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Objective: To study the association between the AKAP12 promoter methylation and recurrence of hepatocellular carcinoma. Methods: A total of 142 primary liver cancer patients underwent surgery in department of Hepatobiliary surgery in Peking University Cancer Hospital from 2003 to 2009 were selected as subjects in the survey; with the inclusion criteria as hepatocellular carcinoma, no cancer cells were observed in the surgical margin(SM) samples. All patients had neither lymph nor distant metastasis at the time of surgery, and receiving complete follow-up data for at least 3 years. By the end of May 2014, a total of 75 patients had relapsed of whom 71 died and there were no lost. All samples were acquired from the frozen surgical tissues. Genomic DNA was extracted using phenol/chloroform method and performed bisulfite modification following with polymerase chain reaction (PCR). AKAP12 methylation in hepatoma and the corresponding SM samples from 142 patients was determined by denature high-performance liquid chromatography (DHPLC) and bisulfite clone sequencing. Kaplan-Meier and Cox proportion hazard regression model were used to identify the factors related to the survival time. Results: In 142 cases, 125 patients (88.0%) were male and 17 (12.0%) cases were female. The median age was 52.5 years, ranging from 34 years to 76 years. AKAP12 methylation-positive rate was significantly higher in hepatomas than SMs (54.9% vs. 10.2%, P< 0.001). Patients with AKAP12 methylation-positive had less risk of the recurrence ( HR= 0.62, 95% CI : 0.39-0.99); with tumor diameter more than 5 cm ( HR= 1.53, 95 %CI: 1.00-2.50),portal vein invasion( HR= 4.53, 95% CI: 2.69-7.64) increased the recurrence risk. Moreover, portal vein invasion had a higher risk of death ( HR= 2.98, 95% CI: 1.73-4.98). Conclusion: There was significant association between AKAP12 DNA methylation and low risk of recurrence and long progression-free survival of hepatocellular carcinoma patients.

Objective: To investigate the relationship between chromobox protein homolog 7 (cbx7) expression and the occurrence and development of colorectal carcinoma (CRC), gastric carcinoma (GC) and hepatocarcinoma (HCC) tissues., Methods: The samples of neoplastic tissues and the corresponding cutting-edge normal tissues from 22 cases of CRC, 20 cases of GC, 30 cases of HCC were surgically collected. Level of cbx7 mRNA was detected with a fluorescent quantitative RT-PCR assay, and the correlationship among expression of cbx7 mRNA, the patients' clinicopathologic features and the surviving time after surgery was analyzed., Results: The relative copy number of cbx7 mRNA in carcinomas and the normal tissues was 0.010 ± 0.015 vs 0.053 ± 0.042 for CRCs, 0.197 ± 0.195 vs 1.891 ± 1.254 for GCs, and 0.008 ± 0.008 vs 0.030 ± 0.021 for HCCs, respectively. Compared with the corresponding normal tissues, cbx7 expression was significantly downregulated in CRCs, GCs, and HCCs (t = -7.351, -5.417 and -6.680, respectively, P < 0.01). The expression of cbx7 mRNA in CRCs had significant differences not only between two age groups (the relative copy number of cbx7 mRNA in age > 55 group was 0.007 ± 0.015, but 0.017 ± 0.012 in age ≤ 55 group, t = -2.586, P = 0.022); but also between vascular embolus-positive and negative groups (the level of cbx7 mRNA in positive and negative group was 0.022 ± 0.021 vs 0.006 ± 0.011, t = -3.175, P = 0.010). The area under the receiver operating characteristics (ROC) curve is 0.769 (P = 0.033). when the Cut-off value of the relative copy number of cbx7 mRNA was 0.002 in CRCs. The values less-than 0.002 were defined as low expression. The CRC patients with low expression of cbx7 had a shorter overall survival time; whose 5 years survival rate was only 30.8% (4/13); while the rate was 77.8% (7/9) in high expression of cbx7 group. The difference had statistical significance (χ(2) = 4.329, P = 0.037). The similar differences could not be found among GC and HCC patients., Conclusion: Downregulation of cbx7 expression was very common among multiple carcinomas cases, and the downregulation influenced the prognosis of CRC patients.

