CHROMOSOME 17P MAY HARBOR MULTIPLE TUMOR SUPPRESSOR GENES ASSOCIATED WITH PRIMARY GLIOBLASTOMA MULTIFORME

Objective: To investigate whether deletion of chromosome 17 is involved in the carcinogenesis of primary glioblastoma multiforme and to localize the possible common deletion region in the aforementioned chromosome. Methods: Polymerase chain reaction-based microsatellite analysis was used to assess loss of heterozygosity (LOH) on chromosome 17 in 20 primary glioblastoma multiforme (GBM). Fifteen fluorescent dye-labeled polymorphic markers were used. Results: Thirteen of twenty (65%) GBM displayed LOH on at least one marker of chromosome 17p. Two tumors showed either LOH or non-informativeness on all markers tested. The most frequent LOH was observed at loci including D17s799 (53.3%), D17s1852 (53.8%), D17s938 (63.20/o), D17s831 (55.6%). The loci D17s831 (on 17p13) and D17s799–D17s1852 (17p11.2–p12) are distal and proximal to p53 respectively. The frequencies of LOH at all loci examined on chromosome 17q were relatively low (<30%). None of informative loci exhibited microsatellite instability in this study. Conclusion: Loss of genetic material on chromosome 17p may play an important role in the pathogenesis of GBM. Besides the well-known TSG p53 on 17p, other unknown TSCs associated with GBM may be present on the chromosomal regions 17p13 and 17p11.2–p12, which are distal and proximal to p53 respectively.

CHROMOSOME 3 MAY HARBOR MULTIPLE TUMOR SUPPRESSOR GENES ASSOCIATED WITH PRIMARY GLIOBLASTOMA MULTIFORME

Objective: To investigate whether deletion of chromosome 3 is involved in the carcinogenesis of primary glioblastoma multiforme (GBM) and to localize the possible common deletion region in the aforementioned chromosome. Methods: PCR based microsatellite polymorphism analyses were performed to detect loss of heterozygosity (LOH). Twenty-three loci on chromosome 3 were examined in 20 cases of GBM. Fluorescence-labeled primers and Perkin Elmer 377 DNA Sequencer were applied. Results: 50% informative cases of GBM displayed LOH on chromosome 3. 50% of informative cases displayed LOH on 3q and 35% on 3p. 25.6% of informative loci showed LOH in our series, in which frequent LOH were observed in the chromosomal region from loci D3S1614 (42.9%) to D3S1565 (35.3%) on 3q24–27 and at loci D3S1569 (35.3%) on 3q22–23 and D3S1289 (33.3%) on 3p14.1–14.3. Conclusion: Loss of genetic material on chromosome 3 may play an important part in the tumorigenesis of GBM. The chromosomal regions from loci D3S1614 to D3S1565 on 3q24–27 and at loci D3S1569 on 3q22–23 and D3S1289 on 3p14.1–14.3 are potential sites for novel tumor suppressor genes associated with GBM.

Integrated transcriptome interactome study of oncogenes and tumor suppressor genes in breast cancer

Breast cancer is the leading cause for mortality among women worldwide.Dysregulation of oncogenes and tumor suppressor genes is the major reason for the cause of cancer.Understanding these genes will provide clues and insights about their regulatory mechanism and their interplay in cancer.In the present study,an attempt is made to compare the functional characteristics and interactions of oncogenes and tumor suppressor genes to understand their biological role.431 breast cancer samples from seven publicly available microarray datasets were collected and analysed using GEO2R tool.The identified 416 differentially expressed genes were classified into five gene sets as oncogenes(OG),tumor suppressor genes(TSG),druggable genes,essential genes and other genes.The gene sets were subjected to various analysis such as enrichment analysis(viz.,GO,Pathways,Diseases and Drugs),network analysis,calculation of mutation frequencies and Guanine-Cytosine(GC)content.From the results,it was observed that the OG were having high GC content as well as high interactions than TSG.Moreover,the OG are found to have frequent mutations than TSG.The enrichment analysis results suggest that the oncogenes are involved in positive regulation of cellular protein metabolic process,macromolecule biosynthetic process and majorly in cell cycle and focal adhesion pathway in cancer.It was also found that these oncogenes are involved in other diseases such as skin diseases and viral infections.Collagenase,paclitaxel and docetaxel are some of the drugs found to be enriched for oncogenes.

