To investigate the role and the underlying molecular mechanisms of epithelial cell differentiation in the efficacy of CCRT in patients with rectal cancer, we focused on epithelial cell differentiation (GO: 0030855) (Supplementary Table S1) and identified 4 probes covering 2 transcripts: DHRS9 and neurogenin 3 (NEUROG3), associated with CCRT resistance (Table 1; Figure 1). Here, DHRS9 is linked to rectal cancer.