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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.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.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.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.

BRG1, a component of the SWI/SNF complex, regulates gene transcription through chromatin remodeling. Certain human cancer cell lines have been shown to contain homozygous deletions or mutations, half of which are concentrated in exons 4 and 10, resulting in aberrant BRG1 expression. We examined the expression of BRG1 in 38 gastric carcinomas and corresponding nonneoplastic mucosa by using the quantitative real-time RT-PCR method. Twenty-three carcinomas (61%) showed increased BRG1 expression in tumor tissue in comparison with that in nonneoplastic mucosa. The T/N ratio (the expression level of BRG1 mRNA in tumor tissues relative to those in corresponding nonneoplastic mucosa) in advanced cases of gastric carcinoma (stages III and IV) was significantly higher than that in cases of stage I and II carcinoma (p = 0.029). Furthermore, gastric carcinomas with lymph node metastasis showed a tendency to express BRG1 at a higher level than gastric carcinomas without metastasis (p = 0.097). We also searched for genetic alterations of the BRG1 gene in 8 gastric carcinoma cell lines and 33 primary gastric carcinomas by PCR-SSCP analysis. No SSCP variants in exons 4, 10 and 16 of the BRG1 gene were found in both gastric carcinoma cell lines and primary gastric carcinomas. These results suggest that, although genetic abnormality of BRG1 might be rare, an increased expression of BRG1 might be associated with the development and progression of gastric carcinoma.

Background: Cervical cancer is the second-most common cancer in women worldwide. In Japan, it was the 11th leading cause of death from cancer for women in 2008 but there has been a unique increase of cervical cancer incidence among women in the 20-39-year age group in spite of the decrease of it among women over age 40. High-risk (hr) HPV infection initiates an early event through which an accumulation of genetic and epigenetic aberrations follows. Aberrant DNA methylation (abMet) is shown to provide disease biomarkers with great potential applicable to clinical specimens. The authors undertook a prospective cohort study, as the first trial in the world up to our knowledge, to examine the relationship between the abMet of DLX4 and SIM1 genes and progression of LSIL. Methods: A total of 113 patients were selected from the Comparative Study on Conventional Pap smear and Liquid-based Cytology (ThinPrep) for Uterine Cervix (CCLBC), in which 11,039 samples were enrolled between October 2007 and March 2010 to compare the cytological features of conventional Pap smears and liquid-based cytology specimens using the ThinPrep method. They were classified into 4 groups according to their cervical cytology, hrHPV infection and follow up. Cytology samples were examined for abMet of DLX4 and SIM1 genes and their protein expressions. CaSki cells were treated with 5-Aza-2´-deoxycytidine (5-aza-dC). Results: 40 samples in group 1 were negative for intraepithelial lesion or malignancy. 21 LSILs in group 2 showed a continuance of LSIL for longer than 365 days, and 12 LSILs in group 3 showed an up-grading to high-grade (H) SIL+ within 365 days after the diagnosis of LSIL. 40 in group 4 were squamous cell carcinoma. All but group 1 were infected with hrHPV. Significant difference existed in frequency of abMet between groups 2 and 3 (p=0.044), between groups 3 and 4 (p=0.020) for DLX4, and between groups 1 and 3 (p=0.0003), as well as between groups 2 and 3 (p=0.005) for SIM1 gene. DLX4 protein expression was significantly reduced in the DLX4 abMet positive tissues, as compared to the negative tissues (p=0.008), and 5-aza-dC treatment extracted DLX4 protein expression of CaSki cells in a dose-dependent manner (p Conclusion: AbMet of DLX4 and SIM1 genes should be a useful and novel progression marker of uterine cervical LSIL with hrHPV infection. Citation Format: Junichi Sakane, Kiyomi Taniyama, Kazuaki Miyamoto, Akihisa Saitou, Kazuya Kuraoka, Kazuhiro Sentani, Naohide Ooue, Wataru Yasui. Aberrant DNA methylation of DLX4 and SIM1 is a predictive marker for disease progression of uterine cervical low-grade squamous intraepithelial lesion. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 289. doi:10.1158/1538-7445.AM2014-289