Screening of tumor suppressor genes on 1q31.1-32.1 in Chinese patients with sporadic colorectal cancer

Background As a model for both multistep and multipathway carcinogenesis, colorectal neoplastic progression provides paradigms for researching both oncogenes and tumor suppressor genes （TSGs）. However, the mechanism of colorectal cancer （CRC） is not completely understood, and many genes may be involved in the colorectal carcinogenesis. The purpose of this study was to screen for the potential TSGs on chromosome 1q31.1-32.1 in Chinese patients with sporadic colorectal cancer, to explore whether colorectal cancer in the Chinese population has unique genetic alterations and determine whether other putative TSGs exist and contribute to colon carcinogenesis. Methods Six polymorphic microsatellite markers, at a density of approximately one marker in every 1.6 cM, were chosen for refined loss of heterozygosity （LOH） mapping of 1q31.1-32.1. Eighty-three colorectal cancer patients＇ tumor and normal DNA were analyzed via polymerase chain reaction （PCR） for these microsatellite markers. PCR products were eletrophoresed on an ABI 377 DNA sequencer. Genescan 3.1 and Genotype 2.1 software were used for LOH scanning and analysis. On the basis of refined LOH mapping results, we undertook a microarray-based expression screening to identify tumor association genes in 19 of the CRC cases. Results The average LOH frequency of 1q31.1-32.1 was 24.41%, with the highest frequency of 36.73% （18/49） at D1S2622, and the lowest of 16.42% （11/67） at D1S412. A minimal region of frequent deletion was located within a 2 cM genomic segment at D1S413-D1S2622. There was no significant association between LOH of any marker in the studied regions and the clinicopathological data （patient sex, age, tumor size, growth pattern, or Dukes stage）. On the basis of refined mapping results, we chose 25 genes located in the D1S413-D1S2622 （1q31.3-32.1） region and presented a microarray-based high throughput screening approach in 19 sporadic CRC cases to identify candidate CRC related tumor suppressor genes. This study found 4 significantly down-expressed genes, including CSRP1, LMOD1, PPP1R12B and CFHL3. There was no significant association between expression levels of CFHL3, CSRP1, LMOD1, PPP1R12B and the clinicopathological data. By database searching, CSRP1 was hypothesized to be a colorectal cancer related tumor suppressor gene. Conclusions Through detailed deletion mapping, we found that the 1q31.3-32.1 region might harbor one or more colorectal cancer related tumor suppressor gene（s）. And by microarray-based high-throughput screening of candidate genes located in this region and by subsequent database searching, we present the first evidence that CSRP1 might be involved in the progression of CRC.

ISOLATION OF TUMOR DIFERENTIALLY EXPRESSED GENES BY MIXING PROBES LIBRARY SCREEN

Objective: This study was designed to clone candidate tumor suppressor genes down-expressed in Nasopharyngeal Carcinoma (NPC). Methods: Differentially expressed cDNA fragments (AF152605 and AF091517) were labeled by PCR, and Northern blot was used to confirmed transcript length of these genes. Skeleton muscle cDNA library was screened with PCR-labeled probe mixture. Results: 23 positive independent and overlapping positive clones were obtained. By sequencing the positive clones directly, three novel genes (Genbank accession number: AF179285, AF170307 and AF194971), with transcripts of 2.1 Kb, 1.1 Kb and 1.4 Kb respectively, were isolated successfully. Conclusions: Library screening using PCR-labeled probes mixture is an efficient method to get full-length cDNA from multi-cDNA fragment simultaneously and quickly.

Expression of the Tumor Metastatic Suppressor Gene in Mouse Melanoma Model: Inverse Association to Metastatic Potential

Data obtained in experimental cutaneous melanomas have suggested that the nm23 gene may function as a metastasis suppressor gene. The nm23 level in 8 human cutaneous melanoma cell lines and 2 murine melanoma cell lines were examined. Each melanoma cell line was transplanted subcutaneously into the flank of nude mice, and the metastatic behavior was evaluated by counting lung tumor fool and by determining host survival time. It was found that expression of 'm23 mRNA in human melanomas is correlated closely with reduced metastatic behavior in experimental animals and may serve as a sensitive prognostic indicator of malignancy and survival in patients with melanomas.

