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At least 631 records · Page 35Linked to original sources
PubMed2006

Classification of breast cancer using genetic algorithms and tissue microarrays.

PURPOSE: A multitude of breast cancer mRNA profiling studies has stratified breast cancer and defined gene sets that correlate with outcome. However, the number of genes used to predict patient outcome or define tumor subtypes by RNA expression studies is variable, nonoverlapping, and generally requires specialized technologies that are beyond those used in the routine pathology laboratory. It would be ideal if the familiarity and streamlined nature of immunohistochemistry could be combined with the rigorously quantitative and highly specific properties of nucleic acid-based analysis to predict patient outcome. EXPERIMENTAL DESIGN: We have used AQUA-based objective quantitative analysis of tissue microarrays toward the goal of discovery of a minimal number of markers with maximal prognostic or predictive value that can be applied to the conventional formalin-fixed, paraffin-embedded tissue section. RESULTS: The minimal discovered multiplexed set of tissue biomarkers was GATA3, NAT1, and estrogen receptor. Genetic algorithms were then applied after division of our cohort into a training set of 223 breast cancer patients to discover a prospectively applicable solution that can define a subset of patients with 5-year survival of 96%. This algorithm was then validated on an internal validation set (n=223, 5-year survival=95.8%) and further validated on an independent cohort from Sweden, which showed 5-year survival of 92.7% (n=149). CONCLUSIONS: With further validation, this test has both the familiarity and specificity for widespread use in management of breast cancer. More generally, this work illustrates the potential for multiplexed biomarker discovery on the tissue microarray platform.

Algorithms↗
PubMed1997

Generation of effective cancer vaccines genetically engineered to secrete cytokines using adenovirus-enhanced transferrinfection (AVET).

Cancer vaccines are based on the concept that tumors express novel antigens and thus differ from their normal tissue counterparts. Such putative tumor-specific antigens should be recognizable by the immune system. However, malignant cells are of self origin and only poorly immunogenic, which limits their capability to induce an anticancer immune response. To overcome this problem, tumor cells have been isolated, genetically engineered to secrete cytokine gene products and administered as cancer vaccines. We used adenovirus-enhanced transferrinfection (AVET), which allows high-level transient transgene expression, to introduce cytokine gene expression vectors into murine melanoma cells. The efficiency of AVET makes laborious selection and cloning procedures obsolete. We administered such modified tumor cells as cancer vaccines to syngeneic animals and investigated their impact on the induction of anticancer immunity. We found that IL-2 or GM-CSF gene-transfected murine melanoma cells are highly effective vaccines. Both of these cytokine-secreting vaccines cured 80% of animals which bore a subcutaneous micrometastasis prior to treatment, and induced potent antitumor immunity. The generation of antitumor immunity by these cytokine-secreting vaccines requires three different steps: (1) tumor antigen uptake and processing by antigen-presenting cells (APCs) at the site of vaccination; (2) migration of these APCs into the regional lymph nodes where T-cell priming occurs; (3) recirculation of specific, activated T-cells that recognize distinct tumor load and initiate its elimination. Extending our previously reported studies, we have now comprehensively analysed the requirements for effective antitumor vaccination in animals. This may also become the basis for treatment of human cancer patients.

Animals↗
PubMed2004

The genetic epidemiology of breast cancer genes.

Genetic susceptibility to breast cancer in women is conferred by a large number of genes, of which six have so far been identified. In the context of multiple-case families, BRCA1 and BRCA2 are the most important. Mutations in these genes confer high lifetime risks of breast cancer and ovarian cancer, and more moderate risks of prostate cancer and some other cancer types. Mutations in the CHEK2 and ATM genes, by contrast, cause much more modest (2-4 fold) risks of breast cancer. Genes so far identified explain approximately 20% of the familial aggregation of breast cancer. The remaining susceptibility genes have, so far, proved illusive, suggesting that they are numerous and confer moderate risks. A variety of techniques including genome-wide association studies, use of quantitative intermediate endpoints, and resequencing of genes may be required to identify them. The identification of such genes can provide a basis for targeted prevention of breast cancer.

