It showed that the high expression of PCSK9 was related to poorer OS in patients with BLCA (P = 0.001), KIRC (P = 0.01), KIRP (P = 0.011), LIHC (P = 0.024), lung adenocarcinoma (LUAD) (P = 0.011) and skin cutaneous melanoma (SKCM) (P = 0.001). This evidence concerns the gene PCSK9 and lung adenocarcinoma.