Expression of Oncoprotein in Rheumatoid Synovium

Kim, Jinseok; Cha, Hoon Suk; Koh, Jay Hyun; Seo, Gi Hyun; Lee, Chang Keun; Kim, Byoung Joon; Choi, Hwa Jung; Han, Joung Ho; Oh, Won Hwan; Koh, Eun Mi

Abstract

OBJECTIVE
The synovium in rheumatoid arthritis(RA) is characterized by an increase in the thickness of lining layer and infiltration of cells into the sublining area. Histomorphologic studies of RA have indicated that initial destruction is more closely related to the presence of transformed appearing proliferating synovial cells than to the presence of subsynovial or periarticular inflammation. Based on the fact that synovial lining cells have some properties of transformed appearing cells, we examined the expressions of Fos, Jun and Myc oncoproteins in the synovial tissue from patients with rheumatoid arthritis and osteoarthritis.
METHODS
Synovial tissues from 15 patients with RA and 15 with osteoarthritis(OA) were studied by the immunohistochemical staining technique. Nine of 15 RA specimen were from arthroscopic synovectomy and the other 6 were from total knee replacement arthroplasty. RESULT: In all specimen studied, Myc and Fos were expressed in the synovial lining cells and Myc, Fos and Jun were expressed in the sublining cells, including lymphocytes, other inflammatory cells and blood vessels. Lymphocytes in the diffuse infiltrates showed increased expression of three oncoproteins compared to lymphocytes in the nodular aggregates. When oncoprotein expressions in RA were compared to OA, Fos and Myc expressions in the synovial lining cell layer were significantly higher in RA than in OA and Jun, Fos and Myc expressions in inflammatory cells were significantly higher in RA than in OA. The expressions of Fos and Myc were significantly correlated with the degree of synovial hypercellularity. In RA, the expressions of all three oncoproteins were increased in synovectomy group than joint replacement group.
CONCLUSION
We observe that there are increased expressions of Myc, Fos and Jun in RA synovium than OA. These changes are more prominent in synovectomy group than joint replacement group, which suggest the differential expression of oncoproteins according to disease progression.