TP53 p.R337H prevalence in a series of Brazilian hereditary breast cancer families

Background: Approximately 5-10% of breast cancers are hereditary. Among hereditary syndromes, Hereditary Breast and Ovarian Cancer Syndrome (HBOC) and Li-Fraumeni Syndrome (LFS) have received the most attention. HBOC is due to mutations in the BRCA1 and BRCA2 genes and is characterized by breast adenocarcinoma and/or epithelial ovarian carcinoma. LFS is associated with germline mutations in TP53; the most frequent cancer types associated with this syndrome are sarcoma, breast cancer, leukemia, brain tumors and adrenocortical carcinomas. Other cancers related to LFS are found at lower frequencies. In Brazil, especially in the southern part of the country, a specific mutation in the TP53 gene, TP53 p. R337H, occurs at a high frequency in childhood adrenocortical tumors. It has been proposed that this mutation increases breast cancer risk in southern Brazilian women. Methods: We carried out a case-control study to determine the prevalence of the TP53 p. R337H mutation in 28 female cancer patients attended at the Cancer Genetic Counseling Service of the General Hospital of the University of Sao Paulo Medical School of Ribeirao Preto who fulfilled Hereditary Breast and Ovary Cancer Syndrome genetic test criteria compared to healthy woman (controls). TP53 p. R337H mutation status was determined using the High Resolution Melting (HRM) method, followed by DNA sequencing. Fisher's test was used to compare the prevalence of TP53 p. R337H in the patient and control groups. Results: Two of the breast cancer cases (7.1%) and none of the controls carried the TP53 p. R337H mutation. At the time of the investigation, both cases fulfilled testing criteria for Hereditary Breast and Ovary Cancer Syndrome but not Li- Fraumeni or Li- Fraumeni- like Syndrome, based on genetic testing criteria of NCCN Clinical Practice Guidelines in Oncology (v.1.2010). Conclusions: We suggest that genetic screening of Brazilian breast cancer patients who fulfilled Hereditary Breast and Ovary Cancer Syndrome criteria and have a family history that includes other tumors of the LFS/LFL spectrum be tested for the TP53 p. R337H mutation.