DPP4 and breast cancer: In addition, the DPP4 inhibitor sitagliptin suppressed the proliferation, migration, and invasion of BC cells, and cotreatment with MMAE effectively induced cell apoptosis, arrested cells in the G<sub>2</sub>M phase of the cell cycle, increased reactive oxygen species production by inhibiting the AKT pathway, and significantly inhibited the in vivo growth of MMAE-resistant cells.