Aberrant expression of genes and proteins in pterygium and their implications in the pathogenesis

Pterygium is a common ocular surface disease induced by a variety of factors. The exact pathogenesis of pterygium remains unclear. Numbers of genes and proteins are discovered in pterygium and they function differently in the occurrence and development of this disease. We searched the Web of Science and PubMed throughout history for literatures about the subject. The keywords we used contain pterygium, gene, protein, angiogenesis, fibrosis, proliferation, inflammation, pathogenesis and therapy. In this review, we summarize the aberrant expression of a range of genes and proteins in pterygium compared with normal conjunctiva or cornea, including growth factors, matrix metalloproteinases and tissue inhibitors of mefalloproteinases, interleukins, tumor suppressor genes, proliferation related proteins, apoptosis related proteins, cell adhesion molecules, extracellular matrix proteins, heat shock proteins and tight junction proteins. We illustrate their possible mechanisms in the pathogenesis of pterygium as well as the related intervention based on them for pterygium therapy.

Loss of chromosome 9p21 and decreased p16 expression correlate with malignant gastrointestinal stromal tumor

AIM: To investigate loss of heterozygosity (LOH) of chromosome 9p21 and the prognostic relevance of p16 expression in gastrointestinal stromal tumor (GIST). METHODS: Fifty-one GIST patients (30 men and 21 women; median age 59 years; range 29-80 years) treated surgically within a 10-year period were grouped by aggressive behavior risk (17 with very low and low, 14 intermediate, and 20 high risk). GISTs were characterized immunohistochemically and evaluated for LOH of 9p21 by microsatellite analysis at D9S1751, D9S1846, D9S942, and D9S1748. LOH of 9p21 and immunohistochemicalexpression of p16 protein encoded at 9p21 were correlated with clinicopathological parameters, and the prognostic significance of p16 alterations was evaluated. RESULTS: Thirty-one (63.3%) cases showed LOH with at least one microsatellite marker. LOH frequency was 37.0% at D9S1751, 37.5% at D9S1846, 42.1% at D9S942, and 24.2% at D9S1748. There was a higher LOH frequency of D9S942 in high-risk than in non-highrisk tumors (P < 0.05, χ 2 = 4.47). Gender, age, tumor size and site were not correlated with allelic loss. Ninety percent (18/20) of the GIST patients in the high risk group showed LOH with at least one of the 9p21 markers, while 57.1% (8/14) in the intermediate risk group and 33.3% (5/15) in the very low and low risk groups, respectively (P < 0.05, χ 2 = 12.16). Eight (28.5%) of 31 patients with LOH and 1 (5.6%) of 18 patients without LOH died of the disease during the follow-up period. Loss of p16 protein expression occurred in 41.2%, but in 60% of the high risk group and 23.5% of the very low and low risk groups (P < 0.05, χ 2 = 4.98). p16 loss was associated with poor prognosis (P < 0.05, χ 2 = 4.18): the 3and 5-year overall survival rates were 84.8% and 70.8% for p16-negative and 100% and 92.0% for p16-positive patients, respectively. CONCLUSION: LOH at 9p21 appears to play an important role in GIST progression; decreased p16 expression in GIST is highly predictive of poor outcome.

TELOMERASE: A NOVEL TARGET OF ANTITUMOR AGENTS

Telomerase activity was found to be high in various human cancers, but absent in most normal tissues. Its expression pattern made it a novel target for antitumor agents. Several strategies against telomerase were presented in this review. Targeting the telomerase RNA component by oligonucleotide/ribozyme was considered to be one of the most hopeful approaches. Some progresses were made in this area, such as the use of PANs and 2–5A antisense compounds. The relationships among telomerase activity and cell differentiation, signal transduction, oncogene, tumor suppressor gene as well as cell cycle modulation also provided a series of valuable ideas in designing anti-telomerase drugs for cancer therapy. In conclusion, although there is still a long way in understanding the mechanism and regulation of telomerase, the advance of studies on telomerase has allowed the development of numerous strategies for the treatment of cancer.

