INFREQUENT SOMATIC MUTATIONS OF THE P16 AND P15 GENES IN HUMAN BLADDER-CANCER - P16 MUTATIONS OCCUR ONLY IN LOW-GRADE AND SUPERFICIAL BLADDER-CANCERS

A recently identified gene, p16, located on chromosome 9p21, has been shown to be deleted and/or mutated in various types of human cancers. To investigate structural alterations of p16 and a neighboring gene, p 15, we examined human bladder cancers for mutations in the entire codi ng region of these genes using polymerase chain reaction and single-st rand conformational polymorphism analysis. Of 50 samples obtained from patients with bladder cancer, 3 (6%), all low-grade and superficial t umors, were found to have p16 gene alterations. The alterations includ ed 1 missense mutation and 2 single-base deletions. We found no p15 ge ne mutations in these 50 bladder cancers. Our results suggested that p 16 gene mutations, although they occurred at low frequency, are involv ed in some low-grade and early stage bladder cancers.