Atsushi Miyoshi

Tumor-stromal cell interaction under hypoxia increases the invasiveness of pancreatic cancer cells through the hepatocyte growth factor/c-Met pathway.

The hypoxic environment in tumor is reported to play an important role in pancreatic cancer progression. The interaction between stromal and cancer cells also contributes to the malignant behavior of pancreatic cancer. In the present study, we investigated whether hypoxic stimulation affects stromal as well as pancreatic cancer cells. Our findings demonstrated that hypoxia remarkably elevated the HIF‐1α expression in both pancreatic cancer (PK8) and fibroblast cells (MRC5). Hypoxic stimulation accelerated the invasive activity of PK8 cells, and invasiveness was thus further accelerated when the hypoxic PK8 cells were cultured with conditioned medium prepared from hypoxic MRC5 cells (hypoxic conditioned medium). MMP‐2, MMP‐7, MT1‐MMP and c‐Met expressions were increased in PK8 cells under hypoxia. Hypoxic stimulation also increased the hepatocyte growth factor (HGF) secretion from MRC5 cells, which led to an elevation of c‐Met phosphorylation in PK8 cells. Conversely, the elevated cancer invasion, MMP activity and c‐Met phosphorylation of PK8 cells were reduced by the removal of HGF from hypoxic conditioned medium. In immunohistochemical study, the HIF‐1α expression was observed in surrounding stromal as well as pancreatic cancer cells, thus indicating hypoxia exists in both of cancer and stromal cells. Moreover, the stromal HGF expression was found to significantly correlate with not only the stromal HIF‐1α expression but also the c‐Met expression in cancer cells. These results indicate that the hypoxic environment within stromal as well as cancer cells activates the HGF/c‐Met system, thereby contributing to the aggressive invasive features of pancreatic cancer.

The Hypoxic Environment in Tumor-Stromal Cells Accelerates Pancreatic Cancer Progression via the Activation of Paracrine Hepatocyte Growth Factor/c-Met Signaling

BackgroundPancreatic cancer is one of the representative solid tumors, in which the hypoxic microenvironment plays a crucial role in malignant progression. We previously demonstrated that tumor-stromal interaction under hypoxia enhances the invasiveness of pancreatic cancer cells through hepatocyte growth factor (HGF)/c-Met signaling.MethodsWe investigated the immunohistochemical expression of hypoxia inducible factor-1α (HIF-1α) c-Met, and HGF in both cancer and stromal cells using 41 pancreatic cancer tissue specimens, and tried to identify any correlations with the clinical features and survival.ResultsPositive staining for HIF-1α was observed in both pancreatic cancer and the surrounding stromal cells in more than 30% of the cases, and it significantly correlated with lymph node metastasis (P < .05). A significant correlation was observed between the expression of HIF-1α and HGF in stromal cells (P < .05). In addition, the c-Met expression in cancer cells was found to significantly correlate with the HGF expression in not only cancer but also stromal cells. The disease-free survival rates of the patients with HIF-1α in cancer, stromal, c-Met in cancer, and an HGF expression in stromal cells was significantly worse than those without such expressions (P < .05).ConclusionsThese data suggest that the HGF/c-Met signaling via HIF-1α ?may therefore negatively affect the prognosis in patients with pancreatic cancer, and targeting tumor stroma under hypoxia might thus be potentially useful as a novel therapy for this cancer.

The significance of aberrant CHFR methylation for clinical response to microtubule inhibitors in gastric cancer

BackgroundWe studied the correlations between CHFR (checkpoint with FHA and RING finger) gene methylation and responses to microtubule inhibitors (MI) in gastric cancer.MethodsWe examined 9 gastric cancer cell lines and 46 gastric cancer specimens from patients who underwent surgical resection. Promoter methylation was determined by methylation-specific polymerase chain reaction (MSP). CHFR mRNA expression was estimated by quantitative reverse transcription–PCR. The MI-induced growth inhibition was assayed by a standard MTT method.ResultsCHFR expression was silenced by aberrant promoter methylation in 3 of 9 gastric cancer cell lines. The level of CHFR mRNA expression was closely correlated with IC50 in the MI-treated cells (R = 0.889, P = 0.005). In 46 patients with gastric cancers, 24 (52%) presented aberrant CHFR methylation. Among them, 12 patients had received treatment with MI because of advanced-stage tumor or tumor recurrence after surgery. The responders to the MI treatment were 29% in patients with CHFR methylation and 20% in those without the methylation. However, 6 (86%) of 7 patients with methylated CHFR tumor showed some regression or no progression, whereas 4 (80%) of 5 patients with unmethylated CHFR tumor manifested progressive deterioration.ConclusionsThese observations indicated that CHFR methylation may be a clinically useful approach to predict the responsiveness of gastric cancers to treatment with MI.

