Whole genome expression profiling of gastric high-grade intraepithelial neoplasia with or without cancer.

OBJECTIVE: To investigate the whole genome expression profiles between gastric high-grade intraepithelial neoplasia (HGIN) tissues with cancer and HGIN tissues without cancer. METHODS: Gastric specimens from an upper magnifying chromoendoscopic targeted biopsy were collected at Peking Union Medical College Hospital from March 2010 to May 2013. Each of the forceps biopsies from the 21 patients was HGIN,but there were 10 HGIN and 11 HGIN with cancer after the endoscopic submucosal dissection. The whole genome expression profiling was performed on 10 HGIN samples and 11 HGIN with cancer samples using Agilent 4 × 44K Whole Human Genome microarrays. Differentially expressed genes between different types of lesions were identified using an unpaired t-test and corrected with the Benjamini and Hochberg false discovery rate algorithm. A gene ontology(GO)enrichment analysis was performed using the GeneSpring software GX 12.6. RESULTS: The gene expression patterns were different between HGIN tissues with cancer and HGIN tissues without cancer. There were 470 significantly differentially expressed transcripts between them (P<0.05,Fold Change>2), with 180 up-regulated genes and 290 down-regulated genes in HGIN tissues with cancer. A GO enrichment analysis demonstrated that the most striking over-expressed transcripts in HGIN with cancer were in the category of triglyceride biosynthetic process,acylglycerol biosynthetic process,neutral lipid biosynthetic process,glycerol ether metabolic process,organic ether metabolic process,and glycerolipid metabolic process. CONCLUSION: The change of lipid metabolism may contribute to the pathogenesis of gastric cancer at an early stage.

[Analyzed the molecular interaction network of tumor suppressor gene 14-3-3 sigma in lung cancer cell based on stable isotope labeling by amino acids in cell culture technology].

OBJECTIVE: To analysis the molecular interaction network of 14-3-3 sigma in non small cell lung cancer (NSCLC) cells. METHODS: Established stable over-expressed 14-3-3 sigma protein PG cells, MTT assay was used to assess the growth rate of PG cells. Though stable isotope labeling by amino acids in cell culture (SILAC) and Mass spectrometry (MS) technology, to identify difference expressed proteins caused by over expressed 14-3-3 sigma. The protein expressed >2 or <0.5 times was termed as the differential protein. By searching Human protein reference database (HPRD) and Kyoto encyclopedia of genes and genomes (KEGG), established the molecular interaction network of tumor suppressor gene 14-3-3 sigma. RESULTS: The growth rate of over-expressed 14-3-3 sigma PG cell was obviously slower down compared to vector PG cells. A database including 147 differential protein was established. And a molecular interaction network of 14-3-3 sigma containing 26 protein was constructed.In this network, the expression of CSNK2A1 (casein kinase II subunit alpha), involved in numerous cellular processes, such as cell cycle progression, apoptosis and transcription, was the most significantly increased. A DNA repair protein, MEN1 (Menin) which functions as a transcriptional regulator was the most significantly decreased. CONCLUSION: After stable transfected with 14-3-3 sigma gene, growth rate of PG cells was inhibited, the proteins associated with cell cycle, DNA damage repair mechanisms were significantly changed, and constructed the molecular interaction network.

Amplification and overexpression of Aurora-A in esophageal squamous cell carcinoma.

Aurora-A/BTAK/STK15 gene which encodes a centrosome-associated kinase is located on chromosome 20q13.2, a highly amplified region in various human tumors. Recent studies have demonstrated the overexpression and amplification of Aurora-A in many malignant human cancers. The purpose of this study was to investigate the amplification and expression of Aurora-A in esophageal squamous cell carcinoma. Amplification of Aurora-A was determined by fluorescence in situ hybridization in 7 esophageal cancer cell lines and real-time PCR in 29 esophageal cancer samples. We detected Aurora-A expression in 7 esophageal cancer cell lines and 38 esophageal cancers samples by semi-quantitative reverse transcription-PCR and Western blot hybridization. The amplification of Aurora-A was detected in 27 of 29 (93.1%) esophageal cancer samples and 6 of 7 (85.7%) cancer cell lines. Aurora-A was overexpressed in 27 of 38 (71.1%) esophageal cancer samples and all 7 esophageal cancer cell lines. We conclude that Aurora-A is amplified and overexpressed in esophageal squamous cancer.

