CHI3L1 and neoplasm: In serum, on the other hand, CHI3L1 and LCN2 were significantly increased at 1, 3, and 6 w p.i. in the 4T1- compared to the Py230-based intraductal model (Figure 4D), reflecting the enhanced metastatic progression of 4T1 tumor cells following intraductal inoculation.