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Loss of heterozygosity of BRCA1, TP53 and TCRD markers analysed in sporadic endometrial cancer.

Genetic alterations of tumour suppressor genes, for which loss of heterozygosity (LOH) is one mechanism of gene inactivation, are important steps in the development of endometrial cancer. To investigate the clinical relevance of LOH of BRCA1 (17q21), TP53 (17p13) and TCRD (14q11) in endometrial cancer, polymerase chain reaction (PCR)-based fluorescent DNA technology for the detection of microsatellite polymorphisms was applied. One hundred and thirteen archival endometrial cancer samples with matched normal tissues were examined. Allele loss at three loci were correlated with age, tumour size, lymph node status, metastases, stage, histological types, grade, expression of oestrogen receptor (ER) and progesterone receptor (PgR), family history of cancer, previous history of cancer or precursor lesions, and previous history of hormone replacement therapy (HRT). LOH for BRCA1 was detected in 18.1%, of TP53 in 26.9%, and of TCRD in 26.3% of informative cases. LOH of BRCA1 correlated with medium grade, positive ER status, and family history of cancer; LOH of TP53 correlated with younger age, high grade, positive PgR status, and with tumours from patients without HRT; LOH of TCRD correlated only with family history of cancer. LOH at all three loci correlated only with grade and positive family history. Allele loss of one of the three tumour suppressor loci did not correlate with disease-free survival (DFS), but LOH of BRCA1 correlated significantly with decreased overall survival (OS). The latter, together with the correlation of LOH of BRCA1 locus with steroid hormone receptor expression, might give a hint to the potential involvement of the co-localised 17 beta-hydroxysteroid dehydrogenase (HSD) gene in the development of endometrial cancer.

Adult↗

Microarray comparative genomic hybridization reveals genome-wide patterns of DNA gains and losses in post-Chernobyl thyroid cancer.

Genetic gains and losses resulting from DNA strand breakage by ionizing radiation have been demonstrated in vitro and suspected in radiation-associated thyroid cancer. We hypothesized that copy number deviations might be more prevalent, and/or occur in genomic patterns, in tumors associated with presumptive DNA strand breakage from radiation exposure than in their spontaneous counterparts. We used cDNA microarray-based comparative genome hybridization to obtain genome-wide, high-resolution copy number profiles at 14,573 genomic loci in 23 post-Chernobyl and 20 spontaneous thyroid cancers. The prevalence of DNA gains in tumors from cases in exposed individuals was two- to fourfold higher than for cases in unexposed individuals and up to 10-fold higher for the subset of recurrent gains. DNA losses for all cases were low and more prevalent in spontaneous cases. We identified unique patterns of copy variation (mostly gains) that depended on a history of radiation exposure. Exposed cases, especially the young, harbored more recurrent gains that covered more of the genome. The largest regions, spanning 1.2 to 4.9 Mbp, were located at 1p36.32-.33, 2p23.2-.3, 3p21.1-.31, 6p22.1-.2, 7q36.1, 8q24.3, 9q34.11, 9q34.3, 11p15.5, 11q13.2-12.3, 14q32.33, 16p13.3, 16p11.2, 16q21-q12.2, 17q25.1, 19p13.31-qter, 22q11.21 and 22q13.2. Copy number changes, particularly gains, in post-Chernobyl thyroid cancer are influenced by radiation exposure and age at exposure, in addition to the neoplastic process.

Adolescent↗

Microsatellite alterations in non-small cell lung cancer.

Genetic alterations at 12 dinucleotide repeat loci located on human chromosomes 2, 3, 12, and 17 have been analyzed in non-small cell lung cancer from Thai patients. Seventeen out of 30 cases (57%) harbored the microsatellite alterations. Of the 30 cases, 19 patients had a history of tobacco smoking, of whom 14 (74%) were in the group with microsatellite alterations, whereas 3 out of 11 non-smokers (26%) had these alterations. The frequency of microsatellite alterations among smokers was significantly higher than it was in non-smokers (P = 0.01 Fisher's exact test; odds ratio; 7.47).

Adult↗

Recent advances in the molecular genetics of cancer. Second joint conference of the American Association of Cancer Research and the European Association of Cancer Research, Oxford, 9-12 September 1997.

