Apolipoprotein A2 isoforms associated with exocrine pancreatic insufficiency in early chronic pancreatitis.

BACKGROUND AND AIM: Apolipoprotein A2 (apoA2) isoforms have been reported to undergo the aberrant processing in pancreatic cancer and pancreatic risk populations compared with that in healthy subjects. This study aimed to clarify whether apoA2 isoforms were as useful as N-benzoyl-p-aminobenzoic acid (BT-PABA) test for exocrine pancreatic dysfunction markers in patients with early chronic pancreatitis (ECP). METHODS: Fifty consecutive patients with functional dyspepsia with pancreatic enzyme abnormalities (FD-P) (n = 18), with ECP (n = 20), and asymptomatic patients with pancreatic enzyme abnormalities (AP-P) (n = 12) based on the Rome IV classification and the Japan Pancreatic Association were enrolled in this study. The enrolled patients were evaluated using endoscopic ultrasonography and endoscopic ultrasonography elastography. Five pancreatic enzymes were estimated. Pancreatic exocrine function was analyzed using the BT-PABA test. Lighter and heavier apoA2 isoforms, AT and ATQ levels were measured by enzyme-linked immunosorbent assay methods. RESULTS: There were no significant differences in clinical characteristics such as age, gender, body mass index, alcohol consumption and smoking among patients with AP-P, FD-P, and ECP. The BT-PABA test and lighter apoA2 isoform, AT level in the enrolled patients had a significant correlation (P < 0.01). The BT-PABA test in patients with ECP was significantly lower (P = 0.04) than that in AP-P. ApoA2-AT level in patients with ECP was lower than that in AP-P, albeit, insignificantly. Interestingly, apo A2-AT level was significantly (P = 0.041) associated with exocrine pancreatic insufficiency by multiple logistic regression analysis. CONCLUSIONS: ApoA2-AT level is a useful tool to evaluate exocrine pancreatic insufficiency in the early stage of chronic pancreatitis.

Intercellular crosstalk between cancer cells and cancer-associated fibroblasts via extracellular vesicles.

Intercellular communication plays an important role in cancer initiation and progression through direct contact and indirect interactions, such as via secretory molecules. Cancer-associated fibroblasts (CAFs) are one of the principal components of such communication with cancer cells, modulating cancer metastasis and tumour mechanics and influencing angiogenesis, the immune system, and therapeutic resistance. Over the past few years, there has been a significant increase in research on extracellular vesicles (EVs) as regulatory agents in intercellular communication. EVs enable the transfer of functional molecules, including proteins, mRNAs and microRNAs (miRNAs), to recipient cells. Cancer cells utilize EVs to dictate the specific characteristics of CAFs within the tumour microenvironment, thereby promoting cancer progression. In response to such "education" by cancer cells, CAFs contribute to cancer progression via EVs. In this review, we summarize experimental data indicating the pivotal roles of EVs in intercellular communication between cancer cells and CAFs.

Identification of microRNA-96-5p as a postoperative, prognostic microRNA predictor in nonviral hepatocellular carcinoma.

AIM: The microRNA (miR) clusters miR-183/96/182 and miR-217/216a/216b are significantly upregulated in nonviral hepatocellular carcinoma (NBNC-HCC). Here, we investigate the impact of each member of these clusters on the clinical outcome of NBNC-HCC and analyze the antitumor effects of miR-96-5p. METHODS: The association between recurrence-free survival of 111 NBNC-HCC patients and the levels of miR-183-5p, miR-96-5p, miR-182-5p, miR-217-5p, miR-216a-5p, and miR-216b-5p in tumor and adjacent tissues was investigated. The impact of miR-96-5p on apoptosis and invasion of a hepatoma cell line, HepG2, was investigated by cell counting, Transwell assay, and flow cytometry, respectively. RESULTS: MicroRNA-183-5p, miR-96-5p, miR-182-5p, miR-217-5p, and miR-216b-5p were significantly upregulated in tumor tissues compared to the adjacent tissues (p = 0.0005, p = 0.0030, p = 0.0002, p = 0.0011, and p = 0.0288, respectively). By multivariate Cox regression analysis, high tumor/adjacent ratios of miR-182-5p (p = 0.007) and miR-217-5p (p = 0.008) were associated with poor recurrence-free survival. In contrast, a low tumor/adjacent ratio of miR-96-5p (p < 0.001) was associated with poor recurrence-free survival. It suggested that further upregulation of miR-96-5p in tumors might have an inhibitory effect on recurrence. Transfection of miR-96-5p mimic significantly induced apoptosis of HepG2 cells, in association with downregulation of Nucleophosmin 1 (NPM1) and a decrease of phosphorylated AKT protein. Interestingly, simultaneous knockdown of the NPM1 and AKT genes induced apoptosis. MicroRNA-96-5p also suppressed proliferation and invasion, which inhibited epithelial-to-mesenchymal transition of HCC cells. CONCLUSION: MicroRNA-96-5p as a tumor suppressor would be valuable to stratify NBNC-HCC patients at high risk of recurrence.

