Shuichi Hokita

Expression of Thymidine Phosphorylase in Human Gastric Carcinoma

The activity of thymidine phosphorylase (dThdPase) has heen reported to increase in several types of malignant tumors. Experimental evidence has shown that dThdPase is identical to platelet‐derived endothelial cell growth factor, and that dThdPase has angiogenic activity. We examined the expression of dThdPase to investigate whether the expression of dThdPase correlates with angiogenesis, clinicopathologic features and the prognosis of patients with human gastric carcinomas. Microvessels were assessed by immnnostaining endothelial cells for factor VIII. We counted microvessels in the tumors of 158 patients whose tumors were completely removed surgically. Microvessels were counted in a × 400 field in the most active areas of neovascularization. We purified a monoclonal antibody (TMA‐1) against dThdPase and studied the expression of dThdPase using TMA‐1 in the same serial sections as those used for the detection of factor VIII. The correlation between angiogenesis and dThdPase, and the clinicopathological significance of dThdPase, in patients with gastric carcinoma were examined. The positive expression of dThdPase was more frequent (P<0.001) in gastric carcinomas (67/158, 43.4%) than that in normal tissues (12/158, 7.6%). The average microvessel count in dThdPase‐positive gastric carcinomas was higher (P<0.001) than that in dThdPase‐negative carcinomas. The percentage of gastric carcinoma cells expressing dThdPase was significantly correlated with the microvessel count (P<0.001). Further, the average size of dThdPase‐positive carcinomas was significantly larger (P<0.001) than that of negative carcinomas and the mean microvessel count in dThdPase‐positive gastric carcinomas was also significantly higher (P<0.001) than that in dThdPase‐negative carcinomas. There was a significant correlation between the positive expression of dThdPase and microvessel count (P<0.001) or lymph node metastasis (P=0.013) by multivariate logistic analysis. Further, patients with dThdPase‐positive carcinoma showed a significantly worse prognosis than those with dThdPase‐negative carcinoma overall and in stage III. These findings indicate that the expression of dThdPase in gastric carcinomas is related to progression and metastasis, and this enzyme affects the prognosis of some patients with the disease.

Evaluation of sentinel node concept in gastric cancer based on lymph node micrometastasis determined by reverse transcription-polymerase chain reaction.

Objective:To determine the adequacy of sentinel node (SN) concept based on micrometastasis using immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR) in gastric cancer. Summary Background Data:The SN concept has recently been introduced in gastrointestinal tract cancers. The precise detection of lymph node metastasis including micrometastasis is important for SN navigation surgery. Methods:Sixty-one patients with gastric cancer who were preoperatively diagnosed with T1-T2 (cT1-T2) and N0 (cN0) were enrolled. They underwent standard radical gastrectomy with lymph node dissection. One day before surgery, 4 mCi of 99mTechnetium-tin colloid was endoscopically injected into the submucosa around the tumor. During surgery, radioisotope uptake in the lymph node was measured using Navigator GPS. All dissected lymph nodes were examined by RT-PCR in addition to hematoxylin and eosin staining and IHC. Results:Sentinel nodes were identified in all patients (100%). The incidences of metastasis determined by hematoxylin and eosin and IHC were 8.2% (5 of 61) and 13.1% (8 of 61), respectively. Micrometastases undetectable by IHC were identified in 14 patients (23.0%) by RT-PCR. Only 1 patient had micrometastasis detectable by RT-PCR in lymph nodes other than SN, but this patient had a cT2 tumor. In patients with cT1 and cN0 tumors, the false negative and accuracy rates were 0% and 100%, respectively. Conclusions:Although the incidence of micrometastasis detected by RT-PCR was quite high, SN navigation identified such metastasis in all patients except one. Thus, the SN concept was applicable to patients with cT1 and cN0 gastric cancer, even when micrometastasis was detectable by RT-PCR.

Detection and prediction of micrometastasis in the lymph nodes of patients with pN0 gastric cancer.

