Chromosomal abnormalities in patients with familial polyposis and colorectal cancer.

A search for chromosomal (cytogenetic, karyotypic) changes with specificity for familial polyposis coli (FPC) and related conditions has not been successful. The cytogenetic anomalies described to date (chromosomal instability, tetraploidy, structural anomalies) are not only nonspecific and inconsistent but may also be seen in other congenital conditions predisposing to cancer of various organs. However, this does not mean that some (eg, tetraploidy) of the changes cannot be used as indices in the study and evaluation of affected individuals and their family members. Future application of DNA probes may be more successful in establishing genetic anomalies unique to FPC and related disorders.