MicroRNA-125b expression and intrahepatic metastasis are predictors for early recurrence after hepatocellular carcinoma resection.

AIM: Early hepatocellular carcinoma (HCC) recurrence after curative resection is a known poor prognostic factor. We aimed to identify microRNAs associated with recurrence after curative HCC resection. METHODS: To identify risk factors for early recurrence and metastasis, 694 patients who underwent primary curative HCC resection were analyzed. We evaluated microRNA expression in cancerous and non-cancerous tissues by microarray and quantitative PCR analyses using 16 HCC samples. We defined patients who had a recurrence within 1 year of resection as the early recurrence (ER) group, patients who had a recurrence within 1-5 years as the late recurrence (LR) group, and patients who did not recur during the 5-year observation period as the no recurrence (NR) group. We examined the relationship between microRNA expression and clinical features. RESULTS: Multivariate analysis revealed that α-fetoprotein >31 ng/mL, tumor size >4 cm, and intrahepatic metastasis (IM) were significant factors. Afterwards, microarray analyses revealed that microRNA (miR)-125b-5p and miR-148a-3p were significantly downregulated in recurrent cases. The ratio of miR-125b-5p expression in cancerous versus non-cancerous tissue (miR-125b ratio), but not miR-148a-3p, was significantly lower in the ER group. Early recurrence was associated with reduced overall survival compared with the LR and NR group. The miR-125b ratio was significantly lower in the ER group than in the LR and NR groups. Multivariate analysis showed that a low miR-125b ratio and IM were independently associated with ER and disease-free survival. CONCLUSIONS: Assessing tissue miR-125b-5p expression and IM is useful for stratifying patients at risk of early HCC recurrence after curative resection.

How cancer cells dictate their microenvironment: present roles of extracellular vesicles.

Intercellular communication plays an important role in cancer initiation and progression through secretory molecules, including growth factors and cytokines. Recent advances have revealed that small membrane vesicles, termed extracellular vesicles (EVs), served as a regulatory agent in the intercellular communication of cancer. EVs enable the transfer of functional molecules, including proteins, mRNA and microRNAs (miRNAs), into recipient cells. Cancer cells utilize EVs to dictate the unique phenotype of surrounding cells, thereby promoting cancer progression. Against such "education" by cancer cells, non-tumoral cells suppress cancer initiation and progression via EVs. Therefore, researchers consider EVs to be important cues to clarify the molecular mechanisms of cancer biology. Understanding the functions of EVs in cancer progression is an important aspect of cancer biology that has not been previously elucidated. In this review, we summarize experimental data that indicate the pivotal roles of EVs in cancer progression.

Multiple Cerebral Infarctions Due to Patent Foramen Ovale in a Patient with Eosinophilic Granulomatosis with Polyangiitis.

