The causative relationship between induction of Wnt activity and apoptosis was analyzed in NaB-treated CRC cells expressing dominant negative Tcf4 (DN-Tcf4), an amino terminally truncated form of Tcf4, which does not bind beta-catenin and which inhibits the activity of endogenous BCT complexes. The gene discussed is PCYT1B; the disease is colorectal carcinoma.