EPCAM and neoplasm: In a parallel set of experiments for phenotypic epithelial and EMT marker analyses based on EpCAM and Vimentin expression, chemotherapy‐treated cultures yielding sufficient tumor organoids (n ≥ 15, at least 20% of baseline results shown in Table S9) were IF stained and EpCAM and Vimentin marker expression was analyzed (Methods, Supporting Information S1 and Table S9).22, 23