PIWIL1 and neoplasm: Interestingly, a recent genome-wide CRISPR–Cas9 loss-of-function genetic screening, prompted by the Achilles project of the Broad Institute to create a catalog of genes essential for cell survival [36], showed that PIWIL1 knockout has an effect on survival in 55 cell lines from different tumor types, including CRC (Supplementary Table S2).