BACKGROUND: A high accumulation of CD8
MATERIALS AND METHODS: We studied 72 resected borderline resectable PDAC patients treated with NACRT between April 2009 and March 2014. Three matched pairs of high CD8
RESULTS: Marginal zone B- and B1-cell-specific protein (MZB1) was detected in the tumor stroma. MZB1 expression was positively correlated with a high accumulation of CD8
CONCLUSIONS: MZB1 is a potential marker of a high accumulation of CD8

Prediction of tumor recurrence after curative resection is critical for determining the prognosis of patients with gastric cancer (GC). The initiation and progression of GC are associated with inappropriate immune responses caused by chronic inflammation of the gastric mucosa. To identify immunoregulatory molecules involved in GC progression, GC cell lines and 200 pairs of tumor and normal tissues from patients with GC were analyzed for gene expression, amplification and methylation as well as function of a differentially expressed gene. The transcriptome analysis revealed that marginal zone B and B1 cell specific protein (MZB1) was expressed at significantly decreased levels in primary GC tissues when compared with the corresponding normal gastric mucosa. PCR array analysis exploring genes expressed cooperatively with MZB1 revealed that differential expression of MZB1 mRNA in GC cell lines correlated positively with the levels of the mRNAs encoding estrogen receptor 1 and desumoylating isopeptidase 1. Hypermethylation of the MZB1 promoter was frequent in cell lines with decreased levels of MZB1 mRNA. siRNA-mediated knockdown of MZB1 significantly increased proliferation, invasion and migration of GC cell lines. Low MZB1 expression was an independent prognostic factor for recurrence after curative gastrectomy and was associated significantly with increased hematogenous recurrence. MZB1 acts as a suppressor of GC. Low MZB1 expression in the primary GC tissue is predictive of recurrence after curative resection.

The proapoptotic caspase adaptor protein (PACAP) is involved in cell-cycle regulation and promotes apoptosis. Both MGC29506 and PACAP are isoforms of the MGC29506 gene and are generated by differential splicing of the alternative splice-acceptor. In studying PACAP, we inadvertently constructed the eukaryotic expression vector MGC29506. At present, the function of the MGC29506 gene is largely unknown with the key exception of information obtained by bioinformatics. We studied the role of MGC29506 in gastric cancer cell proliferation, the cell cycle and apoptosis. In addition, we studied MGC29506 expression in gastric cancer patients and explored its significance. We found that the expression of MGC29506 in gastric cancer samples was lower than in samples from adjacent non-tumor tissues. We found that the MGC29506 protein was localized in the cell nucleus of AGS cells and inhibited their proliferation. Higher percentages of G0/G1 and S phase cells were induced by transfection with the MGC29506 gene than were induced by transfection with the negative control. We showed that cells transfected with MGC29506 were arrested at the G0/G1 and S phases of the cell cycle. However, we found no significant increases in apoptosis of cells transfected with MGC29506 compared with cells transfected with the negative control. Our results suggested that MGC29506 has the potential of functioning as a novel suppressor gene in gastric cancer. Downregulation of MGC29506 may also promote the progression of gastric cancer.

Abstract We recently identified the marginal zone B and B1 cell-specific protein (MZB1) as part of a gene expression signature associated with outcomes in chronic lymphocytic leukemia (CLL). MZB1 is important for B cell function as a key regulator of antibody secretion, calcium homeostasis and adhesion. Therefore, we analyzed the role of MZB1 expression levels in 139 patients with CLL using quantitative real-time polymerase chain reaction (qRT-PCR) and microarray data sets in CLL, follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), multiple myeloma (MM) and acute myeloid leukemia (AML). High MZB1 expression was associated with inferior survival in CLL (hazard ratio [HR]: 1.63 [confidence interval (CI): 1.14-2.33], p = 0.007), FL (221286_s_at HR: 1.16 [CI: 0.98-1.37], p = 0.086; 223565_at: HR: 1.3 [CI: 1.1-1.61], p = 0.015) and DLBCL (221286_s_at: HR: 1.17 [CI: 1.06-1.3], p = 0.003; 223565_at: HR: 1.21 [CI: 1.08-1.35], p = 0.001). In DLBCL MZB1 expression was an additive prognostic marker in a multivariate model including activated B-cell like (ABC) versus germinal center (GCB) subtype. Additionally, MZB1 expression correlated with a unique gene expression pattern. This study is the first to show that the expression level of a single gene has prognostic significance in different lymphoma subtypes. Due to its biological function, MZB1 may play a central role in B cell neoplasms and is a potential target for future therapeutic interventions.

