Objective： This study was designed to investigate the relationship between p16 protein expression and gastric carcinogenesis,depth of invasion, lymph node metastasis, and evaluate the role of deletion and mutation of p16 gene in exon 2 in gastric carcinoma. Methods： p16 protein expression in gastric carcinoma and precancerous lesion was examined by streptavidin-peroxidase conjugated(S-P) method; The deletion and mutation of p16 gene were examined respectively by polymerase chain reaction(PCR) and polymerase chain reaction single-strand conformation polymorphism analysis(PCR-SSCP) in gastric carcinoma. Results： ① The positive rates of p16 protein expression were 96.25％ (77/80) in normal gastric mucosa, 92.00％ (45/50) in dysplastic gastric mucosa, and 47.54％ (58/122) in gastric carcinoma. The positive rate of p16 protein expression in gastric carcinoma was significantly lower than that in normal gastric mucosa and in dysplastic gastric mucosa (P<0.05). ② The positive rate of p16 protein expression in mucoid carcinoma (10.00％ ,1/10) was significantly lower than that of poorly differentiated carcinoma (51.22％ ,21/41), undifferentiated carcinoma (57.69％ ,15/26), and signet ring cell carcinoma (62.50％ ,10/16) (P< 0.05). ③ The positive rates of p16 protein in 30 cases paired primary and lymph node metastatic gastric carcinoma were 46.67 ％ (14/30) in primary gastric carcinoma,16.67％ (5/30) in lymph node metastatic gastric carcinoma. The positive rate of lymph node metastatic carcinoma was significantly lower than that of primary carcinoma(P<0.05). ④ Evaluation of mutation and deletion of p16 gene： There was no mutation of p16 gene in exon 2, but there were 5 cases displayed deletion of p16 gene in exon 2 in the 25 primary gastric carcinoma. Conclusions： ① The expression loss of p16 protein is related to carcinogenesis, histopathological subtypes,and lymph metastasis of gastric carcinoma. ② The mutation of p16 gene in exon 2 may not be involved in gastric carcinogenesis. But the deletion of p16 gene in exon 2 might be involved in gastric carcinogenesis.

Objective To investigate the inhibitory effect of Withaferin A ( WFA) on the growth of orthotopic xenograft tumor of hepatocellular carcinoma in nude mice and the mechanism of its antitumoral effect. Methods For in vivo model, anti-tumor efficacy of Withaferin A was evaluated in nude mice mod-els of human liver cancer orthotopic xenograft. The nude mice were randomly divided into model group, Sunitinib group,and Withaferin A groups [6, 3 mg/(kg·d)]. All mice were given intraperitoneal injec-tion for 14 days. Tumor volume and tumor weight were observed. Antiangiogenic effects were assessed in vi-vo by the tumor inhibition rate and microvessel density. Quantitative polymerase chain reaction ( QPCR) as-say was used to detect the mRNA expression of vascular endothelial growth factor ( VEGF) , basic fibroblast growth factor (bFGF), angiopoietin-2 (Ang-2), vascular endothelial growth factor receptor 2 (VEGFR2) from tumor tissues. For in vitro experiments, the cell count kit 8 ( CCK8 ) assay was used to detect the effect of Withaferin A on HepG2 cells proliferation. QPCR assay and enzyme-linked immunosorbent assay ( ELISA) were used to detect the mRNA expression of VEGF. Results Compared to the model group, the high-dose Withaferin A group and the Sunitinib group had a significantly lower tumor weight (P<0. 05). The tumor inhibition rate was 42. 69％ in the high-dose Withaferin A group, 20. 22％ in the low-dose With-aferin A group, and 49. 43％ in the Sunitinib group. The growth of HepG2 cells was significantly inhibited by different concentrations of Withaferin A,and the 50％ concentration of inhibition ( IC50 ) of Withaferin A were (2. 64 ± 0. 18)μmol/L at 24 h. Withaferin A (6,3 μmol/L) could inhibit the protein and mRNA ex-pression of VEGF ( P<0. 05 ) . Conclusions Withaferin A significantly reduces the growth of orthotopic xenograft tumor of hepatocellular carcinoma in nude mice via antiangiogenic effect. Downregulation of the protein and mRNA expression of VEGF by WFA may be one mechanism of its anti-liver cancer effect.