Hyalinized stroma is a characteristic feature of pancreatic intraductal oncocytic papillary neoplasm: An immunohistochemical study.

Hyalinized stroma (HS) is a dense, eosinophilic, and amorphous extracellular material in the stroma. HS is observed in several tumors; however, it has not been comprehensively studied in pancreatic intraductal papillary mucinous neoplasm (IPMN) or intraductal oncocytic papillary neoplasm (IOPN). Here, we aimed to evaluate the immunohistochemical and microscopic characteristics of HS in IPMN and IOPN. The prevalence of HS was determined in 168 cases of IPMN, including intestinal type (IPMN-I), gastric type (IPMN-G), and pancreatobiliary type (IPMN-PB), as well as in 11 cases of IOPN. Immunohistochemical staining for laminin and collagen (types I, II, III, IV, and V), as well as Congo red staining were performed in IPMN and IOPN cases containing HS. The prevalence of HS among the IPMN and IOPN specimens was 1.2% (2/168 cases) and 45.5% (5/11 cases), respectively. The prevalence rates of HS in each IPMN subtype were as follows: 2.2% (2/91 cases) in IPMN-G, and 0% in IPMN-PB and IPMN-I. All seven HS cases were positive for collagen I, III, IV, and V but were negative for Congo red staining. Most cases showed negative, focal, or weak expression of laminin and type II collagen. These findings indicate that HS is associated with IOPN and is primarily composed of collagen fibers.

Cancer-associated fibroblasts are a useful cytological finding for diagnosing pancreatic ductal adenocarcinoma.

INTRODUCTION: Cancer-associated fibroblasts (CAFs) are activated fibroblasts or myofibroblasts that play a crucial role in the invasiveness of pancreatic ductal adenocarcinoma (PDAC). In this study, the cytological features and diagnostic significance of CAFs based on pancreatic duct brushing cytology (PDBC) were evaluated. METHODS: The prevalence of fibrous stroma (FS) including CAFs on PDBC in 42 PDAC cases and 33 benign cases was retrospectively investigated. The average nuclear size of fibroblasts was compared between PDAC and benign cases to distinguish CAFs from normal FS. RESULTS: Overall, FS was observed in 25 PDAC cases (60%) and eight benign cases (24%). The average nuclear size of FS in PDAC cases was significantly larger than that in benign cases. From the receiver operating characteristics analysis, the cut-off value of the nuclear size of FS for the diagnosis of PDAC was defined as 10.22 µm. FS with nuclei over 10.22 µm in size in PDAC cases had clear prominent nucleoli. In contrast, FS in benign cases had no clear nucleoli. Thus, CAFs on PDBC were considered to be FS with nuclei over 10.22 µm in size and prominent nucleoli. The presence of CAFs on PDBC had 100% positive predictive value and specificity for the diagnosis of PDAC. CONCLUSIONS: This study suggested that CAFs on PDBC could be distinguished from normal FS by large nuclear size (over 10.22 µm) and prominent nucleoli and that CAFs on PDBC may be used for the diagnosis of PDAC.

Fatty Acid ß-Oxidation-dependent and -independent Responses and Tumor Aggressiveness Acquired Under Mild Hypoxia.

BACKGROUND/AIM: The present study assessed whether and how tumor cells undergoing hypoxia contribute to disease progression after moving to areas with different oxygen conditions. MATERIALS AND METHODS: Human colorectal carcinoma HCT116 cells cultured under mild hypoxia were subjected to in vivo experiments using transfer to immunodeficient murine recipients and to in vitro experiments using pharmacological inhibition of fatty acid ß-oxidation (FAO). RESULTS: Bone involvement and hepatic metastases were accelerated in transfer models of hypoxically cultured HCT116 cells. Hypoxic HCT116 cells exhibited FAO-dependent glycogen synthesis. FAO-dependent and -independent induction of gene expression also occurred under hypoxia. The distribution of glucose transporter 1 expression compared with heme oxygenase 1 expression in HCT116 cell spheroids seemed consistent with differential dependence of hypoxic expression of these molecules on FAO. CONCLUSION: These results provide insights into the contribution of hypoxia to tumor progression and the relevance of FAO.

The cytostatic effects of lovastatin on ACC-MESO-1 cells.

