Shigehiro Yanagita

B7‐H3 expression in gastric cancer: A novel molecular blood marker for detecting circulating tumor cells

The clinical significance of B7‐H3 expression in gastric cancer remains unclear, although the B7 ligand family plays a critical role in the T cell‐mediated immune response. We therefore investigated B7‐H3 expression as a blood marker of circulating tumor cells and determined correlations with tumor progression in patients with gastric cancer. B7‐H3 expression in gastric cell lines was initially evaluated by immunocytochemistry. Furthermore, we used quantitative RT‐PCR to assess B7‐H3 mRNA expression in four cell lines and in 95 blood specimens from patients with gastric cancer, as well as in 21 samples of peripheral blood lymphocytes from healthy volunteers. B7‐H3 expression in cell lines was identified by immunocytochemistry and quantitative RT‐PCR. Blood specimens from patients with gastric cancer contained significantly more copies of B7‐H3 mRNA than those from healthy volunteers without cancer (P < 0.0001). Levels of B7‐H3 expression significantly correlated with overall stage (P = 0.013). The 5‐year survival rate was significantly lower in patients with high B7‐H3 expression than with low expression (P = 0.02). Multivariate analysis demonstrated that B7‐H3 expression was an independent prognostic factor (P = 0.046). Our results indicate that B7‐H3 appears to be a useful blood marker for predicting tumor progression in gastric cancer. (Cancer Sci 2011; 102: 1019–1024)

Clinical significance of circulating tumor cells in peripheral blood from patients with gastric cancer

The authors hypothesized that circulating tumor cells (CTCs) in patients with gastric cancer are associated with prognosis and disease recurrence. In this study, they evaluated CTCs in gastric cancer and clarified the clinical impact of CTCs.

Overexpression of vascular endothelial growth factor-C correlates with lymph node micrometastasis in submucosal esophageal cancer

Lymph node metastasis, including lymph node micrometastasis (LMM), is one of the most important prognostic factors in esophageal squamous cell carcinoma (ESCC). Vascular endothelial growth factor C (VEGF-C) plays a key role in the process of lymphangiogenesis. We examined VEGF-C expression and tumor microvessel density of the primary tumors in ESCC and analyzed relationships between VEGF-C expression and clinicopathologic findings including LMM in submucosal ESCC. The subjects were 87 patients with submucosal ESCC. Immunohistochemical staining of VEGF-C and CD34 was performed with primary tumors, and staining of cytokeratin was performed with dissected lymph nodes. Microvessel density was calculated from CD34 expression, and LMM was detected by cytokeratin staining. VEGF-C overexpression significantly correlated with depth of tumor invasion, lymphatic invasion, and lymph node metastasis (P<0.05, P<0.0001, and P<0.0001, respectively). High microvessel density also correlated with lymphatic invasion and lymph node metastasis (P<0.005 and P<0.05, respectively). LMM was detected in 8 cases and 14 lymph nodes by cytokeratin staining. VEGF-C overexpression and high microvessel density were found in tumors with lymph node metastasis and/or LMM, compared with tumors without nodal metastasis or LMM (P<0.0001 and P<0.01, respectively). The present findings indicate that in ESCC with submucosal invasion, VEGF-C overexpression of the primary tumor is a strong high risk factor for lymph node metastasis, including LMM.

Clinical Significance of Lymph Node Micrometastasis in Gastric Cancer

Recently, the existence of lymph node micrometastasis (LNM), including isolated tumor cells, has been focused on during the development of molecular diagnostic tools for lymph node metastasis in various malignant neoplasms. In particular, immunohistochemistry and reverse transcription-polymerase chain reaction have been reported to be available for the detection of LNM in gastric cancer. However, at present, the clinical significance of LNM remains unclear in patients with gastric cancer. Therefore, we cannot strategically make light of this issue in clinical management. Currently, minimally invasive treatments, such as endoscopic submucosal dissection and laparoscopic surgery with personalized lymphadenectomy, are widely performed in consideration of postsurgical quality of life (QOL). However, it is important to maintain the balance between QOL and curability when selecting surgical treatments for patients with gastric cancer. If minimally invasive surgery based on LNM status was established for patients with early gastric cancer, it could be performed safely. We reviewed the clinical significance of LNM as an important strategic target in patients with gastric cancer.

Detection of micrometastases in sentinel node navigation surgery for gastric cancer.

Although lymph node metastasis is one of the important prognostic factors for patients with gastric cancer, the clinical significance of micrometastasis remains controversial. In the 6th edition of the TMN classification, micrometastases were classified as micrometastasis (MM) and isolated tumor cells (ITC) according to its greatest dimension. The accurate diagnosis of micrometastases is required when considering less invasive surgery, especially in early stage of gastric cancer. Since generating useful information about micrometastases by conventional RT-PCR is time-consuming, this procedure is not useful for rapid diagnosis during surgery. Recently some new methods of genetic diagnosis have reduced the amount of time required to obtain information about micrometastases in lymph nodes to 30-40 min. Such methodology can be clinically applied during less invasive surgery. The sentinel node (SN) concept has recently been applied to gastric cancer and SN navigation surgery (SNNS) is ideal for reduction of lymphadenectomy in patients with early gastric cancer. However, we should think about some conditions to establish SN concept for gastric cancer: the particle size of radioisotope, relationship between metastatic area and RI uptake, and the diagnosis of micrometastases by various method such as histological examination, immunostaining and RT-PCR. Here, we described the current status of MM and ITC in the lymph nodes and the SN concept in gastric cancer.

