Consistently, counts of CDKN1A targeting sgRNAs were markedly decreased in CYH33‐treated cells with ratios of .0087 and .3106 in the CRISPR‐SAM‐based screening (Figure S4E), further indicating that overexpression of p21 rendered ESCC cells sensitive to CYH33. The gene discussed is CDKN1A; the disease is esophageal squamous cell carcinoma.