Clinical data regarding diagnosis and examination findings, as well as tissue from biopsies and surgeries will be collected prospectively. The tissue will be frozen in liquid nitrogen according to standard procedures and stored until the molecular analyzes at the Laboratory of Orthopedic Research at Balgrist University Hospital. The processing involves expression analyzes such as polymerase chain reaction, Western Blot, micro arrays, immunohistochemistry and tissue array. The DNA from the taken blood samples shall be compared with the DNA found in the tumor.