CTSL and neoplasm: EpCAM c.344T>C may weaken protein folding, thereby promoting cervical cancer progression (Hu et al., 2012; Sankpal et al., 2021), enhance tumor cell stemness to facilitate breast cancer growth (Jiang et al., 2011), and impair EpCAM’s inhibitory effect on cathepsin L, increasing the invasiveness of non-small cell lung cancer (Yang et al., 2014).