An 80-year-old man had severe lumbago that was diagnosed as multiple myeloma. He was treated with melphalan, prednisone, and zoledronic acid, with a good response. However, he had severe anemia, and endoscopic examination revealed gastric cancer. He died 3 months later. Autopsy revealed verrucous gastric cancer consisting of numerous polypoid mucosal excres- cences that had metastasized to the gallbladder and urinary bladder, showing similar polypoid mucosal lesions. The cancer consisted of poorly differentiated cells (about 85%) and signet ring cells (15%) in the stomach. The cancerous tissue was not associated with a desmoplastic reaction, and the signet ring cells showed a positive reaction to cytokeratin 7 and regenerating islet-derived family member 4 antibodies. The cancer cells had a propensity to proliferate on the mucosal surface of the stomach, gallbladder, and urinary bladder.

Gastric cancer (GC) is one of the most common malignancies worldwide and is one of the leading causes of cancer related mortality. Among gastric cancer subtypes, scirrhous type GC is highly aggressive and has a worse prognosis because of its diffuse infiltration pattern. Because of such pathological features, early clinical diagnosis of scirrhous gastric carcinoma remains difficult. Moreover, peritoneal dissemination occurs frequently even after radical surgery and is the cause of death in many patients. A potential diagnostic or therapeutic target to identify or to inhibit the mechanism of peritoneal dissemination would be an advantageous in this field and need to be elucidated. Escherichia coli ampicillin secretion trap (CAST) method is a powerful technique to identify novel genes that encode secreted or transmembrane proteins. We previously reported DSC2 (desmocollin 2), identified by this method, as a key regulator of GC with intestinal phenotype, using MKN-1 and MKN-28 GC cell lines. In this study, mRNAs were extracted from HSC-44PE and 44As3 scirrhous GC cell lines to analyze the gene expression profile. HSC-44PE cell line was established from pleural fluid of a patient with scirrhous GC. 44As3, derived from HSC-44PE cells, by isolating a highly disseminated clones with a strong capability of inducing ascites in mouse model. Randomly primed cDNAs ligated with pCAST vector were picked up and sequenced thereafter. Among the candidate genes, ZDHHC14 (zinc finger, DHHC-type containing 14) showed higher expression in 44As3 CAST library than in HSC-44PE library. ZDHHC14 is one of the palmitoyl transferase family members and is supposed to be associated with substrates linked to dissemination cascade in scirrhous type GC. Indirect immunofluorescence microscopic analysis also revealed that ZDHHC14 expression was found mostly in large cells of both cell lines, however, ZDHHC14 staining was more frequently observed in 44As3 than in HSC-44PE. High level of ZDHHC14 expression was observed in 27% of GC samples by qRT-PCR. Cell invasion assay and MTT assay revealed that ZDHHC14 influenced the invasion and growth capacity of GC cells. Identification of the palmitoylated proteins, the substrates of ZDHHC14, remain under investigation. ZDHHC14 identified by CAST method, might contribute in the process of peritoneal dissemination of the gastric cancer cells and it might be a potential therapeutic target for scirrhous type GC. Citation Format: Htoo Zarni Oo, Naoya Sakamoto, Naohiro Uraoka, Katsuhiro Anami, Kazuhiro Sentani, Naohide Oue, Kazuyoshi Yanagihara, Wataru Yasui. ZDHHC14, a potential regulator in peritoneal dissemination of scirrhous type gastric cancer, identified by CAST method. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1925. doi:10.1158/1538-7445.AM2013-1925

