Function and diagnostic value of Anosmin-1 in gastric cancer progression.

Gastric cancer (GC) is a major global health problem that urgently requires novel molecular biomarkers for patient stratification as well as therapeutic targets. Anosmin-1 (ANOS1) gene encodes a cell adhesion molecule that plays diverse roles in multiple malignancies. We performed global expression profiling of GC cell lines and small interfering RNA (siRNA) experiments to determine the effect of ANOS1 expression on phenotype. We evaluated the association of ANOS1 mRNA and protein levels in patients' tissue and sera with clinicopathological factors of GC subtypes. Differential expression of ANOS1 mRNA by GC cell lines correlated positively to levels of ITGAV, FOXC2 and NODAL mRNAs and inversely with those of TFPI2. Inhibiting ANOS1 expression decreased the proliferation, invasion and migration of GC cells. The mean level of ANOS1 mRNA was significantly higher in 237 GC tissues compared with the corresponding noncancerous adjacent tissues. Elevated ANOS1 levels associated significantly with the phenotypes of GC, shorter disease-free and overall survival. ANOS1 expression was a more significant prognostic marker for diffuse and distal nondiffuse GC. ANOS1 concentrations in sera increased sequentially in sera of healthy subjects, localized GC and disseminated GCs. Prognosis was worse for patients with preoperative serum ANOS1 ≥ 600 pg/ml compared with those with <600 pg/ml. ANOS1 may represent a biomarker for GC phenotypes and as a target for therapy.

Neurotrophin Receptor-Interacting Melanoma Antigen-Encoding Gene Homolog is Associated with Malignant Phenotype of Gastric Cancer.

BACKGROUND: Identification of novel molecules implicated in the malignancy of gastric cancer (GC) is key to the development of personalized treatments and the improvement of patient outcome. Neurotrophin receptor-interacting melanoma antigen-encoding protein (NRAGE) regulates apoptosis and metastasis via interactions with various genes. This study aimed to evaluate the function and clinical significance of NRAGE in GC. METHODS: The expression of NRAGE and its putative interacting genes apoptosis antagonizing transcription factor (AATF), p75 neurotrophin receptor (p75NTR), and proliferating cell nuclear antigen (PCNA) were determined in GC cell lines using reverse transcription-polymerase chain reaction (RT-PCR). The effect of NRAGE knockdown by small interfering RNA (siRNA) on GC cell behavior also was evaluated. In addition, NRAGE expression was determined in 179 pairs of resected gastric tissues. RESULTS: Expression of NRAGE mRNA positively correlated with that of AATF, and NRAGE knockdown significantly decreased the proliferation, migration, and invasion of GC cells. The mean level of NRAGE mRNA expression was significantly higher in GC tissues than in corresponding adjacent normal tissues. The expression patterns of NRAGE mRNA and protein were closely correlated. A stepwise elevation in NRAGE mRNA expression in GC tissues was observed with increasing Union for International Cancer Control (UICC) stage. High NRAGE expression in GCs was associated with shortened recurrence-free survival and identified as an independent prognostic factor (hazard ratio, 1.83; 95 % CI, 1.12-3.02, p = 0.017). CONCLUSIONS: The results indicate that NRAGE represents a putative oncogene associated with a malignant phenotype of GC. In GC, NRAGE may serve as a predictive biomarker and a target of molecular therapy.

The Expression of Melanoma-Associated Antigen D2 Both in Surgically Resected and Serum Samples Serves as Clinically Relevant Biomarker of Gastric Cancer Progression.

BACKGROUND: Sensitive biomarkers are necessary for risk classification of patients with gastric cancer (GC), especially ones at risk of distant metastases. Melanoma-associated antigen (MAGE)-D2 has been reported to play a role in the process of cell adhesion and metastatic potential of tumor cells in colorectal cancer. The purpose of this study was to identify a novel clinically relevant biomarker of GC. METHODS: Expression analysis of MAGE-D2 was conducted in GC cell lines and clinical samples (surgical specimen and serum) in both mRNA and protein level. Correlations between MAGE-D2 expression status and clinicopathological factors were evaluated. RESULTS: MAGE-D2 mRNA expression levels were similar between GC tissues and the corresponding normal adjacent tissues and were independent of GC differentiation or subtype. In 101 (45 %) of 225 patients, the expression level of MAGE-D2 mRNA was increased in GC tissues compared with the corresponding normal adjacent tissues. Increased expression of MAGE-D2 mRNA in GC tissues was associated with distant metastasis and early recurrence and was an independent prognostic factor (hazard ratio 2.27, 95 % confidence interval 1.39-3.74, P = 0.001). There was a stepwise increase in serum MAGE-D2 level going from healthy volunteers to patients with localized GC and then to those with extended GC (stage IV). Patients with preoperative serum MAGE-D2 levels >130 pg/ml had a more unfavorable prognosis than those with levels ≤130 pg/ml. CONCLUSION: MAGE-D2 was associated with metastatic potential of GC and may represent a promising biomarker, both in gastric tissues and serum samples, for malignant behavior of GC.