Ataxia Telangiectasia↗
PubMed1998

Susceptibility to esophageal cancer and genetic polymorphisms in glutathione S-transferases T1, P1, and M1 and cytochrome P450 2E1.

Genetic polymorphisms in enzymes involved in carcinogen metabolism have been shown to influence susceptibility to cancer. Cytochrome P450 2E1 (CYP2E1) is primarily responsible for the bioactivation of many low molecular weight carcinogens, including certain nitrosamines, whereas glutathione S-transferases (GSTs) are involved in detoxifying many other carcinogenic electrophiles. Esophageal cancer, which is prevalent in China, is hypothesized to be related to environmental nitrosamine exposure. Thus, we conducted a pilot case-control study to examine the association between CYP2E1, GSTM1, GSTT1, and GSTP1 genetic polymorphisms and esophageal cancer susceptibility. DNA samples were isolated from surgically removed esophageal tissues or scraped esophageal epithelium from cases with cancer (n = 45), cases with severe epithelial hyperplasia (n = 45), and normal controls (n = 46) from a high-risk area, Linxian County, China. RFLPs in the CYP2E1 and the GSTP1 genes were determined by PCR amplification followed by digestion with RsaI or DraI and Alw26I, respectively. Deletion of the GSTM1 and GSTT1 genes was examined by a multiplex PCR. The CYP2E1 polymorphism detected by RsaI was significantly different between controls (56%) and cases with cancer (20%) or severe epithelial hyperplasia (17%; P < 0.001). Persons without the RsaI variant alleles had more than a 4-6-fold risk of developing severe epithelial hyperplasia (adjusted odds ratio, 6.0; 95% confidence interval, 2.3-16.0) and cancer (adjusted odds ratio, 4.8; 95% confidence interval, 1.8-12.4). Polymorphisms in the GSTs were not associated with increased esophageal cancer risk. These results indicate that CYP2E1 may be a genetic susceptibility factor involved in the early events leading to the development of esophageal cancer.

Adult↗
PubMed2004

Assessing breast cancer risk: genetic factors are not the whole story.

Genetic syndromes that convey a significant risk of breast cancer are responsible for a small but significant percentage of these cancers. However, the vast majority of breast cancers occur in women with no family history of the disease. Nongenetic risk factors include age, previous breast disease, breast tissue density, radiation exposure, and lifestyle factors, such as weight, exercise, and alcohol consumption. In this article, the authors outline genetic and other risk factors for breast cancer, explore risk-reduction strategies, and encourage primary care physicians to assess breast cancer risk in all their patients.

Adult↗
PubMed2001

[Hereditary cancer: identification, genetic heterogeneity, medico-genetic consult].

The paper deals with a role of inherited factors responsible for the occurrence of malignant tumors. Inherited types of cancer are shown to occur virtually at its sites and averaged 5-15%. Formalized criteria for identifying inherited cancer diseases and their etiological and genetic heterogeneity are presented. A role of genes that genetically predispose to particular forms of cancer is shown, which allows for early (preclinical) diagnosis and prevention of cancer diseases.

Genetic Counseling↗
PubMed1997

Loss of heterozygosity at 7q31 in breast cancer: results from an International Collaborative Study Group. The Breast Cancer Somatic Genetics Consortium.

Loss of heterozygosity (LOH) at 7q31 has been claimed to occur in over 80% of all breast cancers and to be of prognostic significance. This would make this genetic alteration the most common event observed in breast cancer to date. Others, however, have been unable to confirm this high incidence. In this multicenter study, we have complied LOH scorings for three polymorphic markers for 7q31-q32 in 683 breast tumors. Although some significant differences between centers existed, no center reported more than 40% LOH, and the average rate was 19%. Disease-free and overall survival of the patients whose tumors carried LOH at 7q31 did not differ significantly from those patients whose tumors showed retention of heterozygosity at 7q31. In a double-blind scoring of a subset of the raw data, an average discordant rate of LOH scoring of 12% was observed. While startling in itself, this was unable to explain the variation among centers, nor the difference with the initially reported high rate of LOH. We conclude that LOH at 7q31 is not important as a genetic alteration in breast cancer as originally suggested, nor a strong determinant of disease outcome.

