Dr. Salvador Mejia-Guerrero

Post-doctoral fellow

MDM2 characterization in osteosarcoma and parosteal sarcoma

A frequent phenomenon in cancer is the loss of p53, a potent tumor suppressor. Though p53 inactivation is normally the result of mutations or loss of the gene, p53 downregulation could also be playing an important role in its loss of function. On this respect the MDM2 gene is actively involved in the degradation of p53, and our lab and others have determined that MDM2 is frequently amplified in bone cancer. Interestingly, higher levels of MDM2 expression are found in parosteal sarcoma, a relatively benign form of cancer, compared to osteosarcoma, a very aggressive bone tumor. We hypothesize that this gradient of MDM2 expression may be explained by the frequency of gene amplification. Indeed, we have observed a higher frequency of amplification of MDM2 in parosteal sarcomas compared to osteosarcomas. To elucidate the role of MDM2 in cancer progression, we will over-express the gene in different in vitro and in vivo models. These experiments will not only help us understand the MDM2 gene expression gradient, but will also help us identify potential therapeutic targets for bone cancer patients.