PTPRR and colorectal cancer: Colorectal cancer cell lines that do not express PTPRR were treated with the following agents - alone and in combination: 1) 3-deazaneplanocin A (DZNep), an S-adenosylhomocysteine hydrolase inhibitor that has been shown to selectively inhibit the trimethylation of lysine 27 on histone H3 (H3K27me3) and to reactivate silenced genes in cancer cells [17]; 2) the DNA methyltransferase inhibitor, 5-aza-2' deoxycytidine (5-AzaC); and 3) the histone deacetylase inhibitor, trichostatin A (TSA) (Figure 1E and 1F).