NKX2-1 and non-small cell lung carcinoma: TTF1/NKX2-1 (henceforth simply TTF1)2 and ΔNp63/p403,4 (henceforth simply p40) are the most commonly used markers to classify NSCLC upon immunohistochemistry (IHC), with TTF1 confidently identifying LUAD and p40 LUSC5–9.