CHI3L1 and invasive ductal breast carcinoma: Representative positive YKL-40 staining in the 3 pathological types of breast cancer (noninvasive ductal carcinoma [n = 36], invasive lobular carcinoma [n = 24], and invasive ductal carcinoma [n = 60]) are shown in supplemental Figures S1B, S1C, and S1D, respectively.