Differential expression of genes related to drug responsiveness between sparsely and densely granulated somatotroph adenomas.

There are two main subtypes of GH-producing pituitary adenoma: densely granulated (DG-type) and sparsely granulated (SG-type). Despite the difference in drug responsiveness between the two subtypes, their molecular mechanisms remain unknown. The aim of this study is to evaluate the differential expression of genes related to drug responsiveness between the two subtypes of somatotroph adenoma, and their relationship to the clinical characteristics. Eighty-two acromegaly patients (44 DG-type, 38 SG-type) were studied retrospectively. Clinical characteristics were compared between the two subtypes. Among them, 36 tumor tissue specimens (19 DG-type, 17 SG-type) were available for investigation of the expression of SSTR2, SSTR5 and D2R that are reported to be involved in drug responsiveness by realtime RT-PCR. Protein level was evaluated by immunohistochemical study. Patients with SG-type adenomas were younger in age and showed greater GH suppression by octreotide, but not by bromocriptin, and bigger in size and more invasiveness than DG-type adenomas. The mRNA expression of SSTR2 in DG-type adenomas were greater than those in SG-type adenomas and showed significantly positive correlation with GH suppression by octreotide. There was positive correlation between mRNA and protein levels of SSTR2. These data suggested that the differences of responsiveness to octreotide between DG- and SG-type adenomas are based on the expression levels of SSTR2.

Increased expression of HMGA1 correlates with tumour invasiveness and proliferation in human pituitary adenomas.

AIMS: High-mobility group A1 (HMGA1) is highly expressed in various benign and malignant tumours. The development of pituitary adenoma in Hmga1 transgenic mice has been reported. However, no studies have investigated HMGA1 expression and its clinical significance in human pituitary adenomas. METHODS AND RESULTS: Immunohistochemical expression of HMGA1 was analysed with respect to various clinicopathological factors in 95 pituitary adenomas. Nuclear expression of HMGA1 was observed in 62% of pituitary adenomas, whereas normal adenohypophysial tissues were negative. Although HMGA1 expression was frequently detected in clinically non-functioning adenomas - 90% of silent adrenocorticotropic hormone (ACTH), 76.2% of follicle-stimulating hormone/luteinizing hormone and 100% of null cell adenomas - it was also detected in 48.1% of growth hormone (GH), 60% of mixed GH/prolactin (PRL), 62.5% of PRL, 66.6% of thyroid-stimulating hormone and 37.5% of ACTH adenomas. HMGA1 expression was significantly higher in invasive adenomas or macroadenomas than in non-invasive adenomas or microadenomas (invasive versus non-invasive, P < 0.05; macroadenoma versus microadenoma, P < 0.05). In addition, HMGA1 showed the highest level in grade IV, more aggressive pituitary adenomas, than in grades I, II and III (IV versus I, P = 0.01; IV versus II, P = 0.01; IV versus III, P = 0.07). Furthermore, a significant correlation between HMGA1 expression and MIB-1 labelling index was observed (R = 0.368, P < 0.0002). CONCLUSIONS: These findings suggest that HMGA1 up-regulation has an important oncogenic role in pituitary tumorigenesis, as well as being a novel molecular marker of tumour proliferation and invasiveness.

[Successful rituximab monotherapy in a patient with mucosa-associated lymphoid tissue lymphoma of the rectum with trisomy 3, 18].

A 62-year-old man was referred to our hospital with enlargement of mucosa-associated lymphoid tissue (MALT) lymphoma of the rectum after the eradication of Helicobacter pylori. The patient was given a diagnosis of stage I MALT. Endoscopic observation revealed an enlarged rectal tumor with 3, 18 double trisomy. Rituximab monotherapy was given and complete remission was achieved. Rituximab monotherapy can be useful for MALT lymphoma of the rectum.

Selective vacuolar degeneration in dystrophin-deficient canine Purkinje fibers despite preservation of dystrophin-associated proteins with overexpression of Dp71.

