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Background: Tryptophan 2,3-dioxygenase (TDO2) is the primary enzyme catabolizing tryptophan. Several lines of evidence revealed that overexpression of TDO2 is involved in anoikis resistance, spheroid formation, proliferation, and invasion and correlates with poor prognosis in some cancers. The aim of this research was to uncover the expression and biofunction of TDO2 in renal cell carcinoma (RCC)., Methods: To show the expression of TDO2 in RCC, we performed qRT-PCR and immunohistochemistry in integration with TCGA data analysis. The interaction of TDO2 with PD-L1, CD44, PTEN, and TDO2 expression was evaluated. We explored proliferation, colony formation, and invasion in RCC cells line affected by knockdown of TDO2., Results: RNA-Seq and immunohistochemical analysis showed that TDO2 expression was upregulated in RCC tissues and was associated with advanced disease and poor survival of RCC patients. Furthermore, TDO2 was co-expressed with PD-L1 and CD44. In silico analysis and in vitro knockout of PTEN in RCC cell lines revealed the ability of PTEN to regulate the expression of TDO2. Knockdown of TDO2 suppressed the proliferation and invasion of RCC cells., Conclusion: Our results suggest that TDO2 might have an important role in disease progression and could be a promising marker for targeted therapy in RCC. (199 words).

Introduction: Microtubule-associated protein tau (MAPT) overexpression has been linked to poor prognosis in several cancers. MAPT-AS1 is a long noncoding RNA existing at the antisense strand of the MAPT promoter region. The clinical significance of MAPT and MAPT-AS-1 in clear cell renal cell carcinoma (ccRCC) is unknown. This study aimed to assess the expression and function of MAPT and MAPT-AS1 in ccRCC., Methods: The expression of MAPT was determined using immunohistochemistry in ccRCC. The effects of MAPT knockdown on cell growth and invasion were evaluated and the interaction between MAPT and microtubule-associated protein tau antisense (MAPT-AS1) were analyzed. The expression of MAPT-AS1 was determined using quantitative reverse transcription polymerase chain reaction in ccRCC tissues. We investigated the effect of MAPT-AS1 knockdown on cell growth and invasion. We analyzed the regulation of MAPT and MAPT-AS1., Results: Immunohistochemistry in 135 ccRCC cases showed that 61% of the cases were positive for MAPT. Kaplan-Meier analysis showed that the low expression of MAPT was associated with poor overall survival after nephrectomy. Knockdown of MAPT enhanced cell growth and invasion. quantitative reverse transcription polymerase chain reaction revealed a positive correlation between MAPT and MAPT-AS1. The expression of MAPT-AS1 was higher in ccRCC tissue than in nonneoplastic kidney tissue. Kaplan-Meier analysis showed that the low expression of MAPT-AS1 was associated with poor overall survival after nephrectomy by in silico analysis. MAPT-AS1 knockdown promoted cell growth and invasion activity. P53 knockout suppressed the expression of MAPT and MAPT-AS1., Conclusion: These results suggest that MAPT and MAPT-AS1 may be promising predictive biomarkers for survival and play a tumor-suppressive role in ccRCC., Competing Interests: Conflicts of interest The authors declare no conflicts of interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Gastric cancer (GC), one of the most common human cancers, is a heterogeneous disease with different phenotypes, prognoses, and responses to treatment. Understanding the pathogenesis of GC at the molecular level is important for prognosis prediction and determining treatments. Microsatellite instability (MSI), silencing of MLH1, MGMT, and CDKN2A genes by DNA hypermethylation, KRAS mutation, APC mutation, and ERBB2 amplification are frequently found in intestinal type GC. Inactivation of CDH1 and RARB by DNA hypermethylation, and amplification of FGFR and MET, are frequently detected in diffuse type GC. In addition, BST2 and PCDHB9 genes are overexpressed in intestinal type GC. Both genes are associated with GC progression. GC can be divided into gastric/intestinal mucin phenotypes according to mucin expression. MSI, alterations of TP73, CDH1 mutation, and DNA methylation of MLH are detected frequently in the gastric mucin phenotype. TP53 mutation, deletion of APC, and DNA methylation of MGMT are detected frequently in the intestinal mucin phenotype. FKTN is overexpressed in the intestinal mucin phenotype, and IQGAP3 is overexpressed in the gastric mucin phenotype. These genes are involved in GC progression. To characterize cancer stem cells, a useful method is spheroid colony formation. KIFC1 and KIF11 genes show more than twofold higher expression in spheroid-forming cells than that in parental cells. Both KIF genes are overexpressed in GC, and knockdown of these genes inhibits spheroid formation. Alterations of these molecules may be useful to understand gastric carcinogenesis. Specific inhibitors of these molecules may also be promising anticancer drugs.