[Over-expression of osteopontin in non-small cell lung cancers: its clinical significance].

OBJECTIVE: Data obtained from a differentially expressed cDNA library constructed previously in this laboratory demonstrated that the extracellular matrix molecule osteopontin (OPN) is one of most considerably over-expressed genes in non-small cell lung cancers (NSCLCs). The purpose of the present study was to explore the expression status of OPN in a large scale NSCLC tissue samples, and estimate its significance in progression of the malignant disease. METHODS: RT-PCR was performed with the tumor and adjacent normal tissues from 35 patients with NSCLC, at transcriptional levels of OPN. To determine the expression of OPN protein in the tumor tissues, immunohistochemical (IHC) staining was subsequently carried out on paraffin-embedded sections in tissue microarrays containing 662 samples derived from NSCLC cases. The correlation between the expression level of OPN and clinical characteristics was analyzed statistically. RESULTS: Comparing with the paired normal lung tissue, high level RNA of OPN was detected in 80.0% (28/35) of the NSCLC tumor tissues by RT-PCR, which confirmed the information obtained previously by our differentially expressed cDNA library. The results of IHC analysis showed that positively stained OPN protein was observed in 59.6% (331/555) of the tumor tissues, which was remarkably higher than that (25.2%, 27/107) detected in the normal control tissues (P < 0.001). Among the NSCLCs investigated, over-expressed OPN was more frequently found in squamous cell carcinomas (SCCs) than in adenocarcinomas. A further analysis on SCCs demonstrated that the rate of over-expressed OPN was significantly different between the primary tumors with and without lymphatic metastases (68.6% vs. 49.7%, P = 0.001), but similar in the primary tumors and their corresponding metastases in lymph nodes (68.6% vs. 75.5%, P = 0.171). CONCLUSION: Expression of OPN protein is distinctly increased in NSCLCs, particularly in SCCs. OPN over-expression is considerably correlated with lymph node metastasis, increasing the risk of tumor metastasis (OR = 2.212). The resulting data suggest that OPN facilitates the progression of NSCLCs.

Bevacizumab combined with chemotherapy for glioblastoma: a meta-analysis of randomized controlled trials.

Bevacizumab, as antibodies, were applied to inhibit tumor angiogenesis by preventing activation of vascular endothelial growth factor receptor. We analyzed four clinical trials, including 607 patients, to investigate the efficacy and safety of bevacizumab when combined with chemotherapy for the treatment of glioblastomas. Results demonstrated that bevacizumab when combined with chemotherapy improved progression-free survival (HR = 0.66; 95% CI 0.56-0.78; p < 0.00001) compared with bevacizumab or chemotherapy alone. Furthermore, overall survival showed insignificant difference between two arms (HR 0.99; 95% CI 0.8-1.21; p = 0.92). However, we found that patients treated with bevacizumab-containing therapy reported increased objective response rate (OR 1.85, 95% CI 1.17-2.93; p = 0.009), but more treatment-related adverse events (OR 1.75; 95% CI 1.09-2.83; p = 0.02).

Nuclear overexpression of the E2F3 transcription factor in human lung cancer.

BACKGROUND: The E2F3 transcription factor has an established role in controlling cell cycle progression. In previous studies we have provided evidence that nuclear E2F3 overexpression represents a mechanism that drives the development of human bladder cancer and that determines aggressiveness in human prostate cancer. We have proposed a model in which E2F3 overexpression co-operates with removal of the E2F inhibitor pRB to facilitate cancer development. Since small cell lung cancers (SCLC) have one of the highest reported frequencies of functional abnormalities in the pRB protein (90%) of any human cancer, we wish to assess to what extent E2F3 would be overexpressed in this and other classes of human lung cancer. METHODS: Immunohistochemical techniques were used to assess the E2F3 status in 428 samples of lung cancers, lung carcinoids, normal bronchial epithelium and normal lung tissue. RESULTS: E2F3 is overexpressed in 55-70% of squamous cell carcinomas and 79% of adenocarcinomas of the lung. In addition very high level expression of nuclear E2F3 is found in almost all small cell lung cancers analysed. When considered together with published data our observations indicate that co-operation between pRB functional knockouts and E2F3 overexpression may represent a mechanism of development of SCLC.

