Oncogene expression in the peri-articular osteophytes

The aim of this study was to ascertain the proliferative and probably reparative potentials of the periarticular osteophytes by evaluating the sites of expression of c-myc, c-jun and c-fos oncogenes in this neoplastic repair tissue.

Sections of osteophytes were obtained from knees of patients undergoing total knee arthroplasty for osteoarthritis. Decalcified sections of osteophytes were stained for c-myc and c-jun oncogenes using the avidin HRP technique. Sections of breast carcinoma were used as positive controls. Undecalcified or frozen sections of osteophytes were stained for c-fos oncogene using the avidin alkaline phosphatase technique. Sections of the human skin were used as positive control. For both techniques, sections of normal articular cartilage were used as negative controls.

The chondrocytes of the entire cartilage mantle of the peri-articular osteophyte had positive staining for c-myc oncogene but no staining for c-jun oncogene. The basal chondrocytes of the deep layer of the cartilage mantle of the peri-articular osteophyte had positive staining for c-fos oncogene. The normal articular cartilage sections had no staining for any of the oncogenes evaluated.

The expression of c-myc oncogene in the osteophytic chondrocytes suggests that these cells are actively proliferating. However, c-fos expression in the basal chondrocytes implies that these cells are capable of transformation. This result confirms the proliferative ability of the peri-articular osteophytes and this may suggest that this osteochondral repair tissue, which is apparently wrongly sited, may be a source of tissue for osteochondral grafting for full thickness articular cartilage defects.