Background/aim: Gastric cancer (GC) is one of the most common malignancies worldwide. Gremlin1 is an antagonist of bone morphogenetic proteins that plays a critical role in several biological processes including cancer biology., Materials and Methods: We immunohistochemically examined the expression and distribution of Gremlin1 in non-neoplastic gastric mucosa in a series of 159 GC cases., Results: Among 159 GC primary tumors, 59 (37%) were positive for Gremlin1. Gremlin1-negative GC cases showed significantly more advanced clinicopathologic factors and a trend toward intestinal-type GC. Gremlin1 expression was also frequently observed in MUC5AC-positive and G-type GC cases. Gremlin1-negative GCs had a poorer survival rate than Gremlin1-positive GCs (p=0.002). Univariate and multivariate analyses revealed that Gremlin1 expression is an independent predictor of survival in GCs., Conclusion: These results indicate that Gremlin1 could be involved in GC progression and may be a good marker of long-term survival in GC., (Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Objective: Esophageal cancer is one of the deadliest cancers in the world, and the main subtype is esophageal squamous cell carcinoma (ESCC), which comprises 90% of cases. Expression of tryptophan 2,3-dioxygenase (TDO2), an enzyme involved in tryptophan catabolism, has been linked with tumor survival and poor prognosis of brain and breast cancer. However, no studies have investigated the potential role of TDO2 in esophageal cancer. Here we explored the expression and biological significance of TDO2 in ESCC., Methods: TDO2 protein expression was evaluated in 90 ESCC tissue samples by immunohistochemistry. TDO2 function in ESCC cell lines and spheroid colony formation were evaluated by RNA interference (RNAi)., Results: TDO2 overexpression was associated with tumor stage, recurrence status, and the CD44 cancer stem cell marker in ESCC. TDO2 overexpression was correlated with poor outcome of ESCC patients. Inhibition of TDO2 expression by RNAi in TE-10 and TE-11 cell lines reduced both the number and the size of spheroid colonies as well as cell proliferation. Knockdown of TDO2 expression also induced inactivation of the epidermal growth factor receptor signaling pathway., Conclusion: Our results imply that TDO2 could play an important role in the progression of ESCC. Furthermore, TDO2 may be a potential therapeutic target in ESCC., (© 2018 S. Karger AG, Basel.)

Gastric cancer (GC) is one of the most common human cancers. Genes expressed only in cancer tissue, especially on the cell membrane, may be useful biomarkers for cancer diagnosis and therapeutics. In the present study, we focused on the PCDHB9 gene, which encodes the transmembrane protein protocadherin B9. Immunohistochemical analysis revealed that 62 (36%) of 173 GC cases were positive for protocadherin B9. Protocadherin B9 staining was mainly observed on the GC cell membrane. Expression of protocadherin B9 was frequently found in intestinal-type GC and correlated with poor prognosis in patients with intestinal-type GC. Although PCDHB9 knockdown or forced expression of PCDHB9 did not change cell growth or invasion activity in a GC cell line, cell adhesion to fibronectin was significantly reduced by PCDHB9 knockdown and significantly enhanced by overexpression of PCDHB9. Expression levels of ITGA3, ITGA4, ITGA5, and ITGB1 were significantly reduced by knockdown of PCDHB9 and significantly enhanced by overexpression of PCDHB9. Furthermore, both the number and the size of spheres in culture were significantly decreased by PCDHB9 knockdown and significantly increased by overexpression of PCDHB9. In a peritoneal dissemination mouse model, the weight of the total disseminated nodules of MKN-74 cells was significantly increased by forced expression of PCDHB9. These results indicate that protocadherin B9 plays an important role in the progression rather than the pathogenesis of intestinal-type GC. Specific inhibitors of protocadherin B9 may constitute promising anti-cancer drugs with fewer side-effects. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd., (Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.)

Background: Gastrointestinal (GI) cancer, including gastric cancer (GC), colorectal cancer (CRC), and esophageal squamous cell carcinoma (ESCC), is the most common malignancy worldwide. To identify genes that encode transmembrane proteins present in GI cancer, Escherichia coli ampicillin secretion trap libraries were generated from MKN-74 GC cells, and BST2 was identified as overexpressed in GC. This study analyzed the expression and function of the BST2 gene in human GI cancers and examined the relationship between bone marrow stromal antigen-2 (BST-2) expression and GI patient clinicopathologic characteristics., Methods: Expression and distribution of BST-2 protein was analyzed by immunohistochemistry in 180 GC cases, 140 CRC cases, and 132 ESCC cases. Cell growth was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay., Results: Immunohistochemical analysis of BST-2 in GC tissues showed that 65 (36 %) of 180 GC cases were positive for BST-2. Uni- and multivariate analyses demonstrated that BST-2 expression is an independent prognostic classifier of GC patients. Immunohistochemical analysis showed that 46 % of 140 CRC cases and 27 % of 132 ESCC cases were positive for BST-2. In ESCC, BST-2 expression was an independent prognostic predictor for survival. The growth of BST2 small interfering RNA (siRNA)-transfected GC cells was significantly slower than the growth of negative control siRNA-transfected GC cells. The levels of phosphorylated epidermal growth factor receptor, extracellular signal-regulated kinase, and Akt were lower in BST2 siRNA-transfected GC cells than in control cells., Conclusions: The results suggest that BST-2 is involved in tumor progression and serves as an independent prognostic classifier for patients with GC. Because BST-2 is expressed on the cell membrane, BST-2 could be a therapeutic target for GC, CRC, and ESCC.

