The negative association between high levels of MEK5/ERK5 expression and worse prognosis was observed irrespectively of whether lung cancer patients did not have previous history of tobacco smoking (n = 204, p-value = 1.7e−05, HR = 3.22 (1.83–5.66), FDR = 0.01) (Fig. 1c), or were smokers (n = 820, p-value = 6.9e−06, HR = 1.66 (1.33–2.08), FDR = 0.01) (Fig. 1d). This evidence concerns the gene MAPK7 and lung cancer.