BACKGROUND: Respiratory support therapy significantly improves life span in patients with Duchenne muscular dystrophy; cardiac-related fatalities, including lethal arrhythmias, then become a crucial issue. It is therefore important to more thoroughly understand cardiac involvement, especially pathology of the conduction system, in the larger Duchenne muscular dystrophy animal models such as dystrophic dogs. METHODS AND RESULTS: When 10 dogs with canine X-linked muscular dystrophy in Japan (CXMD(J)) were examined at the age of 1 to 13 months, dystrophic changes of the ventricular myocardium were not evident; however, Purkinje fibers showed remarkable vacuolar degeneration as early as 4 months of age. The degeneration of CXMD(J) Purkinje fibers was coincident with overexpression of Dp71 at the sarcolemma and translocation of mu-calpain to the cell periphery near the sarcolemma or in the vacuoles. Immunoblotting of the microdissected fraction showed that mu-calpain-sensitive proteins such as desmin and cardiac troponin-I or -T were selectively degraded in the CXMD(J) Purkinje fibers. Utrophin was highly upregulated in the earlier stage of CXMD(J) Purkinje fibers, but the expression was dislocated when vacuolar degeneration was recognized at 4 months of age. Nevertheless, the expression of dystrophin-associated proteins alpha-, beta-, gamma-, and delta-sarcoglycans and beta-dystroglycan was well maintained at the sarcolemma of Purkinje fibers. CONCLUSIONS: Selective vacuolar degeneration of Purkinje fibers was found in the early stages of dystrophin deficiency. Dislocation of utrophin besides upregulation of Dp71 can be involved with this pathology. The degeneration of Purkinje fibers can be associated with the distinct deep Q waves in ECG and fatal arrhythmia seen in dystrophin deficiency.

Overexpression of HMGA2 relates to reduction of the let-7 and its relationship to clinicopathological features in pituitary adenomas.

High-mobility group A2 is highly expressed during embryogenesis and in various benign and malignant tumors. Recent studies report that high-mobility group A2 is negatively regulated by the let-7 microRNAs (miRNAs) family in vitro. The development of pituitary adenomas in high-mobility group A2 transgenic mice showed that high-mobility group A2 may be involved in pituitary tumorigenesis. However, no studies have investigated the clinical significance of high-mobility group A2 and its relationship to the let-7 miRNA family in human pituitary adenomas. Using immunohistochemistry, we analyzed high-mobility group A2 expression with respect to various clinicopathologic factors in 98 pituitary adenomas. Overexpression of high-mobility group A2 was observed in 39% (38/98) of pituitary adenomas compared with normal adenohypophysial tissue and was frequently found in adenomas including prolactin (PRL), adrenocorticotrophic hormone, or follicle-stimulating hormone/luteinizing hormone and in null cell adenomas, but relatively rare in growth hormone (GH) and mixed GH/PRL adenomas. High-mobility group A2 expression was significantly associated with tumor invasion (P<0.05) and was significantly higher in grade IV than in grades I, II, and III adenomas (P<0.05). High levels of high-mobility group A2 expression were more frequently observed in macroadenomas than in microadenomas (P<0.05). High levels of high-mobility group A2 expression also significantly correlated with the proliferation marker Ki-67 (P<0.0001). Real-time quantitative RT-PCR analysis was carried out to evaluate the expression of let-7 in 55 pituitary adenomas. Subsequently, decreased expression of let-7 was confirmed in 23 of 55 (42%) adenomas and was correlated with high-grade tumors (P<0.05). An inverse correlation between let-7 and high-mobility group A2 expression was evident (R=-0.33, P<0.05). These findings support a causal link between let-7 and high-mobility group A2 whereby loss of let-7 expression induces high-mobility group A2 upregulation that represents an important mechanism in pituitary tumorigenesis and progression.

Expression of p18(INK4C) is down-regulated in human pituitary adenomas.