Breast Neoplasms↗
PubMed1997

Genetic Testing for Cancer Risk Assessment: A Review.

Both environmental factors and an inherited predisposition influence carcinogenesis. The direct role of inheritance in the development of cancer is evident in familial cancer syndromes. These syndromes predispose to cancer through the inheritance of a mutation in a single gene in affected carriers. While many inherited cancer syndromes are rare, an inherited predisposition is directly responsible for 5%-10% of all colon and breast cancers. Complex multigenic inheritance plays an important role in cancer predisposition for the population at large. The identification of genes responsible for an inherited predisposition to colon and breast cancer syndromes has directed public attention to genetic testing for susceptibility to cancer. Assays are currently available to determine individual susceptibility to specific cancers. Cancer genetic testing is currently a time-consuming and complex procedure which requires expertise in its application, interpretation, and follow-up strategic planning. This review discusses cancer genetics and its application to individual and family cancer risk assessment with particular emphasis on breast and colon cancer.

Journal Article↗
PubMed1977

The surgeon, genetics, and cancer control: the Cancer Family Syndrome.

A family manifesting the Cancer Family Syndrome has been evaluated extensively from the medical and genetic standpoint. Findings of excess occurrence of carcinoma of the colon and endometrium, multiple primary cancer, early age of onset, and autosomal dominant mode of genetic transmission mandate a program of increased surveillance and cancer education. Prophylactic surgical implications are provided for certain of these enormously high cancer risk patients.

Adult↗
PubMed2001

Colorado family physicians' knowledge of hereditary breast cancer and related practice.

BACKGROUND: The objective of this study was to describe Colorado family physicians' (FPs') knowledge of hereditary breast cancer and related practice behaviors. METHOD: A survey was mailed to 400 practicing FPs randomly sampled from the board-certified members of the Colorado Academy of Family physicians. RESULTS: Overall, knowledge of hereditary breast cancer was inadequate. Less than half of the respondents knew that BRCA mutations account for 0-10% of all breast cancers; 38% knew the lifetime risk for non-carriers, and 17% responded that a known carrier would have a lifetime breast cancer risk of 50%. Just 45% knew that a BRCA1 mutation could pass from father to daughter. Similarly, only half reported an increased ovarian cancer risk for BRCA1 carriers, and an increased risk for male breast cancer for BRCA2 carriers. All respondents reported that taking a family cancer history was part of their regular clinical practices. The majority reported having referred no patient for cancer genetic counseling or testing within the prior year, with only two reporting having ordered BRCA1 or BRCA2 testing within the year. There was no significant sociodemographic or knowledge difference between the physicians who reported referring patients and the others (p > 0.05). There was interest in learning more about hereditary breast cancer, with rural physicians requesting Internet and teleconference courses. CONCLUSIONS: As cancer genetics emerges into the primary care arena. FPs recognize their knowledge deficit in this area. Future cancer genetic outreach for primary care providers statewide is necessary and would be welcomed, and may require a variety of educational and consultative approaches, depending on geographic location of practice.

Adult↗
PubMed2003

The molecular genetics of prostate cancer.

The molecular genetics of prostate cancer, the second most common cause of cancer-related death in men, is poorly understood. Inherited factors are believed to account for 42% of the risk of prostate cancer, and although multiple chromosomal loci of susceptibility have been identified, the target genes for these loci have not been well defined. Its heterogeneous nature suggests that the predisposition to prostate cancer may involve multiple genes and variable phenotypic expression. Genes that have been found to play a role in progression of prostate cancer include GSTP1 and PTEN, as well as the androgen receptor (AR) gene. Evidence suggests that the AR signaling pathway can be activated by other ligands when androgen levels are low. Recent findings have also implicated Kruppel-like factor 6 (KFL6), E-cadherin, the p40 subunit of eukaryotic translation initiation factor (eIF3-p40), and Elongin C, but confirmatory evidence is required to clarify the roles of these factors. Technologic advances, such as complementary DNA and tissue microarrays, have facilitated identification of genetic alterations and investigations of their function, but improved tools for searching and analyzing genes are still needed.