Expression of B7‐H4 in blood of patients with gastric cancer predicts tumor progression and prognosis

B7‐H4 is a novel molecular B7 ligand that plays an important role as a negative regulator of the T cell‐mediated immune response. However, the clinical significance of B7‐H4 expression in gastric cancer remains uncertain. Here, we assessed B7‐H4 expression in blood of patients with gastric cancer to determine whether or not it can predict tumor progression and prognosis.

Vascular endothelial growth factor-C and -D expression correlates with lymph node micrometastasis in pN0 early gastric cancer.

Vascular endothelial growth factors (VEGF)‐C and ‐D play an important role in lymphangiogenesis, and the expressions of these factors are related to lymphatic invasion and lymph node metastasis in various malignant neoplasms. The present study investigates the expression of VEGF‐C and ‐D in early gastric cancer and analyzes its relationship to lymph node micrometastasis determined by reverse transcription‐polymerase chain reaction (RT‐PCR).

Clinicopathological significance of nuclear factor (erythroid-2)-related factor 2 (Nrf2) expression in gastric cancer

BackgroundThe transcription factor nuclear factor (erythroid-2)–related factor 2 (Nrf2) was originally identified as a critical regulator of intracellular anti-oxidants and of phase II detoxification enzymes through its transcriptional up-regulation of many anti-oxidant response element (ARE)-containing genes. Nrf2 protects not only normal cells but also cancer cells from cellular stress, and enhances cancer cell survival. Some studies have shown that Nrf2 expression in cancer patients has clinical significance. However, there has been no comprehensive analysis of the nuclear expression level of Nrf2 in gastrointestinal cancer cells. In this study we aimed to immunohistochemically evaluate the expression of Nrf2, and to assess its clinical significance in gastric cancer.MethodsA total of 175 gastric cancer patients who received R0 gastrectomy with standard lymph node dissection were enrolled. We immunohistochemically evaluated Nrf2 expression in the paraffin-embedded surgically resected specimens of these 175 patients. Group differences were analyzed using the χ2 test, Fisher’s exact test, and the Mann–Whitney U test. Associations between Nrf2 expression and clinicopathological features, including clinical outcome, were assessed using univariate and multivariate analyses, and Kaplan-Meier curves with the log-rank test, respectively.ResultsNrf2 immunoreactivity was predominantly identified in the nucleus of gastric cancer cells. Nrf2 positivity was closely associated with tumor size, tumor depth, lymph node metastases, lymphovascular invasion, histology and stage (p < 0.05 for all). A log-rank test indicated that the overall survival of the Nrf2-positive group was significantly poorer than that of the Nrf2-negative group (p < 0.01). And, positive Nrf2 expression was significantly associated with resistance to 5FU-based adjuvant chemotherapy (p = 0.024).ConclusionsNrf2 expression was positively associated with aggressive tumor behavior in gastric cancer. This result suggests that Nrf2 expression in gastric cancer is a potential indicator of worse prognosis.

Clinical significance of stanniocalcin 2 expression as a predictor of tumor progression in gastric cancer

Stanniocalcin 2 (STC2) is a glycoprotein hormone that plays an important role in calcium and phosphate homeostasis. Furthermore, recent studies have demonstrated that STC2 expression in the primary site is correlated with tumor progression in several types of malignancies. However, few reports have investigated the clinical significance of STC2 expression in the blood of patients with gastric cancer. Therefore, we examined STC2 expression as a molecular blood marker for detection of circulating tumor cells (CTCs) and assessed the relationship between STC2 expression and clinico-pathological features including prognosis in patients with gastric cancer. Quantitative PCR assay was used to assess STC2 mRNA expression in 4 gastric cancer cell lines and in blood specimens from 93 patients with gastric cancer and 22 healthy volunteers. The numbers of STC2 mRNA copies were significantly higher in the gastric cancer cell lines and in blood from patients with gastric cancer than in blood from healthy volunteers (P=0.0002 and P=0.01, respectively). STC2 expression was positive in 43 (46.2%) of the 93 patients with gastric cancer, and its expression was significantly correlated with age, depth of tumor invasion, lymph node metastasis, stage and venous invasion (P=0.023, P=0.045, P=0.035, P=0.007 and P=0.027, respectively). The 5-year survival rate was significantly lower in patients with STC2 expression compared to patients without STC2 expression (P=0.014). Our results indicate that STC2 could be a useful molecular blood marker for predicting tumor progression by monitoring CTCs in patients with gastric cancer.

Expression of stanniocalcin 1 as a potential biomarker of gastric cancer.

Objective: We investigated stanniocalcin 1 (STC 1) expression to assess its clinical utility as a blood marker in patients with gastric cancer and evaluated its biological impact in terms of tumor aggressiveness. Methods: Blood specimens from 93 patients with gastric cancer and 21 normal healthy volunteers were assessed by quantitative reverse transcription-polymerase chain reaction for STC 1 mRNA expression. Results: The relative numbers of STC 1 mRNA copies were significantly higher in gastric cancer cell lines and in blood specimens from patients with gastric cancer than in blood specimens from healthy volunteers (p = 0.0001 and p = 0.003, respectively). The sensitivity and specificity of STC 1 mRNA expression for discriminating patients with gastric cancer from healthy volunteers were 69.9 and 71.4%, respectively. Furthermore, the sensitivity for STC 1 mRNA was higher than that for serum carcinoembryonic antigen and carbohydrate antigen 19-9. The presence of STC 1 expression was significantly correlated with depth of tumor invasion and tumor stage (p = 0.032 and p = 0.013, respectively). Conclusion: Our data strongly suggest that STC 1 is a potentially useful blood marker for predicting biological tumor aggressiveness in patients with gastric cancer.