Increased constitutional chromosome sensitivity to bleomycin in patients with hereditary non-polyposis colorectal cancer [HNPCC]

It has been suggested that mutagen sensitivity is a constitutional factor which may be useful in identification of patients with an increased risk for the development of tumors. In this study, the chromosome sensitivity to bleomycin was measured according to Hsu in patients with hereditary non-polyposis colorectal cancer (HNPCC), sporadic colorectal cancer and in control persons with no tumor history in family. In vitro lymphocytes were exposed to bleomycin according to Hsu and chromosomal damage was quantified by scoring breaks of 100 cells. A significant difference (P < 0.01) in the mean number of breaks per cell (b/c) was found between HNPCC patients (0.59 ± 0.14; n = 12; mean age 55.4 yrs) and control individuals (0.35 ± 0.13: n = 12; mean age 55.8 yrs). In contrast, patients with sporadic colorectal cancer showed a mean b/c value of 0.43 ± 0.14 (n = 14; mean age 63.4 yrs) which was not significantly higher than that in control individuals for this group (0.42 ± 0.15; n = 14; mean age 63.1 yrs). Selenium protected lymphocytes of HNPCC patients against bleomycin activity in vitro.