The expression of many genes is altered in colon cancer, but the roles of these genes in carcinogenesis are unclear. Using real-time quantitative PCR, we demonstrated that several genes previously implicated in human colon cancer undergo altered expression in the APC min mouse adenomatous polyp, a precursor of cancer, as well as in normal-appearing surrounding mucosa. The five genes that were most highly up-regulated in mouse polyp were also significantly up-regulated in polyp-free colon mucosa. Similar changes occurred in morphologically normal mucosa of surgical sections taken from human cancer patients, frequently extending to the margins. Thus, morphologically normal colon mucosa in APC min mice and in human cancer patients is not metabolically normal. Altered gene expression in this tissue does not appear to result from a field effect because there was no correlation between extent of altered regulation and distance from polyp or tumor. Our data suggest that alterations of expression levels of these genes may be an early event in carcinogenesis and a marker of risk for the development of colon cancer.
Anal gland adenocarcinoma is rare, with information concerning this lesion communicated mostly as case reports. Cases seen by authors, combined with a survey of the membership of The American Society of Colon and Rectal Surgeons, allowed 52 cases with sufficient data for analysis. It became clear from the survey that most colorectal surgeons have not treated this malignancy. Predominant symptoms are anal pain (58 percent), rectal bleeding (40 percent), and the presence of perianal mass (37 percent). Fifty-four percent of patients present with a fistula, the incidence of fistula being significantly higher in males. Metastases, which may be inguinal, pelvic, or hepatic, are present at diagnosis in 13.5 percent of patients. Three-fourths of patients are eventually treated by abdomino-perineal resection (APR). Twelve percent of the patients in this series had an APR after a failed local excision. The conclusions from this study are: 1) if local excision is attempted, it must be complete, and the patient must be followed closely for many years, and 2) APR is needed in most patients for local control, with the role of subsequent radiation therapy and/or chemotherapy not yet defined.
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