Reduced Expression of Adherens Junctions Associated Protein 1 Predicts Recurrence of Hepatocellular Carcinoma After Curative Hepatectomy.

BACKGROUND: Hepatocellular carcinoma (HCC) frequently recurs after curative resection. Therefore, the availability of sensitive biomarkers for progression and recurrence is essential for managing patients' clinical course. Adherens junctions associated protein 1 (AJAP1) may serve this purpose, because it mediates activities of tumor cells. METHODS: AJAP1 mRNA levels and those of genes encoding potential interacting proteins, such as SRC in HCC cell lines, and 144 pairs of resected liver tissues were determined as well as the methylation status of the AJAP1 promoter and copy number changes at AJAP1 locus. The expression pattern of AJAP1 protein was evaluated using immunohistochemistry. RESULTS: AJAP1 mRNA levels varied among nine HCC cell lines, and AJAP1 expression was reactivated after demethylation of its promoter. AJAP1 mRNA levels correlated inversely with those of SRC in HCC cell lines and tissues. AJAP1 mRNA levels were suppressed in HCC tissues. The expression pattern of AJAP1 correlated significantly with that of AJAP1 mRNA. Low levels of AJAP1 mRNA in patients with HCC associated significantly with elevated levels of tumor markers, larger tumor size, serosal infiltration, vascular invasion, hypermethylation of the AJAP1 promoter, and copy number loss at AJAP1 locus. Patients with low levels of AJAP1 expression were more likely to experience shorter disease-free survival (DFS), and multivariate analysis identified low AJAP1 expression as an independent factor for predicting DFS. CONCLUSIONS: AJAP1 may function as a key regulatory molecule associated with the recurrence of HCC. Hypermethylation of the AJAP1 promoter is a key regulatory mechanism controlling AJAP1 expression.

Suppression of SAMSN1 Expression is Associated with the Malignant Phenotype of Hepatocellular Carcinoma.

BACKGROUND: Identification of molecular markers for sensitive detection of hepatocellular carcinoma (HCC) is required to achieve efficacious personalized therapy. METHODS: We focused here on SAM domain, SH3 domain, and nuclear localization signals 1 (SAMSN1) and investigated expression and methylation status of SAMSN1 in HCC cell lines and 144 pairs of surgical specimens. RESULTS: SAMSN1 was expressed at significantly lower levels in tumor tissue compared with the corresponding noncancerous tissues of patients with HCC. Analysis of HCC cell lines revealed that hypermethylation of the SAMSN1 promoter correlated with decreased expression of SAMSN1 mRNA. Furthermore, treating cells with a DNA-demethylating drug increased SAMSN1 transcription. The levels of SAMSN1 mRNA in noncancerous liver were not affected by background liver inflammation or fibrosis. Moreover, the levels of SAMSN1 mRNA in HCC tissues inversely correlated with tumor size and preoperative levels of proteins induced by vitamin K absence. The clinical significance of SAMSN1 was further indicated by the correlation between its decreased expression in patients with HCC and their shorter overall and recurrence-free survival as well as recurrence following initial resection. Moreover, multivariate analysis identified SAMSN1 as an independent prognostic factor of HCC progression. The expression pattern of SAMSN1 correlated significantly with that of SAMSN1 mRNA, making it possible to use PCR techniques to readily quantitate SAMSN1 expression in tumors. CONCLUSIONS: Our findings indicate that inhibition of SAMSN1 transcription through DNA hypermethylation may influence the progression of HCC and thus represent a novel biomarker of the phenotype of HCC cells.

Prognostic impact of expression and methylation status of DENN/MADD domain-containing protein 2D in gastric cancer.