[Expression of serum breast drug-resistance protein in predicting chemosensitivity of NSCLC].

OBJECTIVE: To investigate expression of serum breast cancer resistance protein (BCRP) in non-small cell lung cancer patient (NSCLC) and healthy adult, and its correlation with chemosensitivity as one passible value of BCRP in clinical application. METHODS: Venous blood specimens of 44 advanced NSCLC patients and 30 healthy adults were collected. Antibody of BCRP was used to detect its expression in the experiment. Part of venous specimens were randomly selected for Western-blot, and all specimens were examined by ELISA at last. Chemotherapy response of these patients was observed in order to analyze the correlation between BCRP expression level and chemosensitivity. RESULTS: Western blot result showed that BCRP expression can be detected both in NSCLC patient and normal adult. The expression level in NSCLC patients detected by ELISA was significantly higher than that in the healthy adults (P = 0.00); which was also significantly higher in chemo-resistant patients than that in the chemosensitive (P = 0.02) and the healthy adults (P = 0.00); however, BCRP expression in chemo-sensitive patients was not significantly different from that in the healthy adults (P = 0.08). CONCLUSION: Breast cancer resistance protein (BCRP) is found to be expressed at high level in the serum of NSCLC patient, the intensity of BCRP expression may be correlated with chemotherapy resistance in NSCLC, and the high level expressing of BCRP may indicate resistance to the platinum-based chemotherapy regimen. Detection of serum BCRP may someday become a useful bio-marker in predicting chemosensitivity of NSCLC.

[Influences of PC cell-derived growth factor and breast cancer resistance protein on the curative effects of platinum-based chemotherapeutic regimens for advanced non-small cell lung cancer].

OBJECTIVE: To investigate the influences of PC cell-derived growth factor (PCDGF) and breast cancer resistance protein (BCRP) on the curative effects of platinum-based chemotherapeutic regimens for advanced non-small cell lung cancer (NSCLC). METHODS: Specimens of cancer were collected from 87 chemotherapy-naive patients with advanced NSCLC, 61 males and 26 females, aged 42 - 75. Immunohistochemistry was used to examine the expression of PCDGF and BCRP. After the collection of pathological specimens the patients underwent platinum-based chemotherapy. The relationship between the expression of PCDGF and BCRP and the curative effects of chemotherapy was analyzed. RESULTS: The overall response rate (OR) to chemotherapy of the 87 patients was 41.38% (36/87), 36 of the patients were chemosensitive (41.38%), and the other 51 were chemoresistant (58.62%). Forty-six of the 87 patients (52.9%) were PCDGF positive, the PCDGF positive rate of the chemoresistant patients was 74.5%, significantly higher than that of the chemosensitive patients (19.4%, P = 0.000). The patients with high PCDGF expression intensity were all chemoresistant. PCDGF expression was significantly associated with response of chemotherapy (P = 0.000). The overall positive BCRP expression rate was 67.82% (59/87). Of the 51 chemoresistant patients 46 were BCRP positive (90.2%), a rate significantly higher than that of the chemosensitive patients (36.1%, P = 0.000). The intensity of BCRP expression was significantly associated with response to chemotherapy (P = 0.000). CONCLUSION: PCDGF and BCRP may be used as biomarkers to predict the first-line response to chemotherapy in patients with advanced NSCLC.

[TPX2 expression and its significance in squamous cell carcinoma of lung].

