Molecular targeting to treat gastric cancer.

Trastuzumab that targets human epidermal growth factor receptor 2 (HER2) protein is the only approved molecular targeting agent for treating gastric cancer in Japan and the outcomes have been favorable. However, trastuzumab is effective for only 10% to 20% of the population with gastric cancer that expresses HER2 protein. Molecular targeting therapy with bevacizumab against vascular endothelial growth factors (VEGF) and with cetuximab and panitumumab against the epidermal growth factors pathway that have been approved for treating colorectal cancer are not considered effective for treating gastric cancer according to several clinical trials. However, ramucirumab that targets VEGF receptor-2 prolonged overall survival in a large phase III clinical trial and it might be an effective molecular targeting therapy for gastric cancer. The significance of molecular targeting therapy for gastric cancer remains controversial. A large-scale randomized clinical trial of novel molecular targeting agents with which to treat gastric cancer is needed.

Expression of CD133 in the cytoplasm is associated with cancer progression and poor prognosis in gastric cancer.

BACKGROUND: CD133 is one of the most important stem cell markers in solid cancers. Some recent reports have described a possible relationship between CD133 and hypoxia-inducing factor-1-alpha (HIF-1α). The aim of this study was to clarify the clinical role of CD133 expression in gastric cancer and to investigate the correlation between CD133 expression and HIF-1α expression. METHODS: We studied 189 gastric cancer patients who underwent gastrectomy at Kurume University Hospital. CD133 and HIF-1α expression was examined using immunohistochemical staining. Fifty-six cases were CD133 positive, and they were divided into two expression types: luminal expression of the gland and cytoplasmic expression. We investigated the relationship among CD133 expression types, clinicopathological variables, prognosis, and HIF-1α expression. RESULTS: When comparing clinicopathological variables, expression of CD133 in the cytoplasm was related to metastasis and tumor progression. However, this relationship was not observed with luminal expression of the gland type. The survival rate in patients with cytoplasmic CD133 expression was significantly worse than that in the CD133-negative group. This relationship was observed in the survival rate of the adjuvant chemotherapy group and the curative resection group. Multivariate analysis revealed that the expression of CD133 in the cytoplasm was an independent prognostic factor in gastric cancer. Regarding the correlation between CD133 expression and HIF-1α expression, the HIF-1α positive rate was lower in patients with CD133 luminal expression of the gland type and higher in patients with cytoplasmic expression of CD133. CONCLUSION: Gastric cancer cells with CD133 expression in the cytoplasm were cells with high potential for malignancy, and this phenotype was associated with cancer progression, chemotherapy resistance, recurrence, and poor prognosis. Cytoplasmic expression of CD133 may be a useful prognostic marker in gastric cancer. Significant correlation was observed between HIF-1α expression and the immunohistochemical staining pattern of CD133.

Expression of p27Kip1 protein in gastric carcinoma.

BACKGROUND/AIMS: p27 protein resulted in the accumulation of cyclin E/cyclin dependent kinase 2/p27 ternary complexes inhibits gap1 to synthesis phase transition. Here, we have investigated the correlations, if any, between the expressions of p27 and p53, and proliferation cell nuclear antigen. METHODOLOGY: A retrospective study was performed on 75 cases of gastric cancer that had undergone surgical resection. Immunohistochemical staining was performed using the avidin-biotin-peroxidase complex technique method, with anti-p27 antibody, anti-p53 antibody and anti-proliferation cell nuclear antigen antibody. RESULTS: The rate of lymph node metastasis in the p27 negative cases was significantly higher than that in the p27 positive cases.The rate of tumor limited to the gastric wall in the p27 positive cases was significantly higher than-that in the p27 negative cases.The mean proliferation cell nuclear antigen index of the p27 negative cases was significantly higher than that of the p27 positive cases. The survival rate of the p27 positive cases was significantly higher than that of the p27 negative cases. In Stage III cases, the survival rate of the p53 negative p27 positive or p53 negative p27 negative cases was significantly higher than that of p53 positive p27 negative cases. CONCLUSIONS: p27 was correlated with lymph node metastasis, depth of invasion, and proliferative activity of gastric cancer. Immunoreactivity of combination of p53 and p27 was a useful predictive marker of prognosis of gastric cancer.

Molecular targeting therapy using bevacizumab for peritoneal metastasis from gastric cancer.

AIM: To clarify the significance of vascular endothelial growth factor (VEGF) in peritoneal metastasis from gastric cancer, using the gastric cancer cell line MKN-45 compared with the high potential peritoneal dissemination gastric cancer cell line MKN-45P. METHODS: The supernatant of culture medium of MKN-45 cells or MKN-45P cells was collected and the concentrations were measured of various cytokines, matrix metalloproteinases, growth factor and angiogenic factors, including VEGF. We performed an initial pilot study to explore whether bevacizumab, a humanized monoclonal antibody against VEGF, had any suppressive effect on the peritoneal dissemination from gastric cancer in an experimental nude mouse model of peritoneal metastasis. RESULTS: The concentrations of interleukin-6 (IL-6), IL-8, VEGF and matrix metalloproteinase-2 protein in the culture supernatant were each significantly higher than each of those for MKN-45. In the in vivo study, the volume of ascites and the mitotic index were significantly lower in the therapy group than in the non-therapy group. The survival curve of the therapy group was significantly higher than that of the non-therapy group. These results suggested that VEGF was correlated with peritoneal metastasis from gastric cancer. CONCLUSION: Findings suggested that bevacizumab for inhibiting VEGF could suppress peritoneal dissemination from gastric cancer.

