TTF1 and adenocarcinoma: In contrast, TTF-1, a sensitive marker for adenocarcinomas of lung origin, was substantially lower in the SCC cohort (p<0.001, 3.4-fold lower in SCC), as were several classical receptor tyrosine kinases (RTKs), including pEGFR (p=0.005), Met (p<0.001), pMet (p=0.016), Axl (p=0.007), and FGFR1 (p=0.008).