The second joint conference of the AACR and the EACR held in Oxford from 9-12 September 1997 was successful from many vantage points. While providing an optimal setting in which European and American cancer researchers could meet and exchange information, the conference had an excellent scientific programme which encompassed both methodological updates on important models used in cancer research and presentations of recent key advances in the molecular genetics of cancer. Lower eukaryotes are established model organisms used to elucidate fundamental but complex eukaryotic processes, such as those involved in tumorigenesis and cancer progression, and the progressive availability of their genome sequence makes them even more attractive. Transgenic mouse models are increasingly used not only for the study of one gene of interest but for investigation of the interactions among genes involved in the same pathway. The family of tumour suppressor genes is growing fast and several presentations were devoted to recently identified members such as the Von Hippel-Lindau gene, the FHIT gene and the PTEN gene. The systematic analysis of loss of heterozygosity on multiple loci in tumour specimens can provide the basis for preliminary models of molecular multistep progression in some tumour types, even though this is limited by the high degree of complexity found. Mechanisms of cell cycle regulation and apoptosis continue to be dissected and to constitute a fruitful area of investigation, with important recent insights on the p53-MDM2 autoregulatory loop and on the involvement of E2F-1 in apoptosis.

Animals↗

Exogenous fibroblast growth factors maintain viability, promote proliferation, and suppress GADD45alpha and GAS6 transcript content of prostate cancer cells genetically modified to lack endogenous FGF-2.

Understanding processes regulating prostate cancer cell survival is critical to management of advanced disease. We used prostate cancer cell transfectants genetically modified to be deficient in either endogenous fibroblast growth factor (FGF-1) or endogenous FGF-2 to examine FGF maintenance of transfectant survival and proliferation and FGF-2-regulated expression of transfectant growth arrest DNA damage (GADD) and growth arrest sequences (GAS) family genes (known modulators of cell cycle progression and survival) and the AS3 gene (an androgen-modulated effector of prostate cell proliferation). When propagated in the absence of exogenous FGFs, FGF-2-deficient transfectants undergo exponential death, whereas FGF-1-deficient transfectants proliferate. Exogenous FGF-1, FGF-2, FGF-7, or FGF-8 promote survival and proliferation of FGF-2-deficient transfectants and enhance FGF-1-deficient transfectant proliferation. Transfectants express FGF receptor FGFR1, FGFR2(IIIb), FGFR2(IIIc), and FGFR3 transcripts, findings consistent with the effects of exogenous FGFs. FGF-2-deficient transfectants express high levels of AS3, GADD45alpha, GADD45gamma, GAS8, and GAS11 transcripts and moderate levels of GADD153, GAS2, GAS3, and GAS6 transcripts and lack demonstrable GAS1 or GAS5 transcripts. FGF withdrawal-mediated death of FGF-2-deficient transfectants did not significantly affect cell AS3, GADD153, GADD45gamma, GAS2, GAS3, GAS7, GAS8, or GAS11 transcript content, whereas GADD45alpha and GAS6 transcript content was elevated. These studies establish that endogenous FGF-2 dominantly regulates prostate cancer cell survival and proliferation and that exogenous FGFs may assume this function in the absence of endogenous FGF-2. Additionally, we provide the first evidence that FGFs regulate prostate GADD45alpha and GAS6 transcript content. The latter observations suggest that GADD45alpha and GAS6 proteins may be effectors of processes that regulate prostate cancer cell survival. Additional studies are required to examine this possibility in detail.

Animals↗

Hereditary prostate cancer and other genetic predispositions to prostate cancer.

The incidence of prostate cancer (CaP) and its increase in the last 10 years vary both from country to country and according to the ethnic group, with the highest incidence reported for Afro-Americans and the lowest for Asian men. To date, only three risk factors have been established for CaP: age; familial aggregation of CaP, and ethnic origins. No dietary or environment-related cause has been established. However, some variations in endogenous genetic factors may help explain differences in risk among ethnic groups or geographic areas. Similarly, certain genetic polymorphisms of genes encoding for 5alpha-reductase, androgen receptor or vitamin D, have been associated with different levels of CaP risk, and could explain the variations observed between populations. Different studies support the view that familial CaP may truly be hereditary, and not due to a similar lifestyle. Thus, familial inheritance is a parameter that needs to be considered in recommending screening for high-risk families. Indeed, when 1, 2, and 3 first-degree relatives are affected, the relative risk of first-degree relatives of CaP patients may increase to 2, 5, and 11%, respectively. Some familial forms appear to be associated with transmission of a rare putative dominant gene with a high penetrance (88% at age 85), with the cumulative proportion of CaP attributable to this gene being more marked for younger patients (a 43 versus a 34% risk of CaP appearing before the age of 55 versus 70 years). Using this transmission model and linkage analysis, a predisposing locus on chromosome 1q24-25 (HPC-1) has been described. Moreover, recessive and X-linked transmission has been suggested, showing that a large proportion of familial CaP may not be due to segregation of a few major gene mutations, but rather to familial sharing of alleles at many loci, each contributing to a small increase in cancer risk. Candidate genes may be the same suppressor genes that are involved in other cancers and in sporadic CaP.

