Amplification and protein expression of chromosome 12q13-15 genes in osteosarcomas of the jaws

• Published in: Oral oncology 2001-10, Vol.37 (7), p.566-571
• Main Authors: Lopes, M.A., Nikitakis, N.G., Ord, R.A., Sauk, J.
• Format: Article
• Language: English
• Subjects: Adult; Agglutinins - genetics; Agglutinins - metabolism; Biological and medical sciences; Biomarkers, Tumor - genetics; Biomarkers, Tumor - metabolism; Biotechnology; CDK4; chromosome 13; Chromosomes, Human, Pair 12; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinases - genetics; Cyclin-Dependent Kinases - metabolism; Facial bones, jaws, teeth, parodontium: diseases, semeiology; Female; Follow-Up Studies; Fundamental and applied biological sciences. Psychology; Gene Amplification; Genetic engineering; Genetic technics; Glycoproteins - genetics; Glycoproteins - metabolism; Humans; Immunoenzyme Techniques; Immunohistochemistry; In vitro gene amplification. Pcr technique; Jaw; Jaw Neoplasms - genetics; Jaw Neoplasms - metabolism; Jaw Neoplasms - pathology; Male; MDM2; MDM2 protein; Medical sciences; Methods. Procedures. Technologies; Middle Aged; Neoplasm Proteins - genetics; Neoplasm Proteins - metabolism; Nuclear Proteins; Osteosarcoma; Osteosarcoma - genetics; Osteosarcoma - metabolism; Osteosarcoma - pathology; Otorhinolaryngology. Stomatology; Polymerase Chain Reaction - methods; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins - metabolism; Proto-Oncogene Proteins c-mdm2; Real-time PCR; SAS; SAS protein; Tumors
• ISSN: 1368-8375; 1879-0593
• DOI: 10.1016/S1368-8375(00)00130-5

Overexpression and amplification of several genes (MDM2, CDK4 and SAS) located on chromosome 12q13-15 have been noted to occur in various human sarcomas. As a result, two major growth regulation pathways may be inhibited. MDM2 may down regulate the p53-mediated growth control and CDK4 may affect pRB-mediated events. To determine the frequency of alterations in these genes and their correlation with clinicopathologic features, we analyzed the MDM2 and CDK4 protein levels by immunohistochemistry and assessed MDM2, CDK4 and SAS amplification by real-time PCR in nine osteosarcomas of the jaws. Positive staining for CDK4 and MDM2 was observed in eight cases (88.8%) and five cases (55.5%), respectively. Intense CDK4 staining was noted in four cases (two high grade, one intermediate grade and one low grade). Intense MDM2 staining was observed in the same four previous cases, as well as, one additional high-grade tumor. Individual DNA amplification for CDK4, MDM2 and SAS was observed in six cases for each gene. Co-amplification was observed in five cases that showed CDK4 and MDM2 concomitant amplification and four cases that displayed amplification for all of the genes. In addition, among the five cases that presented CDK4 and MDM2 amplification, strong overexpression of CDK4 and MDM2 was observed in three and in four cases, respectively (three high grade and one intermediate grade). These results suggest that 12q13-15 genes are involved in neoplastic disease and concurrent amplification and overexpression of these genes might help to define high-grade tumors.