General, Visceral and… Research Section Surgical… Projects Examination of tumor…

Examination of tumor stem cells features in Giant Cell Tumor of Bone

This project is carried out together with Dr. J. Fellenberg of the Orthopedic University Hospital Heidelberg. It goes back to the fusion of the Orthopedic Clinic and the University Clinic of Heidelberg in 2010. At that time the Medical Faculty of Heidelberg promoted cooperation projects with orthopedics, to strengthen the teamwork with the other clinics of the faculty. With 4-5% of all primary bone tumors the giant cell tumor (GCT) is a very common, in the group of 25 to 40 year old, the most common bone tumor. He prefers to develop near the joint of the epiphyseal growth plates of the long hollow bones. This tumor is usually a benign tumor, however, locally he has a very aggressive behavior, which leads to extensive bone damage. In rare cases it can lead to malignant transformation and in about 6% of all cases the formation of lung metastases was observed. A surgical removal of the tumor currently offers the only chance of cure, but with 35-50% the recurrence rate is very high, which in turn is associated with an increased risk of metastasis. We suspect that a small population of "dormant" tumor stem cells exists in the giant cell tumor, which is responsible for the formation of recurrence and metastasis. This has already been shown in other tumor entities. However, the field of cancer stem cells is still completely unexplored in the field of giant cell tumor of bone. By comparison of stem cell markers in parental, adherent, spheroidal-growing cell lines, we analyze the expression of tumor stem cell marker of the giant cell tumor and try to find out why the giant cell tumor progresses in some cases and forms metastasis, but not in other cases. Finally, the expected new insights will lead to the development of improved therapeutic options for giant cell tumors of the bone.