[Effect of intraperitoneal chemotherapy on experimental peritoneal dissemination of gastric cancer]

In vitro chemosensitivity test using a collagen-gel method was done on 165 primary gastric cancers. All of 5-FU, CBDCA, CDDP and docetaxel showed a high sensitivity. The effects of per oral (po) administration of TS-1, a combination of po TS-1 and intraperitoneal (ip) administration of CDDP, ip 5-FU and ip docetaxel, were evaluated in athymic mice bearing peritoneal dissemination of a gastric cancer cell line (MKN-45-P that shows a high rate of metastasis to the peritoneal cavity of nude mice). Nude mice were inoculated by ip with 10(7) MKN-45-P cells. No survival benefit was obtained after po administration of TS-1 (12 mg/kg) alone or ip CDDP alone. However, a combination of po TS-1 (8 mg/kg x 10 days, from day 3) and ip CDDP (3.5 mg/kg, day 6 and 13) showed a significant survival improvement than that of po TS-1 or ip CDDP treatment alone. ip administration of 30 mg/kg (3 times/week x 3 weeks) or 15 mg/kg (6 times/week x 3 weeks) of 5-FU significantly improved the survival of mice bearing MKN-45-P. 5-FU concentration of ascites after ip administration of 30 mg/kg of 5-FU was 600-fold higher than po administration of 12 mg/kg of TS-1 at peak level. ip injections of docetaxel of 8 mg/kg, and 2 mg/kg improved the survival of 4 and 1 mice, respectively, and they were tumor-free on day 90. Survival of mice treated with ip injection of CBDCA (100 mg/kg, on day 3, or 50 mg/ kg on day 3 and 10) was significantly better than the control group. These results suggest the potential of po TS-1 + ip CDDP, ip 5-FU, ip docetaxel and ip CBDCA administration for the treatment of peritoneal dissemination of gastric cancer.

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.

Effect of intraperitoneal administration of docetaxel on peritoneal dissemination of gastric cancer

The effect of intraperitoneal (i.p.) administration of docetaxel was evaluated for preclinical evidence of anticancer activity in athymic mice bearing a gastric cancer cell line, MKN-45-P that shows a high rate of metastasis to the peritoneal cavity of nude mice. Nude mice were inoculated i.p. with 10(7) MKN-45-P cells. On days 2, 5, 9, 12, 16 and 19 after tumor inoculation, mice were treated with i.p. injection of docetaxel. Treatment doses of docetaxel were 8 mg/kg (N = 7) 2 mg/kg (N = 7) and 0.5 mg/kg (N = 7). Intraperitoneal carcinoembryonic antigen (CEA) levels, animal body weight, mortality and survival were determined. All control mice developed ascites and died within 19-40 days. The median survival time in the control group was 32 days, while those of mice treated with 8, 2 and 0.5 mg/kg were 90, 63 and 49.5 days, respectively. One of seven mice treated with 8 mg/kg of docetaxel died of toxicity on day 12. Four mice were tumor-free on day 90, but two had tumors in the abdomen when autopsied on day 90. One mouse treated with 2 mg/kg was ascertained to be tumor-free on day 90. All seven mice treated with 0.5 mg/kg of docetaxel died of peritoneal dissemination within 71 days. The results suggest the potential of intraperitoneal docetaxel administration for the treatment of peritoneal dissemination of gastric cancer.

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.

Intraoperative chemohyperthermic peritoneal perfusion as an adjuvant to gastric cancer: final results of a randomized controlled study

BACKGROUND/AIMS

Although the most frequent cause of death after curative resection of advanced gastric cancer is peritoneal recurrence, there was no effective therapy for the prevention of peritoneal recurrence. This randomized trial sought to determine whether intraoperative chemohyperthermic peritoneal perfusion could eliminate microscopic residual disease and thereby improve survival of patients with advanced gastric cancer.

