PKM and small cell lung carcinoma: The unfavorable expression signature (high mRNA expression of ERCC1, PKM2, TOPOIIA and TOPOIIB) in patients with LS-SCLC (n=26) was a significant predictor of shorter median PFS (6 vs. 11 months; p<0.001) and OS (13 vs. 18 months; p=0.007) when compared with those with favorable expression signature (low mRNA expression of ERCC1, PKM2, TOPOIIA and TOPOIIB; n=25) (Figure 3A and 3B).