Cyclin-dependent kinase inhibitors represented by the INK4 family comprising p16(INK4A), p15(INK4B), p18(INK4C), and p19(INK4D) are regulators of the cell cycle shown to be aberrant in many types of cancer. Mice lacking p18(Ink4c) exhibit a series of phenotypes including the development of widespread organomegaly and pituitary adenomas. The objective of our study is to examine the role of p18(INK4C) in the pathogenesis of human pituitary tumors. The protein and mRNA levels of p18(INK4C) were examined by immunohistochemistry and real-time reverse transcription-polymerase chain reaction, respectively. The methylation status of the p18(INK4C) gene promoter and somatic mutations of the p18(INK4C) gene were also investigated. p18(INK4C) protein expression was lost or significantly reduced in 64% of pituitary adenomas compared with levels in normal pituitary glands. p18(INK4C) mRNA levels were low in all ACTH adenomas and non-functioning (NF)-FSH and in 42%, 70% and 66% of GH, PRL, and subtype 3 adenomas, respectively. p18(INK4C) mRNA levels were significantly associated with p18(INK4C) protein levels. Neither methylated promoters in pituitary adenomas, except in one NF-FSH adenoma, nor somatic mutations of the p18(INK4C) gene in any pituitary adenomas were detected. The down-regulation of p18(INK4C) expression may contribute to the tumorigenesis of pituitary adenomas.

Pituitary and stalk lesions (infundibulo-hypophysitis) associated with immunoglobulin G4-related systemic disease: an emerging clinical entity.

Inflammatory lesions of the pituitary gland are rarely encountered. Recently, the concept of immunoglobulin G4 (IgG4)-related systemic disease was proposed in Japan, and more than 20 cases have been reported as possibly associated with infundibulo-hypophysitis since 2000. We herein review such case reports in the published literature and in the abstracts of scientific meetings. Almost all cases involved middle-aged to elderly men presenting with various degrees of hypopituitarism and diabetes insipidus and demonstrating a thickened pituitary stalk and/or pituitary mass. These structures shrank remarkably in response to glucocorticoid therapy, even in a lower dose range similar to that prescribed as a replacement for adrenocortical insufficiency. Some of the anterior pituitary insufficiencies were also resolved by glucocorticoid administration. The presence of IgG4-related systemic disease and an elevated serum IgG4 level before glucocorticoid therapy were the main clues to a correct diagnosis of IgG4-related infundibulo-hypophysitis. Autoimmunity is suggested but not yet established to play a role in the pathogenesis for IgG4-related systemic disease. The fact that hypertrophic pachymeningitis and para-sinusitis accompanied some cases suggested that both sellar and parasellar structures are involved in the chronic inflammation. We therefore classify this disorder not as a variant form of primary autoimmune hypophysitis but as a secondary form of infundibulo-hypophysitis associated with IgG4-related systemic disease.

A growth hormone receptor mutation impairs growth hormone autofeedback signaling in pituitary tumors.

Pituitary tumors are a diverse group of neoplasms that are classified based on clinical manifestations, hormone excess, and histomorphologic features. Those that cause growth hormone (GH) excess and acromegaly are subdivided into morphologic variants that have not yet been shown to have pathogenetic significance or predictive value for therapy and outcome. Here, we identify a selective somatic histidine-to-leucine substitution in codon 49 of the extracellular domain of the GH receptor (GHR) in a morphologic subtype of human GH-producing pituitary tumors that is characterized by the presence of cytoskeletal aggresomes. This GHR mutation significantly impairs glycosylation-mediated receptor processing, maturation, ligand binding, and signaling. Pharmacologic GH antagonism recapitulates the morphologic phenotype of pituitary tumors from which this mutation was identified, inducing the formation of cytoskeletal keratin aggresomes. This novel GHR mutation provides evidence for impaired hormone autofeedback in the pathogenesis of these pituitary tumors. It explains the lack of responsiveness to somatostatin analogue therapy of this tumor type, in contrast to the exquisite sensitivity of tumors that lack aggresomes, and has therapeutic implications for the safety of GH antagonism as a therapeutic modality in acromegaly.

Reduction of GSTP1 expression by DNA methylation correlates with clinicopathological features in pituitary adenomas.