OBJECTIVE: To study the expression of targeting protein for Xklp2 (TPX2) and its significance in squamous cell carcinoma (SCC) of the lung. METHOD: Two SCC cell lines and 4 immortalized bronchial epithelial cell lines (as a precancerous model) were examined by Western blot for TPX2 expression. Reverse transcription-polymerase chain reaction analysis for TPX2 was also performed using tumor tissues from 21 patients with SCC of the lung. The expression of TPX2 was studied by immunohistochemistry (using tissue microarray) on paraffin-embedded sections of pulmonary SCC and corresponding precancerous lesions from a group of 319 patients. RESULTS: TPX2 was variably expressed in all the cell lines studied. Compared with matched controls using normal lung tissue, high level of TPX2 mRNA was detected in 16 of the 21 SCC tumor tissue samples analyzed. Immunohistochemical study showed that TPX2 was mainly present in tumor tissues but not in normal controls. The expression of TPX2 correlated with tumor grade, stage and nodal status. As for precancerous lesions, the level of TPX2 was also increased, in accordance with the degree of dysplasia. CONCLUSIONS: Expression of TPX2 may play a role in carcinogenesis of bronchial epithelium and tumor progression of pulmonary SCC. It may also represent a potential biomarker for surveillance of SCC of lung.

Highly sensitive determination of the methylated p16 gene in cancer patients by microchip electrophoresis.

The p16 tumor suppressor gene is inactivated by promoter region hypermethylation in many types of tumor. Recent studies showed that aberrant methylation of the p16 gene is an early event in many tumors, especially in lung cancer, and may constitute a new biomarker for early detection and monitoring of prevention trials. We detected tumor-associated aberrant hypermethylation of the p16 gene in plasma and tissue DNA from 153 specimens using a modified semi-nested methylation-specific PCR (MSP) combining plastic microchip electrophoresis or slab gel electrophoresis, respectively. Specimens were from 79 lung cancer patients, 15 abdominal tumor patients, 30 positive controls and 30 negative controls. The results showed that the positive rate obtained by microchip electrophoresis was more than 26.6% higher and the same specificity was kept when compared with slab gel electrophoresis. The microchip electrophoresis can rapidly and accurately analyze the PCR products of methylated DNA and obviously improve the positive rate of diagnosis of cancer patients when compared with gel electrophoresis. This method with the high assay sensitivity might be used for detection of methylation of p16 gene and even to facilitate early diagnosis of cancer patients.

[Multivariate analysis of prognosis in gastrointestinal stromal tumor].

OBJECTIVE: To identify prognostic factors in patients with gastrointestinal stromal tumors (GIST). METHODS: Hematoxylin and eosin (H&E) stained histopathological slides of tumors from patients with mesenchymal neoplasms growing in the gastrointestinal tract and abdomen were reviewed. Two histologically representative areas were identified and chosen for tissue microarray. Immunohistochemical staining was performed to demonstrate c-kit protein (CD117), CD34, smooth muscle actin, desmin and S-100 protein. The relations of various clinicopathologic features to outcome were analyzed. RESULTS: The overall disease-specific survival of 194 patients was 93.5% at 1 year, 72.1% at 3 years and 63.2% at 5 years. Univariate analysis indicated that the tumor size, mitotic count, primary location, necrosis, high cellularity, mucosal invasion, mixed cell type, hemorrhage, direct tumor invasion of surrounding tissue, male sex, incompleteness of resection, cytologic atypia were significant predictors of survival. Multivariate analysis showed that tumor size, mitotic count, necrosis, direct tumor invasion of surrounding tissue and male sex were poor prognostic signs. CONCLUSION: Tumor size and mitotic count are important prognostic factors. However, to evaluate the prognosis of these tumors, a surgical pathologist should incorporate multiple parameters into their histologic evaluation in attempt to reach an appropriate opinion on the aggressiveness of GIST.

Advanced colorectal adenoma related gene expression signature may predict prognostic for colorectal cancer patients with adenoma-carcinoma sequence.