Aged↗

Development and pilot testing of a prostate cancer polygenic risk report.

BACKGROUND: Polygenic risk scores (PRS) are increasingly being incorporated into clinical care, yet optimal strategies for communicating PRS results to patients and clinicians remain undefined. Effective report design is critical to ensure comprehension and appropriate use, particularly for complex conditions such as prostate cancer where screening decisions are nuanced. We developed and pilot tested patient-facing materials to communicate integrated polygenic and monogenic risk for prostate cancer in the context of a randomized clinical trial. METHODS: We designed a summary report and accompanying Frequently Asked Questions (FAQ) page to communicate prostate cancer genetic risk within the Prostate Cancer, Genetic Risk, and Equitable Screening Study (ProGRESS). Materials were developed through an iterative, multidisciplinary process informed by existing literature on genomic risk communication. We conducted semi-structured interviews with a national sample of eight men eligible for prostate cancer screening to evaluate comprehension, interpretation of visual elements, perceived usefulness, and preferences for improvement. Interviews were transcribed and analyzed using reflexive thematic analysis. RESULTS: Participants generally found the summary report and FAQ page understandable and visually engaging. Graphical displays of absolute risk, particularly pictograph arrays, facilitated comprehension and helped contextualize risk. Visual cues such as color and bold formatting effectively directed attention to key information, with red coloring perceived as particularly salient for high-risk results. In contrast, more complex visualizations, including bell curves and incidence curves, were frequently misunderstood or not interpreted as intended. Participants expressed a desire for clearer guidance regarding next steps and additional accessible information, suggesting supplementary resources such as hyperlinks or QR codes. Concerns about readability included small font size and high text density. CONCLUSIONS: In this qualitative pilot study, patient-facing materials for communicating prostate cancer PRS were generally well received, with specific design features such as simple visualizations and clear formatting enhancing understanding. Findings highlight the importance of intuitive risk displays and actionable guidance in PRS reporting. These results provide practical insights to inform the design of genomic risk reports as PRS-based prostate cancer screening approaches move toward clinical implementation. TRIAL REGISTRATION: ClinicalTrials.gov NCT05926102; date of registry: July 3, 2023.

Aged↗

Tumor-specific exon 1 mutations could be the 'hit event' predisposing Rb2/p130 gene to epigenetic silencing in lung cancer.

Genetic alterations in Rb2/p130 gene have been reported in several tumors, but till now there are insufficient and conflicting data linking the loss of pRb2/p130 expression with the mutational status of this gene in lung cancer. We recently reported that loss or lowering of pRb2/p130 expression is mainly due to aberrant Rb2/p130 promoter methylation, in retinoblastoma tumors, and indicated that epigenetic silencing of Rb2/p130 can impair its function to negatively regulate cell cycle progression as well as apoptotic response. In order to clarify Rb2/p130 gene inactivation in lung cancer, we investigated whether epigenetic events could impair the expression of this gene in NSLC. Here, we show that specific Rb2-exon 1 homozygous mutations, occurring in an Rb2/p130, region, rich in CpG dinucleotides, could be the 'hit event' that predispose this gene to epigenetic changes, leading to Rb2/p130 gene silencing in lung cancer. Moreover, these homozygous mutations, found in different tumor histotypes, could represent tumor-specific markers.

Base Sequence↗

Loss of heterozygosity at 9p23 defines a novel locus in non-small cell lung cancer.

Genetic studies have previously demonstrated cytogenetic deletions and allelic imbalance or loss of heterozygosity (LOH) on the p arm of chromosome 9, in a number of tumour types. We have analysed 45 Non-Small Cell Lung Cancers (NSCLC) with a panel of highly polymorphic microsatellite markers on chromosome 9. Our results indicate that loss on 9p is concentrated within the D9S156-D9S161 region with 44% (20/45) LOH, however the area with minimal loss in this set of lung tumours was found at D9S157 (9p23), with 30% LOH (10/33), whereas loss at the IFNA locus was only found in 6% (2/34) tumours. Five of the lung tumours in this study which demonstrated LOH at D9S157 retained heterozygosity at the adjacent informative markers lying centromeric and telomeric to D9S157. No correlations were found between any of the clinico-pathological parameters and LOH on 9p or at the D9S157 locus. The results of this study indicates the presence of a further putative tumour suppressor gene on 9p at the D9S157 locus (9p23) to be most likely involved in the pathogenesis of non-small cell lung cancer.

