CHI3L1 and cancer: CHI3L1 has been widely studied as it has been found to be significantly involved in various diseases in the peripheral system, including asthma, arthritis, sepsis, diabetes, liver fibrosis, coronary artery disease, and several cancers, but its role in brain health and disease has not been investigated much even though it is expressed not only in peripheral systems but also in the CNS such as microglia and astrocytes [14,15,16,17].