Five “classifier genes”, MS4A12, LGR5, CDX2, NOX1 and SLC9A2, contributing to distinguishing normal, adenoma and carcinoma tissue were further validated using in situ hybridisation to determine cellular localisation and distribution patterns of expression in normal, adenomatous polyp and carcinoma tissue (Figure 3–7). This evidence concerns the gene SLC9A2 and carcinoma.