HNF4A and malignant colon neoplasm: More recent studies have shown that PROX1 expression is absent or drastically reduced in biliary system carcinomas 31 but preferentially upregulated in colon cancer 32; moreover, PROX1 is a direct target of the beta-catenin/TCF signaling pathway, which is responsible for neoplastic transformation of the colonic epithelium 10.