Treatment results of adenocarcinoma of the gastroesophageal junction.

BACKGROUND/AIMS: In the treatment of cardiac cancer, the selection of surgical procedures is controversial. METHODOLOGY: In this study 297 resectable adenocarcinomas arising around the GE junction, that had their center within 5cm oral and aboral of the anatomical GE junction, were analyzed. They were subdivided into those with the tumor center located more than 1cm above the GE junction (Type 1, N = 7), those with the tumor center located within 1cm oral and 2cm aboral of the GE junction (Type 2) and those with the tumor center 2cm below the junction (Type 3). Type 2 and 3 are subdivided into four groups as Type 2A (N = 47), 2B (N = 18), 3A (N = 37) and 3B (N = 188). Type 2A and 3A have esophageal invasion and Type 2B and 3B have no esophageal invasion. Thoraco-abdominal approach and transhiatal resection were done in 65 and 35 patients. Left and right thoracotomies were performed in 60 and 5 patients, respectively. RESULTS: Esophageal invasion distance of 83 among 84 Type 2A and 3A tumors limited within 5cm from the GE junction. The maximum esophageal length by transhiatal approach was 6cm. Postoperative mortality rates after transhiatal approach and thoracotomy were 0% and 5.8%, respectively. One patient of Type 2A with No110 involvement survived longer than 5 years. No patients with Type 2A and 3A had recurrence in the upper mediastinal nodes after transhiatal approach and left thoracotomy. Mediastinal node involvement was found in 3 of 7 Type 1 tumors. Cox regression analyses revealed that the esophageal invasion distance (< 3cm vs. > 3cm), lymph node status (N0 vs. N2) and extent of lymph node dissection (D1 vs. D2) are the independent prognostic factors. CONCLUSION: Dissection of the lower thoracic paraesophageal nodes is recommended if the esophageal invasion longer than 1cm. Almost all Type 2A and 3A tumors can be treated by transhiatal approach without positive esophageal margin under a routine use of intraoperative frozen section. Right thoracotomy and the dissection of the upper mediastinal nodes are recommended for Type 1 tumor. Cardiac resection with D2 dissection is indicated for Type 1 and T1 tumors of Type 2. Total gastrectomy +D2 dissection is recommended for T2-3 tumors of Type 2 and T1-4 tumors of Type 3. Treatment should be selected according to the proposed classification.

Randomized clinical trial of D2 and extended paraaortic lymphadenectomy in patients with gastric cancer.

BACKGROUND: The survival of patients with advanced gastric cancer after D2 dissection is still poor. Asian surgeons have proposed a more radical lymph node dissection, designated as D4 dissection, where paraaortic lymph nodes are removed in combination with D2 dissection. To evaluate the survival benefit of D4 dissection, a multi-institutional randomized trial of D2 vs D4 gastrectomy was conducted. METHODS: Patients enrolled in the study had potentially curable gastric adenocarcinoma at an advanced stage. Patients were randomized to undergo either D2 or D4 gastrectomy. RESULTS: Two hundred and ninety-three patients were registered and 269 patients were eligible; 135 patients were allocated to the D2 group and 134 to the D4 group. Five-year survival was 52.6% after D2 surgery and 55.0% after D4 gastrectomy. There was no significant difference in survival between the D2 and D4 groups (chi(2) = 0.064; P = 0.801). Hospital deaths occurred in 1 patients (0.7%) in the D2 group and 5 in the D4 group D4 gastrectomy is a more risky surgery than D2 dissection. Seven patients (5.2%) in the D2 and 15 (11.2%) in the D4 group died of causes other than gastric cancer recurrence. Sixty-three patients (46.7%) in the D2 group and 52 (38.8%) in the D4 group had disease recurrence. CONCLUSION: Prophylactic D4 dissection is not recommended for patients with potentially curable advanced gastric cancer.

Proteomic analysis of a highly metastatic gastric cancer cell line using two-dimensional differential gel electrophoresis.

Stomach cancer is still a major cause of death in Asian people despite a complete cure after the resection of early cancers, mainly because peritoneal dissemination is difficult to treat. In the present study, we used two-dimensional differential gel electrophoresis (2-D DIGE) to identify specific proteins differentially expressed between a highly metastatic stomach cancer cell line MKN-45-P and its parental cell line MKN-45. We detected 27 protein spots in at least 2 of 3 experiments which showed statistically significant differences in abundance. All 27 protein spots were identified using matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS) and database-searching software. A proteomic analysis revealed 13 different proteins with some isoforms sharing different biochemical characteristics, and that 8 proteins were up-regulated, and 5 were down-regulated. The 13 proteins were mainly involved in protein synthesis (transfer RNA synthetase), metabolism (flavoprotein subunit, pyruvate kinase, adenylate kinase), receptor and signal transduction (annexins I and A2), the cytoskeleton (keratin 5, cytokeratin 8) and cell cycling (ts11). These results suggested that a proteomic approach including 2-D DIGE would be an efficient way to identify the proteins responsible for specific biological functions. Moreover, these observations might be novel findings leading to the prediction of postoperative peritoneal recurrence.