A 51-year-old man was diagnosed with eosinophilic granulomatosis with polyangiitis 6 years ago due to asthma, sinusitis, hypereosinophilia, and peripheral neuropathy based on the diagnostic criteria of American College of Rheumatology, and corticosteroid therapy achieved a remission. One year ago, he was hospitalized due to deep venous thrombosis (DVT) and pulmonary embolism, and rivaroxaban was administrated. He was admitted to our hospital for acute onset of diplopia and right hemiparesis. Peripheral blood examinations disclosed leukocytosis with hypereosinophilia. Perinuclear anti-neutrophil cytoplasmic antibodies were positive. Diffusion-weighted imaging showed multiple fresh ischemic lesions. Chronic ischemic lesions were seen in subcortical cerebral region. No stenosis or occlusion was shown in extracranial and intracranial arteries on magnetic resonance angiography. Ultrasonography of leg vein showed DVT. Right-to-left shunt through patent foramen ovale after Valsalva maneuver was seen on transesophageal echocardiography. Treatment with corticosteroid and cyclophosphamide alleviated clinical deterioration. Rivaroxaban was changed to warfarin. Diplopia and muscle strength of right limbs were improved. This is a first case of multiple cerebral infarction caused by paradoxical embolism due to patent foramen ovale with DVT based on hypercoagulable state of hypereosinophilia. Overall this case illustrates that eosinophilic granulomatosis with polyangiitis can be a risk factor for multiple cerebral infarction in the systemic phase and that transesophageal echocardiography and ultrasonography of leg vein should be conducted in stroke patient with eosinophilic granulomatosis with polyangiitis.

Global, cancer-specific microRNA cluster hypomethylation was functionally associated with the development of non-B non-C hepatocellular carcinoma.

BACKGROUND: While hepatitis B and C viral infection have been suppressed, non-B non-C hepatocellular carcinoma (NBNC-HCC) is considered to be rising in incidence terms in some developed countries where prevalence of those viral infections among HCC patients had been very high (such as Japan, Korea, and Italy). To elucidate critical molecular changes in NBNC-HCC, we integrated three large datasets relating to comprehensive array-based analysis of genome-wide DNA methylation (N = 43 pairs) and mRNA/miRNA expression (N = 15, and 24 pairs, respectively) via statistical modeling. RESULTS: Hierarchical clustering of DNA methylation in miRNA coding regions clearly distinguished NBNC-HCC tissue samples from relevant background tissues, revealing a remarkable tumor-specific hypomethylation cluster. In addition, miRNA clusters were extremely hypomethylated in tumor samples (median methylation change for non-clustered miRNAs: -2.3%, clustered miRNAs: -24.6%). The proportion of CpGs hypomethylated in more than 90% of the samples was 55.9% of all CpGs within miRNA clusters, and the peak methylation level was drastically shifted from 84% to 39%. Following statistical adjustment, the difference in methylation levels within miRNA coding regions was positively associated with their expression change. Receiver operating characteristic (ROC) analysis revealed a great discriminatory ability in respect to cluster-miRNA methylation. Moreover, miRNA methylation change was negatively correlated with corresponding target gene expression amongst conserved and highly matched miRNA sites. CONCLUSIONS: We observed a drastic negative shift of methylation levels in miRNA cluster regions. Changes in methylation status of miRNAs were more indicative of target gene expression and pathological diagnosis than respective miRNA expression changes, suggesting the importance of genome-wide miRNA methylation for tumor development. Our study dynamically summarized global miRNA hypomethylation and its genome-wide scale consequence in NBNC-HCC.

TSPAN8, identified by Escherichia coli ampicillin secretion trap, is associated with cell growth and invasion in gastric cancer.

BACKGROUND: Gastric cancer (GC) is one of the most common human cancers. Genes expressed only in cancer tissue, especially on the cell membrane, will be useful biomarkers for cancer diagnosis and therapeutics. METHODS: To identify novel genes encoding transmembrane protein specifically expressed in GC, we generated an Escherichia coli ampicillin secretion trap (CAST) library from diffuse-type GC cell line MKN-45. CAST is a survival-based signal sequence trap method that exploits the ability of mammalian signal sequences to confer ampicillin resistance to a mutant ß-lactamase lacking the endogenous signal sequence. RESULTS: By sequencing 1,536 colonies, we identified 23 genes encoding the transmembrane protein present in GC. Among these genes, TSPAN8 (also known as CO-029 and TM4SF3) gene, which encodes transmembrane protein tetraspanin 8, was emphasized as a candidate. Immunohistochemical analysis of tetraspanin 8 in human GC tissues revealed that 72 (34 %) of 210 GC cases were positive for tetraspanin 8, and microvessel density was significantly higher in tetraspanin 8-positive GC than in tetraspanin 8-negative GC. Furthermore, univariate and multivariate analyses revealed that tetraspanin 8 expression is an independent prognostic classifier of patients with GC. TSPAN8 knockdown by siRNA reduced the invasion of GC cell line. The reduction of invasiveness was retrieved by the tetraspanin 8-containing exosome. CONCLUSION: These results suggest that tetraspanin 8 is involved in tumor progression and is an independent prognostic classifier in patients with GC.

