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. © 2009 UICC

We present a methodological framework for estimating the degree of mixing between successive miscible fluids pumped along a near‐horizontal pipe. Either or both of the fluids can be non‐Newtonian, of Herschel–Bulkley type. Overall it is considered that the objective is to minimise mixing. In laminar regimes our estimates are based on front velocity of the leading displacement front. In turbulent regimes the spreading mechanism is dispersion. In addition to the estimates of mixing volumes/lengths, we also predict a minimal flow rate necessary in order to achieve a successful displacement of the residual fluid. © 2013 Canadian Society for Chemical Engineering

Hypermethylation of CpG islands in gene promoters is associated with silencing of various tumour suppressor genes. Recent studies of colorectal and gastric carcinomas have defined a CpG island methylator phenotype (CIMP), which involves the targeting of multiple genes by promoter hypermethylation. In this study, methylation-specific polymerase chain reaction (PCR) was performed to study methylation of CpG islands in the promoters of the p16(INK4a), cadherin 1 (CDH1), and retinoic acid receptor-beta (RAR-beta) genes in 45 gastric carcinomas and to investigate whether CDH1 and RAR-beta promoter hypermethylation is associated with CIMP-positive gastric carcinoma. CpG island hypermethylation of the p16(INK4a), CDH1, and RAR-beta promoters was detected in 12 (27%), 26 (58%), and 24 (53%) of the 45 gastric carcinomas, respectively. Hypermethylation of the p16(INK4a) promoter was more common in intestinal type than in diffuse type gastric carcinomas (p = 0.0023; Fisher's exact test) and was inversely associated with p53 mutations (p = 0.0225; Fisher's exact test). However, CDH1 and RAR-beta promoter hypermethylation was observed more frequently in diffuse-scattered type gastric carcinoma than in other types (intestinal and diffuse-adherent types) (p = 0.0175 and p = 0.0335, respectively; Fisher's exact test) and was not associated with p53 mutation status. Moreover, hypermethylation of the CDH1 and RAR-beta promoters occurred concordantly (p < 0.0001; Fisher's exact test). These results suggest that at least two types of promoter methylation status are involved in the development of the intestinal (p16(INK4a) promoter hypermethylation) and diffuse-scattered types (CDH1 and RAR-beta promoter hypermethylation) of gastric carcinoma.

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.

Osteoprotegerin (OPG), identical with osteoclastogenesis inhibitory factor, is a member of a subgroup of the tumor necrosis factor (TNF)-receptor superfamily, which functions as a soluble decoy receptor. It has been reported that OPG expression is associated with bone metastasis of cancer of the breast and prostate. In the present study, we examined the expression of OPG in gastric carcinomas using immunohistochemistry and reverse-transcription polymerase chain reaction methods, and compared with clinicopathological parameters. The expression of OPG mRNA was confirmed in a gastric carcinoma cell line (MKN-7) and gastric carcinoma tissues. Immunohistochemically, strongly positive staining of OPG was found in 65% (67/103) of gastric carcinomas, whereas OPG protein was not detected in non-neoplastic mucosal epithelia. The expression of OPG protein in gastric carcinoma tissues correlates significantly with depth of tumor invasion, nodal metastases and advanced tumor stage. Furthermore, the prognosis of the cases with strong OPG expression was significantly worse than those with weak or no expression of OPG. These results suggest that OPG may participate in stomach carcinogenesis, invasion and metastasis, and may serve as a novel molecular marker for aggressive gastric cancer.