a) Effect of imatinib in cervical cell line growth. CaLo cells were grown for two days in the absence of serum and then re-plated for treatment with imatinib, PDGFββ or both for five days. PDGFBB stimulated cell gowth as compared to the untreated control. On the contrary imatinib induced growth inhibition and when cells were co-treated with the ligand and imatinib, the growth-inducing activity of the PDGFBB was partly blocked by imatinib (comparison are marked with * or ^, all these differences were statistically significant p < 0.001). Their corresponding pictures of the plates stained with crystal violet is shown below. b) Inhibition of phosphorylation of PDGFRα by imatinib. CaLo cells were stimulated with PDGFBB at 10 ng/mL, for 10 min; treated with imatinib at 10 μM for 2 hours; treated with imatinib for two hours and then with PDGFBB for 15 min; or no treatment as control. Equal loading confirmed with actin. Receptor phosphorylation is increased in the PDGFBB lane and inhibited by imatinib treatment.