BACKGROUND: Patients with advanced gastric cancer (GC) have an adverse prognosis even after curative resection. Development of novel diagnostic and therapeutic approaches for GC is urgently required. METHODS: The expression and methylation status of DENN/MADD domain-containing protein 2D (DENND2D), a member of the membrane trafficking proteins, were evaluated in 12 GC cell lines and 112 pairs of surgical specimens. Subgroup analysis based on tumor differentiation, location, and morphology was also performed. Expression and distribution of DENND2D protein were determined by immunohistochemistry. RESULTS: The majority of GC cell lines (75%) and tissues (79%) showed reduced expression of DENND2D mRNA compared with noncancerous gastric tissues. GC tissues showed a significantly lower mean expression level of mRNA and a higher frequency of promoter hypermethylation of DENND2D than corresponding noncancerous tissues. No significant differences in DENND2D mRNA expression and methylation status were found between GC subtypes categorized by tumor differentiation, location, and morphology. The expression patterns of DENND2D protein were confirmed to be consistent with those of DENND2D mRNA. Downregulation of DENND2D mRNA in GC tissues was significantly associated with factors related to more advanced GC and subsequent adverse prognosis. Among 72 patients who underwent R0 resection, downregulation of DENND2D mRNA in GC tissues was an independent prognostic factor and associated with early recurrence. CONCLUSIONS: Our results suggested that DENND2D is a putative tumor suppressor gene regulated by promoter hypermethylation in GC. Downregulation of DENND2D can serve as a novel tumor biomarker to predict progression and early recurrence of all types of GC.

Diversity of clinical implication of B-cell translocation gene 1 expression by histopathologic and anatomic subtypes of gastric cancer.

BACKGROUND: Genetic signatures may differ by histopathologic and anatomic subtypes of gastric cancer (GC). B-cell translocation gene 1 (BTG1) was identified as one of genes downregulated in GC tissues from our microarray data. AIMS: To evaluate the clinical implications of BTG1 expression in GC and the genetic diversity among GC subtypes. METHODS: BTG1 mRNA expression was analyzed in GC cell lines and 233 pairs of surgical specimens. The mutational and methylation status of BTG1 in GC cell lines was analyzed, and immunohistochemistry was conducted to determine the distribution of BTG1. The pattern and prognostic significance of BTG1 expression were correlated with the three proposed GC subtypes. RESULTS: BTG1 mRNA was downregulated in 82 % of GC cell lines and in 88 % of clinical GC tissues. Promoter hypermethylation events or sequence mutations were not detected in GC cell lines. The pattern of BTG1 expression as observed by immunohistochemistry was consistent with that of its mRNA. Downregulation of BTG1 mRNA in GCs was significantly associated with shorter disease-specific and recurrence-free survival. Multivariate analysis of disease-specific survival identified downregulation of BTG1 transcription as an independent prognostic factor. BTG1 mRNA expression was more strongly suppressed in proximal nondiffuse and diffuse GC compared with distal nondiffuse GC, and subgroup analysis revealed that BTG1 downregulation led to adverse prognosis, specifically in patients with proximal nondiffuse and diffuse GC. CONCLUSIONS: Altered expression of BTG1 is a potential biomarker for carcinogenesis and progression of GC, particularly for proximal nondiffuse and diffuse GC.

Randomised phase II trial of capecitabine plus oxaliplatin with continuous versus intermittent use of oxaliplatin as adjuvant chemotherapy for stage II/III colon cancer (CCOG-1302 study).

BACKGROUND: Peripheral sensory neuropathy (PSN) caused by oxaliplatin-based adjuvant chemotherapy adversely affects patients' quality of life. This study evaluated the efficacy and safety of capecitabine plus oxaliplatin (CAPOX) with intermittent oxaliplatin use compared with the standard CAPOX in adjuvant therapy for colon cancer. PATIENTS AND METHODS: Patients with curative resection for stage II/III colon cancer were randomly assigned to receive either CAPOX with continuous oxaliplatin (eight cycles of CAPOX) or CAPOX with intermittent oxaliplatin (two cycles of CAPOX, four cycles of capecitabine and two cycles of CAPOX). The primary end-point was the 1-year PSN rate, and the key secondary end-point was disease-free survival (DFS). RESULTS: Two hundred patients were enrolled in the intent-to-treat population. After 4 patients withdrew, 196 patients were included in the safety analysis. The overall treatment completion rate was 65% for continuous vs. 89% for intermittent treatment (p < 0.001). The 1-year PSN rate was 60% (95% confidence interval [CI], 50%-70%) for continuous and 16% (95% CI, 10%-25%) for intermittent treatment (p < 0.001). After a median follow-up of 52 months, 40 events (20%) were observed. The 3-year DFS was 81% (95% CI, 71%-87%) for continuous and 84% (95% CI, 75%-90%) for intermittent treatment (hazard ratio [HR], 0.87; 95% CI, 0.47-1.63). Among patients with high-risk disease (T4 or N2-3), the 3-year DFS was 57% for continuous vs. 74% for intermittent treatment (HR, 0.66). CONCLUSION: CAPOX with planned intermittent oxaliplatin may be feasible as an adjuvant therapy for colon cancer and substantially reduce the duration of long-lasting PSN. TRIAL IDENTIFIER: UMIN000012535.