METHODOLOGY

One-hundred and thirty-nine patients with T2-4 gastric cancer underwent curative gastrectomy with extended lymphadenectomy. These patients were randomly allocated into the following three groups. Patients in the CHPP group received surgery + chemohyperthermic peritoneal perfusion, and those in the CNPP group underwent surgery + chemonormothermic peritoneal perfusion. The third group was surgery alone group. In the CHPP and CNPP groups, peritoneal cavity was perfused with 6-8 liters of heated saline at, respectively, 42-43 degrees C and 37 degrees C with 30 mg of mitomycin C and 300 mg of cisplatin by a extracorporeal circulation machine.

RESULTS

Major operative complication occurred in 19% (9/48), 14% (6/44) and 19% (9/47) of the CHPP, CNPP and surgery alone group, respectively. Complication which uniquely developed after chemohyperthermic peritoneal perfusion was bowel perforation. Mortality rates of each group were 4% (2/48), 0% (0/44) and 4% (2/47) in the CHPP, CNPP and surgery alone group, respectively. Overall 5-year survival rates of CHPP, CNPP and surgery alone groups were 61%, 43% and 42%, respectively. In a subset analysis, patients with gastric cancer having serosal invasion or lymph node metastasis have shown a statistically significant improvement in survival when treated with chemohyperthermic peritoneal perfusion. However, chemonormothermic peritoneal perfusion had no survival benefit. By analyzing with Cox proportional hazard model, chemohyperthermic peritoneal perfusion emerged as an independent prognostic factor for good survival. Surgery alone had three-fold higher risk of death than chemohyperthermic peritoneal perfusion.

CONCLUSIONS

Chemohyperthermic peritoneal perfusion had an efficiency for the prophylaxis of recurrence after curative resection of advanced gastric cancer, and is indicated for patients with tumor infiltrating beyond serosal layer and node positive tumor.

Diagnostic value of preoperative RT-PCR-based screening method to detect carcinoembryonic antigen-expressing free cancer cells in the peritoneal cavity from patients with gastric cancer

BACKGROUND

At present the most reliable method for the diagnosis of peritoneal micrometastasis of gastric cancer is peritoneal wash cytology, but the sensitivity of this method is low. The aim of the present study was to verify whether carcinoembryonic antigen (CEA) reverse transcriptase-polymerase chain reaction (RT-PCR) assay can enhance the sensitivity and specificity of conventional cytology, and to determine how this technique can improve the accuracy of peritoneal recurrence.

METHODS

The present study included 230 patients with gastric cancer. Preoperative peritoneal wash was done by a paracentesis, followed by conventional cytology, CEA measurement, and CEA RT-PCR of recovered fluid.

RESULTS

The CEA RT-PCR assay yielded 40 (17%) positives, which included none of the 26 patients with benign disease. The incidence of positive cytology and CEA level in wash fluid was 19% and 15%, respectively. Logistic stepwise regression analysis revealed that lymph node status, depth of invasion, venous invasion, and the results of peritoneal cytological examination, and CEA RT-PCR assay were independently related to peritoneal recurrence. The CEA level in the wash fluid was not related to peritoneal recurrence. Peritoneal cytological examination was the most significant predictive factor for peritoneal recurrence with a sensitivity of 46%, specificity of 94% and accuracy of 73%, while the corresponding values of the CEA RT-PCR assay were 31%, 95%, and 73%. Combining cytological examination with CEA RT-PCR assay resulted in a sensitivity rate for peritoneal recurrence of 57%, an 11% improvement over that of cytology alone.

CONCLUSION

The data indicate that the use of a combination of CEA RT-PCR and cytological assay is more likely to identify patients who will develop peritoneal recurrence. This may be useful for the classification of patients for the most suitable therapeutic trials.

