According to a more detailed pairwise comparison, SCLC-A showed a significant upregulation of proteins Cytochrome C Oxidase Subunit 4 Isoform 1 (COX4I1), Cytochrome C Oxidase Subunit 5B (COX5B) and NADH Dehydrogenase (Ubiquinone) 1 Alpha Subcomplex 5 (NDUFA5) as compared to other (N/P/Y-expressing) subtypes, indicating increased mitochondrial activity (Fig. 1B). This evidence concerns the gene COX4I1 and small cell lung carcinoma.