Fig. 9

Chitin provides enhanced tumor reduction and anti-tumorigenicity compared to anti-CHI3L1 treatment in the 4T1-based intraductal model. A Weekly measurements of primary tumor volumes in the IgG control-, anti-CHI3L1- and chitin-treated 4T1-based model with treatment schedules indicated (n = 6 for all groups at all time points). B Representative images and quantification of bioluminescent signals (total flux density in p/s/cm²) in lungs from the IgG control-, anti-CHI3L1 and chitin-treated 4T1-based model at 5 w p.i. (n = 3 for all groups). C H&E histology of lung metastases from the IgG control-, anti-CHI3L1- and chitin-treated 4T1-based model at 5 w p.i. Dashed inserts highlight H&E-stained metastases at a larger magnification. D,E Immunohistochemistry for the PMN-MDSC/TAN marker Ly6G (D) and the M2 TAM subtype marker CD163 (E) on primary tumor sections from IgG control-, anti-CHI3L1- and chitin-treated 4T1 tumor-bearing mice at 5 w p.i. (n = 12 for all groups; 3 slides with 4 images per slide). Dashed inserts highlight stained tissue at a larger magnification. Black scale bars = 200 µm, red scale bars = 50 μm. F–H Kaplan Meier plots showing relapse-free (F), distant metastasis-free (G) and post-progression survival (H) over 60 months time based on CHI3L1 expression as calculated using publicly available mRNA gene chip data from all BC subtypes and the KM-plotter tool. Number of patients that were included for analysis: 4929 for RFS, 2765 for DMFS and 458 for PPS. Patients were split in high/low CHI3L1 expressors based on auto select of the best cutoff by the KM-plotter tool. Data are presented as the means ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001