Fukutin, identified by the Escherichia coli ampicillin secretion trap (CAST) method, participates in tumor progression in gastric cancer.

BACKGROUND: Gastric cancer (GC) is the fifth commonest malignancy worldwide and still one of the leading causes of cancer-related death. The aim of this study was to identify a novel prognostic marker or therapeutic target for GC. METHODS: We analyzed candidate genes from our previous Escherichia coli ampicillin secretion trap (CAST) libraries in detail, and focused on the FKTN gene because it was overexpressed in both GC cell line CAST libraries, MKN-1 and MKN-45. RESULTS: Quantitative reverse transcriptase PCR analysis of FKTN revealed that FKTN messenger RNA was overexpressed in nine of 28 (32.1 %) GC tissue samples compared with nonneoplastic gastric mucosa. Immunostaining of fukutin showed that 297 of 695 cases (42.7 %) were positive for fukutin. Fukutin-positive GC cases were significantly associated with differentiated histological features, and advanced T grade and N grade. In addition, fukutin expression was observed more frequently in the intestinal phenotype (51 %) of GC than in other phenotypes (37 %) when defined by the expression patterns of mucin 5AC, mucin 6, mucin 2, and CD10. FKTN small interfering RNA treatment decreased GC cell proliferation. CONCLUSIONS: These results indicate that the expression of fukutin may be a key regulator for progression of GC with the intestinal mucin phenotype.

Significance of miR-148a in Colorectal Neoplasia: Downregulation of miR-148a Contributes to the Carcinogenesis and Cell Invasion of Colorectal Cancer.

OBJECTIVE: Colorectal cancer (CRC) develops through the deregulation of gene expression and the accumulation of epigenetic abnormalities, leading to tumor cell acquisition of malignant features. MicroRNAs (miRNAs) play a critical role in cancer development, where they can act as oncogenes or oncosuppressors. METHODS: miR-148a expression was measured by qRT-PCR in patients with colorectal adenoma (n = 21) and CRC (stage I-IV, n = 159) using formalin-fixed paraffin-embedded tissue samples. In situ hybridization (ISH) using an miR-148a-specific probe was also performed. To further confirm the direct effect of miR-148a on matrix metalloproteinase (MMP)7 expression in CRC, MTT and cell invasion assays using HT29 and WiDr cells were performed. RESULTS: miR-148a expression was found to be clearly downregulated in high-grade adenoma compared to low-grade adenoma on both qRT-PCR and ISH analysis. Downregulation of miR-148a expression was significantly correlated with advanced clinicopathological features and was an independent prognostic classifier in patients with stage III CRC. In CRC cells and tissues, miR-148a expression was inversely correlated with the expression of MMP7. CONCLUSION: We showed the collaborative participation of miR-148a and MMP7 in CRC cell invasion. These results also demonstrate that the downregulation of miR-148a expression promotes CRC progression, especially carcinogenesis and cancer cell invasion.

Characteristic miR-24 Expression in Gastric Cancers among Atomic Bomb Survivors.

OBJECTIVE: To elucidate the mechanism of radiation-induced cancers, we analyzed the expression profiles of microRNAs extracted from formalin-fixed paraffin-embedded (FFPE) gastric cancer (GC) tissue samples from atomic bomb survivors. METHODS: The expression levels of miR-21, miR-24, miR-34a, miR-106a, miR-143, and miR-145 were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR). RESULTS: The expression of microRNAs was measured by qRT-PCR in a Hiroshima University Hospital cohort comprising 32 patients in the high-dose-exposed group and 18 patients in the low-dose-exposed group who developed GC after the bombing. The GC cases showing high expression of miR-24, miR-143, and miR-145 were more frequently found in the high-dose-exposed group than in the low-dose-exposed group. We next performed qRT-PCR of miR-24, miR-143, and miR-145 in a cohort from the Hiroshima Red Cross Hospital and Atomic-Bomb Survivors Hospital comprising 122 patients in the high-dose-exposed group and 48 patients in the low-dose-exposed group who developed GC after the bombing. High expressions of miR-24 and miR-143 were more frequently found in the high-dose-exposed group than in the low-dose-exposed group. Multivariate analysis demonstrated that only high expression of miR-24 was an independent predictor for the exposure status. CONCLUSION: These results suggest that the measurement of miR-24 expression from FFPE samples is useful to identify radiation-associated GC.

microRNAs and Hepatitis B.

