OLFM4 and neoplasm: In one early GC sample, we observed that the expression levels of immature intestinal cell markers (OLFM4, DMBT1, and CPS1) along with CDX1 and HKDC1, were significantly higher in a region containing poorly differentiated tumor glands compared to an area with well-differentiated tumor glands, which prominently expressed TFF3 (Supplementary Fig. 11).