Based on the hypothesis that three main cytogenetic subtypes of salivary gland pleomorphic adenomas can be distinguished which may also represent different etiologic entities, we investigated whether these subtypes correspond to clinical, histologic, or biologic features of 220 tumors karyotyped (including 117 tumors with detailed clinical history and histologic subtyping). The following results were obtained. As compared with the group of patients showing salivary gland pleomorphic adenomas with an apparently normal karyotype, the patients in the "8q12-group" were significantly younger (51.1 years versus 39.3 years, p < 0.001). The distribution of histologic subtypes also showed highly significant differences between the groups. Whereas the breakpoint in the 8q12 group was always mapped to a single band, no exact localization of the breakpoint in the group of tumors showing chromosome number 12 abnormalities was possible. In most cases, however, the breakpoints were clustered to 12q15. Finally, all tumors with 8q12 breakpoints showed a characteristic in vitro cellular morphology which was also observed in a few tumors with an apparently normal karyotype but in none of the tumors with the 12q13-15 breakpoint.