BACKGROUND: Malignant pleural mesothelioma is known to be widely resistant to therapy, and new treatment strategies are needed. Statins are small molecules that suppress the production of multiple hydrophobic substrates in the mevalonate pathway. Although still controversial, statins may decrease the risk of certain cancers such as colon cancer, lung cancer, and prostate cancer. Since the evaluations of the direct effect of statins on malignant mesothelioma are still few, the present study was done to evaluate the effects of lovastatin on ACC-MESO-1 cells in vivo and to investigate the potential mechanisms involved in vitro. MATERIALS AND METHODS: The in vivo effect of lovastatin was evaluated using an NOD/SCID/γnull (NOG) mouse model of human malignant mesothelioma using ACC-MESO-1 cells. Lovastatin was also applied to ACC-MESO-1 cells in vitro and the effects were observed. RESULTS: Lovastatin administration reduced primary tumor and metastasis in the NOG mouse model of human malignant mesothelioma. In vitro studies showed that lovastatin administration induced cytostatic effects as per reduced cell viability and cell migration in ACC-MESO-1 cells. These effects were suggested to be dependent on autophagic changes rather than apoptosis. Furthermore, induction of autophagic changes by lovastatin in ACC-MESO-1 cells was independent of mTOR, and was considered to be dependent at least in part on Rac/phospholipase C/ inositol 1,4,5-triphosphate axis. CONCLUSIONS: These results suggest that it may be possible to utilize statins, or other pharmacological agents that are known to induce mTOR-independent autophagy, as an adjunct to standard treatments in malignant mesothelioma.

Lovastatin and valproic acid additively attenuate cell invasion in ACC-MESO-1 cells.

Malignant pleural mesothelioma is known to be widely resistant to therapy and new treatment strategies are needed. Both statins and valproic acid are known to suppress the growth of multiple cancer lines, but the effects on mesothelioma cells are not well defined. In the present study we examined the effects of lovastatin and valproic acid on ACC-MESO-1, which is a human derived mesothelioma cell line. We found that lovastatin (2 µM) and/or valproic acid (5 mM) did not reduce cell viability nor induce apoptosis, but reduced cell invasion. The effect was additive when combined. Furthermore it was speculated that induction of autophagic changes was at least in part involved in this process.

Fine needle aspiration cytology of ductal adenoma of the breast with intracellular mucin: a report of three cases.

BACKGROUND: Ductal adenoma of the breast is a benign lesion that can mimic both the clinical and cytopathologic features of carcinoma. Benign breast lesions with intracellular mucin are extremely rare, and ductal adenoma with intracellular mucin has not previously been reported. Here we present three cases of ductal adenoma of the breast with foci of intracellular mucin. CASES: Three patients were admitted to Tokai University School of Medicine Hospital and underwent fine needle aspiration cytology and histologic examination by excisional biopsy or partial resection. Fine needle aspiration cytology was performed using a 23-gauge needle, and smears were immediately fixed in ethanol and stained as Papanicolaou preparations. Epithelial cells formed cohesive clusters, consisting of biphasic luminal and myoepithelial cells accompanied by apocrine metaplasia with occasional high nuclear atypia. All three cases showed intracellular mucin, in varying amounts, which led to their being overdiagnosed as malignant lesions. CONCLUSION: To avoid overdiagnosis of ductal adenomas as malignant lesions, it is important to recognize that both intracytoplasmic mucin and atypical apocrine features can be usual cytologic findings of this disease.

Evaluation of HER2 gene amplification in invasive breast cancer using a dual-color chromogenic in situ hybridization (dual CISH).

Fluorescence in situ hybridization (FISH) assay is considered the 'gold standard' for evaluation of HER2/neu (HER2) gene status, however, it is difficult to recognize morphologic features of tumors using fluorescence microscopy. Thus, chromogenic in situ hybridization (CISH) has been proposed as an alternative method to evaluate HER2 gene amplification. Here, we examined the dual color CISH (dual CISH) method which provides information regarding the copy number of the HER2 gene and chromosome 17 centromere from a single slide. We examined 40 cases of invasive ductal carcinomas of the breast that were resected surgically. HER2 gene status was assessed with FISH (Abbott) and dual CISH (Dako). HER2 gene amplification status was classified according to the guidelines of the American Society of Clinical Oncology and College of American Pathologists (ASCO/CAP). Comparison of the cut-off values for HER2/chromosome 17 centromere copy number ratio obtained by dual CISH and FISH showed that there was almost perfect agreement between two methods (Kappa coefficient 0.96). The results of the two commercial products were almost consistent for evaluation of HER2 gene counts on the sections. The current study proved that dual CISH is comparable with FISH for evaluating HER2 gene status.

First case of primary phyllodes tumor of the pancreas: case report and findings of immunohistochemical and ultrastructural studies.

