Unlike us, both the correlation between serum/plasma YKL-40 and prognosis and the correlation between YKL-40 in tissue and prognosis were chosen to study in Wan’s study [11], and thus our 95% CI of HR for the prognostic value of YKL-40 in breast cancer would be expanded because of the smaller sample size. The gene discussed is CHI3L1; the disease is breast cancer.