Ratio-based lymph node staging is simple and gives more precise information for prognosis with fewer problems related to stage migration than the 1997 UICC/AJCC staging system.

Survival rates after curative gastrectomy for advanced gastric cancer among 238 patients in whom the cancer was invading the serosa were compared with 283 patients without serosal invasion. Generalized Wilcoxon estimates for 5-year survival rate were 47.1 per cent for patients exhibiting serosal invasion and 75.9 per cent for patients without serosal invasion. The frequency of lymph node metastasis increased proportionately with the extent of serosal invasion: 18.4 per cent in cases of S0; 53.8 per cent in cases of S1; 80.0 per cent in cases of S2; and 91.4 per cent in cases of S3. The higher the aggregate total of S (serosal invasion) and n (lymph node metastasis) factors, the lower the 5-year survival rate. In addition, patients with serosal invasion had a propensity for peritoneal dissemination of cancer cells; the percentage of cases with intraperitoneal free cancer cells increased with the extent of serosal invasion. It is worth noting that when cancer infiltration proceeded to the deeper layers and was accompanied by nodal metastasis, cancerous invasion of the perinodal fatty tissue was frequently evident. Therefore, unfavourable prognosis after curative resection in gastric cancer patients with serosal invasion may be largely dependent on whether or not the cancer has invaded the peritoneal cavity and the perinodal fatty tissue.

Pouch and Roux-en-Y reconstruction is the most useful of the three procedures for improving the postoperative quality of life. In patients with pouch and interposition reconstruction, the clinical assessment was quite poor, even though it is a physiologic route.

The present study was directed towards the identification of novel factors involved in the transformation process leading to the formation of gastric cancer. A cDNA library from human gastric cancer cells was constructed using a retroviral vector. Functional cloning was performed by screening for transformation activity in transduced NIH3T3 cells. Six cDNA clones were isolated, including one encoding the elongation factor 1α α α α subunit, which was already known to play a role in tumorigenesis. One cDNA (clone 56.2), which was repeatedly isolated during the course of screening, encoded a protein identical to a G-protein-coupled receptor protein, GPR35. In addition, another cDNA clone (72.3) was found to be an alternatively spliced product of the GPR35 gene, whereby 31 amino acids were added to the N-terminus of GPR35. Hence, the proteins encoded by clones 56.2 and 72.3 were designated GPR35a and GPR35b, respectively. RT-PCR experiments revealed that GPR35 gene expression is low or absent in surrounding non-cancerous regions, while both mRNAs were present in all of the gastric cancers examined. The level of 72.3-encoded mRNA was consistently significantly higher than that of 56.2 encoded mRNA. An expression pattern similar to that observed in gastric cancers was detected in normal intestinal mucosa. Based on the apparent transformation activities of the two GPR35 clones in NIH3T3 cells, and the marked up-regulation of their expression levels in cancer tissues, it is speculated that these two novel isoforms of GPR35 are involved in the course of gastric cancer formation. (Cancer Science 2004; 95: 131-135)

The diagnostic and therapeutic options in early gastric cancer are reviewed. In Japan, the rate of detection of early gastric cancers has increased so that minute gastric cancers can now be identified as a result of advances in diagnostic methods. The results of histopathological staging of a large number of resected specimens have led to three surgical options based on size and depth of the primary lesion, namely classical R2 resection, radical resection with limited lymphadenectomy and endoscopic surgery.