Fragile sites and genitourinary tumors.

We tested for fragile sites in lymphocytes from nine patients with genitourinary tumors to determine if a correlation existed between their cancer chromosome breakpoints and fragile sites. Induction was done for rare fragile sites in all known classes by exposure of cells to fluorodeoxyuridine and bromodeoxyuridine (BrdU). No rare fragile sites were found. Induction was also done for common fragile sites in all known classes using aphidicolin (Apc), 5-azacytidine, and BrdU. Although 56 common fragile sites were detected, only a single site corresponded in location to a genitourinary tumor chromosome breakpoint. That was the common fragile site in band 3p14. No overall correlation was found between fragile sites and chromosome rearrangements in carcinoma of the kidney, ureter, bladder, and testis. The sole known candidate for a possible biologic role is the 3p14 common fragile site in renal cell carcinoma.