Atsuko Kasajima

Differential expression of histone deacetylases HDAC1, 2 and 3 in human breast cancer - overexpression of HDAC2 and HDAC3 is associated with clinicopathological indicators of disease progression

BackgroundIn breast cancer, the role of epigenetic alterations including modifications of the acetylation status of histones in carcinogenesis has been an important research focus during the last years. An increased deacetylation of histones leads to increased cell proliferation, cell migration, angiogenesis and invasion. Class 1 histone deacetylases (HDAC) seem to be most important during carcinogenesis.MethodsThe immunhistochemical expression of HDAC1, 2 and 3 was analyzed on tissue microarrays (TMAs) from 238 patients with primary breast cancer. We analyzed the nuclear staining intensity (negative, weak, moderate, strong) as well as the percentage of positive tumor cells and calculated the immunoreactivity score (0–12). Expression was correlated with clinicopathological parameters and patient survival.ResultsIn this cohort, we found a differential positive expression of HDAC1, HDAC2 and HDAC3. HDAC2 and HDAC3 expression was significantly higher in less differentiated tumors: HDAC2 (n=207), p<0.001 and HDAC3 (n=220), p<0.001 and correlated with negative hormone receptor status: HDAC2 (n=206), p=0.02 and HDAC3 (n=219), p=0.04. Additionally, a high HDAC2 expression was significantly associated with an overexpression of HER2 (n=203, p=0.005) and the presence of nodal metastasis (n=200, p=0.04).HDAC1 was highly expressed in hormone receptor positive tumors (n=203; p<0.001).ConclusionAs a conclusion, our results show that the class-1 HDAC isoenzymes 1, 2 and 3 are differentially expressed in breast cancer. HDAC2 and HDAC3 are strongly expressed in subgroups of tumor with features of a more aggressive tumor type.

Molecular mechanism of histamine clearance by primary human astrocytes

Histamine clearance is an essential process for avoiding excessive histaminergic neuronal activity. Previous studies using rodents revealed the predominant role of astrocytes in brain histamine clearance. However, the molecular mechanism of histamine clearance has remained unclear. We detected histamine N‐methyltransferase (HNMT), a histamine‐metabolizing enzyme, in primary human astrocytes and the astrocytes of human brain specimens. Immunocytochemical analysis and subcellular fractionation assays revealed that active HNMT localized to the cytosol, suggesting that histamine transport into the cytosol is crucial for histamine inactivation. We showed that primary human astrocytes transported histamine in a time‐dependent manner. Kinetics analysis showed that two low‐affinity transporters were involved in histamine transport. Histamine uptake by primary human astrocytes was not dependent on the extracellular Na+/Cl− concentration. Histamine is reported to be a substrate for three low‐affinity and Na+/Cl−‐independent transporters: organic cation transporter 2 (OCT2), OCT3, and plasma membrane monoamine transporter (PMAT). RT‐PCR analysis revealed that OCT3 and PMAT were expressed in primary human astrocytes. Immunohistochemistry confirmed OCT3 and PMAT expression in the astrocytes of human brain specimens. Drug inhibition assays and gene knockdown assays revealed the major contribution of PMAT and the minor contribution of OCT3 to histamine transport. The present study demonstrates for the first time that the molecular mechanism of histamine clearance is by primary human astrocytes. These findings might indicate that PMAT, OCT3 and HNMT in human astrocytes play a role in the regulation of extraneuronal histamine concentration and the activities of histaminergic neurons.

New trends of immunohistochemistry for making differential diagnosis of breast lesions

Immunohistochemistry is widely used for pathological diagnosis of breast lesions. Other than hormone receptors and HER2/neu analysis for primary breast carcinomas, several markers may be useful for differential diagnoses, although in limited situations. To decide the malignant potential of intraductal proliferative lesions, analysis for the staining pattern of cytokeratins may be a good reference. Most ductal carcinoma in situ cases are diffusely positive for luminal cell markers (CK8, CK18, CK19), but negative for basal cell markers (CK5/6 and CK14). However, usual ductal hyperplasia may show the mosaic staining patterns for any of these markers, which may indicate a heterogeneous cell population in benign lesions. Myoepithelial markers (α-SMA, myosin, calponin, p63, CD10) are almost consistently positive for benign papillomas but they do not completely distinguish intraductal papillary carcinomas. Preservation of myoepithelial layer is the diagnostic key when looking at benign sclerosing lesions, including carcinoma with pseudoinvasive structures. E-cadherin is mostly positive for ductal carcinomas but negative for lobular carcinomas. Some of the lobular carcinomas are positive for 34βE12, but they are consistently negative for CK5/6. Comparison with histopathological findings of hematoxylin and eosin is essential to make proper diagnosis in the individual case.

