CTSL and prostate cancer: After transducing the human Panc-1 tumor cell line with full-length p200 CUX1, we could verify by Western blot analysis that p200 CUX1 is—at least in part—processed into the p110 variant (Figure S6A), most likely via proteolytic cleavage by cathepsin L, as reported before in breast and prostate cancer [32,37,38,39].