were quantified. In the present study, the comparison of gene expression, the TP53 gene, in most cases, was shown to be high in the majority of tissues (65%) and primary cell culture (100%), while BCL-2, BCL-xL, and BAX presented variation among the animals analyzed. Moreover, in these situations, the results suggested that the apoptotic regulation of these genes did not occur for TP53. The P21 gene was shown to be mostly normal (70%); although, absence (6%) and underexpressions (24%) were also observed. Statistical analysis of the BCL-xL gene demonstrated significant differences between the tissues of the animals when compared to the cell cultures; however, to the other genes, no statistical difference was observed between the groups. Preliminarily, the results suggested the presence of alterations in the gene expressions of the TP53, P21, BAX, BCL-2 and BCL-xL leading to loss of function in these genes, which affect the tumorigenesis of CTVT.

RESUMO: O tumor venéreo transmissível canino (TVTC) se trata de uma neoplasia transmissível, que se propaga naturalmente entre os cães pela transferência halogênica de células tumorais, principalmente, durante o coito. É a mais antiga linhagem tumoral conhecida na natureza e relatos sobre mutações gênicas vêm sendo ampliadas. Além disso, este tumor compartilha uma série de mutações genéticas com alguns cânceres em seres humanos, dentre eles, carcinomas de pulmão, melanoma, próstata, mama, entre outros tipos de câncer. Assim, quantificou-se a expressão de genes supressores de tumores, como TP53, P21 e genes relacionados à apoptose, como BAX, BCL-2 e BCL-xL, tanto in vivo quanto in vitro (cultura celular primária). No presente estudo, na comparação das expressões gênicas, o gene TP53 se mostrou elevado na maioria dos casos em tecidos (65%) e em cultura celular primária (100%), enquanto BCL-2, BCL-xL e BAX apresentaram-se variáveis entre os animais analisados. Ademais, nessas situações os resultados sugerem que não ocorreu regulação apoptótica desses genes pelo TP53. O gene P21 mostrou-se, em sua maioria, normal (70%), embora a ausência (6%) e subexpressões (24%) também tenham sido observadas. A análise estatística do gene BCL-xL demonstrou diferenças significativas entre os tecidos dos animais, quando comparadas às culturas celulares, entretanto, para os demais genes, não foi observada diferença estatística entre os grupos. Preliminarmente, os resultados sugerem a presença de alterações nas expressões gênicas dos genes TP53, P21, BAX, BCL-2 e BCL-xL, levando a perda de função desses genes, os quais afetam a tumorigênese do CTVT.

Fenotipos neurológicos en pacientes estudiados con citogenética en el Hospital de Puerto Montt / Neurological phenotypes in cytogenic study from Puerto Montt Hospital patients

El examen citogenético, es una herramienta importante para confirmar el diagnóstico, manejo y consejo genético. El objetivo es analizar las características del fenotipo neuroconductual, protocolizar y orientar en la eficaz solicitud del estudio citogenético. Se revisaron las fichas clínicas de los pacientes controlados del policlínico de Neuropediatría del Hospital de Puerto Montt, con cariograma anormal entre los años 2007 y 2012. De 248 pacientes, 12% se identificó una alteración; 58% aberraciones estructurales, 20% aneuploidías, y 20% alteraciones genético - moleculares. Los elementos clínicos que se encontraron fueron microcefalia 48%, retraso mental 67%, historia familiar 67%, hipotonía 70%, convulsiones 41%, alteraciones del SNC 37%.

Cytogenetic examination is an important tool for confirming diagnosis, case management and genetic counseling. The aim is to analyze the characteristics of neurobehavioral phenotypes, formalize and guide the effective application of cytogenetics. The medical records of patients with abnormal karyotype seen between 2007 and 2012 at the Hospital of Puerto Montt's neuropaediatric outpatient clinic were reviewed. Of 248 patients, in 12% an alteration was identified; 58% structural aberrations, 20% aneuploidy, and 20% genetic-molecular alterations. The clinical elements found were 48% microcephaly, 67% mental retardation, 67% family history, 70% hypotonia, 41% seizures, 37% CNS disorders.

Metastasis: An Overview

Metastasis means the spread of the malignant cells from the origin site to a distant area. It involves the process of separation/detachment, transportation of fragmented primary tumour cell and lodging in the new site, having a favourable environment. It does not result from random survival of cells released from the primary tumour, but from the selective growth of specialised subpopulations of highly metastatic cells endowed with specific properties that benefit them to complete each step of the metastatic process. To understand this complex network we need to explore the molecules involved in it. This article reviews the theories, mechanisms, genes and genetic alterations that are involved in the process of metastasis.