Pi-class glutathione-S-transferase (GSTP1) located on chromosome 11q13 encodes a phase II metabolic enzyme that detoxifies reactive electrophilic intermediates. GSTP1 plays an important role in the protecting cells from cytotoxic and carcinogenic agents and is expressed in normal tissues at variable levels in different cell types. Altered GSTP1 activity and expression have been reported in many tumors and this is largely due to GSTP1 DNA hypermethylation. The role of GSTP1 in pituitary tumorigenesis has not been investigated. In this study, we evaluated the GSTP1 expression level and GSTP1 DNA methylation status in a series of pituitary adenomas. Using immunohistochemistry, we identified expression of GSTP1 in all of the various normal hormone-producing adenohypophysial cell types. In pituitary adenomas, loss or reduced expression of GSTP1 was detected in 27 of 53 tumors (50.9%). Expression of GSTP1 was significantly lower in invasive adenomas than in noninvasive adenomas (P<0.05). Using methylation-specific polymerase chain reaction (MS-PCR), GSTP1 DNA promoter hypermethylation was detected in adenomas (38 of 53, 71.7%) but not in normal tissues. GSTP1 methylation was more frequent in grade II, III, and IV tumors (66.7, 85, and 83%, respectively) than in grade I tumors (33%, P<0.05). In addition, the frequency of GSTP1 methylation was higher in invasive tumors (85%) than in noninvasive tumors (59%; P<0.05). Methylation status correlated with significant downregulation of GSTP1 expression; the frequency of GSTP1 methylation was higher in tumors with reduced-GSTP1 expression (85%) than in tumors with normal or high GSTP1 expression (54%; P<0.05). These data indicate that GSTP1 inactivation through CpG hypermethylation is common in pituitary adenomas and may contribute to aggressive pituitary tumor behavior.

Expression of pituitary tumour-derived, N-terminally truncated isoform of fibroblast growth factor receptor 4 (ptd-FGFR4) correlates with tumour invasiveness but not with G-protein alpha subunit (gsp) mutation in human GH-secreting pituitary adenomas.

OBJECTIVE: Apart from the constitutively activating mutation of the G-protein alpha subunit (Gsalpha) (gsp mutation), factors involved in tumorigenesis or those in tumour behaviour remain elusive in sporadic GH-secreting pituitary adenomas. Recently, the N-terminally truncated form of fibroblast growth factor receptor-4 (ptd-FGFR4) was identified in pituitary adenomas. This aberrant receptor has transforming activity, and causes pituitary adenomas in transgenic mice. The clinical relevance of this receptor warrants investigation. Our objective was twofold: first, to examine how the expression of ptd-FGFR4 relates to gsp mutations; and second, to see whether patients with this receptor have unique clinical characteristics. MATERIALS AND METHODS: mRNA was extracted from excised adenomas of 45 Japanese acromegalic patients. ptd-FGFR4 expression and gsp mutations were determined by reverse transcription polymerase chain reaction (RT-PCR) and direct sequencing. Preoperative clinical data were collected by reviewing medical charts and pituitary magnetic resonance imaging (MRI) scans. RESULTS: ptd-FGFR4 mRNA expression was detected in 19 out of 45 tumours (42.2%) while gsp mutations were detected in 25 out of 45 tumours (55.6%). The prevalence of ptd-FGFR4 expression did not differ between gsp-positive (44.0%) and gsp-negative (40.0%) tumours (P = 1.00). ptd-FGFR4-positive tumours invaded the cavernous sinus more frequently (P = 0.0098) than did the ptd-FGFR4-negative tumours. Tumour size was not statistically different between ptd-FGFR4-positive and -negative tumours (P = 0.198). The presence of ptd-FGFR4 did not correlate with age at operation, sex, preoperative serum GH or IGF-1 levels. CONCLUSIONS: We found that ptd-FGFR4 expression and gsp mutations occur independently of each other, and that ptd-FGFR4 expression is associated with more invasive tumours in patients with GH-secreting pituitary adenomas.

