Recombinant CHI3L1 (rCHI3L1) protein was added to gastric cancer cell culture (MKN-45 and AGS), breast cancer cell culture (MDA-MB-231, MDA-MB-435, and MDA-MB-468), or melanoma cell culture (A375) for cell migration assays using Boyden chambers. Here, CHI3L1 is linked to breast cancer.