A novel chordin-like polypeptide is found out in a protein secreted from mesenchymal stem cells. This polypeptide is useful as a cancer marker and a remedy for parotid cancer, lung cancer, esophagus cancer, gastric cancer, duodenal carcinoma, kidney cancer, ureteral cancer, testicular cancer, ovarian cancer, uterine cancer, leukemia, intestinal cancer, colon cancer, rectal cancer, biliary cancer or thyroid cancer cells, etc. Moreover, it is found out that the above polypeptide has an activity of modulating bone differentiation. Thus, this polypeptide is also useful as a bone disease marker and a remedy for bone diseases such as arthritis deformans, rheumatoid arthritis and osteoporosis.