Satoshi Ohtani

Expression of tight-junction-associated proteins in human gastric cancer: downregulation of claudin-4 correlates with tumor aggressiveness and survival

BackgroundClaudin, occludin, and zonula occludens (ZO)-1 are known as tight-junction-associated proteins. The aim of this study was to examine the expression of these proteins in gastric carcinoma.MethodsGastric cancer tissues (n = 124) were obtained from 124 patients who underwent gastrectomy at our hospital between January 2000 and December 2004. The expression of the above tight-junction-associated proteins in carcinoma, normal mucosa, and metaplastic epithelium was examined using immunohistochemistry. In addition, the expression of claudin-4 mRNA was examined in fresh frozen tissue obtained from 34 patients.ResultsSignificant correlations were seen between the expression of claudin-4, occludin, and ZO-1. In regard to claudin-4, significant correlations were seen between the expression of claudin-4 evaluated by immunohistochemistry and the expression of claudin-4 mRNA. Claudin-4 expression was significantly decreased in tumors with undifferentiated-type adenocarcinoma, advanced T stage, lymph node metastasis, and peritoneal metastasis. Occludin and ZO-1 expression was significantly decreased in tumors with undifferentiated-type adenocarcinoma. Overall survival was significantly shorter in patients with low claudin-4 expression. Cox multivariate analysis revealed that low claudin-4 expression was independently associated with significantly decreased overall survival.ConclusionTight-junction-associated proteins, particularly claudin-4, may play important roles in determining invasiveness, metastatic potential, and survival in gastric cancer.

Gene expression profiles in human gastric cancer: expression of maspin correlates with lymph node metastasis

To seek for a candidate gene that would regulate tumour progression and metastasis in gastric cancer, we investigated gene expression profiles by using DNA microarray. Tumour tissue and adjacent normal tissue were obtained from 21 patients with gastric cancer and then examined for their gene expression profiles by the Gene Chip® Human U95Av2 array, which includes 12 000 human genes and EST sequences. A total of 25 genes were upregulated and two genes were downregulated by at least four-fold in the tumour tissue. In a further analysis according to lymph node metastasis, the expressed levels of maspin, as well as carcinoembryonic antigen and nonspecific crossreacting antigen were significantly higher in tumours with lymph node metastasis than in those without it. Maspin expression in 85 gastric cancer patients was further investigated by using immunohistochemistry. Maspin expression was not observed in normal gastric epithelia without intestinal metaplasia. In contrast, maspin was expressed in 74 of 85 tumour tissues. There was a significant correlation between the incidence of maspin-positive tumour staining and lymph node metastasis. These results suggest that maspin has a potential role for tumour metastasis in gastric cancer.

Prediction of sensitivity to fluoropyrimidines by metabolic and target enzyme activities in gastric cancer

BackgroundThis study was designed to investigate the role of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and thymidine phosphorylase (TP) in tumor progression and sensitivity to 5-fluorouracil (5-FU).MethodsA total of 275 tumor samples from 275 patients with gastric cancer were utilized in this study. TS activity was determined in 130 samples by 5-fluorodeoxyuridine monophosphate binding assay. DPD activity was measured in 140 samples by radioenzymatic assay, and TP protein level was determined in 157 samples by an enzyme-linked immunosorbent assay (ELISA) system. These parameters were compared with several clinicopathologic factors and sensitivity to 5-FU determined by in-vitro ATP assay. The antitumor activities of 5-FU, uracil plus tegafur (UFT), and 1 M tegafur — 0.4 M 5-chloro-2,4-dihydroxypyridine — 1 M potassium oxonate (S-1 [TS-1®]) were also compared, using three human gastric cancer xenografts in nude mice.ResultsThere was no correlation between either TS or TP and sensitivity to 5-FU. However, a weak inverse correlation was found between DPD activity and sensitivity to 5-FU. High DPD activity in tumor resulted in poor prognosis, especially in patients who received 5-FU-based adjuvant chemotherapy. Although TP was significantly correlated with depth of tumor invasion and with lymphatic and venous invasions, TP alone had no impact on survival. On the other hand, TS, as well as peritoneal, hepatic, and lymph node metastases, was selected as an independent prognostic factor in gastric cancer. In the animal model, there was no significant difference in antitumor activities among the drugs in a tumor with low DPD activity. However, S-1 showed superior antitumor activity to 5-FU or UFT in tumors with high DPD activity.ConclusionDPD is considered to be a most important predictive factor of 5-FU sensitivity. The use of DPD inhibitory fluoropyrimidines is strongly recommended for tumors with high DPD activity.

