CDH17 and cancer: The reason for the difference between primary (+)/LN (−) specimens and primary (−)/LN (+) specimens is unclear, although there are several potential explanations: (1) CDH17 expression in cancer cells may change after metastasis, (2) some specimens may not contain CDH17-positive regions due to tumor heterogeneity, and (3) metastasized tumor cells may be CDH17-negative due to the tumor heterogeneity and branched evolution [20].