To assess whether endogenous ERCC2 protein expression levels might account for the metastatic cell line SW620 being more sensitive to PROTACs than the SW480 parental counterpart (Figure 5B), we immunoblotted for ERCC2 in a panel of colon cancer and normal colonic epithelial cell lines (Figure S4). Here, ERCC2 is linked to malignant colon neoplasm.