Evaluation of lymphatic invasion in primary gastric cancer by a new monoclonal antibody, D2-40.

Lymphatic invasion is known as an independent predictor of lymph node metastasis in gastric cancer. However, the diagnosis of lymphatic invasion is sometimes difficult by hematoxylin-eosin (H&E) staining. Immunostaining using D2-40 was performed to study the distribution of lymphatic vessel and lymphatic invasion in a series of 78 primary gastric cancers. D2-40 showed specific staining for the lymphatic vessels, but not for blood vessels. The lymphatic invasion was most frequently found in the upper half of submucosal layer. Positive rate of lymphatic invasion by H&E staining was 27% (21/78), and that by D2-40 was 44% (34/78). Lymphatic invasion on H&E staining was diagnosed as false negative in 17 (21.8%) of 78 primary gastric cancers and false positive in 4 (5.1%) of 78 primary gastric cancers. Sensitivity for lymph node metastasis by the lymphatic invasion diagnosed by D2-40 was significantly higher (89%, 24/27) than by H&E staining (41%, 11/27). These results suggest that the diagnosis of lymphatic invasion by D2-40 is more sensitive than H&E staining. Sensitivity for the prediction of lymph node metastasis from the lymphatic invasion status in primary tumor by D2-40 was significantly higher than by H&E staining. Based on our results, we recommend the use of D2-40 immunoreactions for the routine evaluation of lymphatic invasion in gastric cancer.

Role of VEGF-C and VEGF-D in lymphangiogenesis in gastric cancer.

BACKGROUND: The molecular mechanisms of lymphangiogenesis induced by vascular endothelial growth factor (VEGF)-C and VEGF-D in gastric cancer were studied. METHODS: VEGF-C and VEGF-D gene expression vectors were transfected into the gastric cancer cell line KKLS, which did not originally express VEGF-C and VEGF-D, and stable transfectants (KKLS/VEGF-C and KKLS/VEGF-D) were established. The cell lines were inoculated into the subserosal layer of the stomach and subcutaneous tissue of nude mice. RESULTS: VEGF-C and VEGF-D expression in KKLS/VEGF-C and KKLS/VEGF-D cells was found by reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis. Expression of mouse VEGF receptor (VEGFR)-2 and mouse VEGFR-3 mRNA was detected in the KKLS/VEGF-C and KKLS/VEGF-D gastric tumors. Newly formed lymphatic vessels were detected not only in the periphery but also in the center of the tumors. The intratumor lymphatic vessels connected with the preexisting lymphatic vessels in the muscularis mucosa. The average numbers of lymphatic vessels in KKLS/VEGF-C (52.0 +/- 9.5) and KKLS/VEGF-D (16.4 +/- 0.6) gastric tumors were significantly higher than that in the KKLS/control vector tumors (4.0 +/- 1.4). CONCLUSION: VEGF-C and VEGF-D may induce neoformation of lymphatic vessels in experimental gastric tumors by the induction of VEGFR-3 expression.

Effective therapy for peritoneal dissemination in gastric cancer.

Peritoneal dissemination is the most frequent cause of death from gastric cancer, accounting for death in 20% to 40% of patients. Preoperative intraperitoneal chemotherapy, peritonectomy, intraoperative chemohyperthermic perfusion, and early postoperative intraperitoneal chemotherapy are treatment modalities specifically designed to eliminate peritoneal dissemination and progression. Preoperative intraperitoneal chemotherapy is for containment of peritoneal free cancer cells, and also may facilitate complete eradication of visible peritoneal dissemination by peritonectomy. Further, complete cytoreduction can be achieved more often when peritonectomy is included in the surgical treatment of gastric cancer with peritoneal dissemination. Phase III data shows prolonged survival attributed to complete cytoreduction. Aggressive cytoreduction of peritoneal dissemination by peritonectomy can reduce residual tumor burden to micrometastases on the peritoneal surface that can be treated by intraoperative intraperitoneal chemotherapy and early postoperative intraperitoneal chemotherapy. Among all these modalities, surgical cytoreduction is probably the most important for survival benefit. If the surgical cytoreduction is visibly incomplete, prolonged survival cannot be expected, despite subsequent treatment. The surgeon's goal is to reduce the cancer cell burden to a microscopic level. Continued refinement of phase II studies is needed for maximal benefit and to standardize the technical and chemotherapeutic options of each modality.