AbstractBackground:The clinicopathologic significance of micrometastasis (MM) and tumor cell microinvolvement (TCM) in regional lymph nodes as identified by immunohistochemical staining for cytokeratin expression was evaluated in patients with node-negative gastric cancer. Methods:MM was defined as tumor cells with stromal reaction, and TCM was defined as individual tumor cells without stromal reaction. We investigated 1761 lymph nodes obtained from 67 gastric cancer patients whose diagnosis showed no lymph node metastasis by routine histological examination. The depth of tumor invasion was T1 (submucosa) in 33 patients and T2 (muscularis propria and subserosa) in 34 patients. The lymph nodes were examined immunohistochemically for the presence of tumor cells using anti-cytokeratin AE1/AE3 monoclonal antibody. Both the biopsy tumor specimens obtained prior to surgery and the resected primary tumors were immunostained with E-cadherin (E-cad) monoclonal antibody. Results:Thirty (1.5%) of the 1761 lymph nodes showed MM and/or TCM. MM with or without TCM was found in 10 patients, and TCM alone was found in 4 patients; 6 (18.2%) of the 33 patients with T1 tumor and 8 (23.5%) of the 34 patients with T2 tumor had occult lymph node metastasis. The 5-year survival rate was worse among those with MM with or without TCM, than among those without MM. Nearly all of the patients with MM and/or TCM had reduced or negative E-cad expression in the primary tumor. Conclusions:We demonstrated that the incidence of MM and/or TCM in the lymph nodes of patients with gastric cancer is quite high, and that such metastasis is associated with the prognosis of patients with pN0. Examination of E-cad expression in biopsy tumor specimens may be useful for predicting MM and/or TCM.

Surgical Maneuvers Enhance Molecular Detection of Circulating Tumor Cells During Gastric Cancer Surgery

ObjectiveTo evaluate the relation between the presence of cancer cells in blood according to the time course during a surgical procedure and liver metastases in patients with gastric cancer. Summary Background DataSeveral studies have reported on the detection of circulating cancer cells in blood by reverse transcriptase–polymerase chain reaction (RT-PCR). However, few reports have examined the relation between molecular detection of circulating cancer cells according to the time course during a surgical procedure and blood-borne metastases. MethodsBlood samples from 57 patients with gastric cancer were obtained from the portal vein, peripheral artery, and superior vena cava before and after tumor dissection. After total RNA was extracted from each blood sample, carcinoembryonic antigen (CEA)-specific RT-PCR was performed. ResultsCEA-mRNA was detected in the blood of 21 (36.8%) of the 57 patients. CEA-mRNA was not detected in the blood obtained from 15 healthy volunteers and 15 patients with benign disease. The positive rate increased in proportion to the depth of tumor. The incidence of positive CEA-mRNA did not differ among the various sites of blood sampling. The appearance of circulating cancer cells was related to the surgical maneuver. A significant relation was found between the detection of CEA-mRNA and blood-borne metastases. ConclusionsA high incidence of positive CEA-mRNA was found in the blood during gastric cancer surgery. Surgical maneuvers are a possible cause of hematogenous metastasis. The authors found that patients with positive CEA-mRNA had a high risk of blood-borne metastasis even after curative resection.

Lymphatic invasion using D2-40 monoclonal antibody and its relationship to lymph node micrometastasis in pN0 gastric cancer