The hepatitis B virus (HBV) infection is the leading cause of persistent liver diseases, cirrhosis, and hepatocellular carcinoma (HCC). However, the precise mechanism underlying the development of HBV-related diseases is not fully understood. In addition, the therapeutic strategies for the diseases are less than optimum. microRNAs (miRNAs) are small noncoding RNAs that have been described as a "fine-tuner" in various cellular events. The dysregulation of miRNAs play a role in the development of the cancer as well as viral interference. Recent articles have demonstrated that several miRNAs are deregulated by HBV infection and contribute to viral replication and pathogenesis. Thus, it suggests that the precise mechanism between miRNA and HBV biology will be leading to the development of the novel diagnosis and therapy. This chapter aims to provide the basic principals of miRNAs in development of the HBV-related diseases. We also discuss about the possibility of miRNAs on the clinical application for diagnosis and therapy of HBV-related diseases.

[The Functional Role of Exosomes in Cancer Biology and Their Potential as Biomarkers and Therapeutic Targets of Cancer].

Intercellular communication plays an important role in the regulation of various cellular events. In particular, cancer cells and the surrounding cells communicate with each other, and this intercellular communication triggers cancer initiation and progression through the secretion of molecules, including growth factors and cytokines. Recent advances in cancer biology have indicated that small membrane vesicles, termed exosomes, also serve as regulatory agents in intercellular communications. Exosomes contain functional cellular components, including proteins and microRNAs (miRNAs), and they transfer these components to recipient cells. This exosome-mediated intercellular communication leads to increased growth, invasion, and metastasis of cancer. Thus, researchers regard exosomes as important cues to understanding the molecular mechanisms of cancer biology. Indeed, several lines of evidence have demonstrated that exosomes can explain multiple aspects of cancer biology. In addition, increasing evidence suggests that exosomes and their specific molecules are also attractive for use as biomarkers and therapeutic targets in cancer. Recent reports showed the efficacy of a novel diagnosis by detecting component molecules of cancer-derived exosomes, including miRNAs and membrane proteins. Furthermore, clinical trials that test the application of exosomes for cancer therapy have already been reported. From these points of view, we will summarize experimental data that support the role of exosomes in cancer progression and the potential of exosomes for use in novel diagnostic and therapeutic approaches for cancer.

NRD1, which encodes nardilysin protein, promotes esophageal cancer cell invasion through induction of MMP2 and MMP3 expression.

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignancies worldwide. In the present study, to identify novel prognostic markers or therapeutic targets for ESCC, we reviewed a list of genes with upregulated expression in ESCC compared with normal esophagus, as identified by our serial analysis of gene expression (SAGE) analysis. We focused on the NRD1 gene, which encodes the nardilysin protein. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) in 34 ESCC tissue samples revealed that mRNA expression of NRD1 was upregulated in 56% of ESCC tissue samples. Immunohistochemical analysis of nardilysin in 109 ESCC tissue samples demonstrated that 43 (39%) ESCC cases were positive for nardilysin. Nardilysin-positive ESCC cases were more advanced in terms of T classification (P = 0.0007), N classification (P = 0.0164), and tumor stage (P < 0.0001) than nardilysin-negative ESCC cases. Furthermore, nardilysin expression was significantly associated with poorer prognosis (P = 0.0258). Univariate and multivariate analyses revealed that nardilysin expression is an independent prognostic classifier of patients with ESCC. The invasiveness of NRD1-knockdown TE1 and TE5 esophageal cancer cell lines was less than that of the negative control siRNA-transfected cell lines. Expression of MMP2 and MMP3 mRNA was significantly lower in NRD1-knockdown TE5 cells than in negative control siRNA-transfected cells. These results suggest that nardilysin is involved in tumor progression, and is an independent prognostic classifier in patients with ESCC.