Clinical management for spontaneous spinal epidural hematoma: diagnosis and treatment.

BACKGROUND CONTEXT: Spontaneous spinal epidural hematoma (SSEH) is a very rare condition, so there were few studies assessing the management criteria of SSEH. PURPOSE: To assess the differential diagnosis and clinical results of treatment for SSEH. STUDY DESIGN: A retrospective chart and radiograph review of the patients with SSEH. PATIENT SAMPLE: Seven consecutive patients with SSEH who were treated in our institute. OUTCOME MEASURES: Differential diagnosis, severity of the paresis, and treatment selection were assessed preoperatively and postoperatively. METHODS: We assessed the relationship between the following parameters and clinical results: (1) the initial symptoms, (2) imaging diagnosis of magnetic resonance imaging (MRI), (3) treatment selection (conservative or surgical treatment), (4) the interval of surgery, and (5) the severity of paresis using ASIA impairment scale (AIS) grading. RESULTS: In all patients, the symptoms at onset were severe neck and back pain. MRI showed isointensity to the spinal cord in the T1-weighted view and iso- or high intensity in the T2-weighted view. A solid pattern in MRI was shown in 4 patients, and a mosaic pattern was shown in 3 patients. Decompression was performed in five cases, and spontaneous recovery appeared in two cases. The mean interval time for operation was 29.8 hours. The severity of paresis was grade B in 3 cases and grade C in 4 cases at onset. These cases recovered to become grade E in 3 cases and grade D in 4 cases. Neurological deficits were present in two patients with conservative therapy and in two patients with a long interval for operation. CONCLUSIONS: Precise diagnosis without delay and rapid surgical treatment are essential for the management of SSEH.

NRAGE promotes the malignant phenotype of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a fatal disease, primarily due to the limited effective therapies available for patients with advanced or recurrent stages of the disease. Therefore, in order to improve patient prognosis, it is important to identify an informative biomarker for HCC progression, as well as a molecular target for therapy. Neurotrophin receptor-interacting melanoma antigen-encoding protein (NRAGE), a member of the type II melanoma-associated antigen family, mediates apoptosis and cell death through interactions with a wide range of proteins, and is implicated as a tumor suppressor or oncoprotein depending on cell type. However, the role of NRAGE in HCC is currently unknown, therefore, the present study aimed to identify the underlying function of NRAGE in HCC tumorigenesis. Resected tumor and non-cancerous liver tissues from 151 patients with HCC, alongside HCC cell lines, were analyzed by polymerase chain reaction and immunohistochemical techniques to determine NRAGE expression levels, as well as the expression levels of potential genes encoding interacting proteins. It was demonstrated that the expression levels of NRAGE mRNA correlated significantly with those of apoptosis-antagonizing transcription factor (AATF), and were not affected by cirrhosis in non-cancerous liver tissues when compared to elevated levels in HCC tissues. The expression patterns of NRAGE protein and mRNA were consistent among 30 representative specimen pairs. Furthermore, increased NRAGE expression in patients with HCC correlated significantly with a shorter disease-specific survival time, and was identified as an independent prognostic factor via multivariate analysis (hazard ratio, 2.23; 95% confidence interval, 1.06-3.83; P=0.020). Therefore, the results of the present study indicated that increased NRAGE expression affects HCC progression via its interaction with AATF, and may represent a novel biomarker and molecular target for the treatment of HCC.

Prognostic relevance of SAMSN1 expression in gastric cancer.