Objective: Gastric cancer (GC) is one of the most common human cancers. A useful method of gastric cancer stem cell (CSC) characterization is spheroid colony formation. Previously, we reported that KIF11 expression is >2-fold in spheroid-body-forming GC cells compared with parental cells. Here, we analyzed the expression and distribution of KIF11 in human GC by immunohistochemistry., Methods: Expression of KIF11 in 165 GC cases was determined using immunohistochemistry. For mucin phenotypic expression analysis of GC, immunostaining of MUC5AC, MUC6, MUC2 and CD10 was evaluated. RNA interference was used to inhibit KIF11 expression in GC cell lines., Results: In total, 119 of 165 GC cases (72%) were positive for KIF11. Expression of KIF11 was not associated with any clinicopathologic characteristics; however, it was observed frequently in GC exhibiting an intestinal phenotype. Both the number and size of spheres formed by MKN-74 cells were significantly reduced following transfection of KIF11-targeting siRNA compared with negative-control siRNA. Furthermore, levels of phosphorylated Erk1/2 were lower in KIF11 siRNA-transfected cells than with negative-control siRNA-transfected cells., Conclusion: These results indicate that KIF11 is involved in intestinal mucin phenotype GC., (© 2016 S. Karger AG, Basel.)

Mutations in TGFBR2, a component of the transforming growth factor (TGF)-β signaling pathway, occur in high-frequency microsatellite instability (MSI-H) colorectal cancer (CRC). In mouse models, Tgfbr2 inactivation in the intestinal epithelium accelerates the development of malignant intestinal tumors in combination with disruption of the Wnt-β-catenin pathway. However, no studies have further identified the genes influenced by TGFBR2 inactivation following disruption of the Wnt-β-catenin pathway. We previously described CDX2P-G19Cre;Apcflox/flox mice, which is stochastically null for Apc in the colon epithelium. In this study, we generated CDX2P-G19Cre;Apcflox/flox;Tgfbr2flox/flox mice, with simultaneous loss of Apc and Tgfbr2. These mice developed tumors, including adenocarcinoma in the proximal colon. We compared gene expression profiles between tumors of the two types of mice using microarray analysis. Our results showed that the expression of the murine homolog of GSDMC was significantly upregulated by 9.25-fold in tumors of CDX2P-G19Cre;Apcflox/flox;Tgfbr2flox/flox mice compared with those of CDX2P-G19Cre;Apcflox/flox mice. We then investigated the role of GSDMC in regulating CRC tumorigenesis. The silencing of GSDMC led to a significant reduction in the proliferation and tumorigenesis of CRC cell lines, whereas the overexpression of GSDMC enhanced cell proliferation. These results suggested that GSDMC functioned as an oncogene, promoting cell proliferation in colorectal carcinogenesis. In conclusion, combined inactivation of both Apc and Tgfbr2 in the colon epithelium of a CRC mouse model promoted development of adenocarcinoma in the proximal colon. Moreover, GSDMC was upregulated by TGFBR2 mutation in CRC and promoted tumor cell proliferation in CRC carcinogenesis, suggesting that GSDMC may be a promising therapeutic target., Competing Interests: The authors have declared that no competing interests exist.

Objective: Increased expression of calcineurin in colorectal cancer (CRC) has been reported. Although the oncogenic function has been suggested, the clinical relevance is still unclear. We herein studied calcineurin expression as a prognostic biomarker in patients receiving curative surgery for stages I-III CRC., Methods: In 121 patients with stages I-III CRC treated at Hiroshima University between 1997 and 2003, calcineurin A expression was examined using immunohistochemistry (IHC) staining of surgical specimens. Specimens were considered positive for calcineurin A if any IHC-stained cells were observed within the carcinomatous area, and clinicopathological characteristics and survival outcomes were compared between IHC-positive and -negative groups., Results: Calcineurin A was preferentially expressed in the cytoplasm of cancer cells, and a median of 8% of the cells (range: 0-80%; interquartile range: 0-22.5%) were stained within the carcinomatous areas. Of 121 cases, 81 were determined as IHC positive while 40 were determined to be negative. Positive expression of calcineurin A, as well UICC-TNM stage, was associated with low relapse-free survival (RFS) rates in multivariate analyses (hazard ratio = 2.92; 95% CI: 1.27-7.92; p = 0.010)., Conclusion: Increased calcineurin A expression is associated with lower RFS rates and may have clinical value in predicting recurrence., (© 2016 S. Karger AG, Basel.)