MicroRNA-143 regulates collagen type III expression in stromal fibroblasts of scirrhous type gastric cancer.

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. In the present study, we identified several miRNAs that are expressed at higher levels in scirrhous type GC than in non-scirrhous type GC by miRNA microarray analysis. Among these, microRNA-143 (miR-143) expression was higher in scirrhous type GC than in non-scirrhous types of GC. In situ hybridization and quantitative RT-PCR analysis showed that miR-143 is expressed by stromal fibroblasts but not by cancer cells. In stromal cells, miR-143 enhanced collagen type III expression in normal gastric fibroblasts and cancer-associated fibroblasts through activation of transforming growth factor-ß)/SMAD signaling. Furthermore, high miR-143 expression in GC was associated with worse cancer-specific mortality (P = 0.0141). Multivariate analysis revealed that miR-143 was an independent prognostic factor. Treatment of GC cell lines with 5-aza-2'-deoxycytidine restored the expression of miR-143, and precursor miR-143 caused the inhibition of cancer cell invasion. These data suggest that miR-143 regulates fibrosis of scirrhous type GC through induction of collagen expression in stromal fibroblasts and that miR-143 expression serves as a prognostic marker of GC.

MicroRNA-148a is downregulated in gastric cancer, targets MMP7, and indicates tumor invasiveness and poor prognosis.

Gastric cancer (GC) develops through deregulation of gene expression and accumulation of epigenetic abnormalities, leading to tumor cell acquisition of malignant features. MicroRNAs (miRNAs) play a critical role in cancer development where they can act as oncogenes or oncosuppressors. To identify miRNAs that are associated with some clinicopathologic features of GC and/or participate in tumor progression, miRNA expression in 20 GC tissues and five corresponding non-neoplastic gastric mucosa was examined by miRNA microarray. Oligonucleotide array analysis was carried out for miRNA target prediction. The functions of candidate miRNAs and their target genes were also analyzed by quantitative RT-PCR, Western blotting, reporter gene assay, and cell invasion assay. Comparison of miRNA expression profiles revealed that downregulation of miR-148a was identified in most of the GC tissues. Downregulation of miR-148a was significantly correlated with an advanced clinical stage, lymph node metastasis, and poor clinical outcome. Custom oligonucleotide array analysis revealed that MMP7 expression was markedly downregulated in miR-148a-overexpressing GC cells; MMP7 was found to be a direct and functional target of miR-148a, participating in cell invasion. These results suggest that miR-148a contributes to the maintenance of homeostasis in normal stomach tissue and plays an important role in GC invasion by regulating MMP7 expression.

Hypoxia-mediated CD24 expression is correlated with gastric cancer aggressiveness by promoting cell migration and invasion.

CD24 is a heavily glycosylated cell surface protein that is expressed in putative stem cells and is overexpressed in various human malignancies, yet the significant roles of CD24 in gastric cancer development are still elusive. We investigated the involvement of CD24 in gastric cancer aggressiveness, which is attributed to its heterogeneity. Cultured gastric cancer cells showed diverse expression patterns in CD24, whereas other defined cell surface markers, such as CD44 and CD133, were homogenous. Purely sorted CD24-negative gastric cancer cells showed strong alteration into the CD24-positive cell type in an autochthonous manner, and reached to steady expression levels. Our clinicopathological study revealed that CD24 positivity was an independent prognostic factor in both intestinal and diffuse types of gastric cancer. CD24 expression was correlated with the advanced stages, invasiveness, and lymph node metastasis of gastric cancer. Silencing of CD24 in cultured cells significantly decreased cell migration and invasion. Hypoxic treatment upregulated CD24 expression, and simultaneously induced cell motility and invasion of gastric cancer cells. Hypoxic treatment-induced CD24 expression was significantly attenuated by knockdown of hypoxia-inducible transcription factors. These data suggest that CD24-negative cells are capable of gaining cell motility and invasiveness through the induction of CD24, which is mediated by hypoxia. CD24 would be an attractive marker to define not only the heterogeneity but also the aggressiveness of gastric cancer cells. The mechanisms by which hypoxia induces CD24 expression would also be a potential therapeutic target for gastric cancer.

