Evaluation of TP53 Gene Expression in Patients with Childhood Cancer in Northeast Santa Catarina, Brazil

ABSTRACT Introduction In Brazil, 8,000 new cases of childhood cancer are estimated each year, whose causes are still little known, although some have genetically determined factors. Approximately 70% of human cancers have alterations in the TP53 gene, which encodes the protein responsible for inhibiting the disordered growth of cells exposed to injuries. However, the frequency of alterations in the expression of TP53 in childhood cancers in Brazil remains poorly known. Objective To evaluate the expression of TP53 gene in patients with childhood cancer in northeastern of Santa Catarina, Brazil. Materials and Methods: Retrospectively, 282 patients diagnosed with cancer between 2005 and 2015 in Joinville were included. TP53 expression was evaluated by immunohistochemistry using a score based on the intensity and percentage of stained cells. Results The p53 protein was positive in 25.2% of cases, with no difference between sexes. Considering the five main groups of tumors in the sample, the expression was positive in 31.8%, 27.3%, 20%, 17.2% and 5.9% of lymphomas, nephroblastomas, neuroblastomas, tumors of the Central Nervous System and leukemias, respectively. Conclusion The prevalence of TP53 expression was evaluated in different childhood cancers in the northeastern of Santa Catarina. Positivity was higher among lymphomas and lower in leukemias, but with no significant difference among the five most frequent tumors. Further studies that allow correlation with aggressiveness and disease evolution are required.