Background: The G-Project committee was erected by the Japan Society for Gastroenterological Carcinogenesis with an aim of establishing a new classification scheme based on molecular biological characteristics that would supplement the conventional TNM classification to better predict outcome., Methods: In a literature search involving 822 articles on gastric cancer, eight molecules including p53, vascular endothelial growth factor (VEGF)-A, VEGF-C, matrix metalloproteinase-7 (MMP-7), human epidermal growth factor receptor 2, Regenerating islet-derived family, member 4, olfactomedin-4 and Claudin-18 were selected as candidates to be included in the new molecular classification scheme named G-factor. A total of 210 cases of gastric cancer who underwent curative R0 resection were registered from four independent facilities. Immunohistochemical staining for the aforementioned molecules was performed for the surgically resected specimens of the 210 cases to investigate the correlation between clinicopathological factors and expression of each molecule., Results: No significant correlation was observed between the immunostaining expression of any of the eight factors and postoperative recurrence. However, the expressions of p53 and MMP-7 were significantly correlated with overall survival (OS). When 210 gastric cancer patients were divided into three groups based on the expression of p53 and MMP-7 (G0 group: negative for both p53 and MMP-7, n = 69, G1 group: positive for either p53 or MMP-7, n = 97, G2 group: positive for both of the molecules, n = 44), G2 group demonstrated significantly higher recurrence rate (59%) compared to 38% in G0 (p = 0.047). The multivariate regression analysis revealed that G2 group was independently associated with a shorter disease-free survival (DFS) (hazard ratio 1.904, 95% CI 1.098-3.303; p = 0.022), although the association with OS was not significant. Stage II patients among the G2 group had significantly inferior prognosis both in terms of OS and DFS when compared with those among the G0/G1 group, with survival curves similar to those of Stage III cases., Conclusions: G-factor based on the expression of p53 and MMP-7 was found to be a promising factor to predict outcome of Stage II/III gastric cancer, and possibly to help select the treatment for Stage II cancer, thus supplementing the conventional TNM system.

Gastric cancer (GC) is one of the most common malignancies worldwide. In particular, scirrhous type GC is highly metastatic and is characterized clinically by rapid disease progression and poor prognosis. MicroRNAs (miRNAs) play crucial roles in cancer development and progression. We previously demonstrated by microarray analysis that microRNA-145 (miR-145) is one of the more highly expressed miRNAs in scirrhous type GC vs. non-scirrhous types of GC. In the present study, we investigated the role of miR-145 in scirrhous type GC. The expression levels of miR-145 assessed by quantitative RT-PCR were higher in scirrhous type GC tissue samples than in non-scirrhous type GC and corresponding normal tissues. GC patients with high miR-145 expression were at a more advanced tumor stage (P=0.0156) and had more scirrhous type histology (P=0.0054) than those with low miR-145 expression. Furthermore, miR-145 expression was significantly associated with poor prognosis in GC patients (P=0.0438). miR-145 expression was localized in stromal fibroblasts of scirrhous type GC but not in cancer cells. miR-145 was induced by treatment by transforming growth factor-β, and it enhanced the expression of α-smooth muscle actin, a marker of myofibroblasts, in both normal gastric fibroblasts and cancer-associated fibroblasts. These data suggest that miR-145 may contribute to the progression of scirrhous type GC by regulating activation of peri-tumoral fibroblasts.

Objectives: To investigate the clinical significance of micro-ribonucleic acid-155 in clear cell renal cell carcinoma, in particular focusing on the association of expression levels of micro-ribonucleic acid-155 with clinicopathological factors, cancer-specific survival and therapeutic outcomes in clear cell renal cell carcinoma patients., Methods: Quantitative reverse transcription polymerase chain reaction of micro-ribonucleic acid-155 was carried out on 137 clear cell renal cell carcinoma cases, containing 77 matched pairs of clear cell renal cell carcinoma and normal adjacent kidney tissues from the same patients., Results: Significant overexpression of micro-ribonucleic acid-155 was found in clear cell renal cell carcinoma compared with normal kidney tissue. Expression of micro-ribonucleic acid-155 was not associated with prognosis in all stage groups. However, in 43 patients with stage III and IV clear cell renal cell carcinoma, low expression levels of micro-ribonucleic acid-155 correlated with a poor prognosis. Regarding cancer-free survival of 26 patients with stage III and IV clear cell renal cell carcinoma who received curative resection and cancer-specific survival of 31 patients who received postoperative therapy with interferon-α after radical nephrectomy, low expression levels of micro-ribonucleic acid-155 correlated with poor clinical outcomes in these two groups., Conclusions: Low expression of micro-ribonucleic acid-155 represents a valuable marker of poor clinical outcomes in patients with stage III and IV clear cell renal cell carcinoma., (© 2012 The Japanese Urological Association.)

