Peritoneal metastasis is the most frequent type of recurrence in patients with gastric cancer (GC) and is associated with poor prognosis. Peritoneal lavage cytology, used to evaluate the risk of peritoneal metastasis, has low sensitivity. Here, we assessed the diagnostic potential of exosomal miRNA profiles in peritoneal fluid for the prediction of peritoneal dissemination in GC. Total RNA was extracted from exosomes isolated from six gastric malignant ascites (MA) samples, 24 peritoneal lavage fluid (PLF) samples, and culture supernatants (CM) of two human gastric carcinoma cell lines that differ in their potential for peritoneal metastasis. Expression of exosomal miRNAs was evaluated with Agilent Human miRNA microarrays and quantitative reverse transcription polymerase chain reaction (qRT-PCR). The microarray analysis indicated a low variability in the number and signal intensity of miRNAs detected among the samples. In the six MA fluids, miR-21 showed the highest signal intensity. We identified five miRNAs (miR-1225-5p, miR-320c, miR-1202, miR-1207-5p, and miR-4270) with high expression in MA samples, the PLF of serosa-invasive GC, and the CM of a highly metastatic GC cell line; these candidate miRNA species appear to be related to peritoneal dissemination. Differential expression of miR-21, miR-320c, and miR-1225-5p was validated in the PLF of serosa-invasive and non-invasive GC by qRT-PCR and miR-21 and miR-1225-5p were confirmed to be associated with serosal invasion in GC. PLF can be used to profile the expression of exosomal miRNAs. Our findings suggest that miR-21 and miR-1225-5p may serve as biomarkers of peritoneal recurrence after curative GC resection, thus providing a novel approach to early diagnosis of peritoneal dissemination of GC.

High BMI and high VFA can predict technical difficulties during laparoscopic gastric surgery and postoperative complications. Particularly, LADG should be performed cautiously to prevent surgical complications for male patients with high VFA. Predictive impact of VFA should be further determined in a larger set of patients.

This study aimed to identify predictive factors and to evaluate appropriate treatments for recurrence of esophageal cancer after curative esophagectomy. About 166 consecutive patients, who underwent curative esophagectomy, were enrolled between April 1994 and March 2003. Recurrence was classified as loco-regional or distant. Logistic regression analysis was used to identify predictive factors for recurrence. Prognostic factors were evaluated by Log-rank test and Cox proportional hazard regression analysis. The disease-specific 5-year survival was 56.8%. Recurrence was observed in 72 patients (43.4%), with 64 of these occurring within 3 years. The number of metastatic lymph nodes and lymphatic invasion independently predicted recurrence. There were significant differences in time to recurrence and survival time between loco-regional, distant recurrence, and combined recurrence. The 5-year survival time in patients with recurrence was 11.9%, and median survival time was 24 months. There was also a significant difference in survival after recurrence between treatment methods (no treatment vs chemo-radiotherapy, p=0.0063; chemotherapy, p=0.0247; and radiotherapy, p<0.0001). Meticulous, long-term follow-up is particularly necessary in patients with four or more metastatic lymph nodes to achieve early detection of recurrence. Randomized controlled trials should be used to develop effective modalities for each recurrence pattern to improve therapeutic outcomes.

An assessment of the learning curve of laparoscopy-assisted distal gastrectomy (LADG) might encourage its worldwide spread among inexperienced surgeons. One hundred sixty-seven patients with early gastric cancer were enrolled in this study: 67 underwent conventional open distal gastrectomy and 100 underwent LADG after classification into 5 groups of 20 according to the surgeon's level of experience. Patient characteristics and operative findings were compared between groups. Operation time was significantly longer, time to first flatus earlier, and blood loss reduced in the LADG groups compared with the open distal gastrectomy group. Surgeons with experience of 60 cases performed operations of similar times in both groups, and blood loss decreased with experience of 20 cases. There was no operative conversion, the frequency of nonsteroidal anti-inflammatory drugs administered were significantly less, and length of hospital stay were shorter by surgeons with experience of 60 cases. LADG is a technically feasible surgical procedure, depending on the surgeon's technical proficiency. Experience of at least 60 cases of LADG seems to result in satisfactory patient outcomes.

The number of known mRNA transcripts in the mouse has been greatly expanded by the RIKEN Mouse Gene Encyclopedia project. Validation of their reproducible expression in a tissue is an important contribution to the study of functional genomics. In this report, we determine the expression profile of 57,931 clones on 20 mouse tissues using cDNA microarrays. Of these 57,931 clones, 22,928 clones correspond to the FANTOM2 clone set. The set represents 20,234 transcriptional units (TUs) out of 33,409 TUs in the FANTOM2 set. We identified 7206 separate clones that satisfied stringent criteria for tissue-specific expression. Gene Ontology terms were assigned for these 7206 clones, and the proportion of 'molecular function' ontology for each tissue-specific clone was examined. These data will provide insights into the function of each tissue. Tissue-specific gene expression profiles obtained using our cDNA microarrays were also compared with the data extracted from the GNF Expression Atlas based on Affymetrix microarrays. One major outcome of the RIKEN transcriptome analysis is the identification of numerous nonprotein-coding mRNAs. The expression profile was also used to obtain evidence of expression for putative noncoding RNAs. In addition, 1926 clones (70%) of 2768 clones that were categorized as "unknown EST," and 1969 (58%) clones of 3388 clones that were categorized as "unclassifiable" were also shown to be reproducibly expressed.

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Abstract. Claudins, members of a large family of adherent junction proteins, regulate the integrity and function of tight junctions and influence tumorigenesis. Studies have suggested that altered levels of different claudins are related to carcinoma-cell invasion and disease progression. This study examined the relationship between the relative expression of claudin genes and clinicopathological factors, especially invasion and metastasis, in patients with colorectal cancer. We studied surgical specimens of cancer tissue and adjacent normal mucosa from 205 patients with untreated colorectal carcinoma. The relative expression levels of claudin-1, -3, -4 and -7 mRNA in cancer and in normal adjacent mucosa were measured by quantitative real-time, reverse-transcription polymerase chain reaction. The relative expression levels of the claudin-1, -3 and -4 genes were higher in cancer than in normal adjacent mucosa, whereas the relative expression of the claudin-7 gene was similar. An analysis of the relationship between the clinicopathological features and gene expression showed that reduced expression of claudin-7 correlated with venous invasion and liver metastasis. There was also a correlation between claudin-3 and -4 gene expression. Our results suggested that a reduced expression of the claudin-7 gene might lead to venous invasion and liver metastasis in colorectal cancer. Reduced expression of the claudin-7 gene may thus be a useful predictor of liver metastasis in patients with colorectal cancer.