Objective: To investigate the effects of methylation status of CpG islands of endogenous E-cadherin (CDH1) gene on the promoter activity of corresponding genes in reporter assays., Methods: The methylation statuses of CpG island of CDH1 in 8 different cell lines were detected by methylation-specific PCR. CDH1 protein was analyzed by Western blotting. Two sets of pGL3 reporter vectors with different genotypes/haplotypes of the CDH1 promoter were constructed [ pGL3-A(-73)/-C(-73) pGL3-H1/-H4] and used to transfect these cell lines. The differences between these promoter reporter vectors were analyzed by t-test., Results: (1) CDH1 CpG island was unmethylated in AGS, MCF7, MKN74, and PC-3 cell lines, expressed in MCF7, MKN74, and PC-3, but not in AGS. Expression of CDH1 was silenced by methylation in HeLa, BGC823, A549, and RKO cell lines. (2) In the four CDH1-unmethylated MCF7, MKN74, PC-3, and AGS cell lines, the promoter activities of pGL3-C(-73), (as 0.78 +/- 0.10, 0.17 +/- 0.01, 0.11 +/- 0.01, 1.19 +/- 0.18) were significantly higher than those of pGL3-A(-73) (as 0.30 +/- 0.08, 0.07 +/- 0.01, 0.07 +/- 0.01, 0.39 +/- 0.04) (t values are -6.298, - 12.349, -8.128, -7.388, and P <. 0.1). However, in the four CDH1-methylated HeLa, BGC823, A549, and RKO cell lines, the promoter activity of pGL3-C(-73) (as 0.09 +/- 0.02, 0.13 +/- 0.02, 0.05 +/- 0.01, 0.01 +/- 0.00) was significantly lower than that of pGL3-A(-73) (as 0.16 +/- 0.01, 0.25 +/- 0.01, 0.11 +/- 0.03, 0.03 +/- 0.00) (t valued at 5.958, 11.189, 3.661, 13.866, and P<0.05). (3) In the unmethylated MKN74 and methylated RKO cell lines, the promoter activities of pGL3-H1/-H4 were obviously and contrarily different (as 1.57 +/- 0.23/0.94 +/- 0.06 and 0.38 +/- 0.02/0.50 +/- 0.04, t values were 4.577 and -4.915, P values were 0.010 and 0.003)., Conclusion: The methylation status of CpG island of the target gene in the tested cell lines affects the promoter activity in Reporter Assay significantly. The most active one may be the most suppressive one.

Objective: To observe the alterations of saliva nitrate and nitrite level in patients with oral candidiasis., Methods: Parotid saliva and whole saliva were collected from 33 patients and 34 healthy volunteers. Concentrations of nitrate and nitrite in saliva were determined by high-performance liquid chromatography. Follow-up observation was performed on 10 patients after treatment. The data were statistically analyzed with independent-samples t test or paired-samples t test at alpha = 0.05., Results: There was significant increase of the concentrations and secretion rate of parotid saliva nitrate in patient group as compared with controls: (49.70 +/- 0.50) vs (21.51 +/- 0.60) mg/L (t = 2.692, P = 0.009) and (27.71 +/- 0.50) vs (12.55 +/- 0.60) microg/min (t = 2.554, P = 0.013), respectively. Significantly increased concentrations and secretion rate of nitrate and nitrite [nitrate: (6.46 +/- 0.94) vs (1.11 +/- 0.70) mg/L (t = 3.792, P = 0.000); nitrite: (8.48 +/- 0.58) vs (3.39 +/- 0.53) mg/L (t = 2.888, P = 0.005); nitrate secretion rate: (10.57 +/- 0.91) vs (2.10 +/- 0.74) microg/min (t = 3.464, P= 0.001); nitrite secretion rate: (13.91 +/- 0.55) vs (6.42 +/- 0.58) microg/min (t = 2.397, P = 0.020)] were revealed in whole saliva of patients group. Significantly decreased nitrate and nitrite levels were also observed in patients after treatment, especially the changes of parotid saliva nitrate secretion rate [(37.50 +/- 0.50) vs (14.34 +/- 0.64) microg/min (t = 3.142, P = 0.012)], whole saliva nitrate [(14.29 +/- 1.01) vs (2.59 +/- 1.03) mg/L (t = 3.475, P = 0.007)] and whole saliva nitrate secretion rate [(25.97 +/- 0.93) vs (4.12 +/- 1.00) microg/min (t = 3.922, P = 0.003)]., Conclusion: The present study revealed the significant increase of salivary nitrate and nitrite level in patients with oral candidiasis is considered to be associated with the host defense reaction.