A 37-year-old Japanese man with a solid and cystic pancreatic mass was referred to our hospital. Computed tomography revealed a well-demarcated solid and cystic mass measuring approximately 3.0 cm in diameter in the pancreatic body. The patient underwent middle segment pancreatectomy, and the retrieved tumor specimen was found to be a well-demarcated solid and cystic lesion measuring 3.0 x 3.0 cm. On histological examination, the cyst walls were found to be lined with a monolayer of non-atypical tall columnar epithelial cells. The solid areas surrounded the cystic ones and showed storiform proliferation of spindle cells that contained round, oval, or elongated nuclei and were present among abundant collagen fibers. The solid areas sent phylloid projections into the cystic spaces and the main pancreatic duct. The spindle cells were found to be diffusely positive for alpha-smooth muscle actin, desmin, and h-caldesmon on immunohistochemical analysis. Electron microscopy revealed that these cells possessed well-developed myofilaments with dense bodies, pinocytic vesicles, and basal lumina. Neither metastasis nor local invasion was detected. After the operation (4 years), tumor recurrence has not occurred. The main differential diagnoses of spindle cell tumors are leiomyomas, leiomyosarcomas, inflammatory myofibroblastic tumors, solitary fibrous tumors, extra-gastrointestinal stromal tumors, and schwannomas. However, the histological findings in the present case differed from those of these tumors. The present lesion is the first reported case of a primary pancreatic phyllodes tumor.

Variation of alpha-methylacyl-CoA racemase expression in prostate adenocarcinoma cases receiving hormonal therapy.

alpha-methylacyl-CoA racemase (AMACR) is widely used as a diagnostic marker of prostate adenocarcinoma. It is also used to identify residual adenocarcinoma cells in posthormonal therapy cases. However, there have been very few studies on the relationship between hormonal therapy, which is also called androgen withdrawal therapy and AMACR expression. Here, we carried out a study on AMACR expression in paired pre- and posthormonal therapy prostate adenocarcinoma cases using an immunohistochemical method and a digital imaging system to elucidate the relationship between AMACR expression and hormonal therapy. This study showed that AMACR expression was decreased in 65 of 98 paired cases after hormonal therapy (Mann-Whitney U test, P < .05). Wilcoxon analysis also demonstrated a difference in the AMACR digital average expression in all 98 cases (P < .0001). However, this variation in AMACR expression did not seem to have any relevance to the response to hormonal therapy (P = .5386). We propose that AMACR, as a diagnostic marker, should be carefully used in posthormonal therapy cases. Further investigation of the relationship between AMACR expression and androgen or androgen receptors may provide new insight into novel preventive and curative medicine for prostate adenocarcinoma.

Immunohistochemical evaluation of hormone receptors in breast cancer: which scoring system is suitable for highly sensitive procedures?

To evaluate hormone receptors immunohistochemically, standardized staining procedures and scoring systems are required. The authors previously reported that highly sensitive procedures affected basic factors for technical validation. The aim of the present study was to show the characteristics of scoring systems for highly sensitive procedures. To examine how highly sensitive procedures enhance the staining intensity and increase the positive cell population, two different staining methods were compared. To evaluate scoring systems, three systems--cell counting score, modified immunoreactive score, and H score--were compared using the same samples stained by an autostaining system. It was found that the highly sensitive procedure increased the positive cell population, especially in breast cancers with a low enzyme immunoassay (EIA) level of less than 100 fmol/mg, and strengthened the staining intensity. This enhancement led to a correlation in a logarithmic curve rather than a linear correlation by all three scoring systems. The results showed that scoring systems including a factor of staining intensity did not have an absolute advantage because boosted staining intensity by highly sensitive procedure did not reflect EIA value or protein contents accurately. To the authors' knowledge, there is no report discussing the nonlinear correlation between biochemical and immunohistochemical assay by highly sensitive procedures; however, it is important to select a scoring system and threshold based on nonlinear correlation.

Vascular networks and endothelial cells in the rat experimental pituitary glands and in the human pituitary adenomas.

There has been considerable interest in the relationship between hormone-secreting endocrine cells (HSEC) and their microvessels (MVN) in human pituitary gland. However, microcirculatory networks have rarely been studied in three dimensions (3D). Therefore, this study was designed to visualize and to reveal the relationship between hormone secreting endocrine cells and their microvessel environment including vascular endothelial cells in 3D using rat pituitary glands under various experimental conditions by confocal laser scanning microscopy (CLSM). By CLSM, the 3D distributions of MVN were visualized and revealed a relationship between HSEC and MVN in experimental pituitary glands and human pituitary adenomas. Therefore, 3D reconstructed imaging by CLSM is a useful technique with which to investigate the microvessel environment of hormone-secreting cells and has the potential to reveal dynamic hormone-secreting pathways.