Increased B7-H1 and B7-H4 Expressions on Circulating Monocytes and Tumor-Associated Macrophages are Involved in Immune Evasion in Patients with Gastric Cancer

Expression of the costimulatory molecule B7-H4, a member of the inhibitory B7 family, has been reported to be upregulated on tumor-associated macrophages, and this overexpression may be involved in immune evasion in cancer patients. The present study was designed to investigate B7-H4 expression on monocytes/macrophages and its relationship with immune evasion in gastric cancer patients. B7-H4 expression on circulating monocytes and tumor-associated macrophages was evaluated by multicolor flow cytometry. Carboxyfluorescein succinimidyl ester proliferation assays and quantitative interferon-gamma enzyme-linked immunosorbent assays were carried out to determine the inhibitory effect of B7-H4+ monocytes on CD4+ T cells. B7-H4 expression on circulating monocytes was upregulated and these B7-H4+ monocytes showed immunosuppressive properties. B7-H4 expression was closely related to the depth of invasion, as well as the presence of lymphatic and venous invasion. There were significant correlations between B7-H4 expression and B7-H1 or HLA-DR expression on monocytes/macrophages in gastric cancer patients. B7-H4 expression was remarkably upregulated in gastric cancer tissues compared with peripheral blood samples. Complete surgical removal of the tumor decreased B7-H4 expression on circulating monocytes from gastric cancer patients. Cocultures of gastric cancer cell lines and monocytes led to upregulation of B7-H4 expression on monocytes. Increased B7-H4 expression on circulating monocytes and tumor-associated macrophages may be one of the key mechanisms responsible for immune evasion by tumors in gastric cancer

Clinicopathological Aspects of Gastric Carcinoma in the Remnant Stomach

The clinicopathological differences between remnant gastric carcinoma (RGC) after partial gastrectomy for benign disease (RGC-BD) and RGC after partial gastrectomy for gastric carcinoma (RGC-GC) were evaluated. The incidences of developing gastric carcinomas in patients more than 10 years after partial gastrectomy for benign disease or for gastric carcinoma were compared with those of developing gastric carcinomas in patients with colorectal carcinoma who were determined to have no malignant disease in the stomach preoperatively. Next, we analyzed the clinicopathological differences among RGC-BD, RGC-GC and primary gastric carcinoma (PGC) in the upper third of the stomach. RGC-BD was detected in 8 of 1,187 (0.7%) patients and RGC-GC was detected in 19 of 764 (2.5%) patients. Among the controls, 7 of 226 (3.1%) patients developed gastric carcinoma. The estimated risk of developing of RGC-BD and RGC-GC were 0.12 and 0.798. No difference was found among 18 patients with RGC-BD, 16 patients with RGC-GC and 229 patients with PGC in terms of patient age, histologic type, tumor size and distribution of tumor stage. The 5-year survival rate for patients with PGC (55%) was not different from that for patients with RGC-BD (43%) or that for patients with RGC-GC (65%). However, the interval between initial operation and detection of RGCs was longer in RGC-BD than in RGC-GC (P = 0.004), and RGCs were more frequently detected at the site of anastomosis in patients with RGC-BD (50%) than in patients with RGC-GC (19%, P= 0.057). The incidence of developing RGCs after partial gastrectomy for benign and malignant diseases was low. The histologic type of tumors and tumor stages of RGC-GC were not different from those of RGC-BD; however, RGC-GC developed within a short time and most lesions were at sites remote from the anastomosis. These findings indicate that carcinogenesis of RGC-GC appears to be different from that of RGC-BD

Expression of DNA Methyltransferase (DNMT) 1, 3a and 3b Proteins in Human Hepatocellular Carcinoma

Alteration of aberrant DNA methylation is one of the most consistent epigenetic changes found in human cancers. DNA methylation is catalyzed by DNA methyltransferase (DNMT). In this study, we examined DNMT protein expression by immunohistochemistry in surgically resected hepatocellular carcinomas (HCCs). Sections of paraffin-embedded specimens were obtained from 95 patients with HCC between 1989 and 2002. The specimens were stained with anti-DNMTs (DNMT1, DNMT3a and DNMT3b) antibodies. There were statistically significant associations between DNMT protein expression and tumor differentiation (P < 0.05) and intrahepatic metastasis (P < 0.05). DNMT3a protein expression was significantly correlated with portal vein involvement of tumors (P < 0.05). The overall survival rates of patients with DNMT3a-positive HCCs and DNMT3b-positive HCCs were significantly lower than those of patients negative for these proteins (P < 0.005, respectively). To further evaluate the correlation between DNMT protein expression and patient survival, we classified patients into 3 groups: Group 1, DNMT1(+), 3a(–) and 3b(–); Group 2) DNMT1(+), 3a or 3b(+); and Group 3) DNMT1(+), 3a(+) and 3b(+). The overall survival rate of patients in Group 3 was significantly lower than those of patients in Groups 1 and 2 (P = 0.0009). In conclusion, the results of this study suggest that DNMT1, DNMT3a and DNMT3b are cooperatively involved in determining the extent of HCCs, and that DNMT protein overexpression in HCCs may be a predictive factor for poor survival

Expression of Phospho-Akt and PTEN Proteins in Human Breast Cancer in Relation to Tumor Progression and Patient Survival

Phosphatidylinositol 3-kinase (PI3-kinase) controls mitogenesis, cellular growth and transformation in a variety of cancers. The serine-threonine kinase Akt is a downstream target of PI3-kinase, and phosphorylated Akt (Phospho-Akt) inhibits apoptosis. Phosphatase and tensin homolog detected on chromosome ten (PTEN) is a tumor suppressor that antagonizes PI3-kinase activity, negatively regulates its downstream-target, Akt, inhibits phosphorylation of Akt, and medicates cell-cycle arrest and apoptosis. To clarify whether the PI3-kinase/Akt pathway and PTEN relate to breast cancer, we examined the expression of pathway-related proteins such as Phospho-Akt and PTEN in clinical specimens. Immunohistochemical analysis was performed on tissue specimens surgically obtained from 221 patients with breast cancer. The association of Phospho-Akt and PTEN expression with clinicopathological variables and the prognosis of patients were analyzed. Of 221 breast carcinomas, positive Phospho-Akt expression was observed in 91 (41.1%) and positive PTEN expression in 119 (53.8%). Phospho-Akt expression and loss of PTEN expression significantly correlated with tumor staging, tumor size and lymph node metastasis. Patients with Phospho-Akt-positive tumors had significantly inferior disease-free survival or over-all survival to those with Phospho-Akt-negative tumors, while those with PTEN positive tumors were better than those with PTEN negative tumors. Moreover, patients with Phospho-Akt-positive and PTEN-negative tumors had a significantly inferior disease-free survival and over-all survival compared to those with Phospho-Akt-negative and PTEN-positive tumors. Multivariate analysis revealed that expression of Phospho-Akt and tumor size were the independent factors (P = 0.024). We demonstrated that the expression of Phospho-Akt significantly correlated with tumor progression and patients survival with breast cancer. Phospho-Akt/PTEN expression status is possibly a definitive prognostic factor in clinical breast cancer