Interaction of Human Genes WT1 and CML28 in Leukemic Cells

The molecular pathogenesis of leukemia is poorly understood. Earlier studies have shown both Wilms＇ tumor 1 suppressor gene （WT1） and CML28 abnormally expressed in malignant diseases of the hematopoietic system and WT1 played an important role in leukemogenesis. However, the rela- tionship between molecular CML28 and WT1 has not been reported. Here we described the use of small interfering RNA （siRNA） against WT1 and CML28 in leukemic cell line K562 to examine the interac- tion between CML28 and WT1. WT1 and CML28 gene expression in transfected K562 cells was de- tected by using RQ-PCR and Western blotting. K562 cells transfected with WTI-siRNA could greatly decrease both mRNA and protein expression levels of WT1 and CML28. In contrast, CML28-siRNA did not exert effect on WT1. Further, subcellular co-localization assay showed that the two proteins could co-localize in the cytoplasm of K562 cells, but WT1/CML28 complexes were not detected by us- ing immunoprecipitation. It was suggested that there exists the relationship between CML28 and WT1. CML28 may be a downstream target molecule of WT1 and regulated by WT1, which will provide im- portant clues for further study on the role of CML28 and WT1 in leukemic cells.

Potential effect of hepatitis C Virus non-structural protein 4B on liver carcinogenesis

Objective：To investigate the effect of hepatitis C virus non-structural protein 4B（HCV NS4B） on c-Myc, P53, ras gene expression＂ and apoptosis in hepatic cells and study the possible role that NS4B played in the carcinogenesis of heparoma. Methods： The recombinant plasmid（PCXN2-NS4B, PCXN2-P53） and the empty, vector were transfected or co-transfected into Chang liver cells with liposome. Screening was performed with G418. Plasmid mRNA was detected by RT-PCR. The pro rein expressions of c-Myc and ras genes were analyzed by immunocytochemistry. The expressions of wild-type P53 （wtp53） gene were detected by in situ hybridization. TUNEL（flow cytometry） was used for assessing the rate of apoptosis. Results：No expression of c-Myc gene was found in PCXN2 group. The expression of c-Myc gene in NS4B group was 21.3% ＋ 1.2%. The ex pression of ras gene in PCXN2 group was lower than that in NS4B group. Compared with PCXN2 group, the expression of P53 mRNA was not promoted or inhibited in NS4B group. But the expression of P53 mRNA in NS4B-P53 group was lower than that in P53 group. In PCXN2, NS4B, P53 and NS4B-P53 group, the rates of apoptosis were 17.02% ± 1.24%, 11.94% ± 2.24%, 25.84% ± 3.49% and 18.34% ± 1.55% respectively. Conclusion ：HCV NS4B induces the expression of c-Myc and ras gene. HCV NS4B may play a role in the inhibition of cell death through P53-dependent manner. Results from this study suggested that HCV NS4B might contribute to the viral carcinogenesis.

JARID2 coordinates with the NuRD complex to facilitate breast tumorigenesis through response to adipocyte-derived leptin

Background Proteins containing the Jumonji C(JmjC)domain participated in tumorigenesis and cancer progression.However,the mechanisms underlying this effect are still poorly understood.Our objective was to investigate the role of Jumonji and the AT-rich interaction domain-containing 2(JARID2)—a JmjC family protein—in breast cancer,as well as its latent association with obesity.Methods Immunohistochemistry,The Cancer Genome Atlas,Gene Expression Omnibus,and other databases were used to analyze the expression of JARID2 in breast cancer cells.Growth curve,5-ethynyl-2-deoxyuridine(EdU),colony formation,and cell invasion experiments were used to detect whether JARID2 affected breast cancer cell proliferation and invasion.Spheroidization-based experiments and xenotumor transplantation in NOD/SCID mice were used to examine the association between JARID2 and breast cancer stemness.RNA-sequencing,Kyoto Encyclopedia of Genes and Genomes,and Gene Set Enrichment Analysis were used to identify the cell processes in which JARID2 participates.Immunoaffinity purification and silver staining mass spectrometry were conducted to search for proteins that might interact with JARID2.The results were further verified using co-immunoprecipitation and glutathione S-transferase(GST)pull-down experiments.Using chromatin immunoprecipitation(ChIP)sequencing,we sought the target genes that JARID2 and metastasis-associated protein 1(MTA1)jointly regulated;the results were validated by ChIP-PCR,quantitative ChIP(qChIP)and ChIP-reChIP assays.A coculture experiment was used to explore the interactions between breast cancer cells and adipocytes.Results In this study,we found that JARID2 was highly expressed in multiple types of cancer including breast cancer.JARID2 promoted glycolysis,lipid metabolism,proliferation,invasion,and stemness of breast cancer cells.Furthermore,JARID2 physically interacted with the nucleosome remodeling and deacetylase(NuRD)complex,transcriptionally repressing a series of tumor suppressor genes such as BRCA2 DNA repair associated(BRCA2),RB transcriptional corepressor 1(RB1),and inositol polyphosphate-4-phosphatase type II B(INPP4B).Additionally,JARID2 expression was regulated by the obesity-associated adipokine leptin via Janus kinase 2/signal transducer and activator of transcription 3(JAK2/STAT3)pathway in the breast cancer microenvironment.Analysis of various online databases also indicated that JARID2/MTA1 was associated with a poor prognosis of breast cancer.Conclusion Our data indicated that JARID2 promoted breast tumorigenesis and development,confirming JARID2 as a target for cancer treatment.

