MAPK3 and breast cancer: PNPLA8 correlation analysis based on the TCGA breast cancer data set showed that PNPLA8 was positively correlated with mitogen-activated protein kinase kinase kinase 2 (MAP3K2), mitogen-activated protein kinase kinase kinase kinase 3 (MAP4K3) and Phosphatidylinositol-4-Phosphate 3-Kinase Catalytic Subunit Type 2 Alpha (PIK3C2A), the key molecules of the MAPK and PI3K pathways (Fig. 8B) which are frequently activated in human cancers and are interconnected predominantly by sharing upstream receptors and joint downstream targets [39].