Inverse expression of S100A4 and E-cadherin is associated with metastatic potential in gastric cancer

S100A4 is known to be involved in cancer cell motility by virtue of its ability to activate nonmuscle myosin. E-cadherin has an important role in the homophilic cell-cell adhesion and is called an invasion suppressor gene. In the current study, we investigate the histological type and metastatic potential of gastric cancer from the aspect of the interrelationship of E-cadherin and S100A4 expression. Expression of E-cadherin and S100A4 in gastric cancer cell lines, primary gastric cancers, and their normal counterparts were analyzed by reverse transcription-PCR, Western blot, and immunohistochemical methods. S100A4 protein and E-cadherin were expressed in five of eight gastric cancer cell lines, and inverse expression of the two proteins are found in four cell lines. In the clinical specimens, E-cadherin mRNA expression in differentiated adenocarcinomas (88%, 14 of 16) was significantly more frequent than that in poorly differentiated adenocarcinomas (50%, 22 of 44; P = 0.015). Western blot analysis demonstrates that S100A4 protein expression in poorly differentiated adenocarcinomas was 1.6-fold higher than in well differentiated adenocarcinoma. Immunohistochemically, S100A4 expression was detected in 51 (55%) of 92 primary gastric cancers. Reduced expression of E-cadherin in primary tumors was found in 66 (72%) of 92 tumors. S100A4 expression in the poorly differentiated adenocarcinomas had a strong relation to positive lymph node involvement or peritoneal dissemination. Reduced E-cadherin expression showed a strong relationship with positive serosal involvement and infiltrating type. Tumors classified as a group with reduced E-cadherin and high expression of S100A4 reveal positive peritoneal dissemination, serosal involvement, and infiltrating type in the growth pattern. Furthermore, these tumors showed a strong correlation with the poorly differentiated adenocarcinoma. In contrast, tumors with preserved E-cadherin and low expression of S100A4 have a close relation to the well differentiated adenocarcinoma and a favorable prognosis. By the Cox proportional hazard model, S100A4 and E-cadherin tissue status was judged as an independent prognostic factor. S100A4 and E-cadherin tissue status may be a powerful aid in evaluating metastatic potential or the prognosis of patients with 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.

A new surgical approach (peritonectomy) for the treatment of peritoneal dissemination

BACKGROUND/AIMS

Despite the improvements of chemotherapy and surgical techniques, treatment results of peritoneal dissemination still remain pessimistic.

METHODOLOGY

During a 10-year period, 106 patients with peritoneal dissemination from gastric cancer were treated with chemo-hyperthermic peritoneal perfusion (CHPP), peritonectomy + CHPP, systemic PMUE therapy, and surgery alone in 51, 15, 13, and 27 patients, respectively. In peritonectomy, disseminated nodules were resected as much as possible in combination with the combined resection of the abdominal organs and parietal peritoneum covering diaphragm, pelvis and abdominal wall. After resection, the abdominal cavity was treated with heated saline at 42-43 degrees, containing cisplatinum (CDDP), Mitomycin C (MMC), and etoposide for 1 hour. PMUE therapy was administered with one course of i.v. infusion of 75 mg/m2 of CDDP and 30 mg/body of MMC on the 1st day, followed by etoposide 50 mg/body on the 3rd, 4th, and 5th day, and with oral intake of 400 mg/body of UFT every day from the 1st day.

RESULTS

No post-operative or chemotherapeutic deaths were observed. Systemic PMUE therapy showed no survival improvement, and survival of the peritonectomy + CHPP group was the best, following CHPP, systemic PMUE and surgery alone.

CONCLUSIONS

Peritonectomy and CHPP may be the best choice for the treatment of peritoneal dissemination.

Immunohistochemical study of MT-MMP tissue status in gastric carcinoma and correlation with survival analyzed by univariate and multivariate analysis

Matrix metalloproteinase (MMP) expression is associated with advanced-stage cancer and contributes to tumor progression, invasion, and metastasis. Membrane type matrix metalloproteinase (MT-MMP) has a potential transmembrane domain at the C terminus and activates pro-MMP-2, which is mainly produced from interstitial fibroblasts. Its expression on the membrane of invasive tumor cells results in the pericellular space degradation at cell-matrix contact sites and renders cancer cells more invasive at the migration front. To elucidate the relationship between MT-MMP expression and metastasis and prognosis in gastric cancer patients, MT-MMP expression was analyzed immunohistochemically in 127 primary tumors and results were correlated with several prognostic parameters and patient's survival. MT-MMP immunoreactivity was stained on the cell membrane of cancer cells and fibroblasts in the invasion front. MT-MMP was detected in 72 tumors (57%) (MT-MMP-positive). MT-MMP expression was closely associated with macroscopically invasive type, nodal involvement, lymphatic invasion, vessel invasion, and peritoneal dissemination. Patients with MT-MMP-positive tumor had a significantly worse prognosis than those with MT-MMP-negative tumor (p<0.001). Multivariate analysis showed MT-MMP overexpression as an independent prognostic factor in gastric cancer patients. Immunohistochemical analysis for MT-MMP may be an indicator of metastatic potential or the prognosis of gastric cancer patients.