Tumor Progression Through Epigenetic Gene Silencing of O6−Methylguanine-DNA Methyltransferase in Human Biliary Tract Cancers

ABSTRACTBackgroundWe previously demonstrated in an immunohistochemical study that reduced expression of O6−methylguanine-DNA methyltransferase (MGMT) correlated with a poorer prognosis in patients with biliary tract cancers. The purpose of this study was to clarify how MGMT deficiency leads to a poor outcome in biliary tract cancer. Thus, we examined epigenetic (promoter methylation) and genetic (gene mutation) alterations in biliary tract cancer.MethodsWe examined 37 biliary tract cancer specimens from patients who underwent surgical resection. Promoter methylation was determined by one-step or two-step methylation-specific polymerase chain reaction. Gene mutation was identified by direct sequencing. The expression of MGMT protein in paraffin-embedded tissue was examined by immunohistochemistry.ResultsFrequencies of promoter methylation were 70% for p16/INK4a, 49% for MGMT, 46% for hMLH1, 41% for E-cadherin, and 32% for DAPK genes. MGMT methylation status was closely correlated with the MGMT protein expression determined by immunohistochemistry (P < .001). Although this was not statistically significant, biliary tract cancer tumors with MGMT methylation expressed multigene methylation more frequently than tumors without MGMT methylation (P = .071). A total of 33 mutations were identified in 4 cancer-related genes: p53, K-ras, β-catenin, and p16/INK4a genes. The most common mutation was GC to AT transitions (58%), which were significantly associated with MGMT promoter methylation (P = .011). These findings suggest that loss of MGMT expression by promoter methylation results in accumulation of GC to AT gene mutations.ConclusionsReduced MGMT expression may increase the malignant potential of biliary tract cancer through both epigenetic and genetic mechanisms.

Prediction of postoperative complications in elderly patients with hepatocellular carcinoma

BACKGROUND The aim of the present study was to investigate whether advanced age was associated with a higher rate of postoperative complications and identify the predictive factors for postoperative complications in elderly patients with hepatocellular carcinoma (HCC). METHODS Between January 2000 and December 2010, 256 patients who underwent hepatectomy for HCC were investigated. Elderly patients were defined as those aged ≥75 y. The clinicopathologic data and outcomes after hepatectomy for 64 elderly and 192 younger patients were retrospectively collected and compared. RESULTS There were no significant differences in the incidence of postoperative complications (P = 0.936) or the long-term survival after hepatectomy (P = 0.641) between the elderly and younger patients. In multivariate analysis, the estimation of physiological ability and surgical stress-preoperative risk score (PRS) was an independent risk factor for postoperative morbidity in the elderly patients (P < 0.01). Moreover, the patients were analyzed according to the PRS for the assessment of their general preoperative condition and liver damage grade based on the hepatic reserve. The rate of postoperative complications in the patients with a PRS ≥0.5 and liver damage B was significantly higher in the elderly patients (P < 0.01), whereas a PRS and liver damage grade did not affect the incidence of postoperative morbidity in the younger patients (P = 0.516). CONCLUSIONS Hepatectomy for elderly patients with HCC is feasible as well as safe, and the preoperative assessment using the estimation of physiological ability and surgical stress scoring system, combined with the liver damage grade, can help to improve the safety of this procedure for elderly HCC patients.

Hepatoid carcinoma of the pancreas penetrating into the gastric cavity: A case report and literature review

A 79‐year‐old Japanese woman was admitted to our hospital for treatment of a pancreatic tumor measuring approximately 7 × 5 cm. The tumor had invaded the left adrenal gland and gastric wall and had penetrated into the gastric cavity. Surgical resection was performed. The tumor was composed of a brown to whitish solid area and a zone of hemorrhage, necrosis, and cystic degeneration resembling the gross features of solid pseudopapillary tumor (SPT). Histologically, the tumor showed a heterogeneous growth pattern with a combination of seat‐like, trabecular, papillary and hemorrhagic‐necrotic areas in various proportions. The differential diagnoses first considered were acinar cell carcinoma, neuroendocrine carcinoma and SPT with malignant transformation. Immunohistochemistry showed tumor cells were negative for pancreatic exocrine enzymes and endocrine markers. Tumor cells diffusely expressed cytokeratin 19, alpha‐fetoprotein, carcinoembryonic antigen and glypican‐3, but lacked vimentin or β‐catenin expression. Small proportions of tumor cells expressed hepatocyte paraffin‐1. Although typical morphological features of well‐differentiated hepatocellular carcinoma (HCC) were not distinctly apparent, the tumor morphology partly resembled poorly differentiated HCC. Given these findings and considerations, the tumor was finally diagnosed as poorly differentiated hepatoid carcinoma of the pancreas.