Aims: Genes expressed only in cancer tissue or specific organs will be useful molecular markers. To identify genes that encode secreted proteins present in prostate cancer (PCa), we generated Escherichia coli ampicillin secretion trap (CAST) libraries from PCa and normal prostate (NP)., Methods and Results: We identified 15 candidate genes that encode secreted proteins present in PCa and NP. Quantitative RT-PCR analysis revealed that MSMB, NBL1 and AZGP1 were expressed with much higher specificity in PCa and NP than in 14 other kinds of normal tissue. We focused on NBL1, which was originally identified as a putative tumor suppressor gene. Western blot analysis revealed that NBL1 protein was highly expressed in both cell lysate and culture media of the DU145 PCa cell line. Immunohistochemical analysis showed that NBL1 expression was highly detected in and restricted to NP and PCa and was significantly down-regulated in PCa. NBL1 expression was significantly reduced according to the tumor stage, Gleason grade and preoperative prostate-specific antigen (PSA) value., Conclusion: NBL1 is a secreted protein that is highly restricted to the prostate. Underexpression of NBL1 correlated with PCa progression. NBL1 might be a candidate tumor marker for PCa in addition to PSA., (Copyright © 2012 S. Karger AG, Basel.)

Background: Patients diagnosed with stage II and III esophageal squamous cell carcinoma (ESCC) have variable prognosis. This group would benefit greatly from the discovery of prognostic markers that are capable of identifying individuals for whom adjuvant treatment would be advantageous. The aim of this study was to investigate the impact of immunohistochemically detected cytokeratin 7 (CK7) expression on disease-free survival, overall survival (OS), or therapeutic outcome in patients with ESCC., Methods: Immunohistochemical analysis of CK7 was performed on 225 surgically resected specimens of stage 0-III ESCC., Results: In total, 20 (9%) of 225 ESCC cases were positive for CK7. In stage 0-III ESCC patients, CK7 expression was statistically significantly associated with OS, independent of clinical covariates, including tumor, node, metastasis system stage. In stage II and III ESCC patients (n = 124), CK7 expression was significantly associated with poorer OS (P = 0.0377). Furthermore, in stage II and III ESCC patients who did not receive adjuvant chemotherapy (n = 73), CK7 expression was significantly associated with poorer OS (P = 0.0003). CK7 expression was not associated with therapeutic outcome in patients with stage II and III ESCC who received adjuvant chemotherapy. In patients with CK7-positive ESCC (n = 16), receipt of adjuvant chemotherapy tended to be beneficial for patients with stage II and III ESCC (P = 0.0654)., Conclusions: Immunohistochemical analysis of CK7 will help to identify high-risk patients.

Objective: The expressions of cytokeratin (CK) 7 and 20 have been studied in various primary and metastatic carcinomas, and their determination may help distinguish the site of origin of metastatic carcinomas. However, little is known about the molecular basis that determines variations in CK patterns in gastric cancers (GCs). The aim of the present study was to analyze the CK expression patterns in a large number of GCs and to investigate how the CK patterns correlate with clinicopathologic parameters, histology, mucin phenotype or several tumor-related molecules., Methods and Results: We immunohistochemically examined the CK7/CK20 patterns, mucin expression profiles (MUC5AC, MUC6, MUC2 and CD10), and the cancer-related molecules (CDX2, p53, EGFR and β-catenin), using a tissue microarray with 870 GCs. The GCs were divided into four patterns; 17% of CK7+/CK20+, 57% of CK7+/CK20-, 9% of CK7-/CK20+ and 17% of CK7-/CK20. GCs with the CK7-/CK20- pattern demonstrated a close relation to undifferentiated adenocarcinoma. CK7 expression was significantly correlated with the expression of MUC5AC and MUC6, while CK20 expression was correlated with MUC2 and CDX2. There were statistically significant associations between CK expression patterns and mucin phenotypes., Conclusion: These results indicate that the CK7/CK20 expression patterns in GCs demonstrated different clinicopathologic features and molecular signatures., (Copyright © 2012 S. Karger AG, Basel.)

