Which of the following is not true in relation to Osteosarcoma?

c-myc gene implicated in the genesis is wrong. Osteosarcomas occur in all age groups, with a second peak occuring in elderly persons, usually in association with other conditions like pagets disease, etc. A triangular shadow on the x-ray film between coex and raised periosteum (codman triangle) is charecteristics of osteosarcomas. RB gene mutations account for 60%to70% cases of these tumors Robbins basic pathology 9th edition page no 776,777