MicroRNA and esophageal carcinoma

Objective：An abundant class of non-coding small RNA molecules, 21-25 nucleotide in length, are widely found in animals and plants and named microRNA （miRNA）. MiRNAs are highly evolutionarily conserved, expressing in specific tissue and timing, and negatively regulate the gene expressions at the posttranscriptional level,and subsequently control crucial physiological processes such as metabolism, amplification, differentiation, development and apoptosis, Therefore, miRNAs could provide an access to many human diseases in theory. Recent evidence demonstrates that miRNAs play an important role in the initiation and progression of human cancer, mainly by interrupting the cell cycle at the cellular level and by interacting with signaling The expression profiling of miRNAs can be used as a tool of diagnosis, staging, prognosis and biotherapy of some tumors, as has already been proven to have superiority to mRNA, in the categorization of tumors. This review focuses on the genesis, mechanism of action of miRNA and its relationship to tumors, detection methods and its potential effect on the diagnosis, staging, and biotherapy in esophageal carcinoma.

LOSS OF HETEROZYGOSITY ON CHROMOSOME 13 IN SQUAMOUS CELL CARCINOMAS OF THE LARYNX

Objective: To locate lost region of tumor suppressor gene on chromosome 13q in squamous cell carcinoma of the larynx (LSCC) and to provide clues and evidence for discovering and locating new suppressor gene. Methods: Loss of heterozygosity (LOH) on chromosome 13q was analyzed in 58 LSCC patients by microsatellite polymorphic sequences in loci D13S765 (13q13), RB120 (13q142), D13S133 (13q143) and D13S318 (13q21) on chromosome 13 by PCR. Results: There weren't any LOH on chromosome 13q in 3 cases with preinvasive LSCC. Fortyfive percentage (24/53) of the 53 invasive LSCC cases showed LOH at one or more loci on chromosome 13q region. The highest percentage of LOH on chromosome 13q was 52% (22/53) at D13S765 locus. Conclusion: The deletion region on chromosome 13q was located near by D13S765 locus which is centromeric to RB1. In this region there is suppressor gene, which is related to the genesis and development of LSCC, possibly including RB1. The inactivation of these suppressor genes may be related to the genesis and development of invasive LSCC.

Change of CMTM7 expression, a potential tumor suppressor, is associated with poor clinical outcome in human non-small cell lung cancer

Background CKLF-like MARVEL transmembrane domain-containing 7 （CMTM7） located at 3p22.3,is a frequent deletion site and a tumor suppressor gene （TSG） locus in many cancer,which suggests CMTM7 may be a potential TSG.The aim of this study was to investigate the correlations of CMTM7 expression and survival rate in patients with non-small-cell lung cancer （NSCLC）.Methods Surgical specimens of 180 cases with pathologically confirmed NSCLC were grouped into 18 tissue microarray slides.CMTM7 expression in these specimens were detected by immunohistochemistry staining and representative cases were confirmed by Western blotting.Univariate and multivariate analyses were performed to identify the association of CMTM7 expression with pathological features and survival of patients with NSCLC.Results A total of 78.9％ of the 180 patients had variations of CMTM7 protein expression,either up-regulated or downregulated.Univariate analysis showed that the patients＇ survival rate after surgery was highly correlated with CMTM7 expression （P=0.0091）.In addition,prognostic factors were examined by multivariate Cox regression analysis,and results suggested that CMTM7 expression was a unique prognostic factor in NSCLC survival.Conclusions The CMTM7 expression may be related to survival of patients with NSCLC and a unique prognostic factor.CMTM7 may play an important role in NSCLC development.

