Extended Data Fig. 1: Antibody panel validation.

a, Immunofluorescence images of a PAX8 positive KAFO displaying dim signal for NKX2-1. b, Immunofluorescence images of CDX2 staining on SiAFO, LAFO and KAFO. c, Immunofluorescence images of CDX2 staining on control fetal tissue-derived small intestinal (FSiO), lung (FLO) and kidney (FKO) organoids. d, Immunofluorescence images of NKX2-1/PAX8 co-staining on FLO, FKO, FSiO and SiAFO. e, Example of non-specific extracellular/cytoplasmic NKX2-1 or PAX8 signal in SiAFO (SiAFO_2, SiAFO_3). All scale bars, 50 µm.