CDX2 and infection: Infection with HNF4α alone induced expression of villin, while Cdx2 provoked the expression of K20 and SI. Combined infection with HNF4α and Cdx2 resulted in the induction of villin, K20 and SI. Infection with HNF1α enhanced Cdx2 induced expression of K20 and SI but had a negligible effect on its own.