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Adrenocortical carcinoma (ACC) is rare within the adult population. Ectopic ACC proves even rarer. This variant is formed by cortical fragments arrested during embryologic migration. ACC is also known to be associated with several genetic syndromes and has recently been linked to Lynch syndrome in 3% of cases. We present the case of a 68-year-old male with a confirmed diagnosis of Lynch syndrome secondary to a germline MSH2 mismatch-repair gene-mutation who presented with 2 months history of non-specific abdominal pain. After imaging work-up, the patient was found to have a right upper quadrant, retroperitoneal mass. Biochemical tests were without any evidence of a hormonally active process. Fine needle aspiration of the mass revealed a poorly differentiated carcinoma of unknown etiology. The lesion was resected and found to be consistent with ectopic ACC with an associated MSH2 mutation.
Currently, molecular testing in colorectal cancer (CRC) is aimed at detecting Lynch syndrome and predicting response to anti-epidermal growth factor receptor (EGFR) therapies. However, CRC is a complex disease, with at least 3 molecular pathways of carcinogenesis. The importance of the EGFR signaling pathway in colorectal carcinogenesis is underscored by the availability of anti-EGFR monoclonal antibodies for the treatment of some metastatic CRCs. Potentially, mutations in any of the genes in the EGFR signaling pathway may be associated with prognosis and may predict response to anti-EGFR or other targeted therapies. Although not currently the standard of care, molecular testing of CRCs is expanding to include mutational analysis of the genes in the EGFR pathway, in addition to more widely performed tests for identifying cancers with high microsatellite instability. Multiplex molecular prognostic panels for therapeutic decision making in stage II CRCs also represent expanding use of molecular testing for this common cancer.
Founder mutations are an important cause of Lynch syndrome and facilitate genetic testing in specific ethnic populations. Two putative founder mutations in MSH6 were analyzed in 2685 colorectal cancer (CRC) cases, 337 endometrial cancer (EnCa) cases and 3310 healthy controls of Ashkenazi Jewish (AJ) descent from population-based and hospital-based case–control studies in Israel, Canada and the United States. The carriers were haplotyped and the age of the mutations was estimated. MSH6*c.3984_3987dupGTCA was found in 8/2685 CRC cases, 2/337 EnCa cases, and 1/3310 controls, consistent with a high risk of CRC (odds ratio (OR) = 9.9, 95% confidence interval (CI) = 1.2–78.9, p = 0.0079) and a very high risk of EnCa (OR = 19.6, 95% CI = 1.8–217.2, p = 0.0006). MSH6*c.3959_3962delCAAG was identified in 3/2685 CRC cases, 2/337 EnCa cases and no controls. Each mutation was observed on separate conserved haplotypes. MSH6*c.3984_3987dupGTCA and MSH6*c.3959_3962delCAAG probably arose around 585 CE and 685 CE, respectively. No carriers were identified in Sephardi Jews (450 cases and 490 controls). Truncating mutations MSH6*c.3984_3987dupGTCA and MSH6*c.3959_3962delCAAG cause Lynch syndrome and are founder mutations in Ashkenazi Jews. Together with other AJ founder mutations, they contribute substantially to the incidence of CRC and EnCa and are important tools for the early diagnosis and appropriate management of AJ Lynch syndrome patients.
© 2010 John Wiley & Sons A/S.
The mechanism whereby cyclooxygenase-2 and its prostaglandin (PG) products are involved in colonic carcinogenesis is not fully understood. Prostacyclin (PGI(2)) is a major PG with antiapoptotic activity and is produced in the gastrointestinal tract. We reported previously that a human colorectal cancer (CRC) cell line, HCA-7, produces significant levels of PGE(2), PGD(2), thromboxane, and PGF(2alpha), but not PGI(2). We now report that human colonic fibroblast cell lines produce significant amounts of PGI(2) and that fibroblast lines derived from normal-appearing colonic mucosa of hereditary nonpolyposis CRC individuals produce 50-fold more PGI(2) than normal fibroblast lines derived from individuals with nonhereditary CRC. Coculture of HCA-7 cells with hereditary nonpolyposis CRC fibroblasts, but not normal fibroblasts, markedly reduced butyrate-induced apoptosis of HCA-7 cells. This antiapoptotic effect was inhibited by the cyclooxygenase-2 inhibitor rofecoxib and was restored by the stable PGI(2) analogue carbaprostacyclin. PGI(2) binds either G protein-coupled cell surface PGI(2) receptor or the nuclear peroxisome proliferator-activated receptor (PPAR) delta. PPAR delta likely mediates this antiapoptotic effect because HCA-7 cells express this receptor, and another PPAR delta agonist, docosahexaenoic acid, mimics the effect. We propose a novel mechanism by which stromal production of PGI(2) promotes survival of colonocytes through PPAR delta activation. This mechanism may have relevance to maintenance of cells in the normal crypt and to clonal expansion of mutant colonocytes during tumorigenesis.