INS and breast cancer: Interestingly, Chi et al. found that high expression of BCAAs in breast tumor tissues can reduce breast cancer N-cadherin’s expression level and thus inhibit tumor metastasis.59 Shafei reported that BCAT1 inhibited the Ras/ERK pathway and activates PI3K/AKT pathway through insulin/IGF-1, ultimately promoting the expression levels of FOXO3a and Nrf2 and regulating the proliferation, migration, and invasion in triple-negative breast cancer (TNBC).55 The above studies imply that breast cancers can be classified into subtypes based on their preference for BCAAs metabolism.