We found that both calcium channels CaV1.2 and CaV1.3 are expressed in breast cancer cell lines, and the knockdown of CaV1.2 and CaV1.3 demonstrated the same effect as lacidipine on the expression of JAK/STAT, NF‐κB signaling pathway‐associated proteins, Pyk2, calmodulin, and IDO. The gene discussed is IDO1; the disease is breast carcinoma.