Where does osteosarcoma originate from?

Osteosarcoma is a malignant cancer of osteocytes or bone cells. The cancer may come from osteoblasts (the cells that lay down new bone), osteocytes (the cells that maintain the bone, but these are rare) or osteoclasts (the cells that tear up old bone). In dogs, the most common sites for an osteosarcoma are "away from the elbow, towards the knee" - in the humerus (upper arm bone) by the shoulder blade, in the radius (lower arm bone) by the wrist joint, in the femur (thigh bone) and in the tibia (shin bone) by the knee.