To identify genes whose absence increases the sensitivity of bladder cells to erdafitinib, we performed genome‐wide CRISPR/Cas9 knockout library screen on MGH‐U3 (Y373C mutation) and SW780 (FGFR3‐BAIAP2L1 fusion) bladder cancer cell lines, both known to be FGFR3‐dependent[23, 24] (Figure1A). Here, BAIAP2L1 is linked to urinary bladder cancer.