BACKGROUND: There are still no absolute parameters predicting progression of adenoma into cancer. The present study aimed to characterize functional differences on the multistep carcinogenetic process from the adenoma-carcinoma sequence. METHODS: All samples were collected and mRNA expression profiling was performed by using Agilent Microarray high-throughput gene-chip technology. Then, the characteristics of mRNA expression profiles of adenoma-carcinoma sequence were described with bioinformatics software, and we analyzed the relationship between gene expression profiles of adenoma-adenocarcinoma sequence and clinical prognosis of colorectal cancer. RESULTS: The mRNA expressions of adenoma-carcinoma sequence were significantly different between high-grade intraepithelial neoplasia group and adenocarcinoma group. The biological process of gene ontology function enrichment analysis on differentially expressed genes between high-grade intraepithelial neoplasia group and adenocarcinoma group showed that genes enriched in the extracellular structure organization, skeletal system development, biological adhesion and itself regulated growth regulation, with the P value after FDR correction of less than 0.05. In addition, IPR-related protein mainly focused on the insulin-like growth factor binding proteins. CONCLUSION: The variable trends of gene expression profiles for adenoma-carcinoma sequence were mainly concentrated in high-grade intraepithelial neoplasia and adenocarcinoma. The differentially expressed genes are significantly correlated between high-grade intraepithelial neoplasia group and adenocarcinoma group. Bioinformatics analysis is an effective way to study the gene expression profiles in the adenoma-carcinoma sequence, and may provide an effective tool to involve colorectal cancer research strategy into colorectal adenoma or advanced adenoma.

Exosomal levels of miRNA-21 from cerebrospinal fluids associated with poor prognosis and tumor recurrence of glioma patients.

Glioma is a most common type of primary brain tumors. Extracellular vesicles, in the form of exosomes, are known to mediate cell-cell communication by transporting cell-derived proteins and nucleic acids, including various microRNAs (miRNAs). Here we examined the cerebrospinal fluid (CSF) from patients with recurrent glioma for the levels of cancer-related miRNAs, and evaluated the values for prognosis by comparing the measures of CSF-, serum-, and exosome-contained miR-21 levels. Samples from seventy glioma patients following surgery were compared with those from brain trauma patients as a non-tumor control group. Exosomal miR-21 levels in the CSF of glioma patients were found significantly higher than in the controls; whereas no difference was detected in serum-derived exosomal miR-21 expression. The CSF-derived exosomal miR-21 levels correlated with tumor spinal/ventricle metastasis and the recurrence with anatomical site preference. From additional 198 glioma tissue samples, we verified that miR-21 levels associated with tumor grade of diagnosis and negatively correlated with the median values of patient overall survival time. We further used a lentiviral inhibitor to suppress miR-21 expression in U251 cells. The results showed that the levels of miR-21 target genes of PTEN, RECK and PDCD4 were up-regulated at protein levels. Therefore, we concluded that the exosomal miR-21 levels could be demonstrated as a promising indicator for glioma diagnosis and prognosis, particularly with values to predict tumor recurrence or metastasis.

1st International Lung Cancer Conference in Beijing, October 27-30, 2002.

The 1st International Lung Cancer Conference was held on October 27-30, 2002 in Beijing, China. Leaders in the field of lung cancer came from Europe, Asia, and North America to speak at the event. Over 150 Asian physicians and scientists attended as well as attendees from both Europe and the US. Topics included Primary Prevention and Tobacco Control, Screening and Early Detection, Chemotherapy and Molecular Targeted Therapies, Chemoprevention, Molecular Biology/Pathology, Radiotherapy and Surgery. This paper is a comprehensive review of the data presented at the meeting.

Detailed deletion mapping of loss of heterozygosity on 9p13-23 in laryngeal squamous cell carcinoma by microsatellite analysis.