REG gene expression is associated with the infiltrating growth of gastric carcinoma.

BACKGROUND: The Reg gene is known to be involved in the growth of not only pancreatic B-cells, but also epithelial cells of the gastrointestinal tract and carcinoma of its lineage. METHODS: Because, to the authors' knowledge, no studies have been reported regarding REG expression in gastric carcinoma, the authors investigated REG mRNA and REG protein expression using reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot analysis, and immunohistochemical study and correlated the results with the clinical features of gastric carcinoma. RESULTS: Using RT-PCR and Western blot analyses, reg mRNA and 16-kilodalton REG proteins were detected in two of eight human gastric carcinoma cell lines. Cytoplasmic localization of REG proteins in the cell lines was confirmed by fluorescent immunocytochemistry. The RT-PCR analysis revealed the presence of REG mRNA in as many as 77% (87 of 112 tumors) of primary gastric carcinoma tumors. Screening of a total of 195 patients with primary gastric carcinoma using immunoperoxidase staining revealed positive REG immunoreactivity in 60 of the 195 primary tumors (31%). REG expression in infiltrating tumors was found to be significantly higher compared with localized tumors (P < 0.05). Strong REG expression was noted in the cytoplasm of signet ring cell carcinoma tumors at a significantly higher incidence than in nonsignet ring cell tumors. Moreover, patients with REG-negative differentiated adenocarcinoma were found to have a significantly better prognosis compared with patients with REG-positive tumors. The incidence of venous invasion of REG-positive tumors was significantly higher than that of REG-negative tumors. CONCLUSIONS: The results of the current study suggest that the expression of the REG gene is closely related to the infiltrating property of gastric carcinoma, and may be a prognostic indicator of differentiated adenocarcinoma of the stomach.

Expression of collagenase-3 (matrix metalloproteinase-13) in human gastric cancer.

BACKGROUND: Collagenase-3 (matrix metalloproteinase-13; MMP-13) is a recently identified member of the matrix metalloproteinases (MMPs) with broad substrate specificity, and a potential role in tumor metastasis and invasion has been proposed for this enzyme. To date, in gastrointestinal tract tumors, collagenase-3 expression has been reported only in esophageal carcinoma; the presence and possible implications of this enzyme in the progression of gastric cancer are unknown. METHODS: In this study, MMP-13 mRNA expression was analyzed in a series of 110 matched gastric adenocarcinomas and the corresponding adjacent normal mucosae as well as in nine gastric cancer cell lines. In addition, the mRNA expression of gelatinase a (MMP-2) and membrane type-1 matrix metalloproteinase (MT1-MMP), two MMPs which have the ability to activate MMP-13 in vitro, was also examined in the same cases and cell lines. the production and localization of MMP-13, MMP-2, and MT1-MMP were investigated by immunohistochemistry, immunofluorescence, western blot analysis, and zymography. RESULTS: MMP-13 mrna was expressed in 23 of the 110 carcinomas (21%), and MT1-MMP mRNA was expressed in 45 (40%), but no MMP-13 or MT1-MMP mRNA was detected in any of the normal mucosae. Also, eight of the nine gastric cancer cell lines expressed mRNA of MMP-13, and in each cell line there was coordinate expression with either MT1-MMP or MMP-2 mRNA. MMP-13 and MT1-MMP were detected at the bases of invadopodia of the cultured cancer cells as well as in the invasive front of the tumors, as shown by immunofluorescence and immunohistochemistry, respectively. Western blot analysis revealed the presence of MMP-13 protein in those cell lines and carcinomas that expressed its mrna. on zymography, almost all cell lines that expressed MMP-13 showed gelatinolytic bands corresponding to the active form of MMP-13 or one of its intermediate forms. Also, zymographic analysis of the tumor specimens revealed strong gelatinolytic bands of MMP-13 and MMP-2, whereas these bands in normal mucosa were weak. There was no significant relationship between MMP-13 mRNA expression and histologic type, lymph node metastasis, wall invasion, or distant metastasis. However, patients with MMP-13 mRNA-positive tumors had a poorer prognosis than those with MMP-13-mrna-negative cancer. Furthermore, patients with simultaneous expression of MMP-13 and MT1-MMP mRNA showed the poorest prognosis, as compared with those having tumors expressing either MMP-13 or MT1-MMP, or neither MMP-13 nor MT1-MMP mRNA. CONCLUSION: These findings suggest that MMP-13 expression may contribute to the progression of gastric cancer, and its coordinate overexpression with MT1-MMP and/or MMP-2 may have a cooperative effect in the progression of gastric cancer.

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.