The prognosis for patients with advanced gastric cancer (GC) remains poor. The identification of biomarkers relevant to the recurrence and metastasis of GC is advantageous for stratifying patients and proposing novel molecular targets. In the present study the oncological roles of SAM domain, SH3 domain and nuclear localization signals 1 (SAMSN1), a mediator of B-cell function, were elucidated in GC. The expression and methylation status of SAMSN1 were investigated in a panel of 11 GC cell lines. Immunohistochemical staining was performed to determine the pattern of SAMSN1 protein expression in gastric tissues. The prognostic impact of SAMSN1 expression was determined by analyzing 175 pairs of surgically resected gastric tissues. A marked decrease in the level of SAMSN1 mRNA was detected in 8/11 GC cell lines as compared with that in a non-transformed intestinal epithelium cell line (FHs 74) without promoter methylation. The mean expression level of SAMSN1 mRNA was reduced in GC tissues compared with normal adjacent tissues, an observation that was independent of tumor differentiation. The pattern of SAMSN1 protein expression was significantly correlated with that of SAMSN1 mRNA. Low SAMSN1 mRNA expression was significantly associated with tumor size (>60 mm; P=0.026) and shorter overall survival times (P=0.004). Multivariate analysis identified low SAMSN1 mRNA expression as an independent prognostic factor for poor overall survival (hazard ratio, 1.80; 95% confidence interval, 1.07-3.05; P=0.025). The difference in survival between the low and high SAMSN1 expression groups was more marked in patients with stage II/III GC compared to those with stage IV GC. In patients with stage II/III GC who underwent curative surgery, low SAMSN1 expression was associated with reduced disease free survival times. The results of the present study indicate that downregulation of SAMSN1 transcription may affect the progression and recurrence of GC, and therefore may represent a novel biomarker of GC.

Adherens junctions associated protein 1 serves as a predictor of recurrence of squamous cell carcinoma of the esophagus.

Esophageal squamous cell carcinoma (ESCC), the most common esophageal cancer in East Asia, is among the six cancers with the highest fatality rates worldwide. Unfortunately, multidisciplinary treatment strategies have not achieved satisfactory outcomes. Therefore, novel insights into the molecular biology of ESCC are required to improve treatment. The gene encoding the transmembrane adherens junctions-associated protein-1 (AJAP1) expressed by epithelial cells resides in chromosome 1p36, which is frequently lost or epigenetically silenced in several malignancies. Here, we investigated the expression levels and regulatory mechanism of AJAP1 transcription. We determined the levels of AJAP1 mRNA and the genes encoding potentially interacting proteins expressed by ESCC cell lines, as well as the chromosomal copy number of AJAP1 and the methylation status of its promoter region. AJAP1 mRNA levels of 78 pairs of surgically resected specimens were determined to evaluate the association of AJAP1 expression and clinicopathological factors. Nine ESCC cell lines differentially expressed AJAP1 mRNA, and demethylation of hypermethylated AJAP1 genomic DNA reactivated AJAP1 mRNA expression. The copy number of sequences upstream or downstream of the AJAP1 transcriptional start site was not detectably altered. AJAP1 mRNA levels correlated inversely with those of ezrin (EZR) and were significantly lower in ESCC tissues compared with adjacent normal tissues. AJAP1 mRNA levels decreased gradually with increasing tumor stage. Patients with downregulated AJAP1 transcription were more likely to experience shorter overall and disease-free survival. Multivariate analysis of disease-free survival identified downregulated AJAP1 transcription as an independent prognostic factor. These results suggest that in ESCC, AJAP1 acts as a putative tumor suppressor and that AJAP1 transcription is regulated by promoter hypermethylation. These findings indicate that downregulated AJAP1 transcription may serve as a novel tumor biomarker to predict recurrence of ESCC after esophagectomy.

Dihydropyrimidinase-like 3 is a putative hepatocellular carcinoma tumor suppressor.

