Hereditary diffuse gastric cancer (HDGC). An overview.

It is estimated that up to 10% of gastric carcinomas show familial aggregation. In contrast, around 1-3 % (approximately 33,000 yearly) are genuinely hereditary. Hereditary diffuse gastric cancer (HDGC) is a rare malignancy characterized by autosomal dominant inheritance of pathological variants of the CDH1 and CTNNA1 genes encoding the adhesion molecules E-cadherin and α-catenin, respectively. The multifocal nature of the disease and the difficulty of visualizing precursor lesions by endoscopy underscore the need to be aware of this malignancy as surgical prevention can be fully protective. Here, we provide an overview of the main epidemiological, clinical, genetic, and pathological features of HDGC, as well as updated guidelines for its diagnosis, genetic testing, counseling, surveillance, and management. We conclude that HDGC is a rare, highly penetrant disease that is difficult to diagnose and manage, so it is necessary to correctly identify it to offer patients and their families' adequate management following the recommendations of the IGCL. A critical point is identifying a mutation in HDGC families to determine whether unaffected relatives are at risk for cancer.

Mutational analysis of BRCA1 and BRCA2 genes in Mexican breast cancer patients.

Germline mutations in the BRCA1 and BRCA2 genes predispose to breast and ovarian cancer. A variable incidence of mutations has been reported for these genes. The contribution of BRCA1 and BRCA2 mutations to Mexican women with breast and/or ovarian cancer is not known. Because of the increasing prevalence of breast cancer in this population, it is necessary to study the presence of mutations in both genes. We screened BRCA1 and BRCA2 genes in 40 patients: 29 patients with a history of breast and/or ovarian cancer, and 11 patients with early-onset breast cancer (< 40 years), through denaturing high performance liquid chromatography analyses. We found two frameshift mutations in BRCA1 and one missense mutation in each gene. Additionally we found several intronic variants as well as synonymous mutations. We found 5% of deleterious mutations in the BRCA genes. Larger studies are needed to establish the significance and prevalence of BRCA mutations among Mexican women.

A descriptive study of second primary malignancies associated to breast cancer in a mexican Hispanic population.

Breast cancer is the second most frequent tumor in Mexico. Patients diagnosed with this cancer have a higher risk of developing a second malignancy. The objective of our study was to see the frequency, types of second cancers, and its impact on survival, in order to be able to deliver a proper and efficient follow up to these patients, because our patients differ from the population of breast cancer in the rest of the world. Our patients are younger and therefore at higher risk. The clinical records of breast cancer patients treated at the Instituto Nacional de Cancerologia Mexico from 1983 to 1992 were reviewed. In 1370 evaluable patients, 77 (5.6%) developed a second neoplasm, of those, 56 (72.7%) in the contralateral breast and 21 in other sites (27.3%), thyroid was the most frequent followed by ovary and endometrium. Mean age of the patients was 51.5 yr, 45.5 for the other breast and 55.5 for other malignancies (p = 0.01). Median survival for all the group was of 180 mo (3-238). Patients were significantly younger in the contralateral breast group, although all our breast cancer patients are younger. The most frequent second malignancy after the other breast, was thyroid followed by ovary and endometrium with similar survival for both groups.

An identical, complex TP53 mutation arising independently in two unrelated families with diverse cancer profiles: the complexity of interpreting cancer risk in carriers.

Most inherited TP53 mutations have been identified in individuals with a family cancer predisposition syndrome, in which the activity of p53 mutants is severely reduced. However, germline p53 mutants in children with 'sporadic' adrenocortical or choroid plexus tumors exhibit a wide range of functional activity. Here, we demonstrate the occurrence of a complex germline TP53 mutation in two unrelated families with different cancer phenotypes, neither fulfilling the classic criteria for Li-Fraumeni syndrome. The TP53 mutation consists of a duplication of 7 bp in exon 4, resulting in a frame shift and premature stop signal. Haplotype analysis indicated that the mutation arose independently in the two families. Analysis of the DNA secondary structure predicts the TP53 mutation occurred within a hairpin loop. Additional germline complex mutations occurring within the same region of exon 4 have been identified in the IARC database. Our findings suggest that certain TP53 regions are prone to intrinsic genetic alterations, possibly through defects in DNA replication or repair. Further, carriers of the same TP53 mutation can have diverse cancer profiles, illustrating the complexity of genetic counseling and risk prediction.

Treatment experiences of testicular cancer in Hispanic patients with Down's syndrome at the National Cancer Institute of Mexico

We present 4 case studies of patients with Down's syndrome and testicular germ-cell cancer, treated with conventional methods at the National Cancer Institute of Mexico, with similar outcomes as patients without this syndrome. There are several reports of testicular cancer arising in patients with Down's syndrome worldwide, mainly from Caucasian populations. We discuss some theories about the association and the possible increase of incidence (AU)

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