Expression of the myc-family proto-oncogenes and related genes max and madin synovial tissue

Objective. To examine the expression of myc proto-oncogenes; c-myc, L-myc, and N-myc, and their related genes max and mart, in the arthritic synovium. Methods. Using reverse transcription-polymerase chain reaction (RT-PCR), No rthern and Southern hybridizations, the expression of these genes in the sy novial tissue from rheumatoid arthritis (RA) and osteoarthritis (OA) was an alyzed. Synovial specimens from cadavers without any joint disease and peri pheral blood mononuclear cells (PBMC)From healthy individuals served as con trols. Results. As a novel finding, synovial cells were observed to express L-myc, N-myc as well as their related genes max and mad, in addition to the previ ously described presence of c-myc proto-oncogene in synovium. c-myc, L-myc, N-myc, and mad were expressed in all patient samples studied, including th e controls. Instead, max was detected in only 10/12 of RA patients, in 11/1 3 of OA patients, and in all controls (4/4 cadavers, 5/5 blood donors). Six patients with RA revealed positive signals for max only after hybridizatio n. The same wits;also true of two patients with OA and of one healthy indiv idual donating blood. Conclusions. The L-myc, N-myc, max, and mad genes are expressed in synovial cells, in addition to c-myc proto-oncogene. However, expression of these g enes is not disease-specific, since they were equally expressed in synovial samples from patients with RA or OA as well as from cadavers representing controls without any joint disease.