Molecular cytogenetic alterations associated with rapid tumor cell proliferation in advanced urinary bladder cancer

Invasive urinary bladder carcinomas are characterized by a high number of c ytogenetic alterations which are thought to pinpoint the location of critic al genes, some of which may be involved in cell cycle control. To identify genomic alterations that may affect such genes the proliferative activity ( Ki67 labeling index) was assessed in 93 invasively growing bladder carcinom as analyzed by comparative genomic hybridization. Only a few changes were s ignificantly associated with rapid tumor cell proliferation, including 3p(p=0.0357), 6p+ (p=0.003), 8q+ (p=0.0273), and 11q- (p=0.0329). Among these alterations 6p+ is of particular interest because high level 6p22 amplific ations occur frequently in bladder cancel. The particular strong associatio n between 6p+ and a high tumor cell proliferation being independent of grad e and stage suggests that a putative oncogene on 6p22 involved in cell cycl e regulation.