As previous literature indicated that tumor‐associated macrophages (TAMs) are potent producers of many proteases, including matrix metalloproteinases (MMPs) and cathepsins (Noy and Pollard, 2014; Qian and Pollard, 2010), we then examined several protease genes, including MMP1, 2, 9, and 14 and cathepsin B, H, and L, that are related to the lung cancer cell invasion (Bröker et al., 2004; Merchant et al., 2017; Okudela et al., 2016; Schweiger et al., 2000). Here, CTSS is linked to lung cancer.