The usefulness of endoscopic ultrasound-guided fine-needle aspiration for the diagnosis of pancreatic neuroendocrine tumors based on the World Health Organization classification

Abstract Background. We assessed the controversial topic of using 22-gauge needles in endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) for the diagnosis and evaluation of Ki67 labeling indices (Ki67LI) of pancreatic neuroendocrine tumors (pNET). Methods. Thirty-eight patients with pNET who underwent EUS-FNA between January 1, 2008 and December 31, 2012 were enrolled in this study. When available, the Ki67LI and WHO classifications obtained by EUS-FNA and surgical resection were compared. Results. EUS-FNA with a 22-gauge needle acquired sufficient histological sample to correctly diagnose pNET in 35 cases (92.1%). Both EUS-FNA and surgical histological specimens were available for 19 cases, and grading classes of the 2 procedures were consistent in 17 cases (89.5%) according to the WHO classification based on the Ki67LI. Tumor size was associated with a difference in the Ki67LI between the 2 procedures, although the Ki67LI was almost completely consistent for tumors less than 18 mm in size. Conclusions. EUS-FNA with a 22-gauge needle is a safe and highly accurate technique for the diagnosis of pNET. There was a clear correlation between the Ki67LI of histological specimens acquired by EUS-FNA and surgery. EUS-FNA with a 22-gauge needle is useful to predict the WHO classification of pNET.

3β-hydroxysteroid dehydrogenase isoforms in human aldosterone-producing adenoma

It has become important to evaluate the possible involvement of 3β-hydroxysteroid dehydrogenase type 1 (HSD3B1) and 2 (HSD3B2) isoforms in aldosterone-producing adenoma (APA). In this study, we studied 67 and 100 APA cases using real-time quantitative PCR (qPCR) and immunohistochemistry, respectively. Results of qPCR analysis demonstrated that HSD3B2 mRNA was significantly more abundant than HSD3B1 mRNA (P < 0.0001), but only HSD3B1 mRNA significantly correlated with CYP11B2 (aldosterone synthase) mRNA (P <0.0001) and plasma aldosterone concentration (PAC) of the patients (P <0.0001). Results of immunohistochemistry subsequently revealed that HSD3B2 immunoreactivity was detected in the great majority of APA but a significant correlation was also detected between HSD3B1 and CYP11B2 (P <0.0001). In KCNJ5 mutated APA, CYP11B2 mRNA (P <0.0001) and HSD3B1 mRNA (P = 0.011) were significantly higher than those of wild type APA. These results suggest that HSD3B1 is involved in aldosterone production, despite its lower levels of expression compared with HSD3B2, and also possibly associated with KCNJ5 mutation in APA.

Validation of the Histologic Grading for Ovarian Clear Cell Adenocarcinoma: A Retrospective Multi-institutional Study by the Japan Clear Cell Carcinoma Study Group

Pathologic slides from 150 patients with clear cell adenocarcinoma from the collaborating institutions were reviewed independently by 2 pathologists, and each tumor was graded histologically using the Shimizu-Silverberg and International Federation of Gynecology and Obstetrics (FIGO) grading systems. For the Shimizu-Silverberg grading system, 3 parameters—architectural pattern, nuclear pleomorphism, and mitotic activity—were assessed and scored as 1 to 3. When the summed scores of these parameters were 3 to 5, 6 to 7, and 8 to 9, grades 1, 2, and 3 were assigned, respectively. The FIGO grade was based on the ratio of glandular/papillary growth versus solid growth: grade 1, less than 5% solid tumor; grade 2, 5% to 50% solid tumor; grade 3, greater than 50% solid tumor. Interobserver agreement levels for assignment of both gradings were fair (&kgr;=0.32 and 0.24, respectively). After consensus had been acquired, 82 (55%), 56 (37%), and 12 (8%) tumors were classified as grades 1, 2, and 3 by the Shimizu-Silverberg grading system, and 88 (59%), 38 (25%), and 24 (16%) were classified as grades 1, 2, and 3 by the FIGO grading system, respectively. Survival analyses indicated that patients with grade 3 tumors, as defined by both the grading systems, tended to have a poor outcome, but any differences between them were not statistically significant. Multivariate analysis showed that only the presence of residual tumor after initial surgery was an independent prognostic factor for overall survival. These results suggest that the 2 tested grading systems have limited value for the prognostication of patients with clear cell adenocarcinoma, and that a more effective grading system for this tumor may be required.

Renal epithelioid angiomyolipoma with malignant features: Histological evaluation and novel immunohistochemical findings.

