Previous studies showed that PAK1 was innately associated with ERK pathway in various tumors, such as melanoma, breast cancer, malignant peripheral nerve sheath tumors and Non-small cell lung cancer (Ong et al., 2013; Semenova et al., 2017; Kanumuri et al., 2020; Song et al., 2021). Here, MAPK1 is linked to breast cancer.