RCAN1 and small cell lung carcinoma: Exploring its mechanism, ATO was found to inhibit the expression of calcineurin, NFAT, and its downstream target genes CXCR7 and Rho family GTPase 1 (RND1), while upregulating the regulator of calcineurin 1 (DSCR1), that is, ATO may inhibit the metastasis of the SCLC by blocking the calcium protein nuclear factor in the activated T cell signaling pathway [116].