Higher Risk Of Colon Cancer Research Articles

Mutagens in the feces of 3 South-African populations at different levels of risk for colon cancer

The incidence of mutagens in the feces of 3 South-African populations at different risk levels for colon cancer has been determined. Lyophilized fecal samples were extracted with ether and the mutagenicity of the extracts determined using the Salmonella/mammalian microsome mutagenicity test. 19% of the samples from urban white South-Africans, a population at a high risk for colon cancer, were mutagenic using Salmonella typhimurium strain TA100. This incidence was significantly greater ( p < 0.001) than the incidence of mutagen excretion in the low-risk populations of urban blacks (2%) and rural black (0%). This pattern was also obtained using Salmonella typhimurium strain TA98. The incidence of mutagen excretion for urban whites was 10%, as compared to 5% and 2% for urban and rural blacks, respectively.

Familial polyposis coli: heterogeneous polyp expression in 2 kindreds.

We describe 2 extended kindreds supposedly manifesting familial multiple adenomatous polyposis coli (FPC), but which show marked heterogeneity in the phenotypic expression of colorectal adenomatous polyps. In one family, 2 individuals had diffuse polyposis at very early ages (7 and 10 years), while 6 others (aged 23 to 72 years) had solitary polyps only. Of the patients with solitary polyps, 2 had associated colonic malignancies (ages 26 and 35), while another had a prophylactic colectomy performed at age 46. In the second family, 5 of the 11 patients with evidence of polyps showed the classical presentation of FPC, while the remainder showed marked phenotypic variation. The marked variability in frequency and location of colon polyps points to the need to reassess our traditional criteria for diagnosis of FPC. The high risk of early onset colon cancer in patients from these families who have the most minimal manifestation, namely isolated polyps, recommends more careful scrutiny of supposedly unaffected members of all FPC kindreds.

The Relationship Between Diet and Rat Fecal Bacterial Enzymes Implicated in Colon Cancer 2 3

We studied the effect of diet on the activities of four enzymes found in the intestinal flora of the male F344 rat. Animals initially fed a diet with high vegetable and grain content were shifted to a diet consisting predominantly of beef. While eating the meat diet, the rats had significantly higher levels of nitroreductase, azoreductase, and beta-glucuronidase in their fecal flora when compared to levels measured during grain feeding. However, beta-glucosidase activity was significantly lower during meat feeding, which probably reflected the lack of beta-glucosidic linkages in this diet. These findings suggested that a high-beef diet, similar in composition to that consumed by humans with a relatively high risk of colon cancer, is associated with elevated levels of specific enzymes in the colon microflora. These enzymes have been implicated in the conversion of procarcinogens into carcinogens.

Fecal long chain fatty acids and colon cancer risk

To determine whether excretion of high concentrations of long chain fatty acids might be associated with high colon cancer risk, we compared concentrations of major long chain fatty acids in the feces of four populations at different risk for colon cancer. Concentrations of C18:1 were found to be significantly higher (P less than 0.05) in the feces of the two high risk populations than in the feces of the two low risk populations.