ABSTRACT
Several studies have reported that, in Lynch syndrome resulting from mutations of the mismatch repair (MMR) genes, a CA repeat ≤17 within the IGF1 promoter, SNPs within the xenobiotic metabolizing enzyme gene CYP1A1 and SNPs on 8q23.3 and 11q23.1 modify colorectal cancer (CRC) risk in MMR mutation carriers. We analysed the impact of these polymorphisms on CRC risk in 748 French MMR mutation carriers derived from 359 families. We also analysed the effect of the Novel 1 SNP (18q21), which has recently been shown to increase CRC risk in the general population. We observed a significant difference in the CRC-free survival time between males and females, between MSH2 and MSH6 mutation carriers and between MLH1 and MSH6, indicating that this series is representative of Lynch syndrome. In contrast, the univariate log-rank test, as well as multivariate Cox model analysis controlling for familial aggregation and mutated MMR gene, year of birth and gender showed that the polymorphic alleles tested were not associated with a significant CRC risk increase, neither on the entire sample nor among males and females. This discrepancy with previous reports might be explained both by the genetic heterogeneity between the different populations analysed and the allelic heterogeneity of the MMR mutations. We conclude that genotyping of these polymorphisms is not useful to evaluate CRC risk in MMR mutation carriers and to optimize their clinical follow-up.
Subject(s)
Colorectal Neoplasms, Hereditary Nonpolyposis/genetics , Colorectal Neoplasms/genetics , DNA Mismatch Repair , Genetic Predisposition to Disease , Mutation , Colorectal Neoplasms/diagnosis , Epistasis, Genetic , Female , France , Humans , Male , PenetranceABSTRACT
We report five cases of abdomino-pelvic PEComas diagnosed in the last 10 years in the Rouen University Hospital. Four are hepatic and one is in a pelvic location which is unusual due to its strongly pigmented aspect. The tumors derived from "perivascular epithelioid cells" are rare. They are characterized by spindle or epithelioid cells in an immediate perivascular location. The immunochemistry is positive for HMB45, MelanA and smooth muscle Actin. The criteria for malignancy are infiltrative growth pattern, necrosis, high cellularity, high nuclear grade and mitotic activity. There are 8% of recurrence and 20% of metastasis (lung, bones, liver). This study presents the clinical, pathologic, immunohistochemical and molecular aspects of these PEComas and discusses the main differential diagnosis of the pigmented one.