Gastric cancer (GC) is one of the most common malignancies worldwide. Scirrhous type GC is highly metastatic and characterized clinically by rapid disease progression and poor prognosis. MicroRNAs (miRNAs), small non-coding RNA of 19-25 nucleotides, play a part in crucial biological processes and also have an important role in cancer development and progression. In the present study, we show that microRNA-143 (miR-143) is expressed at higher level in diffuse type GC than in intestinal type GC by microRNA microarray analysis. We investigated whether miR-143 is useful as a diagnostic marker of scirrhous type GC. Quantitative RT-PCR analysis revealed that miR-143 expression was low in GC in comparison with adjacent non-tumorous mucosa. Expression levels of miR-143 were higher in scirrhous type GC than those in other types of GC. Treatment of 5-aza-2′-deoxycytidine retrieved miR-143 expression, suggesting that miR-143 might be repressed by DNA methylation. Quantitative RT-PCR and in situ hybridization analysis showed that miR-143 is expressed at higher level in normal fibroblast and cancer associated fibroblast cell lines than in GC cell lines, indicating that major source of miR-143 in cancer tissue is stromal fibroblasts rather than cancer cells. miR-143 knock down by RNAi repressed collagen type III expression in normal fibroblast and cancer associated fibroblast cell lines. Furthermore, TGF-β treatment induced expression of miR-143 and collagen type III mRNA, and this induction of collagen type III mRNA was repressed by miR-143 knock down. We also studied the relation of miR-143 expression with GC patient prognosis (n=68). High miR-143 expression was associated with worse prognosis (P=0.0141). These data suggest that miR-143 regulates fibrosis of scirrhous type GC through induction of collagen expression in stromal fibroblasts and miR-143 expression is a prognostic marker of GC. Citation Format: Yutaka Naito, Naoya Sakamoto, Naohiro Uraoka, Kazuhiro Sentani, Naohide Oue, Masakazu Yashiro, Kosei Hirakawa, Wataru Yasui. Function of microRNA-143 and its potential of prognostic factor in scirrhous type gastric cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4197. doi:10.1158/1538-7445.AM2013-4197

Gastric cancer (GC) is one of the most common human cancers. We previously performed Serial Analysis of Gene Expression (SAGE) on four primary GCs and identified several GC-specific genes. In the present study, we have built an in-house oligonucleotide array on which 394 genes selected based on our SAGE data and previously reported array data to allow for the study of the genes that are most relevant to gastric carcinogenesis. We focused on the SEC11A gene, which encodes SPC18 protein. SPC18 is one of the member of signal peptidase complex. SPC18 mRNA expression was measured by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) in GC tissue samples. Expression and distribution of SPC18 protein was investigated by immunohistochemistry in two independent GC cohorts (Hiroshima cohort, n = 99 and Chiba cohort, n = 989). To determine the effect of SPC18 on cell growth and invasiveness in vitro, MTT and Boyden chamber invasion assays were performed. To evaluate the influence of SPC18 on cell growth in vivo, GC cells were injected into SCID mice. The levels of TGF-α and EGF in media from the GC cells were measured by ELISA. Overexpression of SEC11A mRNA was observed in 40% of GC cases by qRT-PCR. Immunohistochemical analysis of SPC18 revealed that 26% of GC cases were positive for SPC18 in Hiroshima cohort and 20% of GC cases were positive for SPC18 in Chiba cohort. SPC18-positive GC cases showed poorer survival than SPC18-negative GC cases in both Hiroshima cohort and Chiba cohort by Kaplan-Meier analysis. Forced expression of SPC18 activates GC cell growth in vitro and in vivo. The levels of TGF-α and EGF in culture media from GC cells were reduced by knockdown of SPC18. These results indicate that SPC18 contributes to malignant progression through promotion of EGF and TGF-α secretion in GC. Citation Format: Naohide Oue, Tetsutaro Hayashi, Reiko Ito, Akiko Nagatsuma, Kazuhiro Sentani, Naoya Sakamoto, Katsuhiro Anami, Naohiro Uraoka, Yutaka Naito, Kazuyoshi Yanagihara, Atsushi Ochiai, Hiroki Sasaki, Wataru Yasui. SEC11A contributes to malignant progression through promotion of EGF and TGF-α secretion in gastric cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 412. doi:10.1158/1538-7445.AM2013-412

