• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6261-6265
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• 2013

Background: Recent studies have suggested that expression of the RAS protein activator like-1 gene (RASAL1) is decreased in gastric carcinoma tissues and cell lines, indicated a role in tumorigenesis and development of gastric cancer. Reduced expression of RASAL1 could result in aberrant increase of activity of RAS signaling pathways in cancer cells. However, the exact mechanism which induces down-regulation of the RASAL1 gene remains unclear. This study aimed to determine the methylation status and regulation of RASAL1 in gastric cancer. Materials and Methods: Using the methylation-specific polymerase chain reaction (MSP), the methylation status of CpG islands in the RASAL1 promoter in gastric cancers and paired adjacent non-cancerous tissues from 40 patients was assessed and its clinicopathological significance was analyzed. The methylation status of RASAL1 in gastric cancer lines MKN-28, SGC-790l, BGC-823, as well as in normal gastric epithelial cell line GES-l was also determined after treatment with a DNA methyltransferase inhibitor, 5-aza-2'-doexycytidine (5-Aza-CdR). RAS activity (GAS-GTP) was assessed through a pull-down method, while protein levels of ERK1/2, a downstream molecule of RAS signaling pathways, were determined by Western blotting. Results: The frequencies of RASAL1 promoter methylation in gastric cancer and paired adjacent non-cancerous tissues were 70% (28/40) and 30% (12/40) respectively (P<0.05). There were significantly correlations between RASAL1 promoter methylation with tumor differentiation, tumor size, invasive depth and lymph node metastasis in patients with gastric cancer (all P<0.05), but no correlation was found for age or gender. Promoter hypermethylation of the RASAL1 gene was detected in MKN-28, SGC-790l and BGC-823 cancer cells, but not in the normal gastric epithelial cell line GES-1. Elevated expression of the RASAL1 protein, a decreased RAS-GTP and p-ERK1/2 protein were detected in three gastric cancer cell lines after treatment with 5-Aza-CdR. Conclusions: Aberrant hypermethylation of the RASAL1 gene promoter frequently occurs in gastric cancer tissues and cells. In addition, the demethylating agent 5-Aza-CdR can reverse the hypermethylation of RASAL1 gene and up-regulate the expression of RASAL1 significantly in gastric cancer cells in vivo. Our study suggests that RASAL1 promoter methylation may have a certain relationship with the reduced RASAL1 expression in gastric cancer.

• Asian Pacific Journal of Cancer Prevention
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• 제16권9호
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• pp.3973-3976
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• 2015

Objectives: To explore the expression of aquaporin 1 ($AQP_1$) in bladder uroepithelium cell carcinoma (BUCC) and its relevance to recurrence. Materials and Methods: Tissue samples from 45 BUCC patients who underwent total cystectomy or transurethral resection of bladder tumor (TURBT) and from 40 patients with non-bladder cancers who underwent special detection or treatments were collected. The level of expression of $AQP_1$ in BUCC tissues and normal bladder tissues was assessed by immunohistochemistry so as to analyze the relevance to pathological patterns and time of recurrence in BUCC patients. Results: The expression levels of $AQP_1$ normal bladder tissues and BUCC tissues were $2.175{\pm}0.693$ and $3.689{\pm}0.701$, respectively, and the difference was significant (t=9.99, P<0.0001). Marked increase was noted with BUCC histological grade and pathological stage (P<0.01). Moreover, the expression of $AQP_1$ was evidently higher in cancerous tissues with lymph node metastasis than in those without (P<0.01). With short-term recurrence, the positive cell expression rate of $AQP_1$ was higher in primary tissues, which increased obviously after recurrence. Additionally, the recurrent time of BUCC was negatively associated with the positive cell expression rate of $AQP_1$ and the difference between the expression of $AQP_1$ before and after recurrence (r=-0.843, F=39.302, P=0.000; r=-0.829, F=35.191, P=0.000). Conclusions: $AQP_1$, which reflects the grade, stage, lymph node metastasis and recurrence of BUCC, has potential guiding significance in the diagnosis and treatment of bladder cancarcinoma.

• Journal of Cancer Prevention
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• 제22권1호
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• pp.33-39
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• 2017

Background: MicroRNAs (miRNAs) are key post-translational mechanisms which can regulate gene expression in gastric carcinogenesis. To identify miRNAs responsible for gastric carcinogenesis, we compared expression levels of miRNAs between gastric cancer tissue and non-cancerous gastric mucosa according to Helicobacter pylori status. Methods: Total RNA was extracted from the cancerous regions of formalin-fixed, paraffin-embedded tissues of H. pylori-positive (n = 8) or H. pylori-negative (n = 8) patients with an intestinal type of gastric cancer. RNA expression was analyzed using a 3,523 miRNA profiling microarray based on the Sanger miRBase. Validation analysis was performed using TaqMan miRNA assays for biopsy samples from 107 patients consisted of control and gastric cancer with or without H. pylori. And then, expression levels of miRNAs were compared according to subgroups. Results: A total of 156 miRNAs in the aberrant miRNA profiles across the miRNA microarray showed differential expression (at least a 2-fold change, P < 0.05) in cancer tissue, compared to noncancerous mucosa in both of H. pylori-negative and -positive samples. After 10 promising miRNAs were selected, validations by TaqMan miRNA assays confirmed that two miRNAs (hsa-miR-135b-5p and hsa-miR-196a-5p) were significantly increased and one miRNA (hsa-miR-145-5p) decreased in cancer tissue compared to non-cancerous gastric mucosa at H. pylori-negative group. For H. pylori-positive group, three miRNAs (hsa-miR-18a-5p, hsa-miR-135b-5p, and hsa-miR-196a-5p) were increased in cancer tissue. hsa-miR-135b-5p and hsa-miR-196a-5p were increased in gastric cancer in both of H. pylori-negative and -positive. Conclusions: miRNA expression of the gastric cancer implies that different but partially common gastric cancer carcinogenic mechanisms might exist according to H. pylori status.

