JUN and breast cancer: 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).