Of these significantly changed lipids in patients with lung cancer, the top 6 elevated lipids and top 6 decreased lipids were also identified (Fig. 3, panels C and D): levels of CE(20:1), CE(20:0), CE(24:0), PE(14:0/14:0)-H, TAG42:0-FA16:0, and CE(22:2) were significantly increased, compared to that of HC (all p < 0.05); levels of TAG56:1-FA16:0, TAG56:1-FA18:1, PC(20:0/20:2) + AcO, TAG58:2-FA18:1, PE(14:0/20:2), and TAG58:3-FA18:1 were significantly decreased, comparing to that of HC (all p < 0.05). Here, KLK15 is linked to lung cancer.