p53 Tumor Suppressor Protein and H-RAS Oncogene in Maxillofacial Tumors: Immunohistochemical and Genetic Investigation, Induction Chemotherapy Response and Prognosis Evaluation

AbstractThe authors carried out immunohistochemical and genetic research on the tumor suppressor protein p53 and H-RAS oncogene in oromaxillofacial neoplasms. The purpose was to verify, genetically, the presence of correlations between the degree of histopathological overexpression (per cent) of oncogenes and chemoresistance. The study was carried out on 15 patients with squamous cell carcinoma of the oromaxillofacial region, of equal histopathological grade (G2), who underwent neoadjuvant chemotherapy: cis-diaminodichloroplatinum (CDDP, 20 mg/m2 i.v. days 1-5) and 5-fluorouracil (5-FU 1000 mg/m2 continuous infusion, volumetric pump 2 ml/h, for 5 days). Restaging was carried out after three cycles of chemotherapy to evaluate clinical response. The p53 immunohistochemical study (clone DO-7) showed a pathological overexpression in 9/15 cases; whereas the genetic exam (PCR method, wild DNA) showed mutations in 5/15 cases, with individual corresponding percentages of 95%, 80%, 70%, 45% and 95%. The H-RAS immu...