Prognostic significance of HIF-2alpha expression on tumor infiltrating macrophages in patients with uterine cervical cancer undergoing radiotherapy.

Hypoxia-inducible factor (HIF)-2alpha, a basic helix-loop-helix (bHLH)-PAS protein, is the principal regulator of the hypoxic transcriptional response. An immunohistochemical study reported strong HIF-2alpha expression in the cytoplasm of tumor infiltrative macrophages (TIMs). Thus we assessed the expression of HIF-2alpha in human cervical cancer tissue before radiation therapy and its relationship to the clinical outcome. Seventy three patients with histologically proven primary advanced squamous cell carcinoma of the uterine cervix underwent radiotherapy in Tokushima University Hospital after biopsy specimens were taken. Among 73 specimens stained for HIF-2alpha, 53 (72.6%) exhibited HIF-2alpha immunoreactivity in the TIMs. In only 5 of 73 cases, HIF-2alpha immunoreactivity was observed in the nuclei of tumor cells. The HIF-2alpha positive cell count ratio in TIMs was associated with disease-free survival (DFS) with the worst DFS (p=0.024) being in cases in the group with a high positive cell count ratio. A high HIF-2alpha positive cell count ratio in TIMs increased the risk of local recurrence (p=0.0142). These findings might suggest that the ratio of the HIF-2alpha positive cell in TIMs may be a new predictive indicator for prognosis before radiation therapy for uterine cervical cancer.

Combined gangliocytoma and prolactinoma of the pituitary gland.

Gangliocytomas of the pituitary gland are rare lesions that often occur in combination with pituitary adenomas, which are frequently associated with the hypersecretion of pituitary hormones, particularly growth hormones. We report a case of combined gangliocytoma and prolactinoma of the pituitary gland. A 49-year-old male presented with vertigo. Radiological examination revealed an intrasellar tumor with a suprasellar extension, which was removed via the trans-sphenoidal approach. Histologically, the tumor was composed of adenoma cells, mature ganglion cells and cells with features intermediate between those of adenoma cells and ganglion cells (intermediate cells). Immunohistochemical analysis revealed the ganglion cells and intermediate cells as well as adenoma cells to be positive for prolactin. No growth hormone-positive tumor cells were observed. The ganglion cells were positive for synaptophysin and neurofilament. The findings in this case are discussed in relation to hypotheses proposed for histogenesis, and the presence of intermediate cells supports three hypotheses. The first is that adenoma cells transform into ganglion cells, and the second is that both components originate from the embryonal pituitary cell rests, showing intermediate features between ganglion cells and adenoma cells. The last is that their common origin may be the same stem/progenitor cells in normal adult pituitaries.

Clinicopathological features of growth hormone-producing pituitary adenomas: difference among various types defined by cytokeratin distribution pattern including a transitional form.

Pituitary adenomas producing almost exclusively growth hormones (GH) have been ultrastructurally classified into two distinct types: densely granulated somatotroph (DG) adenomas and sparsely granulated (SG) adenomas. Fibrous body (FB), an intracytoplasmic globular aggregation of cytokeratin (CK) filaments, is a hallmark of SG adenomas. Under light microscope, FB could be identified by CK immunohistochemistry as a dot-pattern immunoreaction versus a perinuclear pattern for cells without FB. However, it has been noted that numerous adenomas contain mixed populations of the two patterns. To clarify clinicopathological characteristics of the adenomas with mixed populations ("intermediate type" adenomas) and to confirm clinicopathological differences between strictly defined DG-type and SG-type adenomas, we performed this study on 104 GH cell adenomas. Having segregated "intermediate-type" adenomas (26 cases), we found significant differences between typical DG-type (47 cases) and SG-type adenomas (31 cases); SG-type adenomas had younger ages (44 vs. 50), higher frequency of macroadenomas (86% vs. 58%), invasiveness (65% vs. 38%), advanced grades (3 or 4) in Knosp's classification (50% vs. 24%), and weaker immunoreaction for GH, beta-TSH, alpha-subunit, E-cadherin, and beta-catenin. Clinicopathological characteristics of "intermediate-type" adenomas were identical to those of DG-type adenomas. These findings confirm that SG-type adenoma is a distinct section of GH cell adenomas with special properties and biological behavior, and suggest that intermediate-phenotype adenomas are enrolled in DG-type adenomas. Special properties and biological behavior of SG-type adenomas may appear after the majority of tumor cells possess a fully developed fibrous body.