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignancies worldwide. Because most ESCC is diagnosed at advanced stages, the overall 5-year survival rate of ESCC still remains low in spite of the use of various treatment modalities. Therefore, identification of new diagnostic markers and therapeutic targets for ESCC is important. Serial Analysis of Gene Expression (SAGE) is one of the common comprehensive methods to analyze transcript expression levels, and enables the quantitative and simultaneous analysis of a large number of transcripts. To identify potential diagnostic markers and therapeutic targets for ESCC, the SAGE library was generated from one ESCC sample. A total of 14,430 tags were generated, including 5,765 that were unique. By comparing SAGE tags from the ESCC sample with those from normal human squamous esophagus, several genes that is upregulated in ESCC compared with normal squamous esophagus in ESCC were identified. Among these, we focused on the nardilysin (N-arginine dibasic convertase, NRD1) gene. NRD1 has been reported to be associated with ectodomein shedding of TNF-α through activation of ADAM proteases. There is only one report in the literature mentioning the association of NRD1 with cancer (breast cancer), however, there is no report that links expression of NRD1 and ESCC. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis showed a high level of NRD1 expression in three of five esophageal cancer cell lines and seven of 14 ESCC samples, but not in 14 normal systemic tissues. Western blot analysis also showed upregulation of NRD1 protein in total five esophageal cancer cell lines. Immunohistochemical analysis revealed expression of NRD1 in cytoplasm of 43 out of 109 ESCC cases (39%), as well as heart, skeletal muscle, and testis in agreement with previous reports. In clinicopathological analysis, expression of NRD1 correlated with the advanced T grade, N grade and tumor stage, and was an independent predictor of survival in patients with ESCC. Knockdown of NRD1 in TE5 cells inhibited cell invasion ability. Furthermore, qRT-PCR analysis showed a reduction of matrix metalloproteinase-2 (MMP-2) expression in NRD1 knocked down cells. In conclusion, NRD1 is an independent predictor of survival, and contribute to cell invasion through regulation of MMP-2 in ESCC. NRD1 could be a novel diagnostic and therapeutic target for ESCC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-91. doi:1538-7445.AM2012-LB-91

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.

To elucidate the mechanism of radiation-induced cancers, molecular analysis of cancers in atomic bomb (A-bomb) exposure is important. DNA double-strand breaks (DSBs) are thought to be caused by the deleterious effects of ionizing radiation, and gammaH2AX (serine 139 phosphorylated form of histone H2AX) is reported to be a significant marker for DSBs. In the present study, we performed immunohistochemical analysis of gammaH2AX in gastric cancers (GCs) from 66 exposed and 47 non-exposed patients who developed GC after the bombing. Of the 47 GCs from non-exposed patients, 6 (13%) cases showed nuclear positive staining for gammaH2AX, whereas of the 66 GCs from exposed patients, 20 (30%) cases were positive (P=0.0405). However, among stage I GC, there was no significant difference in gammaH2AX expression frequency between exposed patients and non-exposed patients. Among exposed patients, stage II-IV cases were more frequently positive for gammaH2AX than stage I cases (P=0.0197). Among GCs from non-exposed patients, gammaH2AX staining showed no significant association with Lauren's classification, depth of invasion, lymph node metastasis or TNM stage. These results suggest that the characteristics of tumor cells differ between GCs from exposed and non-exposed patients. DSBs may be involved in progression of GC in exposed patients.

Regenerating gene family, member 4 (REG4, encodes Reg IV), was originally identified from cDNA library of inflammatory bowel disease tissues, and is specifically expressed in gastrointestinal tract. We have identified REG4 as an overexpressed gene in gastric cancer from SAGE analysis in gastric cancer tissues and noticed as a novel serum marker of cancer. The expression of Reg IV is associated with intestinal mucin differentiation, and RegIV is expressed in CDX2-positive cells. CDX2, the intestine-specific caudal-related homeobox transcription factor, plays a key role in intestinal development and differentiation. In the present study, we investigated whether CDX2 induce RegIV expression. Western blot analysis indicated that forced expression of CDX2 in HT29 colon cancer cell line induced Reg IV expression. In silico analysis of 2-kilobase upstream region of REG4 revealed at least four putative CDX2 consensus sequences. To assess the role of these putative CDX2 consensus sequences in regulating REG4 transcription, we performed luciferase assay into HSC39 gastric cancer cell line, in which CDX2 is highly expressed. Reporter gene constructs containing 2-kilobase of 5’-flanking region from the REG4 gene showed strong reporter activity. Significant change of reporter activity was not observed between 2.0 and 0.65-kilobase upstream region of REG4 constructs, apart from that significant lower expression level at 0.1-kilobase. These results suggest that expression of REG4 is regulated by CDX2, and upstream region of REG4 has enhancer sequences at proximal region at 0.1-kilobase upstream region. Based on the analysis of single mutation in the putative CDX2 consensus sequences in the 5’-flanking region of the REG4 gene, two putative CDX2 consensus sequences were found to activate REG4 expressions. Therefore, RegIV may be a key factor mediating CDX2 function in intestinal determination. To identify the CDX2-binding site in detail, ChIP assay and mutagenesis with multiple mutations in the putative CDX2 consensus sequences must be carried out. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 272. doi:10.1158/1538-7445.AM2011-272