Carcinoma, Non-Small-Cell Lung↗

Future possibilities in the prevention of breast cancer: role of genetic variation in breast cancer prevention.

Risk factors for breast cancer are related to endogenous hormones and reproductive events. As such, traditional cancer prevention strategies are not easily applicable. Tamoxifen and other selective estrogen receptor modulators (SERMs) offer a new preventive strategy for some high-risk women, but have not yet been shown to be efficacious for all women. New tools to identify high-risk women are needed. One such tool is the development of a multigenic model of breast cancer susceptibility that can be used to screen women in order to identify those who carry a combination of alleles that puts them at significantly increased risk.

Adult↗

Carcinoembryonic antigen (CEA) in the cancer family syndrome.

We present findings on plasma CEA in relatives and spouses from six kindreds manifesting the Cancer Family syndrome. The CEA distributions per se were transformed to square root CEA to correct for skewness and kurtosis. Significant effects of age and duration of smoking were adjusted for by linear regression. Relatives were classified as: 1) cancer patients, 2) individuals at high genetic cancer risk (one or more first-degree relatives affected, and 3) individuals at low genetic cancer risk (no first-degree relatives affected) for statistical comparisons. Unrelated spouses were also classified into corresponding groups according to their directline mate's status. Cancer patients and relatives at high genetic risk had significantly greater mean square root CEA than relatives at low genetic risk, and, surprisingly, unrelated spouses had mean levels of square root CEA which were similar to that in the corresponding cancer risk class of their direct-line mates. Our results suggest the existence of both a genetic and connubial effect on CEA, presumably due to a common environmental agent acting in concert with the degree of genetic predisposition to oncogenesis in this syndrome.

Carcinoembryonic Antigen↗

Clonality of precursors of cervical cancer and their genetical links to invasive cancer.

Two problems were the focus of this study. (1) Is precancer and/or invasive cancer of the human cervix a poly- or monoclonal proliferation of neoplastic cells? (2) Are simultaneously present precancers and cancers of the cervix clonally related, or do they arise independently? Microdissection of 37 neoplastic lesions with different degrees of histologic severity in 22 patients followed by polymerase chain reaction-based analysis of X-chromosome inactivation was used as a principal method. Invasive cancers were interpreted as monoclonal because samples invariably showed monoclonal signals. In two thirds of these cases, simultaneously present precursors had the identical X-chromosome inactivation pattern, but in one third the pattern was different. Polyclonality was seen in a subgroup of precursors, where there was no simultaneous presence of invasive cancer. In contrast, when invasive cancer was present, no precursor signaled polyclonality. Data taken together indicate that the pathogenesis of cervical cancer is probably even more complicated than that of other cancers involving selection of subclones from originally polyclonal precursors and possibility of coexistence of precursors of different monoclonal composition. The study also observed that a large field of normal cervical squamous epithelium (approximately 500 basal squamous epithelial cells) with nonrandom X-chromosome inactivation was present. It remains to be further investigated whether this phenomenon represents an embryologic lyonization pattern of X-chromosome inactivation or postembryologic clonal expansion of submorphologically transformed cells.

Clone Cells↗

Correlates of psychologic distress in colorectal cancer patients undergoing genetic testing for hereditary colon cancer.

In this article the authors describe the demographic and psychosocial correlates of 2 measures of psychologic distress among 200 colorectal cancer patients undergoing genetic testing for hereditary nonpolyposis colon cancer. The prevalence of symptoms of depression on the Center for Epidemiologic Studies Depression (CES-D) Scale was 24%. In multivariate analysis, female sex, less formal education, fewer sources of social contacts, and less satisfaction with them were associated with high scores on the CES-D Scale. Characteristics associated with high scores on the State-Trait Anxiety Inventory were younger age, less formal education, non-White race, local-regional stage of disease, fewer social contacts, and less satisfaction with them. Information on psychosocial correlates of psychologic distress may prove useful in guiding genetic counseling sessions, in identifying subgroups that need more intensive follow-up, and in developing interventions to facilitate adjustment to genetic test results.

Adaptation, Psychological↗

Association between p53 mutation and clinicopathological features of non-small cell lung cancer.