Importancia de los estudios de inmunohistoquímica en el diagnóstico y la evaluación pronóstica de la neoplasia intraepitelial y el cáncer cervical: revisión / Importance of immunohistochemical studies in the diagnosis and the prognostic evaluation of cervical intraepithelial neoplasia and invasive squamous cell carcinoma of the uterine cervix: review

Se evaluó la expresión de proteínas dependientes de genes en el epitelio cervical, en la neoplasia intraepitelial cervical (NIC) y en el carcinoma del cuello uterino (CC) a través de diversos estudios de inmunohistoquímica (IHQ). Se examinó la detección de ciertas proteínas como p53, bcl2, C-Myc, Ki 67, Ciclinas, P16 INK4a, p21, p27, b-catenina, Wnt y MCM, en relación con la evolución de la neoplasia intraepitelial, el carcinoma cervical y la infección con el virus del papiloma humano (VPH). Se señaló como la actividad transcripcional de diversos genes provoca alteraciones de la heterocigosis y pérdida de regiones cromosómicas que influyen en la sobrexpresión de proteínas o en la pérdida parcial de la expresión de algunas glicoproteínas en la superficie celular por la activación de genes del VPH.

Immunohistochemical studies in cervical intraepithelial neoplasia and cervical carcinoma are evaluated in this review. A variety of proteíns like p53, bcl2, C-Myc, Ki 67, Cyclines, P16 INK4a, p21, p27, b-catenin, Wnt and MCM, have been related to the development of cervical neoplasia and human papilloma virus infection. It is described how transcriptional factors of genes induce loss of heterozygosity, numerical chromosome abnormality and inactivation of gene products or the partial loss of some membrane glycoproteins induced by oncogenic human papillomaviruses (HPV).

Etiology and Carcinogenesis of Pancreatic Ductal Adenocarcinoma / 대한소화기학회지

Pancreatic cancer is currently the major leading cause of cancer-related deaths in the Western countries with an overall 5-year survival rate of less than 3. The key aim of investigation is to identify the cellular population in which some of the earliest molecular events occur, presumably the ultimate target for carcinogenic insult. Advances in pathological classification and genetics have improved our descriptive understanding of this disease. However, important aspects of pancreatic cancer biology remain poorly understood. Factors associated with the increased risk of pancreatic cancer include smoking, chronic pancreatitis, diabetes, prior gastric surgery, and exposure to radiation or chemicals. A number of syndromes have been identified with the increased incidence of pancreatic cancer, including familial atypical multiple-mole melanoma syndrome, hereditary nonpolyposis colorectal cancer, and hereditary pancreatitis, etc. Recently, there have been growing evidences that stem cell biology could provide new insights into the understanding of cancer biology. Three postulates regarding the relationship between stem and tumor cells have been proposed. First, the similarities in the mechanims that regulate self-renewal of normal stem cells and cancer cells. Second, the possibility that tumor cells might arise from normal stem cells and third, the notion that tumors might contain 'cancer stem cells' - rare cells with indefinite proliferative potential which drive the formation and growth of tumors. New insights for the cancer stem cells and their possible markers in pancreatic cancer have been suggested recently. Further observations of molecular and cellular events in the early stage of pancreatic carcinogenesis may have important implications regarding the cellular lineage responsible for pancreatic ductal metaplasia and neoplasia, and provide further support for the presence of stem cell capabilities within mature pancreatic epithelium.

Chromosomal Alterations in Hepatocellular Carcinoma Cell Lines Detected by Comparative Genomic Hybridization / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: There have only been a few cytogenetic studies of hepatocellular carcinoma (HCC), and so far, no consistent specific chromosomal abnormalities have been described. Here, we have used comparative genomic hybridization (CGH), a powerful molecular cytogenetic technique for detecting changes of the copy number throughout the genome, to screen for genetic alterations in HCC cell lines. The CGH results were compared with those derived from G-banding and chromosome painting. MATERIALS AND METGODS: Conventional cytogenetic analyses were performed on five HCC cell lines, SNU-354, SNU-368, SNU-387, SNU-449 and SNU-475, using a G- banding staining technique. In CGH, equal amounts of differently labeled DNA from the cell lines, and normal reference DNA, were hybridized simultaneously to normal metaphase chromosomes. They were visualized by different fluorochromes, and the signal intensities quantified separately as gray levels along the single chromosomes. The over- and under-represented DNA segments were determined by computation of ratio images and average ratio profiles. To confirm the CGH results, florescence in situ hybridization (FISH), with chromosome specific painting, was performed using indirectly labeled chromosome specific paints. RESULTS: Complex unbalanced chromosomal aberrations, which could not be identified reliably by conventional cytogenetics in HCC cell lines, were successfully resolved by CGH analysis. CGH results were validated using FISH with chromosome specific probes. In HCC cell lines, gains in DNA copy number were more common than losses. The most prominent changes were gains of 1q12- qter (80% of cases), 1q41-qter (100%), 7 (80%), 8q12-qter (60%), 8q23-qter (80%) and 20q12-qter (60%). Recurrent losses were mapped on 4q13-qter (60%), 16q12-qter (60%), 16q21-qter (80%), 13q12-q14.2 (60%) and Yq11.2 (100%). All four male HCC cell lines showed loss or rearrangement of the Y chromosome. CONCLUSION: Conventional cytogenetics, CGH and FISH using painting probes, represent complementary approaches that, when employed in combination, could greatly facilitate the comprehensive analysis of chromosomal imbalances in HCC cell lines. Our results suggest the existence of an oncogene, or protooncogenes, on chromosome 1q41-qter, and the tumor suppressor genes on Yq11.2, that play a role in the development and/or progression of hepatocellular carcinogenesis.

