Among the specific SCF signaling inhibitors tested (PB98059, H89 and Wortmannin), the MEK inhibitor, PD98059, significantly suppressed the SCF-stimulated phosphorylation of ERK and of MITF at 5–30 min post-treatment in SCF-treated ALM melanoma cells, whereas H89 and Wortmannin did not affect the SCF-stimulated phosphorylation of ERK, MITF or CREB during that time (Figure 3). The gene discussed is CREB1; the disease is melanoma.