413P - The state of molecular biological markers in osteosarcoma

Abstract

BackgroundTo study of immunohistochemical markers of proliferation and apoptosis are important prognostic indicators for predicting the clinical course of tumours and the development of therapeutic tactics. MethodsThe p53 suppressor gene, the bcl-2 oncogene and the Ki-67 antigen are responsible for DNA repair, cell division and apoptosis. In all patients, tumour material was obtained using biopsies and operations. In tumour tissue samples fixed by neutral formalin with standard wiring and embedded in paraffin, tumour markers of apoptosis and proliferation were determined - p53, bcl-2, Ki – 67. A positive result was the presence of specific brown staining of the nuclei in the detection of the Ki-67 antigen and the p53 gene suppressor and the cytoplasm in the detection of the expression of bCl-2. ResultsCases where the nucleus or cytoplasm was not stained by reaction with antibodies to p53, Ki-67 and bcl-2 or the number of positive cells was less than 10%, the reaction was considered negative (0). Weak (1+) reaction was considered when staining 10-30% of cells; medium reaction (2+) - when staining 30-50% of cells; strong reaction (3+) - intense staining from 70 or more cells. We carried out a comparative assessment of the effectiveness of treatment of patients depending on the type of therapy and the phenotype of tumour cells. Among patients who received systemic chemotherapy, the full effect was observed in 13% of patients. With negative and weakly positive reactions to the mutant p53 gene and Ki 67 among them was 70.6%, and with moderate and strong expression of bcl-2 (80%). Patients with a phenotype of tumour cells with a negative or weakly positive IHC response to the mutant p53 gene (58.5% of patients), weakly positive expression of Ki 67 (70.6% of patients), and high expression of bcl-2 (46.4 % of patients). In 37.4% of patients from this group, the effect of therapy was negative, most of them had tumour cells with high expression of the mutant p53 and Ki 67 gene, and no expression of bcl-2. ConclusionsIt was established that with positive expression of p53 + Ki-67 + and negative bcl-2 parameters, patients had an unfavourable prognosis. Legal entity responsible for the studyRonc. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.