Increased chromosome-type chromosome aberration frequencies as biomarkers of cancer risk in a blackfoot endemic area

To examine whether biomarkers such as sister chromatid exchanges (SCEs) and chromosome aberrations (CAs) can predict cancer development, a nested case -control study was performed in a blackfoot endemic area with a known high cancer risk, A cohort of 686 residents was recruited from three villages in the blackfoot endemic area. Personal characteristics were collected, and v enous blood was drawn for lymphocyte culture and stored in a refrigerator. The vital status and cancer development were followed using the National De ath Registry, Cancer Registry, and Blackfoot Disease Registry. The follow-u p period was from August 1991 to July 1995, During this 4-year period, 31 r esidents developed various types of cancer. Blood culture samples from nine of these subjects were unsuitable for experiments due to improper storage. Finally, a total of 22 cancer cases had cytogenetic samples that could be analyzed. Twenty-two control subjects were selected from those who did not develop cancer in the study period, and these subjects were matched to case s by set, age, smoking habits, and residential area. The results showed tha t there was no significant difference in the frequencies of SCE and chromat id-type CAs between the case and control groups. How-ever, the frequencies of chromosome-type CAs, e.g., chromosome-type gaps, chromosome-type breaks, chromosome-type breaks plus exchanges, total chromosome-type aberrations, and total frequencies of CAs in the case group, were significantly higher t han those in the control group (P < 0.05), The odds ratio of cancer risk in subjects with more than zero chromosome-type breaks was 5.0 (95% confidenc e interval = 1.09-22.82) compared to those with zero chromosomal breaks. Th e odds ratios for more than zero chromosome-type breaks plus exchanges and a frequency of total chromosome-type aberrations of >1.007% were 11.0 and 1 2.0, respectively (P < 0.05, Subjects with a total Ch frequency of >4.023% had a 9-fold increase for cancer risk. These results indicate that chromoso me-type CAs are good biomarkers for the prediction of cancer development, w hereas SCEs and chromatid-type CAs cannot predict cancer risk.