In summary, molecular analysis established that the naïve NPC population (SIX1 + /SIX2 + /WT1 + /ZO-1-) was exhausted by PC35-36 (P4-P5), with MET and nascent nephron formation completed by PC40-41 (~ P10-P11). Here, SIX1 is linked to nasopharyngeal carcinoma.