Keizou Taniguchi

Mapping sentinel nodes in patients with early-stage gastric carcinoma†

Nodal status in gastric carcinoma is related not only to prognosis but also to the extent of nodal dissection. However, a method for accurate assessment of nodal status during operation has not been established. This study aimed to map the sentinel nodes of gastric carcinoma and to estimate the clinical usefulness of sentinel node biopsy.

Role of MMP-7 in the formation of peritoneal dissemination in gastric cancer.

Background. Matrix metalloproteinase-7 (MMP-7) is an important matrix-degrading enzyme that has a large role in the invasion and metastasis of cancer. To discover the mechanism of the formation of peritoneal dissemination in gastric cancer, we studied the mRNA and protein expression of MMP-7 in primary gastric cancers and peritoneal dissemination.Methods. MMP-7 expression in primary gastric cancers (136 patients) was studied by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR), and the results were compared with chinicopathological parameters.Results. MMP-7 mRNA was expressed in 28 (53%) of 53 primary gastric cancers, but not in normal gastric mucosa, fibroblasts, or mesothelial cells. An immunohistochemical method demonstrated that MMP-7 immunoreactivity was found on the cell membrane and cytoplasm of cancer cells. Among 136 primary tumors, 70 (53%) tumors overexpressed MMP-7, and MMP-7 tissue status had significant positive correlation with serosal involvement, lymph node metastasis, poor differentiation of cancer, and peritoneal dissemination. Patients with MMP-7-positive tumor had significantly poorer survival and more frequently died of peritoneal recurrence than did those with MMP-7-negative tumors. All 6 examined peritoneal disseminations expressed MMP-7 mRNA, and 13 of 14 peritoneal disseminations showed immunoreactivity to anti-human MMP-7 monoclonal antibody. Logistic regression analysis showed that MMP-7 immunohistological status was an independent risk factor for peritoneal dissemination, and patients with MMP-7 mRNA-positive tumors had a 9.9-fold higher relative risk for peritoneal metastasis.Conclusion. These results strongly suggest that MMP-7 may have a large role in the formation of peritoneal dissemination in gastric cancer, and that clonal selection of cancer cells with MMP-7 overexpression may occur during the invasion of intraperitoneal free cancer cells from the peritoneal surface into the subperitoneal tissue. MMP-7 tissue status in the primary tumor may be a good indicator of peritoneal dissemination.

Mapping sentinel nodes in patients with early-stage gastric carcinoma

BACKGROUND Nodal status in gastric carcinoma is related not only to prognosis but also to the extent of nodal dissection. However, a method for accurate assessment of nodal status during operation has not been established. This study aimed to map the sentinel nodes of gastric carcinoma and to estimate the clinical usefulness of sentinel node biopsy. METHODS Following laparotomy, a vital dye (0.2 ml 2 per cent patent blue) was injected through a gastroscope into the submucosal layer at four sites around a clinical T1 gastric carcinoma. The dye immediately appeared at the serosal surface and stained lymphatic vessels and nodes. The stained nodes were removed and examined by frozen sectioning. RESULTS The assay was successful in mapping the lymphatic basins in 203 (96.2 per cent) of 211 patients. The dye stained one or more metastatic nodes in 31 patients, but failed to indicate a metastatic node in four patients with a large involved node. Meticulous postoperative examination of all resected nodes in the standard paraffin slices revealed no new metastases. The accuracy of the assay was 98.0 per cent. CONCLUSION The method was accurate in predicting nodal status in patients with early-stage gastric carcinoma.