Investigation of BRAF and CTNNB1 activating mutations in adrenocortical tumors

BACKGROUND: Activating mutations of the BRAF oncogene play a central role in the development of various cancer types, but their role in human adrenocortical tumors is unknown. At variance, activating mutations of another oncogene, CTNNB1, which encodes beta-catenin, have been shown to be common events in both benign and malignant adrenocortical tumors. AIM: To investigate the prevalence of BRAF and CTNNB1 activating mutations in sporadic adrenocortical tumors. MATERIALS AND METHODS: Tissue samples from 15 adrenocortical carcinomas and 41 adrenocortical adenomas were investigated for the presence of BRAF and CTNNB1 activating mutations by PCR amplification and direct sequencing. RESULTS: An advanced invasive non-functioning adrenocortical carcinoma carried a somatic heterozygous BRAF V600E mutation, while 4 functioning and 4 non-functioning adenomas and 3 functioning carcinomas carried different CTNNB1 activating mutations. CONCLUSIONS: Activating BRAF somatic mutations may be occasionally found in advanced adrenocortical carcinomas, while CTNNB1 activating mutations are early and common events in adrenal tumorigenesis.