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignancies worldwide. To identify potential targets for diagnosis and therapeutics of ESCC, we performed Serial Analysis of Gene Expression (SAGE) on the ESCC sample. We generated the SAGE library from one ESCC sample and obtained a total of 14,430 tags, including 5,765 that were unique. By comparing SAGE tags from ESCC samples with those from normal human squamous esophagus (Gene Expression Omnibus accession number, GSM52501), we found several genes and tags that were differentially expressed between ESCC and normal squamous esophagus. Among these, we focused on the ADAM metallopeptidase with thrombospondin type 1 motif, 16 (ADAMTS16) gene. ADAMTS has been described as part of a family of zinc dependent proteases (metzincin family), which play important roles in a variety of normal and pathological conditions including arthritis and cancer. Although ADAMTS16 is expressed in some organs, the relationship with cancers, including ESCC, has not been studied. Quantitative reverse transcription-polymerase chain reaction analysis showed a high level of ADAMTS16 expression in 8 out of 20 ESCC samples (40%) but not in 15 kinds of normal tissues. We also investigated the mRNA expression levels of SCCA1, which encodes SCC antigen. High levels of SCCA1 mRNA expression were found in 4 of 20 cases (20%). We then investigated the relation of ADAMTS16 expression to clinicopathologic characters and found that ADAMTS16 overexpression correlated with the advanced T grade (p = 0.0215). Western blot analysis revealed that ADAMTS16 protein expression was detected in all 4 ESCC cases, whereas in 1 of the 4 corresponding non-neoplastic mucosa. Furthermore, ADAMTS16 protein was detected in culture media from the TE5 ESCC cell line which expressed significant level of ADAMTS16 mRNA, indicated that ADAMTS16 is surely secreted. To evaluate the biological significance of ADAMTS16 in ESCC, we performed MTT assay and transwell invasion assay. These examination revealed that knockdown of ADAMTS16 by siRNA in TE5 cells inhibited both cell growth and invasion ability. These results suggest that ADAMTS16 has a high potential as a serum tumor marker and therapeutic target for ESCC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2178.

Prostate cancer (PCa) is one of the most common human cancers. Identification of novel genes that encode membrane-spanning or secreted proteins expressed specifically in PCa has a great advantage to develop of ideal biomarkers for cancer diagnosis and therapeutics. Escherichia coli Ampicillin Secretion Trap (CAST) is a signal sequence trap method to identify genes encoding cell surface and secreted proteins. In this study, to identify novel diagnostic and therapeutic targets of PCa, CAST method was used. We generated cDNA libraries from normal prostate and two PCa cell lines, LNCaP and DU145. These CAST libraries were ligated into the pCAST which was plasmid with a mutant beta-lactamase lacking the endogenous signal peptide. Survival on ampicillin was observed only when various cDNA fragments encoding a signal sequence were inserted. We sequenced 960 ampicillin-resistant colonies for normal prostate CAST library, 1344 colonies for LNCaP CAST library and 960 colonies for DU145 CAST library. By comparing these sequences to those deposited in the public databases using BLAST (NCBI), 223 genes from normal prostate CAST library, 234 genes from LNCaP and 228 genes from DU145 were identified. To extract highly expressed genes in PCa, the genes expressed in normal prostate were excluded. Quantitative RT-PCR analyses of 64 candidate genes were performed and compared mRNA levels in 9 PCa tissues, 2 normal prostate tissues and 14 kinds of normal tissues. Quantitative RT-PCR analyses revealed that CDON was highly expressed in PCa. Overexpression of CDON (tumor/normal ratio > 2) was observed in 8 (89%) of 9 PCa tissues. CDON is a cell surface receptor of the immunoglobulin /fibronectin type III repeat family. By western blot analysis, low to moderate CDON expression was noted in LNCaP cell extracts and moderate to high CDON expression was noted in DU145 cell extracts. The expression of CDON in LNCaP and DU145 was suppressed by treatment with CDON specific siRNA. Cell invasion assay and MTT assay revealed that knockdown of CDON in LNCaP cells did not inhibit both cell growth and invasion ability, but knockdown of CDON in DU145 cells inhibited both cell growth and invasion ability. In conculusion, CAST is a robust and rapid method to identify cell surface and secreted proteins. CDON was up-regulated in PCa and participated in cell growth and invasion. These finding suggest that CDON may be a good therapeutic target. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 242.

