PCNA and neoplasm: Following the treatment with cisplatin, immunostaining showed that PCNA-positive cells in tumors formed from siRNA/HOTAIR1-transfected cells (17.4±3.2%) were significantly decreased compared with that in tumors formed from siRNA/control-transfected cells (44.6±5.4%; P<0.05; Figure 6D), and TUNEL staining assay indicated that the rate of apoptotic tumor cells was significantly increased in tumors formed from siRNA/HOTAIR1-transfected cells compared with that in tumors formed from siRNA/control-transfected cells (P<0.05; Figure 6E).