BACKGROUND: Patients with hepatocellular carcinoma (HCC) may relapse after curative resection. Sensitive biomarkers for HCC are required to enhance disease management. Dihydropyrimidinase-like 3 (DPYSL3) suppresses cell proliferation and tumorigenicity of certain malignancies; however, its role in HCC is unknown. METHODS: The expression levels of DPYSL3 and genes encoding potential interacting proteins vascular endothelial growth factor (VEGF), focal adhesion kinase (FAK), ezrin, and cellular src were determined using RT-PCR. Further, we determined the methylation status of the DPYSL3 promoter in HCC cells lines and the effect of inhibiting DPYSL3 expression on their phenotype. DPYSL3 expression was determined in 151 pairs of resected liver tissues. RESULTS: DPYSL3 mRNA levels were down-regulated in most HCC cell lines with DPYSL3 promoter hypermethylation, and expression was restored after demethylation. DPYSL3 expression levels inversely correlated with those of VEGF and FAK. Knockdown of DPYSL3 significantly increased migration and the invasive properties of HCC cells. The mean level of DPYSL3 mRNA was significantly lower in HCC tissues compared with corresponding noncancerous tissues. The expression patterns of DPYSL3 mRNA and protein were consistent. DPYSL3 mRNA expression in HCC tissues inversely correlated with preoperative serum tumor markers and was significantly lower in patients with extrahepatic recurrences. Disease-specific and recurrence-free survival was significantly shorter in patients with down-regulated DPYSL3 expression. CONCLUSIONS: Our results indicate that DPYSL3 is a putative HCC tumor suppressor, and promoter hypermethylation potently regulates DPYSL3 transcription. Down-regulation of DPYSL3 expression in HCC tissues may serve as a predictive biomarker for HCC after curative resection.

B­cell translocation gene 1 serves as a novel prognostic indicator of hepatocellular carcinoma.

Although the B­cell translocation gene 1 (BTG1) plays an important role in apoptosis and negatively regulates cell proliferation, BTG1 expression in hepatocellular carcinoma (HCC) has not been evaluated. In this study expression analysis of BTG1 was conducted to clarify the role of BTG1 in the initiation of HCC carcinogenesis and progression. BTG1 mRNA expression levels were determined for HCC cell lines and 151 surgical specimen pairs using quantitative real­time reverse transcription polymerase chain reaction (RT­qPCR) assay. The mutational and methylation status of HCC cell lines were analyzed via high resolution melting (HRM) analysis and direct sequencing analysis to elucidate the regulatory mechanisms of BTG1 expression. The expression and distribution of the BTG1 protein in liver tissues were evaluated using immunohistochemistry (IHC). Decreased expression of BTG1 mRNA was confirmed in the majority of HCC cell lines (89%) and clinical HCC tissues (85%) compared with non­cancerous liver tissues. Mutations or promoter hypermethylation were not identified in HCC cell lines. BTG1 mRNA expression levels were not influenced by background liver status. The pattern of BTG1 protein expression was consistent with that of BTG1 mRNA. Downregulation of BTG1 mRNA in HCC was significantly associated with shorter disease­specific and recurrence­free survival rates. Multivariate analysis of disease­specific survival rates identified BTG1 mRNA downregulation as an independent prognostic factor for HCC (hazard ratio 2.12, 95% confidence interval 1.12­4.04, P=0.022). Our results indicate that altered BTG1 expression might affect hepatocarcinogenesis and may represent a novel biomarker for HCC carcinogenesis and progression.

Aberrant expression of melanoma-associated antigen-D2 serves as a prognostic indicator of hepatocellular carcinoma outcome following curative hepatectomy.

Hepatocellular carcinoma (HCC) is the most common cause of cancer-related mortality globally. Since the prognosis of advanced HCC patients is extremely poor, the development of novel molecular targets for diagnosis and therapy is urgently required. In the present study, the expression of the melanoma-associated antigen-D2 (MAGE-D2) gene was investigated to determine whether it affects the malignant phenotype of HCC and thus, may serve as a marker of prognosis. Therefore, the expression of MAGE-D2 mRNA and MAGE-D2 protein in nine HCC cell lines and 151 pairs of surgical tissues was analyzed. mRNA expression levels were analyzed using reverse transcription-quantitative polymerase chain reaction and immunohistochemistry was used to compare the clinicopathological parameters of the tumors. A significant difference in the level of MAGE-D2 expression was observed between the normal liver and chronic hepatitis tissues, however, no significant differences were identified among the levels of the chronic hepatitis, cirrhosis and HCC tissues. The expression patterns of the MAGE-D2 protein were consistent with those of its mRNA. The expression levels of MAGE-D2 mRNA in 66 of 151 (44%) patients were higher in the HCC tissues compared with the corresponding non-cancerous tissues. In addition, the disease-specific survival time was significantly shorter for patients with higher levels of MAGE-D2 mRNA expression. Multivariate analysis identified increased expression of MAGE-D2 mRNA as an independent prognostic factor for disease-specific survival (hazard ratio, 2.65; 95% confidence interval, 1.43-4.98; P=0.002). However, increased expression levels of MAGE-D2 mRNA were not significantly associated with other clinicopathological parameters, including extrahepatic recurrence. These results indicated that MAGE-D2 mRNA affects tumor progression and may serve as a prognostic indicator following curative resection. In addition, MAGE-D2 may provide a target for the therapy of HCC.

