Variation in the expression of aphidicolin-induced fragile sites in human lymphocyte cultures.

A correlation between specific fragile sites and cancer breakpoints has been suggested raising the question of fragile site expression as a predisposing factor in the occurrence of cancer in some persons. Before addressing the question of increased fragility among patients at high risk for cancer, we analyzed the variability of aphidicolin-induced fragile sites among nine normal persons and also among repeated samples from three of these individuals. Considerable variation in both the frequency and location of these fragile sites was observed and the data strongly suggest the significant variation of 6 of the 16 selected sites to be primarily due to sampling differences. These findings indicate that the use of fragile sites as a screening tool for patients at high risk of cancer should be carefully monitored relative to the variation inherent in both culture and individual expression.