Importantly, increased CHI3L1 level is in significantly associated with poor prognosis and known to affect the survival of patients suffering from a variety of tumors including breast cancer, bladder cancer, lung squamous cell carcinoma, ovarian cancer, GC, sarcoma, and glioma, as analyzed from KMplot (https://kmplot.com) and CGGA (http://www.cgga.org.cn) website (Fig. 6). Here, CHI3L1 is linked to breast cancer.