PCNA and neoplasm: On days 5, 10 and 15 following treatment, the tumor samples were observed and a selection of parameters were recorded, including the level of tumor growth inhibition, the pathological changes in the tumor specimens, the expression levels of matrix metalloproteinase-9 (MMP-9), proliferating cell nuclear antigen (PCNA), tissue inhibitor of metalloproteinases type-1 (TIMP-1) and vascular endothelial growth factor (VEGF) and the apoptosis indices in the tumor samples.