Similar to the corresponding epithelial cells in vivo, the tumor tissue-derived organoid cells in the conditioned medium showed high expression of stem/progenitor cell marker OLFM4 and low expression of differentiation marker CA2, while normal tissue-derived organoid cells showed low expression of OLFM4 and high expression of CA2. However, tumor tissue-derived organoid cells and normal tissue-derived organoid cells cultured in a chemical-defined medium have similar expression patterns of CA2 and OLFM4, which cannot accurately mimic the expression patterns of the corresponding cells in vivo. This evidence concerns the gene OLFM4 and neoplasm.