Evidence for the upregulation of osteogenic protein-1 mRNA expression in musculoskeletal neoplasms

Little is known about bone and cartilage tumors at the molecular level; thus, the identification of genes associated with these tumors may be useful as markers and therapeutic targets. To address this issue and to test the hypothesis that abnormal expression of one or more growth factors in the transforming growth factor-β superfamily is associated with musculoskeletal neoplasia, degenerate primers based on the conserved sequences in these genes were made for screening tumor samples by reverse transcription-polymerase chain reaction. First, these primers were used to obtain a comparative profile between a low-grade chondrosarcoma and its dedifferentiated high-grade counterpart in the same patient. This experiment identified an amplified DNA product in the high-grade sample that was identical to osteogenic protein-1/bone morphogenetic protein-7. Osteogenic protein-1 mRNA expression was 17-fold greater in this high-grade sample than in the low-grade one. Osteogenic protein-1 was highly expressed (three of three) in human osteosarcoma cell lines but was not expressed (zero of four) in normal osteoblast samples. Screening for gene expression of osteogenic protein-1 in 57 osteosarcomas and chondrosarcomas indicated that 44% (range: 38-52%) of them were positive for osteogenic protein-1 mRNA. Screening of breast and prostate tumors revealed a similar association with osteogenic protein-1 mRNA expression.