Cytogenetic studies on peripheral lymphocytes of members from two multiple familial polyposis coli families

Cytogenetic studies were carried out on peripheral lymphocytes of 30 members from two typical familial polyposis coli (FPC) families. It was found that, under low folic acid culture conditions, the chromosome aberration rate of FPC family members (10%) was much higher than that of the control group (2.3%). No significant difference in SCE was found between the two groups. We suggest that the chromosome aberration rate under certain conditions may be used as a parameter for the early detection of FPC in certain FPC families. The analysis of fragile sites sensitive to low folic acid in FPC family members revealed that besides the significant increase of 3p14, which is frequently seen in tumor patients, other unique sites (1p22, 1p32 and 6q21) were also present in most of the FPC patients. Fragile sites 1p22, 1p32 and 6q21 are located near certain well known oncogene loci; thus, they may have something to do with the pathogenesis of FPC. The actual relationship between these fragile sites and FPC remains to be elucidated.