Renal epithelioid angiomyolipoma (EAML) is a potentially malignant tumor type whose characteristics and biomarkers predictive of malignant behavior have not been elucidated. Here, we report three cases of renal EAML with malignant features but without histories of tuberous sclerosis complex. Case 1 involved a 29‐year‐old man with a 12‐cm solid mass in the right kidney who underwent radical right nephrectomy. Case 2 involved a 22‐year‐old woman with a retroperitoneal mass who underwent radical right nephrectomy and retroperitoneal tumorectomy. Local recurrence was detected 7 years post‐surgery. Case 3 involved a 23‐year‐old man with a 14‐cm solid mass in the left kidney who underwent radical left nephrectomy. Microscopically, the tumors in all cases demonstrated proliferation of epithelioid cells with atypia, mitotic activity, necrosis, hemorrhage, and vascular invasion. Epithelioid cells in all cases were immunohistochemically positive for melanocytic and myoid markers and weakly positive for E‐cadherin and β‐catenin. Immunohistochemistry revealed activation of the mammalian target of rapamycin pathway. Here, we report the morphological and immunohistochemical features of clinically or histologically malignant renal EAML.

The expression and function of histamine H3 receptors in pancreatic beta cells

Histamine and its receptors in the CNS play important roles in energy homeostasis. Here, we have investigated the expression and role of histamine receptors in pancreatic beta cells, which secrete insulin.

The prognostic significance of vasohibin 1-associated angiogenesis in patients with hepatocellular carcinoma ☆

Vasohibin 1, an endothelium-derived negative feedback regulator of angiogenesis, is induced by fibroblast growth factor 2 (FGF-2) and vascular endothelial growth factor A (VEGF-A). In this study, we retrospectively evaluated immunoreactivity of FGF-2 and VEGF-A as well as microvessel density (MVD) determined by expression of vasohibin 1 and CD34 (MVD-CD34) and correlated the findings with clinical outcomes of 181 patients with hepatocellular carcinoma (HCC). Double immunostaining of an endothelial marker CD34 and vasohibin 1 with Ki-67 was also performed to assess angiogenic activity of endothelial cells in HCC. The ratio of Ki-67-positive endothelial cells in vasohibin 1-positive vessels (22%) was significantly higher than that of CD34-positive vessels (9%, P < .001), suggesting the correlation between vasohibin 1 and neovascularization in endothelial cells of HCC. MVD-CD34 decreased, but the ratio of MVD determined by expression of vasohibin 1 to MVD-CD34 (vasohibin 1/CD34) increased significantly according to histologic grade. Vasohibin 1 was significantly correlated with the status of FGF-2 (P = .007) but not with that of VEGF-A (P = .055). The 10-year overall survival and the 2-year disease-free survival rates of the low vasohibin 1/CD34 group (vasohibin 1/CD34 ≤0.459) were significantly higher than those of the high vasohibin 1/CD34 group (vasohibin 1/CD34 >0.459) (survival, 48% versus 38% and 52% versus 35%; P < .001 and P < .05, respectively). In addition, vasohibin 1/CD34 in HCC patients was an independent marker of poor prognosis, as determined by multivariate analysis (risk ratio, 1.973; 95% confidence interval, 1.049-3.711; P = .035). Vasohibin 1/CD34 could identify the proliferative vessels and could be a useful biomarker for predicting the clinical outcome of HCC patients.

Clinicopathologic significance of immunostaining of α-thalassemia/mental retardation syndrome X-linked protein and death domain–associated protein in neuroendocrine tumors

α-Thalassemia/mental retardation syndrome X-linked protein (ATRX) and death domain-associated protein (DAXX) genes are tumor suppressors whose mutations have been identified in sporadic pancreatic neuroendocrine tumors as well as in patients with MEN1. However, it is unknown whether ATRX and DAXX alterations are specific for pancreatic neuroendocrine tumor. In addition, the association of ATRX/DAXX protein loss with tumor cell proliferation has not been examined. We, therefore, immunostained ATRX and DAXX in 10 gastric, 15 duodenal, 20 rectal, 70 pancreatic, and 22 pulmonary neuroendocrine tumors with 15 nonneoplastic pancreases and 27 pancreatic adenocarcinomas to elucidate the site-specific roles of ATRX/DAXX abnormalities. At least 1 loss of ATRX and DAXX immunoreactivity was detected in all neuroendocrine tumor cases but not in any of nonneoplastic pancreatic tissues or pancreatic adenocarcinomas. The loss of DAXX protein was correlated with the Ki-67 index (ATRX, P = .904; DAXX, P = .044). The status of DAXX immunoreactivity correlated positively with World Health Organization histologic grade (P = .026). These results suggest that the status of ATRX or DAXX protein loss in neuroendocrine tumor differed among the organs in which these tumors arose, and these proteins may play site-specific roles in the development of these tumors.