PLPP4 and cancer: We first analyzed the expression levels of LPPs proteins, including PLPP1-7, in the high throughput paired cancers’ RNA expression profile datasets from TCGA and found that the expression levels of PLPP1, PLPP2, PLPP3, PLPP5, PLPP6, and PLPP7 were expressed in both cancer tissues and normal tissues, except PLPP4 (Figure 1A).