SIX2 and neoplasm: The presence of NP and the expression of SIX2 or CITED1 in WT tumor cells has been confirmed[12, 13, 14, 15] but unlike previous studies of human WT NP/CSC in which limited subtypes of WT were examined,[70] or analysis was performed in chemotherapy‐treated samples,[70, 71] or focused only on SIX2+ committed NP,[13] our study incorporated several unique design features.