ATRX and osteosarcoma: Presenting the data in another way, it can be seen that 67% of osteosarcoma cell lines (2/3) and 82% of fibroblast cell lines (14/17) were ATRX deficient, whereas a lung cancer cell line (SKLU-1) and a mesothelial cell line (MeT-4A) were both ATRX proficient.