Gastric cancer (GC) is one of the most common human cancers. Identification of novel genes encoding secreted or transmembrane proteins expressed specifically in GC is important for the development of ideal biomarkers for cancer diagnosis and therapeutics. In the present study, we tried to identify genes encoding cell surface and secretory proteins in GC using Escherichia coli ampicillin secretion trap (CAST) method. CAST libraries were generated from two GC cell lines, MKN-1 and MKN-28. Ampicillin-resistant 1,440 colonies from each library were sequenced and these sequences were compared to the public databases using BLAST (NCBI). Many genes encoding secreted and transmembrane proteins including some known genes were identified. Quantitative RT-PCR was performed to confirm the overexpression of the candidate genes in GC, and the expressions of several genes are narrowly restricted in GC. Among these genes, we focused on the desmosomal cadherin desmocollin 2 (DSC2). DSC2 is ubiquitously expressed in several normal tissues where desmosomes exist. In cancers, the reduction of DSC2 in sporadic colorectal cancer is reported as desmocollin switching. It is also known that the homeodomain transcription factors Cdx1 and Cdx2 regulate DSC2 expression in colon cancer cells. Quantitative RT-PCR analyses with 14 kinds of normal tissues and 9 GC cases showed that DSC2 is highly expressed in GCs. In normal tissues, the expression was seen in the heart and pancreas at the lower levels, but not in the stomach. Overexpression of DSC2 was observed in 13 (31%) of 41 GC cases. Immunohistochemical analyses revealed that DSC2 was preferentially expressed in the cases with mucosal or submucosal invasion. DSC2 expression was significantly associated with the well differentiated cases. There were no correlations between DSC2 expression and lymph node metastasis, pathological stage, or overall survival. Additionally, DSC2 was significantly associated in GCs positive for MUC2 and CDX2. Cell invasion assay and MTT assay revealed that knockdown for DSC2 of GC cell lines by siRNA did not inhibit either cell growth or invasion ability. These findings suggest that DSC2 is involved in GC with intestinal differentiation. DSC2 is a good biomarker of intestinal type GC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 235.

Background We experience many cases of liver metastasis from colorectal cancer, but synchronous occurrence of intrahepatic cholangiocarcinoma (ICC) and liver metastasis from a rectal cancer is extremely rare. We herein report a case of ICC coinciding with a liver metastasis from a known rectal carcinoma. Case presentation A 68-year-old man was referred to our hospital for investigation of multiple liver tumors. Total colonoscopy and computed tomography (CT) revealed a rectal carcinoma, coinciding with liver metastasis. He was planned to receive chemotherapy following rectal resection. During chemotherapy for the rectal cancer, one of the liver tumors gradually grew after first shrinking. The following hepatectomy revealed the presence of intrahepatic cholangiocarcinoma (ICC). Despite intensive chemotherapy for the ICC, he passed away 6 months after the hepatectomy. Conclusions We should also suspect the possibility of multiple primary cancers, even if the patient has a history of cancer that is likely to cause metastatic lesions. When simultaneous neoplasms are diagnosed, systematic treatment should be targeted to the tumor with the worst prognosis.