CASQ1 and neoplasm: Indeed, several downstream targets of MEF2 involved in muscle structure and function were among the top FoxP1 target genes repressed in response to tumour burden (Data S2), including Casq1, Casq2, Lmod3, Ky, and Mef2c (Figure9F)—suggesting that FoxP1 up‐regulation disrupts MEF2 transcriptional activity.