Translational implication of Kallmann syndrome-1 gene expression in hepatocellular carcinoma.

Accumulation of epigenetic alterations causes inactivation of tumor suppressors and contributes to the initiation and progression of hepatocellular carcinoma (HCC). Identification of methylated genes is necessary to improve our understanding of the pathogenesis of HCC and develop novel biomarkers and therapeutic targets. The Kallmann syndrome-1 (KAL1) gene encodes an extracellular matrix-related protein with diverse oncological functions. However, the function of KAL1 in HCC has not been examined. We investigated the methylation status of the KAL1 promoter region in HCC cell lines, and evaluated KAL1 mRNA levels and those of genes encoding potential interacting cell adhesion factors. KAL1 mRNA expression level was heterogeneous in nine HCC cell lines, and reactivation of KAL1 mRNA expression was observed in cells with promoter hypermethylation of KAL1 gene after demethylation. In addition, KAL1 mRNA levels inversely correlated with those of ezrin in all nine HCC cell lines. KAL1 expression levels in 144 pairs of surgically-resected tissues were determined and correlated to clinicopathological parameters. KAL1 mRNA level was independent of the background liver status, whereas HCC tissues showed significantly lower KAL1 mRNA levels than corresponding noncancerous liver tissues. Downregulation of KAL1 mRNA in HCC was significantly associated with malignant phenotype characteristics, including elevated tumor markers, larger tumor size, vascular invasion, and hypermethylation of KAL1. Patients with downregulation of KAL1 were more likely to have a shorter overall survival than other patients, and multivariate analysis identified downregulation of KAL1 as an independent prognostic factor (hazard ratio 2.04, 95% confidence interval 1.11-3.90, P=0.022). Our results indicated that KAL1 may act as a putative tumor suppressor in HCC and is inactivated by promoter hypermethylation. KAL1 may serve as a biomarker of malignant phenotype of HCC.

Dihydropyrimidinase-like 3 facilitates malignant behavior of gastric cancer.

BACKGROUND: Gastric cancer (GC) remains to have a poor prognosis via diverse process of cancer progression. Dihydropyrimidinase-like 3 (DPYSL3) is a cell adhesion molecule that has been reported to be involved in the metastatic process of tumor cells. The aim of this study was to identify a novel clinically-relevant biomarker of GC. METHODS: Expression analysis of DPYSL3 mRNA and protein levels was conducted using GC cell lines and 238 pairs of surgically resected gastric tissues. Correlations between expression status of DPYSL3 and clinicopathological parameters were investigated. RESULTS: DPYSL3 mRNA expression levels positively correlated with those of potentially interacting genes (VEGF, FAK and EZR) in GC cell lines. GC tissues from tumors with distant metastases (stage IV cancer) showed elevated expression levels of DPYSL3 mRNA. The DPYSL3 staining intensity in immunochemical staining was consistent with the mRNA expression patterns in GC tissues. High DPYSL3 mRNA expression in GCs was significantly associated with more malignant phenotypes and was an independent prognostic factor. Moreover, patients with high DPYSL3 mRNA expression had a significantly shorter recurrence free survival after curative resection. In subgroup analysis based on tumor histology, similar tendency was observed between patients with differentiated and undifferentiated GCs. CONCLUSIONS: Expression status of DPYSL3 in GC tissues may represent a promising biomarker for the malignant behavior of GC.

Clinical utility of PDSS2 expression to stratify patients at risk for recurrence of hepatocellular carcinoma.

