Strikingly, SS was the most sensitive subtype of cancer to knocking down UBE2I (UBC9), SUMO2 (the most widely expressed SUMO in humans (Salas-Lloret and Gonzalez-Prieto, 2022)), PIAS1, SAE1 and UBA2 (SAE2) (Fig. S1A-E), molecules encompassing the entire SUMOylation process (Fig. S1F) and pointing to a selective dependency of SS on this PTM. This evidence concerns the gene PIAS1 and cancer.