Identification of novel transmembrane proteins in scirrhous-type gastric cancer by the Escherichia coli ampicillin secretion trap (CAST) method: TM9SF3 participates in tumor invasion and serves as a prognostic factor.

OBJECTIVE: Scirrhous-type gastric cancer (GC) is highly aggressive and has a poor prognosis due to rapid cancer cell infiltration accompanied by extensive stromal fibrosis. The aim of this study is to identify genes that encode transmembrane proteins frequently expressed in scirrhous-type GC. METHODS: We compared Escherichia coli ampicillin secretion trap (CAST) libraries from 2 human scirrhous-type GC tissues with a normal stomach CAST library. By sequencing 2,880 colonies from scirrhous CAST libraries, we identified a list of candidate genes. RESULTS: We focused on the TM9SF3 gene because it has the highest clone count, and immunohistochemical analysis demonstrated that 46 (50%) of 91 GC cases were positive for TM9SF3, which was observed frequently in scirrhous-type GC. TM9SF3 expression showed a significant correlation with the depth of invasion, tumor stage and undifferentiated GC. There was a strong correlation between TM9SF3 expression and poor patient outcome, which was validated in two separate cohorts by immunostaining and quantitative RT-PCR, respectively. Transient knockdown of the TM9SF3 gene by siRNA showed decreased tumor cell-invasive capacity. CONCLUSION: Our results indicate that TM9SF3 might be a potential diagnostic and therapeutic target for scirrhous-type GC.

Clinicopathological significance of MMP-7, laminin γ2 and EGFR expression at the invasive front of gastric carcinoma.

BACKGROUND: For several types of cancer, including gastric cancer (GC), tumor cells at the invasive front are considered to have a more aggressive behavior compared with those in the more central region. The aim of the present study was to analyze the expression of MMP-7, laminin γ2 and EGFR in a large number of GCs and to investigate how these expression patterns correlate with clinicopathologic parameters, infiltrative patterns, histology or mucin phenotype. METHODS: We immunohistochemically examined the expression of MMP-7, laminin γ2 and EGFR using a tissue microarray analysis of 790 GCs, and evaluated their clinicopathological significance. RESULTS: MMP-7, cytoplasmic laminin γ2, extracellular laminin γ2 and EGFR expression were observed in 25, 25, 8 and 21 % of the 790 GC cases, respectively. Expression of MMP-7, cytoplasmic laminin γ2 and EGFR was associated with advanced T grade, N grade and tumor stage. Extracellular laminin γ2 expression was not associated with any clinicopathologic parameters, infiltrative patterns, histology or mucin phenotype. Furthermore, we investigated the correlations of MMP-7, laminin γ2 and EGFR expression. MMP-7 expression was significantly more frequent in positive expression of cytoplasmic laminin γ2 than negative cases, and EGFR expression was significantly more frequent in positive expression of cytoplasmic laminin γ2 and MMP-7. CONCLUSIONS: Molecular expression of MMP-7, laminin γ2 or EGFR, and their combinations, may be associated with GC tumor aggressiveness. Assessment of expression of these molecules at the invasive front of primary tumors is clinically significant in predicting the malignant behavior of GC.

Liquid Biopsy for Oral Cancer Diagnosis: Recent Advances and Challenges.

"Liquid biopsy" is an efficient diagnostic tool used to analyse biomaterials in human body fluids, such as blood, saliva, breast milk, and urine. Various biomaterials derived from a tumour and its microenvironment are released into such body fluids and contain important information for cancer diagnosis. Biomaterial detection can provide "real-time" information about individual tumours, is non-invasive, and is more repeatable than conventional histological analysis. Therefore, over the past two decades, liquid biopsy has been considered an attractive diagnostic tool for malignant tumours. Although biomarkers for oral cancer have not yet been adopted in clinical practice, many molecular candidates have been investigated for liquid biopsies in oral cancer diagnosis, such as the proteome, metabolome, microRNAome, extracellular vesicles, cell-free DNAs, and circulating tumour cells. This review will present recent advances and challenges in liquid biopsy for oral cancer diagnosis.