Evidence for cancer-associated expression of NADPH oxidase 1 (Nox1)-based oxidase system in the human stomach.

Helicobacter pylori infection has been suggested to stimulate expression of the NADPH oxidase 1 (Nox1)-based oxidase system in guinea pig gastric epithelium, whereas Nox1 mRNA expression has not yet been documented in the human stomach. PCR of human stomach cDNA libraries showed that Nox1 and Nox organizer 1 (NOXO1) messages were absent from normal stomachs, while they were specifically coexpressed in intestinal- and diffuse-type adenocarcinomas including signet-ring cell carcinoma. Immunohistochemistry showed that Nox1 and NOXO1 proteins were absent from chronic atrophic gastritis (15 cases), adenomas (4 cases), or surrounding tissues of adenocarcinomas (45 cases). In contrast, Nox1 and its partner proteins were expressed in intestinal-type adenocarcinomas (19/21 cases), diffuse-type adenocarcinomas (15/15 cases), and signet-ring cell carcinomas (9/9 cases). Confocal microscopy revealed that Nox1, NOXO1, Nox activator 1, and p22(phox) were predominantly associated with Golgi apparatus in these cancer cells, while diffuse-type adenocarcinomas also contained cancer cells having Nox1 and its partner proteins in their nuclei. Nox1-expressing cancer cells exhibited both gastric and intestinal phenotypes, as assessed by expression of mucin core polypeptides. Thus, the Nox1-base oxidase may be a potential marker of neoplastic transformation and play an important role in oxygen radical- and inflammation-dependent carcinogenesis in the human stomach.

p53 and MIB-1 expression of esophageal carcinoma concominant with achalasia.

Achalasia, insufficient relaxation of the lower esophageal sphincter (LES) causes the retention and stasis of food and secretions, chronic hyperplastic esophagitis and eventual malignant transformation. p53 alternation has been suggested to play an important role in the malignant transformation. A 53-year-old man was endoscopically followed up for esophageal achalasia for seven years, and endoscopy revealed an ulcerative region in the upper thoracic esophagus, and histopathologically the biopsy specimens showed moderately differentiated squamous cell carcinoma. In resected specimens, p53 staining was strong and diffuse in the tumor and MIB-1 immunoreactivity was strong and patchy in the tumor and the basal layer of squamous mucosa of the esophagus. No staining for either immunostains was noted in normal esophageal mucosa. It is necessary for patients with esophageal achalasia to be followed-up with endoscopy, and that p53 and MIB-1 immunostaining of biopsy specimens should be performed to detect pre-cancerous lesions.

Usefulness of cytokeratin immunoreactivity pattern for distinction of Barrett's esophagus from intestinal metaplasia of the stomach.

The histological distinction between Barrett's esophagus involving the distal esophagus and intestinal metaplasia of the stomach has important clinical implications and can be difficult even with the use of histochemical stains. Cytokeratin (CK) 7 and 20 are cytoplastic structural proteins that show restricted expression in normal and malignant epithelia of the gastrointestinal tract. CK7 and 20 immunostaining were performed on a 67-year-old male with cardiac cancer with reflux esophagitis due to sliding hernia. The CK7/20 immunoreactivity pattern of cancer and reflux esophagitis in this case showed superficial CK20 staining and strong CK7 staining of both superficial and deep glands. In intestinal metaplasia of the stomach, strong CK20 immunostaining in superficial and deep glands and absent CK7 immunoreactivity were noted. Neither CK7 nor CK20 immunoreactivity was noted in squamous cell epithelium. Therefore, we concluded that in this patient intestinal metaplasia of the esophagus was BE. The CK7/20 reactivity pattern is useful for identifying the intestinal metaplasia of the esophagus from the stomach using histological materials from biopsy and surgically resected specimens.