Clinicopathologic features of advanced gallbladder cancer associated with adenomyomatosis

Adenomyomatosis of the gallbladder has not been considered to have malignant potential, but gross features of adenomyomatosis are sometimes encountered in gallbladders resected under a diagnosis of gallbladder carcinoma. The purpose of this study was to determine the clinicopathologic features and survival rates in cases of gallbladder cancer with gross features of adenomyomatosis. The study subjects were 97 surgically treated gallbladder carcinoma patients. Only gallbladder showing typical gross features of adenomyomatosis was judged as adenomyomatosis-positive gallbladder cancer. In terms of gross findings, 25 cases (25.8%) were classified as adenomyomatosis-positive. The status of adenomyomatosis was significantly associated with the T stage (P = 0.0004), lymph node (LN) metastasis (P < 0.0001), distant metastasis (P = 0.008), and stage (P = 0.0005). In the adenomyomatosis-positive group, 16 of the 25 cases (64.0%) were classified as segmental type and 9 cases (36.0%) were classified as fundal type. No diffuse-type cases were present in this series. The status of adenomyomatosis correlated significantly with survival (P = 0.0007). However, the multivariate analysis of significant variables identified from the univariate analysis identified only T stage (P = 0.0178) and LN metastasis (P = 0.0048) as independent prognostic factors. Subset analysis with T stage according to the status of adenomyomatosis showed no significant impact on survival. These results indicate that adenomyomatosis-positive gallbladder cancer is more often diagnosed clinically in the advanced stages. Since preceding adenomyomatosis may prevent the early detection of gallbladder cancer, the usefulness of preventive cholecystectomy in cases of asymptomatic adenomyomatosis should be considered.

Percutaneous Transhepatic Portal Embolization for Persistent Bile Leakage After Hepatic Resection : Report of a Case

Bile leakage is a relatively common complication after hepatic resection. We report a case of intractable bile leakage after hepatectomy, which was successfully treated by percutaneous transhepatic portal embolization (PTPE). A 58-year-old Japanese man underwent anterior resection of the rectum followed by central bisegmentectomy of the liver (S4 + S5 + S8) for rectal cancer with liver metastasis. Bile leakage from the cut surface of the posterior segment developed on postoperative day 2. Conservative management with simple drainage and ethanol injections into the fistula proved ineffective. Thus, we performed PTPE in the posterior portal branch to eliminate the production of bile from the posterior segment and to block the enterohepatic circulation to that segment. His post-treatment course was uneventful and the bile leakage resolved immediately.

Improvement of glucose metabolism after a pancreatoduodenectomy.

Objectives: The aim of this study was to investigate the mechanisms of the change in glucose metabolism after a pancreatoduodenectomy (PD). Methods: Oral glucose tolerance tests were performed in 17 patients before and 1 month after a PD. The changes in plasma glucose and insulin concentrations, homeostasis model of insulin resistance, and insulinogenic index (&bgr;-cell function) were analyzed. Two additional factors, gastric emptying function and plasma glucagon-like peptide-1 (GLP-1) concentration, that possibly affect perioperative glucose metabolism were also assessed. Results: The plasma glucose and insulin concentrations were significantly lower after the operation, especially in preoperative diabetic patients. &bgr;-Cell function did not change after the operation. On the other hand, insulin resistance became normal 1 month after the operation. The value of gastric emptying function after the operation was not statistically different in comparison with that before the operation. Postoperative plasma GLP-1 concentration was significantly higher than the preoperative value. Conclusions: &bgr;-Cell function is maintained after a PD, whereas the improvement of insulin resistance may cause a short-term transient improvement of the glucose metabolism after the operation. The significance of increased postoperative GLP-1 concentration remains an unsolved issue.

A case of unclassified multicystic biliary tumor with biliary adenofibroma features.

A 40‐year‐old Japanese man was admitted to our hospital for evaluation of upper abdominal pain. Abdominal computed tomography (CT) revealed a well‐circumscribed multicystic mass measuring approximately 7 × 6 cm. The mass contained a solid lesion measuring 3 × 2 cm. Biopsy of a swollen cervical lymph node led to a diagnosis of diffuse large B‐cell lymphoma. After initial chemotherapy for lymphoma, the multicystic mass was surgically resected. The tumor was composed of a multicystic lesion and a solid lesion. Histopathologic examination of the multicystic lesion revealed that the locules were lined by biliary epithelium, demonstrating various degrees of cytological atypia. The stroma was fibrous, and the tumor showed marked apocrine snouts. Part of the tumor showed papillary growth with strong cytological atypia. The solid lesion showed tubulocystic proliferation of tumor cells, with prominent apocrine snouts, embedded in dense and partially hyalinized fibrous stroma. The morphology of the solid part was quite similar to that of reported biliary adenofibroma. Despite lengthy discussion, an appropriate pathological diagnosis could not be found among the current classifications of biliary tumor. The tumor was finally diagnosed as unclassified multicystic biliary tumor with adenofibroma features.