Figure 4. The effect of imatinib in cultured human testicular peritubular cells (HTPCs) on (A) cell viability (ATP assay), (B) the proportion of proliferating cells showing a mitotic figure (%) and (C) total cell counts. Imatinib blocked the PDGF-induced increase in cell proliferation of HTPCs. (D) Example of a mitotic figure stained with DAPI indicating a proliferating HTPC. Bar: 3 µm. Results are means + SEM. Different letters indicate significant differences. Numbers in columns indicate the number of patients used for cell harvesting. RLU, relative luminescence units.