Song Z, et al. - Three hundred and thirty-five patients without distant metastasis at their first visit (Group 1), 51 patients with colorectal cancer (CRC, one of the most common cancers and the second leading cause of cancer-related mortality worldwide) with synchronous liver metastasis (Group 2), 100 healthy age-matched controls (Group 3) and 40 patients with liver cancer (Group 4) were analyzed by the experts in order to assess the value of chitinase activity in prognosticating the occurrence of metastasis and prognosis of patients with CRC. In comparison to those with low chitinase activity in the training and testing sets during follow-up, both at stage I/II and stage III, a markedly greater metastasis risk was observed in high chitinase activity patients. Chitinase activity was recognized as an independent risk factor prognosticating liver metastases. Moreover, the combination of chitinase activity and the N stage enhanced the strength of prognosticating the occurrence of metastasis. Hence, inhibiting chitinase activity could serve as a new approach to tackle the metastases of CRC.