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"description": "Colorectal cancer (CRC) is the second largest cause of cancer-related deaths in Western countries. CRC arises from the colorectal epithelium as a result of the accumulation of genetic alterations in defined oncogenes and tumour suppressor genes (TSG). Two major mechanisms of genomic instability have been identified in sporadic CRC progression. The first, known as chromosomal instability (CIN), results from a series of genetic changes that involve the activation of oncogenes such as K-ras and inactivation of TSG such as p53, DCC/Smad4, and APC. The second, known as microsatellite instability (MSI), results from inactivation of the DNA mismatch repair genes MLH1 and/or MSH2 by hypermethylation of their promoter, and secondary mutation of genes with coding microsatellites, such as transforming growth factor receptor II (TGF-RII) and BAX. Hereditary syndromes have germline mutations in specific genes (mutation in the tumour suppressor gene APC on chromosome 5q in FAP, mutated DNA mismatch repair genes in HNPCC)." |
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"text": "CONTEXT:\nDiabetes is a serious and costly disease that is becoming increasingly common in many countries. The role of diabetes as a cancer risk factor remains unclear.\n\nOBJECTIVE:\nTo examine the relationship between fasting serum glucose and diabetes and risk of all cancers and specific cancers in men and women in Korea.\n\nDESIGN, SETTING, AND PARTICIPANTS:\nTen-year prospective cohort study of 1,298,385 Koreans (829,770 men and 468,615 women) aged 30 to 95 years who received health insurance from the National Health Insurance Corp and had a biennial medical evaluation in 1992-1995 (with follow-up for up to 10 years).\n\nMAIN OUTCOME MEASURES:\nDeath from cancer and registry-documented incident cancer or hospital admission for cancer.\n\nRESULTS:\nDuring the 10 years of follow-up, there were 20,566 cancer deaths in men and 5907 cancer deaths in women. Using Cox proportional hazards models and controlling for smoking and alcohol use, the stratum with the highest fasting serum glucose (\u003e or =140 mg/dL [\u003e or =7.8 mmol/L]) had higher death rates from all cancers combined (hazard ratio [HR], 1.29; 95% confidence interval [CI], 1.22-1.37 in men and HR, 1.23; 95% CI, 1.09-1.39 in women) compared with the stratum with the lowest level (\u003c90 mg/dL [\u003c5.0 mmol/L]). By cancer site, the association was strongest for pancreatic cancer, comparing the highest and lowest strata in men (HR, 1.91; 95% CI, 1.52-2.41) and in women (HR, 2.05; 95% CI, 1.43-2.93). Significant associations were also found for cancers of the esophagus, liver, and colon/rectum in men and of the liver and cervix in women, and there were significant trends with glucose level for cancers of the esophagus, colon/rectum, liver, pancreas, and bile duct in men and of the liver and pancreas in women. Of the 26,473 total cancer deaths in men and women, 848 were estimated as attributable to having a fasting serum glucose level of less than 90 mg/dL. For cancer incidence, the general patterns reflected those found for mortality. For persons with a diagnosis of diabetes or a fasting serum glucose level greater than 125 mg/dL (6.9 mmol/L), risks for cancer incidence and mortality were generally elevated compared with those without diabetes.\n\nCONCLUSION:\nIn Korea, elevated fasting serum glucose levels and a diagnosis of diabetes are independent risk factors for several major cancers, and the risk tends to increase with an increased level of fasting serum glucose." |
