High CHI3L1 expression is reported to be independently associated with poorer overall survival in both non‐small‐cell lung carcinoma (NSCLC) and small‐cell lung carcinoma (SCLC) patients [7], and serum CHI3L1 levels in 120 SCLC patients were higher in the group with poorer response to chemotherapy [8]. Here, CHI3L1 is linked to small cell lung carcinoma.