ITPKA and gastric cancer: Phosphatidylinositol signaling system network (Fig. 4c) included inositol trisphosphate receptors and kinases (ITPR2, ITPR3, and ITPKA) and their downstream signaling molecules (CAML5, PRKCA, and PRKCB), which belonged to the DEPs and DPPs, indicating that their abundances and phosphorylation levels both were collectively altered in gastric cancers.