PURPOSE: The aim of this study was the identification of novel tumor suppressor genes (TSG) silenced by DNA hypermethylation in hepatocellular carcinoma (HCC).
EXPERIMENTAL DESIGN: We conducted integrative array-based approach for genome-wide screening of methylation targets using a methylated DNA immunoprecipitation-CpG island microarray and expression array in three universal hepatoma cell lines and normal liver tissue. Through detailed expression and functional analyses using hepatoma cell lines and primary HCC samples, we isolated novel TSGs for HCC.
RESULTS: A total of 642 genes were identified as methylated in three hepatoma cell lines but unmethylated in normal liver tissue, whereas 204 genes on autosomes were identified as genes unexpressed but restored after treatment with 5-aza-2'-deoxycytidine in these cell lines and expressed in normal tissue. Through the integration of results of the two-array analyses and further validation analyses of expression and methylation status in 17 cell lines and 30 primary tumors of hepatoma, we identified MZB1, marginal zone B and B1 cell-specific protein, encoding an endoplasmic reticulum protein, as a putative TSG frequently methylated within its CpG island in hepatoma. Among 162 patients with primary HCC, silencing of MZB1 protein was significantly and independently associated with a worse outcome. Restoration of MZB1 expression in hepatoma cells reduced cell proliferation in vitro and in vivo through G(1)-arrest.
CONCLUSIONS: These results suggest that methylation-mediated silencing of MZB1 expression leads to loss of its tumor-suppressive activity, which may be a factor in the hepatocarcinogenesis, and is a useful prognosticator in HCC.

Microarray analyses is applied for prognosis of gastric cancer, including risk assessments of lymph-node metastasis and peritoneal dissemination. EST AA769445 derived from an unknown gene is reported to be frequently down-regulated in intestinal-type gastric cancer based on microarray analyses. Here, we identified and characterized the gene corresponding to EST AA769445 by using bioinformatics. EST AA769445 overlapped with MGC29506 cDNA (BC021275) and PACAP cDNA (AF338109). MGC29506 protein (189 aa) and PACAP protein (123 aa) were identical in codon 1-59, but were divergent in the C-terminal region due to a frame shift caused by sixteen-base insertion in PACAP cDNA. MGC29506 and PACAP were derived from the same gene, consisting of four exons, due to alternative splicing of alternative splice-acceptor-site type. Fourteen human ESTs were the MGC29506 type, while one human EST was the PACAP type. MGC29506 was the major isoform of the MGC29506/PACAP gene on human chromosome 5q31.2. MGC29506 orthologs in other species were next searched for. AK088094 and AK008016 cDNAs with nucleotide substitutions resulting in four-amino-acid substitutions were derived from mouse Mgc29506 gene. Rat Mgc29506 gene was identified in the rat genome draft sequence AC135285. ESTs AJ396310 and AJ441435 were derived from chicken Mgc29506 gene, while ESTs BW315632 and BW251767 from ciona mgc29506 gene. N-terminal signal peptide, six cysteine residues and other amino acids were conserved among human, mouse, rat, chicken, and ciona MGC29506 proteins. MGC29506 gene, frequently down-regulated in intestinal-type gastric cancer, was found to encode secreted-type protein with six conserved cysteine residues.