CTBP1 and neoplasm: To determine if 4-Cl-HIPP could similarly inhibit human TIC populations in cancer cells, and mirror effects of CtBP2 deficiency, we utilized human colorectal cancer cell lines that form tumor spheroids (tumorspheres) that are enriched for TIC’s [19] to assay the effect of CtBP inhibition or CtBP2 genetic depletion.