Objective To investigate the effects of 5-Aza-2′-deoxycytidine (5-Aza-Cde)on DNA methylation and expression of hMLH1 and MGMT gene in the human lung cancer cell line A549/DDP.Methods A549/DDP cells were cultured with RPMI 1 640 medium and were treated with 5 μmol/L DNA methyhransferase inhibitor 5-Aza-Cde.Methylation-specific pol-ymerase chain reaetioll (MSP)was used to detect the promoter methylation state of the hMLH1 and MGMT gene.RT-PCR was used to detect the mRNA expression of hMLH1 and MGMT before and after treatment with 5-Aza-Cde,respectively. Results Before treatment with 5-Aza-Cde,hMLH1 and MGMT expressions were absent,and promoter hypermethylation of the hMLH1 and MGMT gene were detected in A549 cells.After treatment with 5-Aza-Cde,the promoter region of the hM-LH1 and MGMT gene exhibited a demethylation state,and their mRNA expressions were increased.Conclusion Promoter hypermethyhtion is amajor mechanism of hMLH1 and MGMT gene silencing in human lung cancer cells,and can be reversed by the demethylating agent 5-Aza-Cde,which can regulate the expressions of the hMLH1 and MGMT gene.

Objective To detect the expression of p16 and discuss the significance in genesis and development of cervical cancer. Methods FQ-PCR method was used to detect the expression levels of p16 mRNA in cervical cancer(CC),cervical intraepithelial neoplasia(CIN),and normal tissues.And in situ hybridization was used to detect HR-HPV in these tissues.Results The expres-sion levels of p16 were 0.79±0.34,0.70±0.36,0.26±0.21 in CC,CIN and normal cervical tissues,respectively.The difference was significant (P <0.05).The expression level of p16 was significantly associated with FIGO stage (P <0.05),but it showed no significant relationship with age,tumor size,cell differential degree and lymphoid node metastasis (P >0.05).The expression level of p16 in HR-HPV positive cases was significantly higher than that in HR-HPV negative cases (P <0.05).Conclusion p16 shows high expression level in cervical cancer,which is closely related to the infection of HR-HPV infection.It suggests that the high ex-pression of p16 play an important role in genesis and development of cervical cancer.

Objective To investigate the changes of CD 4+CD25+CD127 low regulatory T ( Treg ) cells in peripheral blood samples from patients with lung cancer and their correlation with clinicopathologic features of lung cancer .Methods Flow cytometry was used to measure the percentages of CD 4, CD8, nat-ural killer ( NK) and Treg cells in peripheral blood samples collected from 160 patients with lung cancer and 60 healthy subjects .The correlations between the levels of Treg cells and clinicopathologic features of lung cancer were analyzed .The percentages of Treg cells in 60 patients with lung cancer before and after surgery were compared .Results The percentages of CD 4+and NK cells and the ratios of CD 4+/CD8+cells in pa-tients with lung cancer were significantly lower than those in healthy control , while the percentages of Treg cells in patients with lung cancer were decreased as compared with those in healthy subjects .The percenta-ges of Treg cells in patients with advanced cancer were significantly higher than those in patients at early stage (P<0.05), which dropped significantly after surgery (P<0.01).Conclusion The results of this study indicated that Treg cells in patients with lung cancer might inhibit antitumor immune responses and correlate with the progression of cancer .It would be worthwhile to check Treg cells in patients with lung cancer for monitoring the prognosis and treatment effects .