We did not find any significant relations between serum FIS1 and MFN1 levels, and the histopathological type of lung cancer (p > 0.05; Kruskal–Wallis test), or the cancer staging according to the TNM staging system (the tumor-node-metastasis) (p > 0.05; Kruskal–Wallis test, U Mann–Whitney test). The gene discussed is FIS1; the disease is neoplasm.