SPDEF and lung carcinoma: Though VTCN1 was more correlated with mucous gene markers than PD‐L1 (Fig 3C), VTCN1 was not regulated by the transcription factor SPDEF, FOXA3, or NKX2‐1 in A549 lung carcinoma cells (Dataset EV7; Maeda et al, 2012; of note, A549 cells do not express endogenous VTCN1).