Objective: To detect the therapeutic effect of selenium-enriched garlic (SeG) on chronic gastritis., Methods: Chronic gastritis was induced of the glandular stomach of male Mongolian Gerbils via gastric instillation of H. pylori TN2 strain once every 4 days for 5 consecutive times followed by random classification into six groups. Fresh SeG suspension was administrated daily at dosages of 4.70, 1.5, 0.47, 0.15 g.kg(-1).d(-1) for four weeks. The gerbils in the positive control group were treated with omeprazole, clarithromycin, and amoxicillin for one week. The gerbils were killed for pathological examination four weeks after SeG-treatment., Results: Chronic gastritis (CAG), low-grade dysplasia or gastric intraepithelial neoplasia (DYS/GIN) were observed among 77% and 38.5% of the 13 H. pylori-treated animals in the negative control group, respectively; whereas 40% and 26.7% in the positive control group (n = 15), respectively. The incidences of CAG and DYS/GIN in the SeG groups (n = 21 - 27) were reduced dose-dependently, 16.7% - 38.7% and 11.1% - 14.3% for CAG and DYS/GIN, respectively., Conclusion: SeG administration inhibits the development and progression of CAG induced by H. pylori remarkably.

Objective: To establish a sensitive assay to detect methylation status of the critical 7862nt CpG site related to transcription of HPV16 E6 and E7 genes., Methods: Genomic DNA of two HPV16-infected cell line SiHa and CaSki was extracted and modified by sodium bisulfite to convert the unmethylated Cs to Us (Ts in PCR products). The target sequence of HPV16 including the 7862nt CpG site was pre-amplified by PCR. Then, the methylation status of the 7862nt site was differentiated in a primer extension reaction with an HPV16-specific primer, and separated by DHPLC at 80 degrees C., Results: The primers without extension and with extension, whether matched to CpG or TpG, could be separated by DHPLC completely. The peak for ddTTP-extension products corresponding to the demethylated CpG site was observed at retention time 6.7 min in both cell lines. However, the peak for ddCTP-extension products representing the methylated CpG site could be detected at retention time 6.3 min in CaSki cell line only, which integrated with 499 methylated and one demethylated HPV16 copies., Conclusion: The established DHPLC-primer extension assay can be used to detect methylated and demethylated HPV16 copies simultaneously with a sensitivity up to 1/500 (0.2%).

Objective: To investigate relationship between methylation status of the APC and Bikunin CpG islands and clinicopathological characteristics of breast carcinomas., Methods: The methylation status of APC and Bikunin CpG islands in 152 sporadic breast carcinoma samples were analyzed by methylation specific PCR., Results: 40.8% of breast carcinomas examined showed methylated signals for the APC. The methylation frequency of APC was significantly correlated to the tumor size (chi(2) = 4.041; P = 0.044), but not to patients' age, pathologic type of tumor, clinical stage, histological grade, lymph node metastasis and the status of estrogen or progestogen receptor. In addition, 24.6% of carcinoma samples examined revealed strong methylated signals for Bikunin. No significant correlation was found between the aberrant methylation of Bikunin and the clinicopathological characteristics of sporadic breast carcinomas., Conclusion: The aberrant methylations of APC and Bikunin are frequent events during breast carcinogenesis. APC methylation might play a role in the progression of breast cancer.

Objective: To compare binding activity of different zinc finger domain of human Kaiso with methylated CpG., Methods: pGEX constructs with different human Kaiso domain were generated and then corresponding fusion proteins were induced and purified. Electrophoretic mobility shift assays were applied to evaluate the binding activity of fusion proteins with methylated CpG., Results: The purified GST-KaisoZF fusion protein (without the POZ protein binding domain) could bind with methylated CpG probe specifically, but not for three or two zinc fingers without flanking domains., Conclusion: Human zinc finger protein Kaiso could bind with methylated CpG specifically, only in the assistance of the neighboring flank sequence of the zinc finger domain.

Objective: To setup a quantitative assay for detection of methylation of SNCG CpG island in human tissue samples., Methods: Methylation status of the 16 tested CpG sites within the CpG island was analyzed by bisulfite-clone-sequencing for 2 gastric carcinoma cell lines, 2 normal gastric mucosa samples, and 2 pairs of primary gastric carcinomas and their corresponding non-neoplastic tissues, respectively., Results: The methylation of -88 and other four CpG sites was well correlated with the methylation of the overall CpG island. Thus, a combined bisulfite-restriction assay (COBRA) was developed based on the enzyme AciI, which digested the only one GCGG sequence in the PCR products of the methylated CpG island, but not the GTGG in the demethylated one. The digested fragments (144 bp and 85 bp) and undigested fragment (229 bp) could be completely separated by denaturing high performance liquid chromatography (DHPLC). According to the peak areas of these fragments, the proportion of the methylated copies of the SNCG CpG island was calculated easily. The result of the COBRA-DHPLC assay was reproducible and consistent with that of clone-sequencing., Conclusion: A COBRA-DHPLC assay is setup successfully for quantification of methylation of the SNCG CpG island.