EYA4 gene functions as a prognostic marker and inhibits the growth of intrahepatic cholangiocarcinoma

Background:The molecular prognostic markers and carcinogenesis of intrahepatic cholangiocarcinoma(ICC) have not been well documented.The purpose of this study was to investigate the prognostic value of the eyes absent homolog 4(EYA4) gene in ICC and its biological effects on ICC growth in vitro and in vivo.Methods:One hundred twelve patients with ICC who underwent hepatectomy were enrolled in the study.EYA4 mRNA and EYA4 protein levels in ICC and adjacent non-tumoral tissues were evaluated using real-time quantitative polymerase chain reaction and immunohistochemical staining,respectively.EYA4 protein levels in ICC cells were determined using western blot analysis.The associations between EYA4 expression and clinicopathologic features of ICC were analyzed.To identify independent prognostic factors,univariate and multivariate analyses were performed.The biological effects of EYA4 on ICC cells were evaluated by establishing stable EYA4-overexpressing transfectants in vitro,and EYA4's effects on tumor growth were evaluated by intra-tumoral injection of EVA4-expressing plasmids in a NOD/SCID murine model of xenograft tumors.Results:ICC tissues had significantly lower EYA4 mRNA and protein levels compared with adjacent non-tumoral tissues(both P < 0.001).Univariate and multivariate analyses showed that EYA4 protein level,tumor number,adjacent organ invasion,lymph node metastasis,and tumor differentiation were independent prognostic factors for diseasefree survival and overall survival(all P < 0.05).In vitro,EYA4 overexpression inhibited tumor cell growth,foci formation,and cell invasiveness.In vivo,intra-tumoral injection of EYA4-expressing plasmids significantly inhibited ICC growth in the murine xenograft model compared with the control group(P < 0.05).Conclusion:EYA4 gene functioned as a molecular prognostic marker in ICC,and its overexpression inhibited tumor growth in vitro and in vivo.

Aberrant methylation of secreted protein acidic and rich in cysteine gene and its significance in gastric cancer

BACKGROUND Aberrant methylation in DNA regulatory regions could downregulate tumor suppressor genes without changing the sequences.However,our knowledge of secreted protein acidic and rich in cysteine(SPARC)and its aberrant methylation in gastric cancer(GC)is still inadequate.In the present research,we performed fundamental research to clarify the precise function of methylation on SPARC and its significance in GC.AIM To investigate promoter methylation and the effects of the SPARC gene in GC cells and tissues and to evaluate its clinical significance.METHODS Plasmids that overexpressed the SPARC gene were transfected into human GC BGC-823 cells;non-transfected cells were used as a control group(NC group).Quantitative real-time polymerase chain reaction and western blotting(WB)were then used to detect the expression of SPARC.Methylation-specific polymerase chain reaction was executed to analyze the gene promoter methylation status.Cell viability was measured by the cell counting kit-8 assay.The migration and invasion ability of cells were detected by scratch assays and transwell chamber assays,respectively.Cell cycle events and apoptosis were observed with a flow cytometer.RESULTS The expression of SPARC mRNA in GC tissues and cells was significantly lower and showed differing degrees of hypermethylation,respectively,than that in normal adjacent tissues and control cells.Treatment with 5-Aza-2’-deoxycytidine(5-Aza-Cdr)was able to restore the expression of SPARC and reverse promoter hypermethylation.Overexpression of the SPARC gene significantly inhibited proliferation,migration,and invasion of GC cells,while also causing cell cycle arrest and apoptosis;the NC group exhibited the opposite effects.CONCLUSION This study demonstrated that SPARC could function as a tumor suppressor and might be silenced by promoter hypermethylation.Furthermore,in GC cells,SPARC inhibited migration,invasion,and proliferation,caused cell cycle arrest at the G0/G1 phase,and promoted apoptosis.

