Lipocalin-2 (LCN2), which is a member of the lipocalin family and functions to ligate ferric siderophore-like molecules, is involved in various cancers including lung cancer (Shiiba et al., 2013), breast cancer (Yang et al., 2013), ovarian cancer (Cho and Kim, 2009), colon cancer and pancreatic cancer (Mannelqvist et al., 2012). Here, LCN2 is linked to lung cancer.