Overexpression of the fat mass and obesity associated gene (FTO) in breast cancer and its clinical implications.

Background And Purpose: Incidence of breast cancer is increasing and seems to be associated with fatty foods, metabolism, and so on. The fat mass and obesity associated gene (FTO) has been intensively investigated in diabetes, obesity and the other diseases. Previous studies have reported that FTO SNPs are associated with breast cancer risk. Here, we investigated the expression of FTO in human breast cancer tissues and its relationship with the clinicopathological features.

Methods: In this retrospective study, tissues from 79 patients with breast cancer were collected, as well as 43 cases of adjacent breast tissues. Immunohistochemistry was used to detect the expression of FTO. Statistical analysis was performed to assess the association between FTO expression and the clinicopathological features of breast cancer.

Results: FTO was expressed in both mammary epithelial and breast cancer tissues, but with different degree. The expression level of FTO in breast cancer tissues was significantly higher than that in the adjacent breast tissues (P < 0.001). The percentage of FTO-positive expression in cases with hormone receptor (HR) negative and HER2 amplification was significantly higher than that in those with HR positive and HER2 negative (P = 0.001, P < 0.001). The positivity rate of FTO in breast cancer with P53 positive and histological grade 3 seemed to be higher than that with P53 negative and histological grade 1 or 2, respectively (P = 0.077, P = 0.082). There was no association between FTO expression and age, T stage, LN status, TNM stage, Ki67, and BMI in breast cancer. Besides, FTO expression in HER2-overexpressed subtype was significantly higher than that in Triple-negative and Luminal A/B1 subtypes (P < 0.001).

Conclusion: Our study suggests that FTO expression may have a vital role in the carcinogenesis of breast cancer, especially in HER2-overexpressed breast cancer.