Allelic Frequencies of HLA-A, HLA-B and HLA-DRB1 Genes in Children with Adrenocortical Tumor who are Carriers of the Germline Mutation R337H in the TP53 Gene

Context: Most children and adolescents with Adrenocortical Tumors (ACT) in Paraná (Brazil) carry the germline mutation R337H in the TP53 gene. However, the mutation alone is not sufficient for the development of the tumor. Close association of the HLA system with certain types of malignancies, such as osteosarcoma, leukemia and Hodgkin´s disease, has been documented and in recent studies, reduced expression of class II HLA complex genes has been shown in adrenocortical carcinomas. Objectives: To evaluate the allelic frequency of the HLA-A, HLA-B and HLA-DRB1 genes in ACT patients with the TP53 R337H mutation and in Caucasian controls. Design: Genomic study. Patients and participants: 39 ACT patients following up regularly at the Pediatric Endocrine Unit of Federal University of Paraná School Hospital and 50,665 controls. Main Outcome Measure: Frequency of allelic variants of the HLA-A, HLA-B and HLA-DRB1 genes. Results: Compared with controls, the allelic variants HLA-A*31, HLA-B*39 and HLA-DRB1*08 were significantly more frequent in patients. Conclusion: These results suggest an association between the HLA system and the development of ACT in children and adolescents with the TP53 gene germline mutation R337H.