Relationship of body mass index with BRAF (V600E) mutation in papillary thyroid cancer.

Current evidences suggest an influence of overweight body mass index (BMI) on the carcinogenesis in malignancies. However, the role of BMI is unclear in papillary thyroid cancer (PTC). The aim of the present study is to investigate the relationship between BMI and BRAF (V600E) mutation status in PTC. BRAF (V600E) mutation in 108 patients with PTC was analyzed by Sanger sequencing. The cutoff point of BMI was identified by X-tile for predicting mutation by overweight. Odds ratios (OR) and 95 % confidence interval (CI) of BRAF (V600E) mutation according to BMI and clinicopathologic variables were calculated using logistic regression models. Fifty-one patients were positive for BRAF (V600E) mutation. A positive relationship existed between BRAF (V600E) mutation and BMI (p = 0.039). A 24.3 kg/m(2) was identified as cutoff point for differentiating greater than 52.0 % observed probability of mutation for BRAF (V600E) in entire cohort, which was similar to the midpoint between the upper limit of normal BMI and overweight defined by WHO (≥24 kg/m(2)). Multivariate analysis confirmed the association between BRAF (V600E) mutation with overweight BMI range (OR 7.645, 95 % CI 1.275-45.831, p = 0.026). This study suggests an influence of overweight BMI on the status of BRAF (V600E) in patients with PTC, whereas the underlying mechanism need to be further investigated.