The monoclonal antibody D2-40 is a specific lymphatic endothelial markers and D2-40 staining have been applicable to evaluate lymphatic invasion in various malignant neoplasms. In the present study, we investigated lymph node micrometastasis determined by immunohistochemistry (IHC) and reverse transcription–polymerase chain reaction (RT–PCR) in all dissected lymph nodes obtained from 80 patients with node-negative gastric cancer, and analysed the relationship between micrometastasis and clinicopathological findings including lymphatic invasion of the resected primary tumour using D2-40 immunohistochemical staining. The incidence of micrometastasis determined by IHC and RT–PCR was 11.3% (nine out of 80) and 31.3% (25 out of 80), respectively. Although haematoxylin–eosin (HE) staining revealed lymphatic invasion in 11.3% (nine out of 80) of patients, D2-40 staining uncovered new invasion in 23.8% (19 out of 80) of patients. In the diagnosis of HE and D2-40 staining, the incidence of micrometastasis was significantly higher in patients with lymphatic invasion than in those without lymphatic invasion (P=0.0150 and P<0.0001, respectively). Micrometastasis correlated more closely with D2-40 than with HE staining. We demonstrated a high incidence of micrometastasis and lymphatic invasion and a correlation between them even in pN0 gastric cancer. When planning less invasive treatment, the presence of such occult cancer cells should be considered.

Clinical impact of intratumoral natural killer cell and dendritic cell infiltration in gastric cancer.

Intratumoral natural killer cells (NKC) and dendritic cells (DC) may affect the clinical features of various gastrointestinal cancers. However, the relationship between intratumoral NKC and DC remains unclear. We examined 169 patients with gastric cancer who underwent gastrectomy at Kagoshima University Hospital. Immunohistochemical staining of CD57 and S-100-protein was performed to evaluate NKC and DC infiltration, respectively. A total of 25 areas containing pericancerous tissue were selected for determining the number of NKC and DC under high power microscopy (x400). Patients were classified into two groups according to NKC and DC population. Intratumoral lymphocytic infiltration was also calculated in 15 areas with a high power (x400) objective. The degree of NKC and DC infiltration was gradually decreased according to the progression of nodal involvement. Patients with many NKC infiltration had a lower positivity of lymph node metastasis and lymphatic invasion than patients with little NKC infiltration. DC infiltration was also negatively correlated with depth of invasion, lymph node metastasis and curativity. DC infiltration was positively correlated with lymphocytic infiltration (P=0.01. r=0.6). The 5-year survival rates of patients with many NKC infiltration and patients with DC many infiltration were 75 and 78%, respectively, both of which were significantly better than that of patients with little NKC and DC infiltration (P<0.05). NKC may be activated without DC or intratumoral lymphocytes. Intratumoral NKC may act as an independent immunologic effector against tumor cells, unlike DC.

Detection of sentinel nodes and micrometastases using radioisotope navigation and immunohistochemistry in patients with gastric cancer

Patients with early gastric cancer may be treated by minimally invasive surgery. This study investigated the value of sentinel node (SN) navigation surgery, including detection of micrometastases, in patients with clinical (c) T1 and T2 gastric cancer.

Evaluation of colloid size for sentinel nodes detection using radioisotope in early gastric cancer

The purpose of this study was to investigate the relationship between colloid size and the detection of sentinel nodes (SN) in early gastric cancer. Three size of 99mTechnetium-tin colloids (500, 100 and 50 nm) were preoperatively injected into the submucosa under endoscopic control. Lymph node metastasis and micrometastasis was examined. RI-uptake in the hottest nodes and the total RI-uptake in the hot nodes were highest in the size of 100 nm. At least one lymph node metastasis, including micrometastasis, was included in the hot nodes. RI-labeled colloid size was one of the important factors to detect SN in early gastric cancer.

The comparison of the prognosis between Epstein-Barr virus (EBV)-positive gastric carcinomas and EBV-negative ones.

The relationship between the degree of lymphocytic infiltration into the tumor and the prognosis has not been completely evaluated between Epstein-Barr virus (EBV)-positive and -negative gastric carcinoma (GC). Although the average numbers and the grades of the infiltrating CD8+T cells, natural killer cells, dendritic cells, Ki67-positive cells were significantly greater in EBV-positive GCs than in -negative GCs, there was no significant survival improvement in EBV-positive group. These findings suggest that the infiltration of lymphocytes in the EBV-positive GC does not necessarily meant better prognosis and that the EBV status is not a significant prognostic factor in the patients with gastric cancer.

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.