Rectal epithelial proliferation characteristics of first degree relatives of sporadic colon cancer patients.

Hyperproliferation of rectal epithelium is characteristic of families at high genetic risk for large bowel neoplasia, but has not been well-documented in families of sporadic colorectal cancer patients. This was studied in 119 such first degree relatives and 44 comparison subjects without this family history. All screened negative for large bowel neoplasia. Within the family group proliferation was significantly higher in the men and those aged less than 45 years, also higher (insignificantly) in non-Europeans and those having greater than 1 first degree colorectal cancer relative. In comparison to the nonfamily group the labelling index (LI) of the relatives showed a significant negative correlation with age (R = -0.20, P = 0.03). Within this family group the probability of having an elevated LI (greater than 6.0%) was greatest in the young (less than 50 years old) men (odds ratio = 2.0). Measurements of rectal epithelial proliferation (REP) in these first degree relatives, at a young age, might help delineate a high risk subgroup for prospective primary and secondary intervention.