Four cells out of 74 expressed GC-specific genes (namely MUC5AC, MUC5B and TFF3), together with MCC-specific genes (FOXJ1), and more specifically, immature MCC genes (PLK4, MYB and CDC20B) (Revinski et al., 2018) (Fig. S7A,B). The gene discussed is TFF3; the disease is Merkel cell skin cancer.