Thus, when colon carcinoma cell lines carrying tetracycline-inducible constructs coding for dominant negative versions of TCF1 or TCF4 were subjected to tetracycline treatment, significant downregulation of TCF targets expressed in colon carcinomas were observed, but hTERT transcript levels were similar to levels in tumors lacking the dominant negative constructs. The gene discussed is TCF4; the disease is colon carcinoma.