In addition, we searched for the levels of PRSS3, PAR2, FOSL1, and JUN in the RNA‐seq data of the breast cancer cell lines MCF7‐C3 and MDA‐MB‐231‐C3 (231‐C3).[14, 38] One previous study from our group has revealed the higher metastatic ability of 231‐C3 cells compared with MCF7‐C3 cells.[22] All four genes had higher mRNA levels in 231‐C3 cells, suggesting the positive correlation of these four genes with cancer metastasis (Figure S4B, Supporting Information). This evidence concerns the gene PRSS3 and breast cancer.