I'd like to start by talking about some of the methods used to identify CDX2 as a prognostic biomarker.
First, In the NCBI GEO repository, CDX2 was one of 16 candidate genes that fulfilled the "X-negative implies ALCAM-positive" Boolean implication. How can Boolean relationships be used to further advance our knowledge of cancer biomarkers? Are there other well-established differentiation markers, like ALCAM, that could be used to further stratify colorectal (or other) tumors?
Second, CDX2 was the only gene (among the 16 candidate genes) that encoded a protein for which a clinical-grade diagnostic test was available. How can the prognostic relevance of the other candidate genes be assessed? Is there value in developing diagnostic tests for the proteins encoded by the other candidate genes?