ASS1 and colorectal carcinoma: In order to verify if ASS1 upregulation upon arginine deprivation is hampered in CRC cells with a CpG methylator phenotype, the genetically most divergent ASS1 low/non-expressor cell lines HCT-116 and HT29, which reflect the two major pathways of CRC carcinogenesis, were chosen for further analyses (Supplementary Table S1).