Prognosis of metastatic splenic hilum lymph node in patients with gastric cancer after total gastrectomy and splenectomy.

AIM: To clarify the significance of combined resection of the spleen to dissect the No. 10 lymph node (LN). METHODS: We studied 191 patients who had undergone total gastrectomy with splenectomy, excluding non-curative cases, resection of multiple gastric cancer, and those with remnant stomach cancer. Various clinicopathological factors were evaluated for any independent contributions to No. 10 LN metastasis, using χ(2) test. Significant factors were extracted for further analysis, carried out using a logistic regression method. Furthermore, lymph node metastasis was evaluated for any independent contribution to No. 10 LN metastasis, using the same methods. The cumulative survival rate was calculated using the Kaplan-Meier method. The significance of any difference between the survival curves was determined using the Cox-Mantel test, and any difference was considered significant at the 5% level. RESULTS: From the variables considered to be potentially associated with No. 10 LN metastasis, age, depth, invasion of lymph vessel, N factor, the number of lymph node metastasis, Stage, the number of sites, and location were found to differ significantly between those with metastasis (the Positive Group) and those without (the Negative Group). A logistic regression analysis showed that the localization and Stage were significant parameters for No. 10 LN metastasis. There was no case located on the lesser curvature in the Positive Group. The numbers of No. 2, No. 3, No. 4sa, No. 4sb, No. 4d, No. 7, and No. 11 LN metastasis were each found to differ significantly between the Positive Group and the Negative Group. A logistic regression analysis showed that No. 4sa, No. 4sb, and No. 11 LN metastasis were each a significant parameter for No. 10 LN metastasis. There was no significant difference in survival curves between the Positive Group and the Negative Group. CONCLUSION: Splenectomy should be performed to dissect No. 10 LN for cases which have No. 4sa, No. 4sb or No. 11 LN metastasis. However, in cases where the tumor is located on the lesser curvature, splenectomy can be omitted.

Malignant potential of gastrointestinal stromal tumor of the stomach.

Here, we report the Ki-67 Labeling Index, the expression of c-kit, p53, bcl-2, and apoptosis in 11 gastrointestinal stromal tumors (GISTs). The Ki-67 Labeling Index in the malignant GIST group was higher than that in the benign group. The Ki-67 Labeling Index in the p53-positive cases was higher than that in the p53-negative cases. The Ki-67 Labeling Index in the C-kit-positive group was higher than that in the C-kit-negative group. The bcl-2 expression was not correlated with potential malignancy. The apoptotic count in the bcl-2-positive cases was higher than that in the bcl-2-negative cases. The Ki-67 Labeling Index, the p53 overexpression, and the C-kit expression were useful in predicting the potential malignancy.

VEGF significance in peritoneal recurrence from gastric cancer.

BACKGROUND: In gastric cancer, the management of peritoneal dissemination in the Peritoneal cavity is extremely important; however, peritoneal dissemination in the final stage of gastric cancer remains untreatable. Peritoneal dissemination involves several steps, including tumor-cell attachment, invasion, and growth in the peritoneum. Many cytokines, growth factors, matrix metalloproteinases (MMPs), and angiogenic factors play important roles in these steps. So far, few studies have investigated the correlation, if any, between peritoneal dissemination and the angiogenic factor, vascular endothelial growth factor (VEGF). METHODS: Immunohistochemical staining, using the avidin-biotin peroxidase complex method, was performed on slides of surgical specimens from 40 patients with stage II gastric cancer with serosal invasion, who underwent surgery at our hospital between 1990 and 2000. Anti-human VEGF rabbit polyclonal IgG was used as the primary antibody. VEGF expression was classified in one of four categories depending on the percentage of tumor-cell staining (P). VEGF expression was also classified in one of three categories depending on the staining intensity (I). The VEGF expression score was calculated as P x I. RESULTS: There were ten patients with peritoneal recurrence. Of these, seven had macroscopic type-4 scirrhous-type gastric carcinoma. In the immunohistochemical study, the VEGF score of patients with peritoneal recurrence was 9.40 +/- 2.46; on the other hand, that of patients without peritoneal recurrence was 3.47 +/- 2.36. The VEGF score of patients with peritoneal recurrence was significantly higher than that of patients without peritoneal recurrence. In patients with macroscopic type 4, the VEGF score of those with peritoneal recurrence was 9.14 +/- 2.19, while on the other hand, that of the patients without peritoneal recurrence was 3.80 +/- 3.03. The VEGF score of these patients with peritoneal recurrence was significantly higher than that of those without peritoneal recurrence. The survival rate in the VEGF low-expression group was significantly higher than that in the VEGF high-expression group. Multivariate analysis showed that the VEGF score was a significant parameter of peritoneal recurrence. CONCLUSION: These results suggested that VEGF was correlated with peritoneal metastasis from gastric cancer, and that VEGF was a useful indicator of peritoneal recurrence.