Carcinosarcoma of the esophagus with metastases showing osteosarcoma: a case report and review of the literature

Carcinosarcoma of the esophagus includes both carcinomatous and sarcomatous elements. The classification and histogenesis of carcinosarcoma is controversial. In a polypoid carcinosarcoma diagnosed in a resected esophagus the sarcomatous component was composed of dense interlacing bundles of spindle-shaped cells in the submucosa. Areas with transitional features between the two components were observed. Immuno-histochemical examination showed vimentin-positive cells in the sarcomatous areas. Subsequently, obtained autopsy specimens from the lung, kidney and iliac bone showed metastatic osteosarcoma composed of an interlacing pattern of bone or osteoid components. We suspected that the sarcomatous elements in the esophagus resulted from sarcomatous transformation of carcinoma cells, and that the metastatic lesions showed differentiation of neoplastic cells to the osteosarcoma.

[A fatal case of aggressive-phase multiple myeloma with ileus and invasion into extramedullary organs]

A 62-year-old woman with IgA-lambda type monoclonal gammopathy had been followed up since January 1988. In March 1991, multiple myeloma (IgA-lambda) was diagnosed on the basis of bone marrow biopsy findings and increased serum IgA levels. She was treated intermittently with melphalan and prednisolone over a perioa of about 6 years, but was eventually admitted due to renal dysfunction, hypercalcemia, increased serum IgA and the formation of subcutaneous masses. During chemotherapy she underwent emergency surgery for obturative ileus. Histological examination of the resected tissues revealed invasion of myeloma cells into the small intestine and peritoneum. Despite continued chemotherapy, the patient's soft tissue masses enlarged, and new lesions appeared in other organs. In the terminal stage, lower serum IgA levels were observed despite an increase in Bence-Jones protein levels in urine. The patient died five months after admission. An autopsy found infiltration by atypical myeloma cells in multiple organs. An immunohistochemical examination revealed and increase in lambda-light chain positive cells relative to the number of alpha-heavy chain positive cells. The terminal course was considered to be representative of aggressive phase multiple myeloma. The case was rare in that the patient's ileus was caused by invasion of myeloma cells into the small intestine.

Prognostic significance of c-erbB-2 gene expression in the poorly differentiated type of adenocarcinoma of the stomach

Prognostic significance of c-erbB-2 gene abnormalities is unclear in the poorly differentiated type of gastric carcinoma, because the abnormalities of this gene have been reported to be restricted to the differentiated type of gastric carcinoma. In this study, correlation of c-erbB-2 gene amplification/overexpression of mRNA and protein were studied in the poorly differentiated type of gastric carcinoma. c-erbB-2 gene amplification determined by the slot-blot hybridization was observed in 11 (13%) of 82 gastric cancer, and 8 of 11 tumors were poorly differentiated. In addition, c-erbB-2 mRNA expression was studied by the reverse transcriptase-polymerase chain reaction. Four (17%) of 24 tumors showed overexpression of c-erbB-2 mRNA, and all these four exhibited morphologically a poorly differentiated type. Among 157 poorly differentiated gastric cancers, 20 (13%) tumors showed immunohistochemically c-erbB-2 protein expression. These tumors had significantly higher incidences of larger tumor, serosal invasion-positive tumors, node-positive tumor, or peritoneal dissemination-positive tumor than those without c-erbB-2 expression. Furthermore, patients with c-erbB-2 protein overexpression ran poorer prognoses than those without c-erbB-2 expression. From these results, we conclude that expression c-erbB-2 tissue status may be a good prognostic indicator in poorly differentiated gastric carcinoma.

