Association Between Obesity and BRAFV600E Mutation Status in Patients with Papillary Thyroid Cancer.

Background: The prevalence of papillary thyroid cancer (PTC) is thought to be related to obesity, which affects the prognosis for PTC patients. However, the mechanisms implicated in the relationship between obesity and PTC is a matter for debate. In this study, we aimed to gain insight into the relationship between obesity and the clinicopathological features of PTC, including the BRAFV600E mutation.
Methods: The medical records of 1121 PTC patients were reviewed and the relationships between anthropometric factors, biochemical parameters, and clinicopathological parameters, including BRAFV600E mutation status, were analyzed.
Results: Body mass index (BMI) showed a strong association with advanced TNM stage (p < 0.001) and BRAFV600E mutation status (p = 0.008). We also found that BRAFV600E (+) patients had a higher body weight (p = 0.024) and a higher BMI (p = 0.003) than patients with BRAFV600E (-) PTC. In addition, BRAFV600E (+) PTC patients had a significantly higher incidence of extrathyroidal extension (p = 0.025) and more advanced T, N, TNM stage (p < 0.001) than BRAFV600E (-) PTC patients. Consistent with this observation, female BRAFV600E (+) PTC patients had a higher BMI (p = 0.011) and more aggressive tumor behaviors than female BRAFV600E (-) PTC patients. In multivariate analysis, BMI was persistently associated with BRAFV600E mutation in the entire cohort (odds ratio [OR] 1.387; 95 % CI 1.036-1.859; p = 0.028) and in the female subcohort (OR 1.221; 95 % CI 1.014-1.631; p = 0.046).
Conclusion: The positive association between BMI and BRAFV600E supports the hypothesis that excessive bodyweight influences tumor progression.