Aims: Urothelial carcinoma (UC) with squamous differentiation tends to present at higher stages than pure UC. To distinguish UC with squamous differentiation from pure UC, a sensitive and specific marker is needed. Desmocollin 2 (DSC2) is a protein localized in desmosomal junctions of stratified epithelium, but little is known about its biological significance in bladder cancer. We examined the utility of DSC2 as a diagnostic marker., Methods and Results: We analysed the immunohistochemical characteristics of DSC2, and studied the relationship of DSC2 expression with the expression of the known markers uroplakin III (UPIII), cytokeratin (CK)7, CK20, epidermal growth factor receptor (EGFR), and p53. DSC2 staining was detected in 24 of 25 (96%) cases of UC with squamous differentiation, but in none of 85 (0%) cases of pure UC. DSC2 staining was detected only in areas of squamous differentiation. DSC2 expression was mutually exclusive of UPIII expression, and was correlated with EGFR expression. Furthermore, DSC2 expression was correlated with higher stage (P = 0.0314) and poor prognosis (P = 0.0477)., Conclusions: DSC2 staining offers high sensitivity (96%) and high specificity (100%) for the detection of squamous differentiation in UC. DSC2 is a useful immunohistochemical marker for separation of UC with squamous differentiation from pure UC., (2011 Blackwell Publishing Limited.)

Aims: Prostate cancer (PCa) is one of the most common malignancies worldwide. Genes expressed only in cancer tissue, and especially related to proteins located on the cell membrane, will be useful molecular markers for diagnosis and may also be good therapeutic targets. The aim of this study was to identify genes that encode transmembrane proteins present in PCa., Methods and Results: We generated Escherichia coli ampicillin secretion trap (CAST) libraries from 2 PCa cell lines and normal prostate tissues. By sequencing 3,264 colonies from CAST libraries, we identified 18 candidate genes that encode transmembrane proteins present in PCa. Quantitative RT-PCR analysis of these candidates revealed that STEAP1, ADAM9 and CDON were expressed much more highly in PCa than in 15 kinds of normal tissues. Among the candidates, CDON encodes the CDO protein, which is an orphan cell surface receptor of the immunoglobulin superfamily. Additional quantitative RT-PCR revealed that 83% of PCa tissues showed CDON overexpression. Knockdown of CDON in DU145 cells induced 5-fluorouracil-induced apoptosis and inhibited invasion ability., Conclusion: These results suggest that CDON has a high potential as a therapeutic target for PCa., (Copyright © 2011 S. Karger AG, Basel.)

Aims: The mucin phenotype is associated with clinicopathological findings and tumorigenesis in gastric cancer (GC). The aim was to search for a novel marker regulating the intestinal phenotype of GC., Methods and Results: We performed microarray analyses, and GJB6 (encoding connexin 30) was identified as a gene associated with the intestinal phenotype. Immunostaining of connexin 30 in 169 GC cases revealed that 47 (28%) cases were positive for connexin 30, while connexin 30 was negative in nonneoplastic gastric tissue. Connexin 30-negative GC cases showed more advanced T grade, N grade, and tumor stage than connexin 30-positive GC cases. Six (13%) GC cases positive for connexin 30 were histologically of the differentiated type. In addition, the expression of gastric and intestinal phenotypes of GC was examined by immunostaining for MUC5AC, MUC6, MUC2, and CD10. Connexin 30 expression occurred more frequently in the intestinal phenotype (48%) than in other phenotypes (21%) of GC., Conclusion: These results indicate that the expression of connexin 30 is a novel differentiation marker mediating the biological behavior of intestinal phenotype GC., (Copyright © 2010 S. Karger AG, Basel.)

Gastric cancer (GC) is 1 of the most common human cancers. Early detection remains the most promising approach to improving long-term survival of patients with GC. We previously performed Serial Analysis of Gene Expression (SAGE) on 4 primary GCs and identified several GC-specific genes including Reg IV. Of these genes, olfactomedin 4 (OLFM4, also known as GW112 or hGC-1) is a candidate gene for cancer-specific expression. In this study, we examined the expression of olfactomedin 4 in human GC by immunohistochemistry. We also assessed serum olfactomedin 4 levels in GC patients by enzyme-linked immunosorbent assay. 94 (56%) of 167 GC cases were positive for olfactomedin 4 by immunostaining. Olfactomedin 4 staining was observed more frequently in stage I/II cases than in stage III/IV cases. The serum olfactomedin 4 concentration in presurgical GC patients (n = 123, mean +/- SE, 36.3 +/- 3.5 ng/mL) was significantly higher than that in healthy individuals (n = 76, 16.6 +/- 1.6 ng/mL). In patients with stage I GC, the sensitivity of serum olfactomedin 4 (25%) and Reg IV (35%) was superior to that of CA19-9 (5%) or CEA (3%). Furthermore, in patients with stage I GC, the combination of olfactomedin 4 and Reg IV elevated the diagnostic sensitivity to 52%. These results suggest that serum olfactomedin 4 is a useful marker for GC and its measurement alone or in combination with Reg IV has utility in the early detection of GC.