Association of progression and reduced expression of VLA-2 in gastric cancer

We investigated the expression of VLA-2 in gastric cancers by immunohistochemistry using anti-integrin alpha 2 and beta 1 antibodies and the data were compared with the pathological findings of each gastric cancer. The specimens were stained with an immunohistological technique for integrin alpha 2 and beta 1 subunits. Tumors, simultaneously expressing both integrin alpha 2 and beta 1 subunits were defined as positive for VLA-2. Tumors expressing either subunits of integrin alpha 2 or beta 1 or those showing reduced expression of both subunits were defined as VLA-2 negative tumors. In the 77 primary tumors, 55 (71%) were VLA-2 positive. 38 (90%) of 42 tumors showing differentiated type including tubular adenocarcinoma and papillary adenocarcinoma expressed VLA-2, whereas 19 (55%) out of 35 undifferentiated type of cancers including poorly differentiated adenocarcinoma, mucinous carcinoma and signet ring cell carcinoma stained for VLA-2. In the undifferentiated type of cancers, VLA-2 negative tumors had a significantly higher incidence of vessel invasion than VLA-2 positive ones (p<0.05). VLA-2 negative tumors showed a tendency to peritoneal dissemination, lymph node metastases, lymphatic invasion or invasion beyond the subserosal layer. In the specimens of peritoneal dissemination, VLA-2 expression rate was found in 56% (9/16), with a higher expression rate than that of primary lesions. These data indicate that reduced expression of VLA-2 may strongly associate with vessel invasion especially in the undifferentiated type of adenocarcinoma of the stomach.

Effects of intraoperative chemohyperthermia in patients with gastric cancer with peritoneal dissemination

BACKGROUND

The most common cause of noncurative resection and recurrence is gastric cancer is peritoneal seeding. However, the results of treatment of peritoneal dissemination with chemotherapy have been poor with 5-year survival rates of 0%.

METHODS

A new in vitro thermochemosensitivity test was performed on gastric cancer cells obtained from 19 surgically resected specimens by using tetrazolium-based colorimetric assay (MTT assay). A novel treatment of the intraoperative chemohyperthermia was undertaken in 83 patients with gastric cancer with peritoneal dissemination. After aggressive resection of primary tumor, lymph nodes, and peritoneal metastases, warmed saline solution containing mitomycin C 30 mg, etoposide 150 mg, and cisplatin 300 mg was introduced into the peritoneal cavity via a closed circuit continuous hyperthermic peritoneal perfusion (CHPP) for 60 minutes to keep the abdominal temperature at 42 degree to 43 degrees C by means of a heat exchange mechanism.

RESULTS

The in vitro thermochemosensitivity test that 43 degrees C enhanced the cytotoxin effects on gastric cancer cells under clinically achievable drug concentrations. During CHPP, drug concentrations of cisplatin, mitomycin C, and etoposide in the perfusate remained statistically higher than in the peripheral venous circulation. Among 43 evaluable patients with residual peritoneal seeding, eight (19%) and nine (21%) exhibited complete response and partial response, respectively. The overall 1- and 5-year survival rates were 43% and 11%, respectively. Patients who underwent complete resection survived significantly longer than those with residual disease, and those with complete response had a significantly better prognosis than did those with partial response, and nonresponders. One-year survival rates with complete response, partial response or nonresponders were 88%, 27% and 22%, respectively. Five patients survived longer than 5 years.

CONCLUSIONS

Our triple treatment combining surgery and CHPP is an effective therapy for selected patients with gastric cancer with peritoneal dissemination.

