SRC‐2 and SRC‐3 (also named AIB1) have been shown to concomitantly promote human adipocyte differentiation by attenuating phospho‐PPARγ S114 and modulating PPARγ cellular heterogeneity.[40] Ablation of AIB1 in mice impairs adipogenesis and enhances energy expenditure.[41] Many reports demonstrate strong HBO1 expression in various human cancers, such as breast cancer and gastric cancer.[42, 43, 44] AIB1 is overexpressed in many cancers and its overexpression correlates with poor survival of patients.[45, 46, 47] AIB1 and HBO1 have distinct roles in the regulation of lipogenic gene expression. This evidence concerns the gene PPARG and breast cancer.