FOXP3 Allelic Variants and Haplotype Structures Are Associated with Aggressive Breast Cancer Subtypes.

FOXP3 genetic polymorphisms have been associated with cancer development and prognosis. In this context, the present study aimed to evaluate the g.10403A>G (rs2232365) polymorphisms and g.8048A>C (rs3761548), in aggressive breast cancer (BC) subtypes, including, Luminal B HER2+ (LB), HER2-enriched (HER2+), and triple-negative (TN). Polymerase chain reaction followed by enzymatic restriction was performed to genotyping 117 BC samples and 300 controls. A significant association of AA genotype (g.10403A>G) in relation to BC susceptibility (OR = 1.93; 95% CI = 1.01-3.66; p = 0.046) was observed. The GG (g.10403A>G) genotype was correlated with higher proliferation index (Ki-67) in HER2+ subtype ( τ  = 0.47; p = 0.019) and advanced TNM staging in TN ( τ  = 0.23; p = 0.032). A correlation of AA genotype (g.8048A>C) with higher Ki-67 ( τ  = -0.47; p = 0.018) and lower histological grade ( τ  = 0.39; p = 0.026) in HER2+ was also found. GA haplotype was correlated with lower histological grade ( τ  = -0.15; p = 0.009) and higher Ki-67 ( τ  = 0.43; p = 0.036) in HER2+ and advanced staging in TN ( τ  = 0.29; p = 0.044). On the other hand, AC haplotype was correlated with lower Ki-67 ( τ  = -0.54; p = 0.005) and staging ( τ  = -0.29; p = 0.027) in HER2+ and TN respectively. Results showed that FOXP3 influence regarding clinical outcome depends greatly on the BC subtype and indicated this transcription factor as a promising marker in aggressive BC subtypes.