CTSK and neoplasm: Furthermore, Ctsk is involved in the pathogenesis of pulmonary fibrosis (Bühling et al., 2004), atherosclerotic plaque progression (Guo et al., 2009), and some tumor metastasis, such as epithelial ovarian cancer, melanoma, prostate cancer, and breast cancer (Brubaker et al., 2003; Munari et al., 2017; Petricevic et al., 2017; Fan et al., 2018; Gu et al., 2019).