Background: The human homologue of Drosophila prune (PRUNE, which encodes h-prune) protein interacts with glycogen synthase kinase 3 and promotes cell motility. The aim of our study was to investigate the impact of immunohistochemically detected h-prune expression on the survival of patients with esophageal squamous cell carcinoma (ESCC)., Methods: Immunohistochemical staining of h-prune was performed for 205 surgically resected specimens of ESCC., Results: In total, 43 (21%) of 205 ESCC cases were positive for h-prune. h-prune-positive ESCC cases showed a more-advanced T stage (P < 0.0001), N stage (P < 0.0001), and tumor stage (P < 0.0001) than h-prune-negative ESCC cases. In the group of 116 stage II and III ESCC cases, recurrence of ESCC was frequently found in h-prune-positive cases. In patients with lung recurrence, the tumors were more likely to be h-prune positive than h-prune negative. Univariate analysis revealed that T stage (P < 0.0001), N stage (P < 0.0001), tumor stage (P < 0.0001), and h-prune staining (P < 0.0001) were significant prognostic factors for survival. Multivariate analysis indicated that N stage (P = 0.0182) and h-prune staining (P < 0.0001) were independent predictors for survival., Conclusions: These results indicate that immunostaining of h-prune is useful to identify patients at high risk for recurrence or poor prognosis associated with ESCC.

Gastric cancer is the fourth most common malignancy in the world, and mortality due to gastric cancer is second only to that from lung cancer. 'Transcriptome dissection' is a detailed analysis of the entire expressed transcripts from a cancer, for the purpose of understanding the precise molecular mechanism of pathogenesis. Serial analysis of gene expression (SAGE) is a suitable technique for performing transcriptome dissection. Gastric cancers of different stages and histology were analyzed on SAGE, and one of the largest gastric cancer SAGE libraries in the world was created (GEO accession number GSE 545). Through SAGE, many candidate genes have been identified as potential diagnostic and therapeutic targets for the treatment of gastric cancer. Regenerating islet-derived family, member 4 (Reg IV) participated in 5-fluorouracil (5-FU) resistance and peritoneal metastasis, and its expression was associated with an intestinal phenotype of gastric cancer and with endocrine differentiation. GW112 expression correlated with advanced tumor stage. Measurement of Reg IV and GW112 levels in sera indicated a sensitivity of 57% for detection of cancer. SPC18 participated in tumor growth and invasion through transforming tumor growth factor-alpha upregulation. Palate, lung, and nasal epithelium carcinoma-associated protein (PLUNC) was a useful marker for gastric hepatoid adenocarcinoma. Expression of SOX9, HOXA10, CDH17, and loss of claudin-18 expression were associated with an intestinal phenotype of gastric cancer. Information obtained from transcriptome dissection greatly contributes to diagnosis and treatment of gastric cancer.

Regenerating islet-derived family, member 4 (Reg IV) is a candidate marker for cancer and inflammatory bowel disease and is associated with neuroendocrine and intestinal differentiation. We have reported that 14% of prostate cancer (PCa) cases are positive for Reg IV by immunohistochemistry. In the present study, we performed immunohistochemical analysis of Reg IV in other major urological cancers, including 101 renal cell carcinoma (RCC), and 95 urothelial carcinoma (UC) of urinary bladder by immunohistochemistry. We also investigated neuroendocrine differentiation by chromogranin A and synaptophysin staining along with intestinal differentiation by MUC2 staining. Immunohistochemical analysis of Reg IV revealed no expression of Reg IV in RCC, and only one case (1%) of UC expressed Reg IV. Neither neuroendocrine nor intestinal differentiation was found in RCC. Among 95 UC cases, neuroendocrine differentiation was detected in 13 cases (14%), and intestinal differentiation was observed in 33 cases (35%). In one Reg IV-positive UC case, MUC2 staining was observed. Since Reg IV expression was frequently found in PCa, we also measured Reg IV levels in sera from patients with PCa by enzyme-linked immunosorbent assay. The serum Reg IV concentration in PCa patients (n=38, mean +/- SE, 1.69+/-0.16 ng/ml) was significantly higher than that in control individuals (n=40, 1.28+/-0.11 ng/ml, P=0.0199, Mann-Whitney U test). The sensitivity and specificity for detection of PCa were 34% (13/38) and 90% (36/40), respectively. These results suggest that among major urologic cancers, Reg IV is expressed frequently in PCa, and that serum Reg IV represents a novel biomarker for PCa.

