HTR1A and colorectal carcinoma: To address this issue, we established HTR1A‐deficient CRC cells and control cells using CRISPR/Cas9 (Figure S5A, Supporting Information) and found that HTR1A knockout did not abolish the inhibitory effect of aripiprazole on HT29 cells (Figure S5B, Supporting Information), suggesting that in addition to HTR1A, there may be other targets involved in the anticancer function of aripiprazole.