Amplification of epidermal growth factor receptor gene and its relationship to survival in human gastric cancer

The correlation between the clinical features in 103 patients with primary gastric carcinoma and amplification of epidermal growth factor receptor (EGFR) gene was analyzed retrospectively. EGFR gene amplification was examined by slot-blot hybridization using DNA extracted from formalin-fixed, paraffin-embedded tissues. EGFR expression was also examined immunohistochemically using the same tissues with a monoclonal antibody that is monospecific for EGFR. In 5 of 103 cases (4.9%), a 2- to 11-fold amplification of EGFR gene was detected. Four of these 5 cases were poorly differentiated adenocarcinomas. All of them had overexpressions of EGFR. The cumulative survival rate of patients with EGFR gene amplification was significantly lower than that of the patients without amplification (p < 0.05) and all of them died within 3 years. Except for tumor size (p < 0.03), there were no significant clinicopathologic differences between the two groups. On the other hand, 41 of 103 cases (39.8%) exhibited expression of EGFR. However, there was no significant correlation between EGFR expression and clinicopathologic factors or prognosis. These results indicate that EGFR gene amplification may occur in advanced stages during the progression and be an important indicator of poor short-term prognosis in gastric carcinoma.

Decreased E-cadherin expression correlates with poor survival in patients with gastric cancer

E-cadherin, Ca(2+)-dependent intracellular adhesion molecule, is known to be an invasion suppressor gene. To elucidate the correlation between E-cadherin expression and invasion or metastasis in gastric cancer, we examined E-cadherin tissue status immunohistochemically. Ninety-eight primary gastric cancer, prepared by AMeX method, were retrospectively analyzed with anti-E-cadherin monoclonal antibody. In normal gastric epithelium, E-cadherin is expressed homogeneously with a typical membranous staining at cell-cell borders. Decreased and heterogeneous expression is found in 70 of 98 tumours. Tumours with decreased E-cadherin expression had a tendency to infiltrate more deeply in stomach wall, and metastasize in lymph nodes or peritoneal surface. More importantly, decreased E-cadherin expression correlates with shorter survival (z = 3.98, P = 0.00086). These results may indicate that E-cadherin tissue status is a powerful prognostic indicator in gastric cancer. The high malignant potential of tumours with decreased E-cadherin expression may be associated with high potential of lymph node metastasis and peritoneal dissemination.

Serum erbb-2 protein for the diagnosis of gastric-cancer

A new tumor marker was tested (serum erbB-2 protein) in 128 patients with gastric cancer and 110 patients with benign gastric diseases, and the results were correlated with erbB-2 tissue status and clinicopathological parameters. Abnormal level of erbB-2 protein was found in 15/128 (12%) of gastric cancer patients and in 2/110 (2%) of benign gastric diseases. Elevated erbB-2 levels did not correlate with age, sex, tumor size, macroscopic type, histologic type, serosal invasion, nodal status, or clinical stage. In all the 15 patients except one case, with abnormally high level of serum erbB-2, erbB-2 immunoreactivity was confirmed in the primary tumors by immunohistochemical staining. The percentage of positive serum levels of alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA) and CA 19-9 were 6%, 16% and 20%, respectively. However, there was no relation between serum erbB-2 level and CA 19-9, CEA or AFP level. If the CA 19-9 was assayed in combination with erbB-2, the overall sensitivity was 30%. In addition, the combination of the three markers of erbB-2, CEA and CA 19-9 gave a sensitivity of 41%. Patients with abnormal erbB-2 serum level run poorer prognoses than did the patients with normal erbB-2 serum level. We conclude that erbB-2 protein is an attractive tumor marker, and a powerful prognostic indicator of gastric cancer patients.

Correlation between altered expression of retinoblastoma protein and clinical outcome in patients with gastric-cancer

We studied the expression of RB protein in 136 endoscopically obtained biopsied materials from primary gastric cancers by means of immunohistochemistry. The expression of RB protein was variably observed in the nuclei of tumor cells. Tumors could be divided into two groups. Group 1 (RB-positive) comprised 74 tumors (54%) that expressed RB protein in 20% or more of tumor cells, and Group 2 (altered RB) included 62 tumors (46%) that showed RB immunoreactivity in less than 20% of tumor cells. RB-positive tumors (Group 1) were more frequently observed in the early cancers (74%, 28/38) than in advanced ones (48%, 46/98). The incidence of distant metastases was higher and involvement of serosa or lymph nodes was more frequently observed in Group 2 than in Group 1. In addition, patients of Group 1 survived significantly longer than those of Group 2 (p<0.05). However, no correlation could be found between RB tissue status and proliferative activity. These results indicate that tumors with decreased RB-protein expression may have more aggressive biological behavior than tumors showing high expression of this protein.

