Evidence suggests that CRIPTO-1 (CR-1) might be involved in the pathogenesis of human carcinoma. In the present study, we have screened the expression of CR-1 mRNA and protein in a wide panel of human cancer cell lines by using reverse transcriptase (RT)-PCR, real-time PCR and immunocytochemistry. Results of these experiments demonstrate that CR-1 is expressed in several, different carcinoma types. The anchorage-independent growth of colon, ovarian, lung and breast carcinoma cells was significantly inhibited by treatment with anti-CR-1 second generation antisense oligonucleotides. Similar results were obtained with anti-transforming growth factor alpha (TGF-alpha) and anti-amphiregulin (AR) antisense oligonucleotides. Treatment of carcinoma cells with CR-1 antisense oligonucleotides resulted in a significant reduction in the levels of expression of CR-1 mRNA and protein, and in the levels of activation of Akt. Finally, oral administration of either CR-1, AR or TGF-alpha antisense oligonucleotides produced a significant reduction in the growth of GEO colon carcinoma xenografts in nude mice that was associated with a reduction in the levels of expression of the target proteins. Taken together, these data strongly suggest that CR-1 might represent a novel target for therapeutic intervention in different carcinoma types.