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      Aspirin use, tumor PIK3CA mutation, and colorectal-cancer survival.

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          Abstract

          Regular use of aspirin after a diagnosis of colon cancer has been associated with a superior clinical outcome. Experimental evidence suggests that inhibition of prostaglandin-endoperoxide synthase 2 (PTGS2) (also known as cyclooxygenase-2) by aspirin down-regulates phosphatidylinositol 3-kinase (PI3K) signaling activity. We hypothesized that the effect of aspirin on survival and prognosis in patients with cancers characterized by mutated PIK3CA (the phosphatidylinositol-4,5-bisphosphonate 3-kinase, catalytic subunit alpha polypeptide gene) might differ from the effect among those with wild-type PIK3CA cancers.

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          Most cited references31

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          CpG island methylator phenotype underlies sporadic microsatellite instability and is tightly associated with BRAF mutation in colorectal cancer.

          Aberrant DNA methylation of CpG islands has been widely observed in human colorectal tumors and is associated with gene silencing when it occurs in promoter areas. A subset of colorectal tumors has an exceptionally high frequency of methylation of some CpG islands, leading to the suggestion of a distinct trait referred to as 'CpG island methylator phenotype', or 'CIMP'. However, the existence of CIMP has been challenged. To resolve this continuing controversy, we conducted a systematic, stepwise screen of 195 CpG island methylation markers using MethyLight technology, involving 295 primary human colorectal tumors and 16,785 separate quantitative analyses. We found that CIMP-positive (CIMP+) tumors convincingly represent a distinct subset, encompassing almost all cases of tumors with BRAF mutation (odds ratio = 203). Sporadic cases of mismatch repair deficiency occur almost exclusively as a consequence of CIMP-associated methylation of MLH1 . We propose a robust new marker panel to classify CIMP+ tumors.
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            A randomized trial of aspirin to prevent colorectal adenomas.

            Laboratory and epidemiologic data suggest that aspirin has an antineoplastic effect in the large bowel. We performed a randomized, double-blind trial of aspirin as a chemopreventive agent against colorectal adenomas. We randomly assigned 1121 patients with a recent history of histologically documented adenomas to receive placebo (372 patients), 81 mg of aspirin (377 patients), or 325 mg of aspirin (372 patients) daily. According to the protocol, follow-up colonoscopy was to be performed approximately three years after the qualifying endoscopy. We compared the groups with respect to the risk of one or more neoplasms (adenomas or colorectal cancer) at least one year after randomization using generalized linear models to compute risk ratios and 95 percent confidence intervals. Reported adherence to study medications and avoidance of nonsteroidal antiinflammatory drugs were excellent. Follow-up colonoscopy was performed at least one year after randomization in 1084 patients (97 percent). The incidence of one or more adenomas was 47 percent in the placebo group, 38 percent in the group given 81 mg of aspirin per day, and 45 percent in the group given 325 mg of aspirin per day (global P=0.04). Unadjusted relative risks of any adenoma (as compared with the placebo group) were 0.81 in the 81-mg group (95 percent confidence interval, 0.69 to 0.96) and 0.96 in the 325-mg group (95 percent confidence interval, 0.81 to 1.13). For advanced neoplasms (adenomas measuring at least 1 cm in diameter or with tubulovillous or villous features, severe dysplasia, or invasive cancer), the respective relative risks were 0.59 (95 percent confidence interval, 0.38 to 0.92) and 0.83 (95 percent confidence interval, 0.55 to 1.23). Low-dose aspirin has a moderate chemopreventive effect on adenomas in the large bowel. Copyright 2003 Massachusetts Medical Society
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              CpG island methylator phenotype, microsatellite instability, BRAF mutation and clinical outcome in colon cancer.

              The CpG island methylator phenotype (CIMP), characterised by widespread promoter methylation, is associated with microsatellite instability (MSI) and BRAF mutation in colorectal cancer. The independent effect of CIMP, MSI and BRAF mutation on prognosis remains uncertain. Utilising 649 colon cancers (stage I-IV) in two independent cohort studies, we quantified DNA methylation in eight CIMP-specific promoters (CACNA1G, CDKN2A (p16), CRABP1, IGF2, MLH1, NEUROG1, RUNX3 and SOCS1) as well as CHFR, HIC1, IGFBP3, MGMT, MINT1, MINT31, p14, and WRN by using MethyLight technology. We examined MSI, KRAS and BRAF status. Cox proportional hazard models computed hazard ratios (HRs) for colon cancer-specific and overall mortalities, adjusting for patient characteristics and tumoral molecular features. After adjustment for other predictors of patient survival, patients with CIMP-high cancers (126 (19%) tumours with >or=6/8 methylated CIMP-specific promoters) experienced a significantly low colon cancer-specific mortality (multivariate HR 0.44, 95% confidence interval (CI) 0.22 to 0.88), whereas the BRAF mutation was significantly associated with a high cancer-specific mortality (multivariate HR 1.97, 95% CI 1.13 to 3.42). A trend toward a low cancer-specific mortality was observed for MSI-high tumours (multivariate HR 0.70, 95% CI 0.36 to 1.37). In stratified analyses, CIMP-high tumours were associated with a significant reduction in colon cancer-specific mortality, regardless of both MSI and BRAF status. The relation between CIMP-high and lower mortality appeared to be consistent across all stages. KRAS mutation was unrelated to prognostic significance. CIMP-high appears to be an independent predictor of a low colon cancer-specific mortality, while BRAF mutation is associated with a high colon cancer-specific mortality.
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                Author and article information

                Journal
                N. Engl. J. Med.
                The New England journal of medicine
                New England Journal of Medicine (NEJM/MMS)
                1533-4406
                0028-4793
                Oct 25 2012
                : 367
                : 17
                Affiliations
                [1 ] Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02215, USA.
                Article
                NIHMS422936
                10.1056/NEJMoa1207756
                3532946
                23094721
                06b7389b-6731-4312-aee5-b7dc5c9a0b9d
                History

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