Expression level of novel tumor suppressor gene FATS is associated with the outcome of node positive breast cancer

Background Recently, we reported the identification of a previously uncharacterized and evolutionarily conserved gene, fragile-site associated tumor suppressor （FATS）, at a frequently deleted region in irradiation （IR）-induced tumors. However, the role of FATS in breast cancer development and its clinical significance has not been defined. The aim of this study was to determine the role of FATS in breast cancer development and to evaluate its clinical significance in breast cancer. Methods The expression level of FATS mRNA was determined in 106 breast carcinomas and 23 paired normal breast tissues using quantitative real time reverse transcription-polymerase chain reaction （RT-PCR）. The relationship between FATS expression and clinicopathological parameters were also analyzed. Results The mRNA level of FATS was down-regulated in breast cancer compared with paired normal tissues. Low expression of FATS was correlated with high nuclear grade. There was a tendency to a favorable outcome for patients with high expression of FATS （P=0.346）. However, low expression of FATS was associated with poor outcome of breast cancer patients with node positive （P=0.011）. Furthermore, the mRNA level of FATS showed an independent value in predicting the outcome of breast cancer patients with positive lymph nodes. Conclusion FATS is involved in the carcinogenesis and development of breast cancer and could be a potential biomarker and prognostic factor for breast cancer therapy.

HYPERMETHYLATION OF p14^(ARF) PROMOTER REGION AND EXPRESION OF p14^(ARF) GENE PRODUCT IN NON-SMALL CELL LUNG CANCER

Objective： This study was designed to investigate promoter methylation status and protein expression of p14^ARF gene in non-small cell lung cancer, and value the role of p14^ARF promoter methylation in carcinogenesis of non-small cell lung cancer. Methods： Promoter methylation status and protein expression of p14^ARF gene in 40 cases of non-small cell lung cancer were analyzed by methylation specific polymerase china reaction （MSP）, restriction enzyme-related polymerase chain reaction （RE-PCR） and immunohistochemistry （IHC）. Results： The positive rates of p14^ARF promoter methylation in tumor tissues and normal tissues adjacent to cancer were 17.5% （7/40） and 2.5% （1/40） respectively. There were statistically significant differences between them, P〈0.05. The results of RE-PCR were consistent with that of MSP. The expression rate of p14^ARF protein in tumor tissues was significantly lower than that in normal tissues adjacent to cancer, p〈0.01. Promoter methylation status and protein expression of p14^ARF gene in non-small cell lung cancer showed significantly an inverse correlation （r=-0.56, P〈0.01）, and both of them did not relate statistically with the clinicopathologic characteristics of patients such as histological classification, clinical stage, differentiation grade and lymph node involvement. Conclusion： Promoter methylation is a crucial mechanism of inactivation of p14^ARF gene. Promoter methylation of p14^ARF gene might he involved in carcinogenesis of non-small cell lung cancer, and is an early event in development process of non-small cell lung cancer. It might be used as a new target in gene treatments in the future.

INACTIVATION OF THE CDKN2/pl6 GENE INDUCED BY METHYLATION AT 5'-CpG ISLAND AND ITS RELATION TO LUNG CANCER

Objectives: To investigate the methylation status of the CDKN2/pl6 gene 5′-CpG island, and study the relationship between the CDKN2/pl6 gene inactivation by methylation and lung cancer. Methods: Genomic DNA extracted from the specimens of lung cancer and normal lung tissue was digested with methylation-sensitive endonucleases, and Southern blotting was used to analyze the methylation status of the CDKN2/pl6 gene in 89 cases of lung cancer and 10 cases of normal lung tissue. Results: In 89 cases of lung cancer studied, the CDKN2/pl6 gene was shown to be methylated in 21 cases with the total methylation rate of 23.6% (21/89), in which there were 15 cases (16.9%) methylated atSmaI sites, 12 cases (13.5%) atSmaI sites and 6 cases at bothSmaI andSacII sites. The methylation of the CDKN2/pl6 gene occurred in 17 among 42 of pl6 protein negative cases of lung cancer with a rate of 40.5% (17/42), and in 3 among 47 of pl6 protein positive cases with a rate of 6.4% (3/47). The CDKN2/pl6 gene was not methylated in 10 cases of normal lung tissue. Conclusion: The aberrant methylation of the CDKN2/pl6 gene 5′-CpG island is probably an important mechanism of the gene inactivation, it may be involved in the genesis and progress of lung cancer.