TTF1 and small cell lung carcinoma: Comparing mRNA [30] and protein expression data [27,42] between cell lines identified as sensitive and resistant by DISARM, we identified low expression of the gene NKX2-1 and its protein (TTF1) as common markers of sensitivity to PI3K inhibitors (Figure 4C), in agreement with our proteomic subtyping of SCLC (Figure 2D) [31].