• Asian Pacific Journal of Cancer Prevention
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• 제15권21호
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• pp.9511-9515
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• 2014

Cholangiocarcinoma (CCA) is a cancer of the bile duct epithelial cells. The highest incidence rate of CCA with a poor prognosis and poor response to chemotherapy is found in Southeast Asian countries, especially in northeastern Thailand and Lao PDR. Cathepsin B is a lysosomal cysteine protease which is regulated by cysteine proteinase inhibitors such as cystatin C. Elevation of cathepsin B levels in biological fluid has been observed in patients with inflammatory diseases and many cancers. We aimed to investigate the serum cathepsin B and cystatin C levels of CCA patients to evaluate the feasibility of using cathepsin B and cystatin C as markers for the diagnosis of CCA. Fifty-six sera from CCA patients, 17 with benign biliary diseases (BBD) and 13 from controls were collected and the cathepsin B and cystatin C levels were determined. In addition, cathepsin B expression was investigated immunohistochemically for 9 matched-pairs of cancerous and adjacent tissues of CCA patients. Serum cathepsin B, but not cystatin C, was significantly higher in CCA and BBD patient groups compared to that in the control group. Consistently, all cancerous tissues strongly expressed cathepsin B while adjacent tissues were negative in 7 out of 9 cases. In contrast, serum cystatin C levels were comparable between CCA and control groups, although serum cystatin C levels in the BBD group was higher than that in the control or CCA groups. When the serum cathepsin B to cystatin C ratio was calculated, that of the CCA group was significantly higher than that of the control group, and, although statistically not significant, the ratio of CCA group showed a trend to be higher than that of the BBD group. Thus, the cathepsin B to cystatin C ratio might be used as an alternative marker for aiding diagnosis of CCA.

• Asian Pacific Journal of Cancer Prevention
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• 제14권12호
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• pp.7295-7300
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• 2013

Lung cancer is the most common cause of cancer-related death in the world. The main types are small-cell lung carcinoma (SCLC) and non-small-cell lung carcinoma (NSCLC), the latter including squamous cell carcinoma (SCC), adenocarcinoma and large cell carcinoma. NSCLCs account for about 80% of all lung cancer cases. Microcephalin (MCPH1), also called BRIT1 (BRCT-repeat inhibitor of hTERT expression), plays an important role in the maintenance of genomic stability. Recently, several studies have provided evidence that the expression of MCPH1 gene is decreased in several different types of human cancers. We evaluated the expression of protein MCPH1 in 188 lung cancer and 20 normal lung tissues by immunohistochemistry. Positive MCPH1 staining was found in all normal lung samples and only some cancerous tissues. MCPH1-positive cells were significantly lower in lung carcinoma compared with normal tissues. Furthermore, we firstly found that MCPH1 expression in lung adenocarcinoma is higher than its expression in squamous cell carcinoma. Change in MCPH1 protein expression may be associated with lung tumorigenesis and may be a useful biomarker for identification of pathological types of lung cancer.

• Asian Pacific Journal of Cancer Prevention
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• 제13권4호
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• pp.1557-1561
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• 2012

Objective: To investigate the promoter methylation status of the E-cadherin gene in non-small cell lung cancer (NSCLC) and its association with clinical pathological parameters, and to explore the relationship between downregulation of E-cadherin gene expression and the methylation status of its promoter region. Methods: Nested methylation-specific PCR was performed to examine CpG methylation within the 5' CpG island of the E-cadherin gene in lung cancer and para-cancerous tissue from 37 patients with primary non-small cell lung cancer. Quantitative real-time PCR was performed to measure the level of E-cadherin mRNA. Results: Of thirty-seven cases, 12 (32.4%) samples showed aberrant CpG methylation in tumor tissues compared with the corresponding normal tissues. In addition, a reduction in E-cadherin mRNA levels was observed in 11 of the 12 (91.7%) tumor tissues carrying a methylated E-cadherin gene. However, only 10 (43.5%) cases displayed reduced mRNA levels in tumor tissues from the remaining 23 cases (excluding 2 samples from which mRNA was unavailable) without methylation events. Downregulation of E-cadherin gene expression significantly correlated with the promoter methylation status of this gene. Conclusion: These results provide strong evidence that the methylation status of E-cadherin gene contributes to a reduction in the expression of E-cadherin mRNA, and may play a role in the development and progression of NSCLC.

