Mutation spectrum of p53 gene in highly malignant human osteosarcomas. In this study, we analyzed the spectrum of p53 tumor suppressor gene mutations in 40 highly malignant osteosarcomas, one osteosarcoma metastasis, and one osteoblastoma with malignant transformation. Using predominantly formalin-fixed and paraffin-embedded material, we performed polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis of exons 4-8 and direct sequencing. Molecular genetic findings were correlated with immunohistochemical detection of p53 protein. A total of eight alterations (19%) were identified. Two splice mutations were detected in one case of a highly malignant osteosarcoma and its metastasis, and in one osteoblastoma with focal malignant transformation. Four of the mutations were missense mutations, one was of the silent type. These data correspond to the results found in the literature on bone and soft tissue tumors. Therefore, retrospective studies of p53 gene turn out to be quite appropriate for molecular biologic examinations.