Adenocarcinoma↗
PubMed1997

Etiology, natural history, management and molecular genetics of hereditary nonpolyposis colorectal cancer (Lynch syndromes): genetic counseling implications.

We estimate that 5-10% of virtually all forms of cancer are due to a primary hereditary etiology. However, a hereditary cancer diagnosis is often missed because the family history of cancer is given short shrift in medical practice. Hereditary nonpolyposis colorectal cancer (HNPCC) certainly fits this estimate, although some studies suggest that a minimum of 2% with a range as high as 10% of the total colorectal cancer burden is due to HNPCC. Mutations in one of the four mismatch repair genes, i.e., hMSH2, hMLH1, hPMS1, and hPMS2, account for about 70% of HNPCC kindreds. Other germ-line mutations are likely to be identified to account for the remainder of HNPCC patients. By far the most common HNPCC mutations involve hMSH2 and hMLH1, with hPMS1 and hPMS2 accounting for only about 3% of such families. Prior to these molecular genetic discoveries, the genetic counselor could only provide the patient with an estimate of a 50% likelihood of manifesting HNPCC based on the counselee having one or more first-degree relatives manifesting syndrome cancers in their direct genetic lineage. Because DNA testing has become available in families with known mutations, we have provided pretest group education in the form of a family information service with intensive education about the natural history, genetic risk, surveillance, and options for management of HNPCC, as well as discussion of the potential for fear, anxiety, apprehension, and insurance or employer discrimination that might impact on this DNA testing. Following informed consent, these relatives were then counseled on a one-to-one basis. Using DNA-based genetic counseling involving hMSH2 or hMLH1, we have provided this service to four extended HNPCC kindreds. Details of this genetic counseling experience on these four kindreds will be discussed.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Hormonal imbalance in two types of endometrial cancer and genetic polymorphism of steroidogenic enzymes.

OBJECTIVES: Modern data on endometrial cancer (EC) incidence demonstrate that it is one of the most prevalent gynecologic malignancies. It is possible that some allelic polymorphisms of the genes involved in steroidogenesis or steroid metabolism differently contribute into susceptibility to described types of this disease, namely to type I (which is considered to be hormone dependent) and type II. METHODS: Distribution of allelic polymorphisms of CYP17 (17alpha-hydroxylase/17,20-lyase), CYP19 (aromatase), catechol-O-methyltransferase (COMT) and CYP1B1 (primarily, estrogen 4-hydroxylase) genes was compared totally in 156 endometrial cancer patients, approximately two-third of who belonged (on the basis of case history and some characteristics of host and tumor) to type I of the disease, and one-third to type II. Blood leukocytes were used as source of normal DNA for PCR-genotyping. RESULTS: No differences were found in distribution of CYP17 and CYP1B1 genotypes between patients belonging to type I or II of the disease. On the other side, in case of CYP19, the ratio of incidence of A6A6 genotype to the frequency of A1A6 and A3A6 genotypes was higher in type II patients (1.0) than in type I patients (0.3). Besides, incidence of high activity (HH) COMT genotype was higher among patients with type I of disease than in patients with type II of it (33.3% versus 14.7%, OR=2.9, z=1.96, p=0.05) revealing tendency to the lower inactivation of catecholestrogens in the latter group. CONCLUSION: It may be suggested that more aggressive clinically and frequently receptor-negative type II of endometrial cancer is associated with indirect signs of mainly intratumoral hyperproduction of estrogens (excess of CYP19 A6A6 genotype) without their sufficient inactivation into methoxyderivatives that warrants further study.

Adult↗
PubMed2000

Cancer population genetics and tumour prevention: an unfulfilled paradigm.

The molecular approach to cancer has identified specific abnormalities that contribute to malignant pathogenesis in an aetiological manner and define individuals who are at higher risk for specific malignancies. Studies of cancer distribution in families suggest that 15-20% of all malignancies may have a significant germ line hereditable mutation that directly or indirectly contributes to tumour development. Additionally, the identification of many genetically-determined polymorphisms that regulate carcinogen metabolism indicate that their assessment may contribute to selecting individuals for preventive surveillance or intervention as well. Locating individuals in the population who have moderate to high risk germ line mutations in critical oncogenic regulatory genes and assessing a panel of polymorphisms that underlie a significant attributable risk for cancer development may allow the recruitment of individuals at high risk for a particular malignancy and, therefore, represent good candidates for either directed organ surveillance and/or chemoprevention trials.