Signet-ring cell carcinoma (SRCC) is a unique subtype of adenocarcinoma that is characterized by abundant intracellular mucin accumulation and a crescent-shaped nucleus displaced toward one end of the cell. Identification of an SRCC's primary site is important for better planning of patient management because the treatment and prognosis differs markedly depending on the origin of the SRCC. In the present study, we analyzed the immunohistochemical characteristics of 94 cases of SRCC, including 21 cases of gastric SRCC, 16 of colorectal SRCC, 10 of breast SRCC, and 47 of pulmonary SRCC, with antibodies against Reg IV and claudin-18, which we previously identified as gastric cancer-related genes. We also tested known markers cytokeratin 7, cytokeratin 20, MUC2, MUC5AC, caudal-related homeobox gene 2 (CDX2), thyroid transcription factor-1, mammaglobin, gross cystic disease fluid protein 15, and estrogen receptor. All 21 cases of gastric SRCC and 16 cases of colorectal SRCC were positive for Reg IV, and the remaining SRCCs were negative. Eighteen of 21 (86%) gastric SRCCs and 6 of 16 (38%) colorectal SRCCs were positive for claudin-18, whereas another SRCCs were negative. In conclusion, Reg IV staining and claudin-18 staining can aid in diagnosis of gastrointestinal SRCC.

Gastric cancer is one of the most common malignancies worldwide. In this study, we screened for genes upregulated in gastric cancer by comparing gene expression profiles from serial analysis of gene expression and microarray and identified the palate, lung, and nasal epithelium carcinoma-associated protein (PLUNC) gene. Immunostaining for PLUNC in 140 gastric cancer cases revealed strong and extensive staining of PLUNC in hepatoid adenocarcinoma of the stomach, whereas 7% of conventional gastric cancer cases showed focal immunostaining of PLUNC. Gastric hepatoid adenocarcinoma is an extrahepatic tumor characterized by morphologic similarities to hepatocellular carcinoma. To investigate the utility of PLUNC immunostaining in the diagnosis of gastric hepatoid adenocarcinoma, six cases of gastric hepatoid adenocarcinoma (six primary tumors and two associated liver metastases) were studied further. PLUNC staining was observed in all six primary hepatoid adenocarcinomas. PLUNC staining was observed in both the hepatoid adenocarcinoma and tubular/papillary adenocarcinoma components of primary tumors, although PLUNC staining was preferentially localized in tubular/papillary adenocarcinoma components. Staining of PLUNC was also detected in both liver metastases. PLUNC staining was not observed in 52 cases of primary hepatocellular carcinoma or in normal adult or fetal liver. These results indicate that PLUNC is a novel marker that distinguishes gastric hepatoid adenocarcinoma from primary hepatocellular carcinoma.

Objective: Regenerating islet-derived family, member 4 (regenerating gene type IV, Reg IV) is overexpressed in colorectal cancer (CRC). The aim of this study was to investigate the diagnostic utility of Reg IV determination in sera from patients with CRC., Methods: We examined the expression and distribution of Reg IV in CRC by immunohistochemistry and determined Reg IV levels in sera from patients with CRC by enzyme-linked immunosorbent assay., Results: Immunostaining revealed that 23 of 80 (29%) CRC cases were positive for Reg IV. CRC cases with metastatic recurrence in the liver showed more frequently Reg IV staining than those without (p = 0.0102). Patients with CRC showing Reg IV staining had a significantly worse survival than those without Reg IV staining (p = 0.0117). Preoperatively, serum Reg IV concentrations were not elevated in CRC patients at stage 0-III, being in contrast to the significantly increased preoperative levels in stage IV CRC patients with liver metastasis., Conclusion: These results suggest that Reg IV is a prognosticator for poor survival. Serum Reg IV concentration may predict CRC recurrence in the liver., ((c) 2008 S. Karger AG, Basel)

Objectives: RHOC, a member of the RAS-related small GTPase protein family, regulates cytoskeletal structures and has the potential to transform cultured cells. It has recently been reported that RHOC contributes to the metastatic phenotype of melanoma cells. The purpose of this study was to clarify its biological relevance to gastric carcinogenesis and metastasis., Methods: We examined the expression of RHOC by quantitative RT-PCR in 51 cases of gastric carcinoma tissues from prior surgical cases (intestinal type: 24 cases, diffuse type: 27 cases) and in 8 gastric carcinoma cell lines., Results: RHOC expression levels in primary tumors were significantly higher in cases with metastasis than in those without metastasis (p = 0.0202; Mann-Whitney U test). RHOC expression levels in primary tumor and their metastatic tumors were significantly higher than their corresponding nonneoplastic mucosa (p = 0.0357, and 0.0173, respectively; Wilcoxon signed rank test). RHOC mRNA expression was confirmed in the gastric carcinoma cell lines., Conclusion: Our findings suggest that elevated expression of the RHOC gene may be involved in the metastasis of gastric carcinomas and may be a good genetic marker for the prediction of a metastatic potential., (Copyright 2004 S. Karger AG, Basel)