Proto-oncogene expression and nuclear factor specifically bound to c-myc gene in peripheral blood mononuclear cells from progressive systemic sclerosis patients as the indicator of clinical activity.

In the present study, we examined the expression of various protooncogenes and the specific binding of nuclear factor to c-myc gene in peripheral blood mononuclear cells (PBMC) from progressive systemic sclerosis (PSS) patients. We demonstrated first amplified expression of c-myc and c-myb gene and the existence of a nuclear protein specifically bound to 5'-non-coding fragment of c-myc gene. We then found a positive correlation between the degree of expression and/or affinity for the c-myc gene fragment of the nuclear protein and clinical disease activity. The amount of the factor was significantly reduced along with or prior to the amelioration of clinical symptoms and laboratory abnormalities with treatment. The significance of c-myc and c-myb proto-oncogene expression and nuclear factor specifically bound to c-myc gene is discussed.