NONRANDOM CHROMOSOMAL-ABNORMALITIES IN LYMPHOCYTE-CULTURES OF INDIVIDUALS WITH COLORECTAL POLYPS AND OF ASYMPTOMATIC RELATIVES OF PATIENTS WITH COLORECTAL-CANCER OR POLYPS

We studied chromosomal alterations in the peripheral blood lymphocytes of 10 individuals with colorectal polyps and 10 asymptomatic first-de gree relatives of patients with colon cancer or colorectal polyps. The analysis was performed on T-lymphocytes using short term blood cultur es and on B-lymphocytes by establishing lymphoblastoid cell lines by E pstein-Barr virus transformation. Chromosomal changes were not common in T- and B-lymphocytes. Chromosomes 1 and 5 were most frequently invo lved in numerical or structural changes in the patients with polyps as well as in the asymptomatic relatives. These alterations were observe d in either the T-lymphocytes or the B-lymphocytes but rarely in both, thus accentuating the importance of studying both the cultures concur rently. Chromosome 5, which is known to play an important role in the development of adenomatous polyps, was found to be involved in 6 (60%) of 10 patients with polyps and 4 (40%) of 10 asymptomatic relatives. These findings show that lymphocytic chromosomal analysis can aid in i dentifying individuals who are genetically susceptible and are at a hi gher risk of developing colorectal cancer. Because lymphocytic chromos omal analysis is relatively simple and inexpensive, we expect that it will be very useful in screening asymptomatic individuals who are at a higher risk due to inherited or environmental factors.