Prediction of the prognosis of patients with gastric-cancer by erbb-2 tissue status and expression of proliferating cell nuclear antigen

Correlation between erbB-2 tissue status and expression of proliferating cell nuclear antigen (PCNA) was studied in 164 gastric carcinomas, and these results were compared with the risk of metastasis and prognosis. Thirty-one (19%) tumors showe evidence of erbB-2 protein expression, and the PCNA index ranged from 8.2% to 77.2% (mean; 40%). erbB-2 protein positive tumors were most often encountered in the following clinicopathological groups: tumors with serosal invasion, lymph node metastasis, and venous invasion. There was a significant correlation between PCNA index and lymph node metastasis. In addition, erbB-2 positive tumors showed significantly higher PCNA index than erbB-2 negative tumors. Cox prortional hazard model identified lymph node metastasis. In invasion, liver metastasis, and erbB-2 tissue status as independent prognostic factors, but PCNA index was not an independent prognostic factor. However, by combining erbB-2 tissue status and PCNA index, PCNA index. was a good prognostic factor particularly in patients with erbB-2 negative tumors. These results indicate that the determination of erbB-2 tissue status, when combined with PCNA index, may be useful in the prediction of the prognosis and in deciding the therapeutic schedule of patients with gastric cancer.

Correlation of c-erbB-2 protein expression and lymph node status in early gastric cancer

For the prediction of nodal status of early gastric cancer, sections of formalin-fixed, paraffin-embedded tissue from 220 early gastric cancers were analyzed immunohistochemically, using a polyclonal antibody against erbB-2 protein. The data of erbB-2 protein expression have been correlated with pathologic data, and a logistic regression analysis was made for the estimation of the significant factors responsible for lymph node metastasis. A pattern consistent with cell membrane staining was regarded as most specific for the erbB-2 expression. There were 22 (10%) cancers with evidence of erbB-2 protein expression. Positive staining was associated with only lymph node metastasis. The risk of lymph node metastasis was 3-fold greater in tumors having erbB-2 protein expression than in tumors without the expression. When the erbB-2 tissue status and clinicopathological parameters were entered into the logistic regression analysis, erbB-2 protein expression emerged as one of the independent significant factors for lymph node metastasis. These results indicate that early gastric cancer with erbB-2 protein expression may represent a potential risk of lymph node metastasis.

Expression of c-erbB-2 oncoprotein in gastric carcinoma. Immunoreactivity for c-erbB-2 protein is an independent indicator of poor short-term prognosis in patients with gastric carcinoma

Correlations of c-erbB-2 protein expression with clinical outcomes of gastric carcinomas were studied in 189 gastric carcinomas. There were 23 (12.2%) carcinomas with evidence of c-erbB-2 protein in which the reaction was localized to the cell membrane. There was no significant association between c-erbB-2 staining and the macroscopic or histologic type of the carcinomas. c-erbB-2-stained tumors were more likely to be associated with serosal invasion, nodal involvement, and peritoneal metastasis, than c-erbB-2-unstained ones. In addition, c-erbB-2 was stained in none of early gastric carcinomas. The 5-year survival rates of the c-erbB-2 protein-positive and the protein-negative group were 11% and 50%, respectively. When the c-erbB-2 tissue status and seven clinicopathologic variables as conventional prognostic factors were entered simultaneously into the Cox regression model, serosal invasion, hepatic metastasis, peritoneal metastasis, nodal status, and c-erbB-2 tissue status emerged as independent prognostic variables. The results suggested that c-erbB-2 protein expression might be enhanced in advanced stages during the progression of gastric carcinoma. In this particular group of patients, immunoreactivity for c-erbB-2 protein is an indicator of poor short-term prognosis.