Identification of novel genetic and epigenetic alterations is required for optimal stratification of patients with hepatocellular carcinoma (HCC) at risk for recurrence and adverse prognosis. Coenzyme Q10 (CoQ10), which mediates apoptosis, is synthesized by prenyl diphosphate synthase subunit 2 (PDSS2). In the present study we evaluated the clinical significance and regulatory mechanisms of PDSS2 expression in HCC. PDSS2 expression levels and those of genes encoding potentially interacting proteins as well as the methylation status of the PDSS2 promoter region were analyzed in HCC cell lines. PDSS2 mRNA levels in 151 pairs of resected specimens were determined to evaluate the association of PDSS2 expression and clinicopathological factors. The expression and distribution of PDSS2 were determined using immunohistochemistry. PDSS2 mRNA expression was decreased in six of nine HCC cell lines and significantly correlated with those of hepatocyte nuclear factor 4α. PDSS2 transcription in HCC cells with decreased PDSS2 expression accompanying hypermethylation was reactivated after treating these cells with a methylation inhibitor. Mean expression levels of PDSS2 mRNA relative to that of uninvolved liver diminished gradually in the order of chronic hepatitis to cirrhosis, and each was significantly higher than those of HCCs. PDSS2 and PDSS2 mRNA levels were consistent. Decreased PDSS2 mRNA levels were detected in HCC tissues of 56 patients, correlated with shorter disease-specific survival, and was identified as an independent prognostic factor. PDSS2 is a putative tumor suppressor, and promoter hypermethylation is a key regulatory mechanism in HCC. Decreased levels of PDSS2 mRNA expression may represent a novel biomarker of HCC.

Decreased expression of prenyl diphosphate synthase subunit 2 correlates with reduced survival of patients with gastric cancer.

BACKGROUND: Identification of novel molecular biomarkers will improve the management of patients with gastric cancer (GC). Prenyl diphosphate synthase subunit 2 (PDSS2) is required for coenzyme Q10 biosynthesis and acts as a tumor suppressor; however, the role and regulatory mechanisms of PDSS2 in GC are not understood. The aim of this study was to determine expression status and regulatory mechanisms of PDSS2 in GC. METHODS: Associations between expression and methylation of PDSS2 were evaluated using GC cell lines. The clinical significance of PDSS2 expression was evaluated using 238 pairs of surgically resected gastric tissues with subgroup analysis based on GC subtypes. RESULTS: The expression of PDSS2 mRNA was decreased in 73% of GC cell lines compared with the control non-cancerous cell. The PDSS2 promoter was hypermethylated in cells with decreased PDSS2 expression, and treating these cells with a methylation inhibitor reactivated PDSS2 expression. GC tissues expressed significantly lower mean levels of PDSS2 mRNA compared with adjacent normal tissues (P <0.001). The expression pattern of PDSS2 protein was consistent with that of its mRNA. The decrease of PDSS2 mRNA expression in GC tissues (less than half the level of expression detected in the corresponding normal adjacent tissues) correlated significantly with elevated levels of carbohydrate antigen 19-9 (P = 0.015), lymph node metastasis (P = 0.022), and shorter recurrence-free survival after curative resection (P = 0.022). Further, multivariate analysis identified PDSS2 mRNA expression as an independent prognostic factor (hazard ratio 1.95, 95% confidence interval 1.22-3.09, P = 0.005), and its expression pattern and prognostic significance were similar among three GC subtypes. CONCLUSIONS: PDSS2 encodes a putative tumor suppressor, and we show here that its expression was regulated by hypermethylation of its promoter in GC cells. Inhibition of PDSS2 mRNA expression may serve as a novel biomarker of all types of GC.

Microsatellite variation and differentiation among local populations of Castanopsis species in Japan.

Microsatellite variations in Castanopsis species in Japan were examined to clarify the genetic relationships among 25 local populations according to the difference in the number of layers of adaxial epidermis in the leaves. Six microsatellite loci were assayed for 629 seedlings from the populations, and these seedlings were classified into five types according to the state of the leaf epidermis. Remarkable differences in the allele frequency of the six microsatellite loci were observed among these local populations. The coefficients of genetic differentiation, R(ST), of each locus ranged from 0.209 to 0.388. An unweighted pair-group method (UPGMA) phenogram constructed on the population pairwise R(ST) over the loci revealed three clusters (A-C), and six sub-clusters. These clusters reflected the differences in the occurrence frequency of seedlings in each epidermis type within a population. Our findings suggest that clusters A and C are the local populations dominated by Castanopsis sieboldii and Castanopsis cuspidata, respectively, while local populations of cluster B are composed of the two Castanopsis species and/or include many individuals derived by hybridization. The six sub-clusters were found to reflect the geographic relationship among the populations, suggesting a different process for geographic population dynamics during the postglacial period.