BACKGROUND: This study was designed to investigate the hot spots of microsatellite loss of heterozygosity (LOH) on 9p13-23 in laryngeal squamous cell carcinoma and to find out the correlation between the incidence of microsatellite LOH and the clinicopathological parameters. METHODS: Tumor tissues were obtained from paraffin embedded sections with microdissection. Genomic DNA was extracted from tumor tissues and peripheral blood lymphocytes with the phenol-chloroform. Polymerase chain reaction (PCR) amplification and denaturing gel electrophoresis were carried out in a set of 42 squamous cell carcinoma (SCC) of larynx and corresponding peripheral blood lymphocytes using 13 highly polymorphic microsatellite markers on 9p13-23. The correlation was analyzed between microsatellite LOH at the high frequency on 9p13-23 and clinicopathological parameters in the patients with squamous cell carcinoma of larynx. RESULTS: Of the 42 laryngeal cancers, 41 (97.6%) showed LOH in at least one of the microsatellite markers tested on 9p13-23. The most frequently deleted marker was D9S162 in 17 of the 19 (89.5%) informative samples. The marker D9S171, which is located on 9p21, had LOH detected in 12 of the 15 informative cases (80.0%). LOH at the D9S1748 marker (closest to the p16 gene locus) was detected in 18 of the 36 informative cases (50.0%). Allelic deletion mapping revealed two minimal regions of LOH encompassing markers D9S161-D9S171 on 9p21 and IFNA-D9S162 on 9p22-23. Multiple LOH (> or = 4) on 9p21-23 was found more frequently in the patients under 60 years, with supraglottic SCC or cervical lymph node metastasis than those over 60 years, with glottic SCC or without cervical lymph node metastasis (P < 0.01 or 0.01, 0.05, respectively). On the contrary, there was no correlation between T stages or pathologic classification and the frequency of LOH on 9p21-23 in 42 SCC of Larynx. CONCLUSIONS: These findings imply the presence of at least two putative tumor suppressor genes on 9p13-23 in laryngeal SCC. Multiple genetic alterations are probably implicated in supraglottic SCC with cervical lymph node metastasis in younger patients.

Quantification of plasma DNA as a screening tool for lung cancer.

BACKGROUND: Recent studies suggest that circulating DNA may be a potential tumor marker for lung cancer, but most of these studies are conducted between healthy controls and lung cancer patients, with few or no benign lung disease patients included. The objective of this study was to evaluate the performance of plasma DNA quantification in discriminating lung cancer from the healthy and benign lung disease. METHODS: Plasma DNA was extracted with a QIAamp DNA Blood Midi kit and quantified by a PicoGreen dsDNA quantitation kit in 44 healthy individuals, 36 benign lung disease patients and 67 lung cancer patients. Discrimination power was evaluated by the receiver operating characteristic curve. RESULTS: Plasma DNA values were significantly increased in lung cancer patients, especially in those with metastases, and in benign lung disease patients compared with that in the healthy individuals (P < 0.001, respectively). The values in lung cancer patients were significantly increased compared with that in the benign lung disease patients (P < 0.001). The area under the curve was 0.96 [95% confidence interval (CI) 0.92 - 0.99] for the healthy versus lung cancer, 0.73 (95% CI 0.64 - 0.83) for lung cancer versus benign lung disease, and 0.86 (95% CI 0.80 - 0.91) for lung cancer versus the healthy and benign lung disease. CONCLUSIONS: Plasma DNA quantification has a strong power to discriminate lung cancer from the healthy and from the healthy and benign lung disease, less power to discriminate lung cancer from benign lung disease. Plasma DNA quantification may be useful as a screening tool for lung cancer.

Pharmacokinetics of rapamycin-eluting stents in miniswine coronary model.

BACKGROUND: The results of clinical trials of rapamycin-eluting stents reduce restenosis have been quite promising. The main purpose of this study was to characterize the in vivo pharmacokinetics of high dose rapamycin (Rapa)-eluting stents in a miniswine coronary model. METHODS: Ten miniswines underwent placement of 18 high dose Rapa-eluting stents in the left anterior descending and right coronary arteries. At the planned times of the 1.5th, 12th, 24th hour, 3th, 7th and 28th day, the animals (n = 1, 1, 2, 2, 2, and 2, respectively) were euthanized after completion of coronary angiography. Blood samples were obtained at 0, 10, 20, 30 minutes; 1, 2, 6, 24 hours; and 3, 7, 28 days to determine systemic Rapa levels. Rapa levels in whole blood, arterial wall, heart, renal and liver tissues were determined by high-performance liquid chromatography/mass spectroscopy. RESULTS: Peak whole blood concentration (Cmax), time to peak concentration (tmax), elimination half-life (t1/2beta), area under the curve (AUC), and apparent systemic clearance (Cl/F) were (10.91 +/- 1.28) ng/ml, (2.0 +/- 0.2) hours, (7.25 +/- 0.63) hours, (1.15 +/- 0.11) ng x h x ml(-1), and (180 +/- 12) ml x h(-1) x kg(-1), respectively. More than 95% Rapa detected is localized in the coronary artery surrounding the stent and heart. CONCLUSION: Stent-based delivery of Rapa via a copolymer stent is feasible and safe. This strategy holds promise for the prevention of stent restenosis.