Detection of cancer cells disseminated in bone marrow using real-time quantitative RT-PCR of CEA, CK19, and CK20 mRNA in patients with gastric cancer

BackgroundTo determine the significance of bone marrow disseminated tumor cells in gastric cancer, we investigated the mRNA expression levels of carcinoembryonic antigen (CEA), cytokeratin 19 (CK19), and cytokeratin 20 (CK20) using the real-time quantitative reverse-transcription polymerase chain reaction (RQ-PCR).MethodsBone marrow samples were aspirated from the sternum at the time of surgery in 65 patients with resectable gastric cancer. Total RNA was extracted from bone marrow; and the expression levels of CEA, CK19, and CK20 mRNA were determined by RQ-PCR using an ABI PRISM 7000 and quantified against the GAPDH mRNA level.ResultsThe detection limits of these genes were determined in the gastric cancer cell line MKN-45 and the colon cancer cell line C-1, which had been serially diluted in peripheral blood mononuclear cells (PBMCs). A rate of 1 cancer cell/million PBMCs was obtained by detecting CEA and CK19 mRNA in MKN-45 and by detecting CK20 mRNA in C-1. In the clinical samples, only 1 of the 65 gastric cancer patients (1.5%) who had stage IV disease was positive for CEA, CK19, and CK20 mRNA; none of CEA, CK19, or CK20 mRNA was positive in the remaining 64 patients. No significant correlation was observed between disseminated cancer cells in bone marrow and clinicopathological features, including simultaneous or metachronous hepatic metastasis and patient survival.ConclusionThe incidence of disseminated cancer cells in bone marrow in our study appears low, unlike that in previous reports. The significance of disseminated cancer cells in bone marrow may also be quite low in gastric cancer.

Prognostic role of immunosuppressive acidic protein in patients with esophageal cancer

Immunosuppressive acidic protein (IAP) suppresses several immune responses in vivo and in vitro , and high preoperative IAP levels could predict the impairment of the hosts immunity. In this study prognostic significance of preoperative IAP levels was investigated in 68 esophageal cancer patients with curative resection and eight with non-curative resection. The curative group had significantly lower levels than the non-curative group (432 +/- 183 mg/mL vs. 739 +/- 235 mg/mL, P < 0.0001). The IAP levels were associated with T-status (P < 0.0001), lymphatic invasion (P < 0.05), and p-stages (P < 0.0001). When 5-year survival rate of patients with curative resection was compared by setting various cutoff values of IAP between high and low IAP groups, several cutoff points (400-580 mg/mL) were revealed to be significantly associated with survival. Setting cutoff value of IAP to 560 mg/mL resulted in a most significant difference of 5-year survival rate of patients between the high and low IAP groups (13.9% and 61.5%, P < 0.0001). These data indicate that pre-operative IAP level is a useful parameter to predict the prognosis of esophageal cancer patients after curative resection.

A Case of Small Gastric Carcinoid Tumor with Lymph Node Metastasis-Usefullness of Sentinel Node Navigation Surgery-

症例は59歳の女性で, 健康診断の上部消化管内視鏡検査にて胃体中部大彎に約10mmの隆起性病変を指摘され, 生検にて胃カルチノイドと診断された. 血液検査では血清ガストリン値が2,069pg/mlと高値であった. 超音波内視鏡検査では粘膜下層までの浸潤が認められた. 胃カルチノイドの診断で手術を施行. 術中色素法によるセンチネルリンパ節 (sentinel node; 以下, SNと略記) 生検にて, SNがNo4dに2個同定され, 1個に転移が認められた. 幽門側胃切除術およびD2リンパ節郭清を施行した. 病理組織検査にて腫瘍は長径9mmで深達度がSM2であり, SNとして同定されたリンパ節以外にリンパ節転移は認めなかった. 胃粘膜に慢性萎縮像は認めなかった. 術後血清ガストリン値は正常化した. sm胃カルチノイドではsm胃癌と同等のリンパ節転移が認められることから, SN生検は術中の正確なリンパ節転移診断法として有用であると思われる.