YKL-40 could play an important role in promoting tumor metastasis and impairing survival via multiple mechanisms, such as upregulating the secretion of matrix metalloproteinases, activating the TGFẞ pathway [17], inducing angiogenesis via its receptor IL-13α2 and membrane protein TMEM219, and binding to RAGE (receptor for advanced glycation end products) [12]. The gene discussed is CHI3L1; the disease is neoplasm.