L-myc polymorphism was investigated in 95 breast cancer (BC), 63 colorectal cancer (CC) and 58 lung cancer (LC) patients, as well as in 122 healthy, middle-aged blood donors (HBDs) and 184 elderly, tumor-free individuals. The occurrence of the S allele in the BC cohort (57%) was significantly higher than that in middle-aged, healthy females (41%) and elderly, non-affected women (47%), implying involvement of the L-myc genotype in BC susceptibility (age-adjusted OR = 1.74, 95% CI 1.11-2.73, p = 0.016). L-myc allele distribution in CC and LC was similar to that in controls. Contrary to earlier reports, L:S allele frequencies ratio in elderly blood donors (EBDs) did not significantly differ from that in HBDs (0.49:0. 51 and 0.54:0.46, respectively). However, the S allele had a tendency to be over-represented among elderly compared with middle-aged smokers (55% vs. 44%; OR = 1.57, 95% CI 0.98-2.50, p = 0. 059), which implies that it may be linked with tolerance to smoking effects.
Copyright 2000 Wiley-Liss, Inc.