IQGAP1 and breast cancer: IQGAP2 acts as a tumor suppressor in breast cancer [23], limiting the malignant proliferation and invasive capacity of breast cancer cells by inhibiting the IQGAP1-mediated activation of ERK (extracellular signal-regulated kinase), further attenuating the oncogenic properties of the cells by regulating the MEK-ERK and p38 signaling pathways, thus maintaining the health of breast tissue [24,25,26].