Antineoplastic Agents↗
PubMed2004

[Genetic predisposition and ovarian cancer].

The genetic predisposition to epithelial ovarian cancer can be distinguished in two different forms: familial breast and/or ovarian cancer; familial colon, endometrium, ovarian cancer or HNPCC syndrome (hereditary non polyposis colorectal cancer). The BRCA1 and BRCA2 genes are involved in familial breast and (or) ovarian cancer. Mutations of these two genes could explain 5.5% (2-7%) of ovarian cancers. The hMLH1, hMSH2, and hMSH6 genes are involved in the HNPCC syndrome. The mutations of these genes could explain 1% to 2% of ovarian cancers. The clinical management of women at ovarian cancer risk is variable and dependent on the predisposition going from regular examination until prophylactic oophorectomy in the presence of BRCA mutations.

Breast Neoplasms↗
PubMed2006

Ovarian cancer and genetic susceptibility in relation to the BRCA1 and BRCA2 genes. Occurrence, clinical importance and intervention.

The Nordic countries have the highest incidences of ovarian cancer in the world (around 15 cases per 100,000 women). We have conducted a review of the recent literature with focus on the Nordic countries, on genetic susceptibility to ovarian cancer, and the clinical implications in relation to the BRCAI and BRCA2 genes. One of the strongest risk factors for ovarian cancer is a family history of ovarian and/or early-onset breast cancer. It is thought that germline mutations in BRCA1/2 might be responsible for as much as 10% of all ovarian cancer cases and all families containing either multiple case, site-specific ovarian cancer cases or breast and ovarian cancers together. Data from several international studies suggest that the lifetime risk of ovarian cancer in a BRCA 1 mutation carrier can vary from 18 to 56% and from 14 to 27% in a BRCA2 carrier, depending on the presence/absence of a family history of the disease. Genetic evaluation and testing is used in many countries to identify families with BRCA1/2 mutations. Once a mutation has been identified, genetic counseling and testing can be offered to unaffected family members. Prophylactic oophorectomy in unaffected mutation carriers will eliminate the risk of ovarian cancer, although there is a slight residual risk of peritoneal cancer. During oophorectomy, the Fallopian tube should also be removed. If a woman does not want prophylactic oophorectomy, then tubal ligation or oral contraceptive use can be considered as these have been shown to reduce ovarian cancer risk also in mutation carriers.

Contraceptives, Oral↗
PubMed2000

Apoptosis induced by 5-flucytosine in human pancreatic cancer cells genetically modified to express cytosine deaminase.

AIM: To elucidate the pattern of 5-flucytosine (5-FC)-induced apoptosis and its role in gene therapy of human pancreatic cancer. METHODS: The human pancreatic cancer SW1990 cells (CEA-producing) were infected with recombinant adenoviruses (Adex1CEA-prCD or Adex1CEA-prZ). Expression of CD gene protein was examined by western blot. Apoptosis induced by 5-FC in human pancreatic cancer SW1990 cells genetically modified to express cytosine deaminase was observed by means of electron microscopy, DNA electrophoresis, and flow cytometry analysis techniques. RESULTS: The SW1990 cells infected with Adex1CEA-prCD were treated with 5-FC at 100 mumol.L-1 for 48 h, and cell apoptosis was observed. Typical apoptosis morphological feature appeared and DNA ladder could be demonstrated on DNA electrophoresis. Apoptosis peak was also showed by flow cytometry. Apoptotic cells accounted for 34.6% of the cell population. Cells in G1, S, and G2/M phase of cell cycle were 64%, 11%, and 7%, respectively. CONCLUSION: The apoptosis induced by 5-FC may be a primary mechanism in CD gene therapy of pancreatic cancer.

Adenoviruses, Human↗