• Asian Pacific Journal of Cancer Prevention
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• 제15권7호
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• pp.2971-2977
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• 2014

Background: Long non-coding RNAs (lncRNAs) have been recently observed in various human cancers. However, the role of lncRNAs in pancreatic duct adenocarcinoma (PDAC) remains unclarified. The aim of this study was to detect the expression of lncRNA MALAT1 in PDAC formalin-fixed, paraffin embedded (FFPE) tissues and to investigate the clinical significance of the MALAT1 level. Methods: The expression of MALAT1 was examined in 45 PDAC and 25 adjacent non-cancerous FFPE tissues, as well as in five PDAC cell lines and a normal pancreatic epithelium cell line HPDE6c-7, using qRT-PCR. The relationship between MALAT1 level and clinicopathological parameters of PDAC was analyzed with the Kaplan-Meier method and Cox proportional hazards model. Results: The relative level of MALAT1 was significantly higher in PDAC compared to the adjacent normal pancreatic tissues (p=0.009). When comparing the MALAT1 level in the cultured cell lines, remarkably higher expression of MALAT1 was found in aspc-1 PDAC cells compared with the immortal pancreatic duct epithelial cell line HPDE6c-7 (q=7.573, p<0.05). Furthermore, MALAT1 expression level showed significant correlation with tumor size (r=0.35, p=0.018), tumor stage (r=0.439, p=0.003) and depth of invasion (r=0.334, p=0.025). Kaplan-Meier analysis revealed that patients with higher MALAT1 expression had a poorer disease free survival (p=0.043). Additionally, multivariate analysis indicated that overexpression of MALAT1, as well as the tumor location and nerve invasion, was an independent predictor of disease-specific survival of PDAC. Conclusion: MALAT1 might be considered as a potential prognostic indicator and may be a target for diagnosis and gene therapy for PDAC.

• Asian Pacific Journal of Cancer Prevention
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• 제13권9호
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• pp.4707-4712
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• 2012

Annexin A1 is a 37-kDa calcium- and phospholipid-binding protein of the annexin superfamily considered to play an important role in tumorigenesis. However, associations with clinicopathological features in pancreatic ductal adenocarcinoma (PDAC) cases have yet to be fully defined. We therefore investigated the prognostic value of annexin A1 protein as a PDAC biomarker in 83 tumor and matched non-cancerous tissues or normal pancreas tissues. Expression was analyzed using real-time RT-PCR, Western blotting and immunohistochemistry. In non-tumor tissue, myoepithelial cells showed no or weak expression of annexin A1 while expression was strong and sometimes even located in the nuclei of endothelial cells in tumor tissue. High expression was significantly associated with advanced stage (P <0.05) and a worse overall survival (P <0.05). These results provide new insights to better understand the role of annexin A1 in PDAC survival, and might be relevant to prediction of prognosis and development of more effective therapeutic strategies aimed at improving survival.

• Asian Pacific Journal of Cancer Prevention
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• 제13권6호
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• pp.2949-2953
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• 2012

The glutathione S transferase (GST) family is a major part of cellular defense mechanisms against endogenous and exogenous substances, many of which have carcinogenic potential. Alteration in the expression level or structure of the glutathione-S-transferase (GST) enzymes may lead to inadequate detoxification of potential carcinogens and consequently contribute to cancer development. A member of the glutathione-S-transferase (GST) family, GSTP1, is an attractive candidate for involvement in susceptibility to carcinogen-associated colorectal cancer. An $Ag{\rightarrow}G$ transition in exon 5 resulting in an Ile105Val amino acid substitution has been identified which alters catalytic efficiency. The present study investigated the possible impact of Ile105Val GSTP1 polymorphism on susceptibility to colorectal cancer. in Jordan We examined 90 tissue samples previously diagnosed with colorectal carcinoma, and 56 non-cancerous colon tissues. DNA was extracted from paraffin embedded tissues and the status of the GSTP1 polymorphism was determined using a polymerase chain reaction restriction fragment length polymorphism (RFLP) method. No statistically significant differences were found between colorectal cancer cases and controls for the GSTP1 Ile/Ile, Ile/Val and Val/Val genotypes. The glutathione S-transferase polymorphism was not associated with risk in colorectal cancer cases in Jordan stratified by age, sex, site, grade or tumor stage. In conclusion, the GSTP1 Ile105Val polymorphism is unlikely to affect the risk of colorectal cancer.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.68-71
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• 1997

The early detection of brest cancer is clearly a key ingredient for any strategy designed to reduce breast cancer mortality. Microcalcification(MCC) is one of the primary signatures to discriminate between normal and cancerous tissue. The detection and locating procedures can be automated by digital image processing, however, MCCs have various sizes, shapes, and intensity levels in film images, so it is difficult to find accurate locations and sizes. Firstly, we made quantitative analysis for many characteristic features of mammograms that can be used to segment MCCs from normal tissues. Secondly, we developed algorithms proper to segmentation like pattern matching. The performance was evaluated with TP and FP rates.