Genetic alterations in exons 5-8 of the p53 gene, determined by single-strand conformation polymorphism and sequencing analyses, and the clinicopathological characteristics of 108 patients with non-small cell lung cancer were compared. Mutations in this gene were found in 37 of the 108 patients (34%): in 30% (23/76) of those with adenocarcinomas, 46% (12/26) of those with squamous cell, 33% (1/3) of those with large cell and 33% (1/3) of those with adenosquamous carcinomas. No associations between the incidence of p53 mutations and the histological or cytological subtypes of adenocarcinomas were found. The analysis of types of mutations, however, showed that GC transversion was relatively common in papillary and clara subtypes, whereas it accounted for only 17% at most of p53 mutations in tubular and bronchial surface epithelial cell subtypes of adenocarcinomas. Univariate analyses revealed that large tumor size, high nodal stage and positive vascular invasion of non-small cell lung cancers, and high nodal stage and high-grade nuclear atypia of adenocarcinomas were associated significantly with p53 mutations. Multivariate analyses showed that the tumor sizes of non-small cell lung cancer correlated with p53 mutations with marginal significance (P = 0.099) whereas nuclear atypia of adenocarcinomas correlated significantly (P = 0.028). No differences between the overall or relapse-free survival rates of patients with and without p53 mutations in non-small cell lung cancers or adenocarcinomas were found. These findings indicate that p53 mutations in adenocarcinomas of the lung are associated with the malignant phenotype of tumor cells, but not with patient survival.

Adenocarcinoma↗

[Molecular diagnosis of pancreatic cancer].

Genetic alterations such as K-ras mutation, inactivation of the p53, p16 and DPC4 genes and frequent chromosomal loss of the 17p, 9p, 18q and 1p are thought to play a crucial role in the carcinogenesis of pancreatic cancer. Mutations of K-ras oncogene could be detected frequently in pancreatic juice samples from patients with pancreatic carcinoma and intraductal papillary neoplasm (IPN), although they could be detected in some of the samples from patients with chronic pancreatitis and pancreatic cyst. This suggests that K-ras mutation is an early event in the carcinogenesis of the exocine pancreas. In IPN, analysis of other genetic alteration would be available, since pancreatic juice samples from the patient are relatively rich in the proportion of the tumor cells. A new diagnostic modality of sensitive allelotyping would be useful for evaluating malignant potential of these borderline lesions.

Gene Deletion↗

Facilitating informed decision making about breast cancer risk and genetic counseling among women calling the NCI's Cancer Information Service.

Despite increased interest among the public in breast cancer genetic risk and genetic testing, there are limited services to help women make informed decisions about genetic testing. This study, conducted with female callers (N = 279) to the National Cancer Institute's (NCI's) Atlantic Region Cancer Information Service (CIS), developed and evaluated a theory-based, educational intervention designed to increase callers' understanding of the following: (a) the kinds of information required to determine inherited risk; (b) their own personal family history of cancer; and (c) the benefits and limitations of genetic testing. Callers requesting information about breast/ovarian cancer risk, risk assessment services, and genetic testing were randomized to either: (1) standard care or (2) an educational intervention. Results show that the educational intervention reduced intention to obtain genetic testing among women at average risk and increased intention among high-risk women at 6 months. In addition, high monitors, who typically attend to and seek information, demonstrated greater increases in knowledge and perceived risk over the 6-month interval than low monitors, who typically are distracted from information. These findings suggest that theoretically designed interventions can be effective in helping women understand their cancer risk and appropriate risk assessment options and can be implemented successfully within a service program like the CIS.

Breast Neoplasms↗

Apparent Mendelian inheritance of breast and colorectal cancer: chance, genetic heterogeneity or a new gene?

It is not uncommon for cancer geneticists to be referred families with apparently Mendelian co-inheritance of breast and bowel cancer. Such families present a particular problem as regards the intensity of their screening for these diseases and the utility of genetic testing. Many 'breast-colon' cancer families probably result from chance clustering of two common cancers. Other 'breast-colon' cancer families may result from known cancer syndromes, such as hereditary breast-ovarian cancer or hereditary non-polyposis colon cancer, either by conferring a high risk of one cancer type and a slightly increased risk of the other, or through a predisposition to one of the two cancers and chance occurrence of the other. Anecdotally, however, many geneticists wonder about the existence of a distinct 'breast-colon cancer syndrome', since some families present good a priori evidence of genetic disease and yet cannot readily be accounted for by known genes or chance. The identification of unknown 'breast-colon cancer' genes is likely to be difficult, relying primarily on candidate gene analysis, including loci separately implicated in breast or colorectal cancer, or in other multiple cancer syndromes. Studies such as those on APC I1307K and CHEK2 1100delC may suggest the way forward for the identification of 'breast-colon cancer' genes.

Adult↗