CD34 and neoplasm: To evaluate the effects of DUSP1 silencing and gemcitabine treatment on tumor angiogenesis, proliferation, and apoptosis, tumor tissues were next analyzed by immunohistochemical staining for CD34 (angiogenesis) and Ki67 (proliferation), as well as by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and cleaved caspase 3 immunoreactivity, both of which are markers of apoptosis.