[A case of parathyroid hormone-related peptide producing gallbladder carcinoma presenting humoral hypercalcemia of malignancy].

Humoral hypercalcemia of malignancy (HHM) in neoplastic syndrome has been most commonly reported in squamous cell carcinoma. Gallbladder carcinoma with HHM is uncommon. In this report, we describe a male case of gallbladder carcinoma with marked hypercalcemia and a high level of serum parathyroid hormone-related peptide (PTHrP). An immunohistochemical examination using PTHrP was also positive.

Malignant B-lymphoid cells with bone lesions express receptor activator of nuclear factor-kappaB ligand and vascular endothelial growth factor to enhance osteoclastogenesis.

PURPOSE: Receptor activator of nuclear factor-kappaB ligand (RANKL) is a key mediator of osteoclastogenesis. Because certain types of tumor cells aberrantly express RANKL, and because bone destruction also develops in B-cell lymphomas of bone origin, we investigated RANKL expression and the mechanisms of osteoclastogenesis in B-lymphoid neoplasms. EXPERIMENTAL DESIGN AND RESULTS: Immunohistochemistry of bone specimens resected from patients with primary B-cell lymphoma of bone with bone destruction revealed that lymphoma cells express RANKL as well as vascular endothelial cell growth factor (VEGF). The tumor cells isolated from the bone specimens enhanced osteoclastogenesis in vitro. In contrast, B-cell lymphoma infiltrating to the bone marrow without bone destruction did not express RANKL. Both RANKL and VEGF were expressed by a portion of B-lymphoid cell lines, including Daudi and IM-9. These RANKL-expressing tumor cells enhanced osteoclastogenesis from RAW264.7 cells and human monocyte-derived preosteoclasts in the absence of stromal cells/osteoblasts in a RANKL-dependent manner. Furthermore, conditioned media from Daudi cells enhanced transmigration of preosteoclasts that was inhibited by anti-VEGF antibody, suggesting that tumor cell-derived VEGF mediates recruitment of osteoclast precursors. Moreover, cocultures of B-lymphoid cell lines with osteoclasts enhanced the growth of B-lymphoid cells. CONCLUSIONS: Some malignant B cells aberrantly express functional RANKL as well as VEGF to enhance osteoclastogenesis. The coexpression of RANKL and VEGF may also contribute to the close cellular interactions with osteoclastic cells, thereby forming a vicious cycle between osteoclastic bone destruction and tumor expansion in bone.

Diversity of ACTH-immunoreactive cells in the human adenohypophysis: an immunohistochemical study with special reference to cluster formation and follicular cell association.

Horvath et al. called relatively small ACTH-immunoreactive (ACTH-IR) cells observed in basophil invasion "proopiomelanocortin (POMC) cells," and these cells were supposed to be different from larger ACTH-IR cells in human adenohypophysis. To clarify the existence of "anterior POMC cells," we examined 21 autopsy cases taking note of follicular cells (FCs). We found that smaller ACTH-IR cells were clustered forming small areas without FC association, clustered small cell island (CSCI). CSCI was found in all the specimens we examined using immunohistochemical staining for ACTH and cytokeratin (AE1/AE3) in serial sections. ACTH-IR cells outside CSCI were of various sizes, mainly consisting of larger ACTH-IR cells that were diffusely scattered among other hormone-secreting cells and closely associated with FCs. By immunohistochemistry, ACTH-IR cells within CSCI and basophil invasion showed uniformly weak reactivity and common patterns for cytokeratins (CAM5.2 and 35 beta H11), carboxypeptidase D, and LeuM1, whereas those outside CSCI showed a great variety of immunoreactivity. The similarity in the immunoreactivity of ACTH-IR cells between CSCI and basophil invasion suggests that ACTH-IR cells in these two areas have common characteristics and ACTH-IR cells in CSCI are most likely "POMC cells." The clustered "anterior POMC cells" may be distinguishable by light microscopic immunohistochemistry.