[Hypermethylation of p16 gene in clinical specimens of patients with lung cancer].

OBJECTIVE: To evaluate aberrant methylation of the p16 promoter as a useful biomarker of lung cancer. METHODS: A modified methylation-specific semi-nested PCR was performed to detect p16 hypermethylation in the matched samples of tumor tissue, blood plasma and sputum derived from 51 cases of lung cancer patients. RESULTS: Hypermethylation of p16 promoter was demonstrated in 84.3% of the tumor tissues, 70.6% of the blood plasma and 76.5% of the sputum specimens, respectively. Only the patients whose tumor tissues had p16 hypermethylation exhibited aberrant methylation in their plasma and/or sputum specimens. Combining with cytological examination, 92.2% of the patients with lung cancer could be detected by p16 hypermethylation assay in both sputum and plasma samples. CONCLUSION: The results indicate that p16 hypermethylation in plasma and sputum identified by semi-nested PCR is a biomarker of lung cancer which can be useful as an auxillary diagnostic parameter.

[Screening of hypermethylated DNA fragments in tumor tissue derived from patients with lung cancer].

The investigations on the role of DNA methylation in carcinogenesis have been mainly focused on promoter hypermethylation of tumor suppressor genes. As a number of genes associated with cancer development may be influenced by DNA methylation, identification of these genes is of great importance for understanding the epigenetic alteration in carcinogenesis. In this study, hypermethylated regions of genomic DNA from Chinese lung cancer patients were identified by a modified methylation-sensitive arbitrarily primed PCR (MS-AP-PCR). Eight hypermethylated DNA fragments (HMDF) were separated from a PCR product region between 300 and 500bp in size. After cloning, sequencing and searching with Blast and NewCpGseek programs,the result showed that all of them were typical CpG island sequences, four fragments had 99% approximately 100% homology to regions on human chromosome 2, 7, 9 and 10, respectively,but only one revealed to be known gene. Neural Network Promoter Prediction, TSSG and TSSW programs were run to analyze possible functions of the rest 7 fragments, of which 4 were identified as candidate promoter regions, indicating that they might belong to new genes. The hypermethylated DNA fragments identified in this study might be specific epigenetic alterations in the Chinese lung cancer.

[Detection of hypermethylation of p16 gene in plasma DNA from lung cancer patients].

OBJECTIVE: To detect hyper methylation of p16 gene in plasma DNA from patients with lung cancer, and to assess its potential as a malignant marker. METHODS: Using a modified semi-nested methylation-specific PCR (MSP), the status of methylation of the p16 was investigated in plasma DNA from 137 lung cancer patients and 112 matched tumor tissues. RESULTS: Hypermethylation of the p16 was present in 75.2% (103/137) of the plasma samples and 80.4% (90/112) of the tumor tissues. Hypermethylation of the p16 in the plasma was detected in 77.9% squamous-cell carcinoma, 65.1% adenocarcionma, 75.1% adeno-squamous-cell carcinoma, and 91.7% small-cell lung cancer. Only in those patients whose tumor tissues had hypermethylation of p16 gene, similar changes could be detected in their plasma samples. Hypermethylation of the p16 in plasma and the corresponding tumor tissues was not significantly correlated with the clinical stage and pathological type of the tumor. CONCLUSION: The result indicates that hypermethylation of the p16 may be a useful marker in the auxiliary diagnosis of lung cancer.