Chromosomal Alterations in Gastric Cancer Cell Lines Detected by Comparative Genomic Hybridization / 대한암학회지

PURPOSE: There are only a few cytogenetic studies in gastric cancer and so far no consistent specific chromosomal abnormalities have been described. In this study, we have used comparative genomic hybridization (CGH), a powerful molecular cytogenetic technique for detecting changes of the copy number throughout the genome, to screen for genetic alterations in gastric cancer cell lines. The CGH results were compared with those derived from G-banding and chromosome painting. MATERIALS AND METHODS: Conventional cytogenetic analysis was performed on five human gastric cancer cell lines, AGS, SNU-1, SNU-16, SNU-620, and SNU-719, by a G-banding staining technique. In CGH, equal amounts of differently labeled DNA from the cell lines and normal reference DNA were hybridized simultaneously to normal metaphase chromosomes. They were visualized by different fluorochromes, and the signal intensities were quantitated separately as gray levels along the single chromosomes. The over- and under- represented DNA segments were determined by computation of ratio images and average ratio profiles. To confirm the CGH results, fluorescence in situ hybridization (FISH) with chromosome specific painting was performed using indirectly labeled chromosome specific paints. RESULTS: Complex unbalanced chromosomal aberrations that could not be identified reliably by conventional cytogenetics in gastric cancer cell lines were successfully resolved by CGH analysis. CGH results were validated by using FISH with chromosome specific probes. In gastric cancer cell lines, gains of DNA copy number were more common than losses. Gains were detected on 1p, 1q, 2p, 3q, 6p, 7q, 10q, 11p, and 19q, and losses were observed on 4p, 4q, 5q, 12p, 12q, and 18q. Interestingly, all the five gastric cancer cell lines tested showed gain of DNA copy number on the chromosome 20, suggesting an existence of oncogene. CONCLUSION: Conventional cytogenetics, CGH, and FISH using painting probes represent complementary approaches that, when employed in combination, could greatly facilitate the comprehensive analysis of chromosomal imbalances in gastric cancer cell lines. Our results suggest the existence of an oncogene or oncogenes on chromosome 20 that play a role in the development and/or the progression of gastric carcinogenesis.

Genetic Alterations in Bladder Cancer Detected by Comparative Genomic Hybridization / 대한암학회지

PURPOSE: Cytogenetic and genetic alterations of tumors are closely related with progressian and promotion of cancers. Comparative genomic hybridization (CGH) has known to be a novel tool for the detection of genetic alteration in solid cancers. We performed CGH for the detection of new genetic alterations of bladder tumors. MATERIALS AND METHODS: Biotin-labeled tumor DNA and digoxigenin-labeled normal DNA were hybridized to normal metaphase cells. The fluorescence signals were captured by fluorescence microscope after detection by avidin FITC and antidigoxigenin rhodamin. Then, the ratio of fluorescence was calculated by an image analyzer. RESULTS: CGH results showed amplifications on chromosomes 1q, 3q, 4q, 5p, 6pq, 7p, 8q, 11q, 12q, 13q, 17q, 18q and 20pq (more than 20% of cases). Deletions were on chromosome 2q21-qter, 4q13-q23, 5q, 8p12-p22, 9pq, 11p13-p15 (more than 20% of cases). High level amplifications were noted on chromosomes 1q31-qter, 3p21, 3q24, 4q26, Sq21-qter, llq14-qter, 12q15-q21, 12q21-q24, 13q21-q31, 17q22, 18q22. CONCLUSION: We considered that the amplification on chromosome 4q26, 11q14-qter, 12q21-q24, 18q12 and deletion on 4qll-4q13 as a novel genetic alterations of bladder cancer. Our results revealed different pattem of amplifications that affect other regions from previous study on chromosome 7, llq, 12q, 13q, and 18q. CGH was very useful for the screening of genetic alterations of solid tumors.