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PubMed2003

Ovarian steroid cell tumors: an immunohistochemical study including a comparison of calretinin with inhibin.

Ovarian steroid cell tumors, not otherwise specified (SCTs, NOS) are uncommon sex cord-stromal tumors that may be difficult to distinguish from other oxyphilic or clear-cell neoplasms. Immunohistochemical staining for inhibin, although generally useful in the diagnosis of SCTs, NOS, is not positive in every case and not all laboratories have this marker available. Recently, it has been reported that calretinin is expressed by sex cord-stromal tumors. We studied six SCTs, NOS for both calretinin and inhibin expression to evaluate the sensitivity of calretinin in comparison to inhibin. We also tested for CD99, Melan-A (A103), and S-100, other markers reported to be positive in these tumors. HMB-45 and MART-1 (Ab3) completed our panel of markers. All six tumors were positive for both calretinin and inhibin. Calretinin positivity was present in 60% to >90% of tumor cells, whereas inhibin reactivity ranged from <5% to >90% of tumor cells. Membranous staining for CD99 was present in one tumor. S-100-positive cells were seen in two tumors, whereas four tumors were immunoreactive for HMB-45. All six tumors were positive for Melan-A (A103), but in general the staining was less diffuse than with calretinin. All of the tumors were essentially negative for MART-1 (Ab3). The consistent diffuse staining of the tumors in this study for calretinin, in comparison to inhibin and Melan-A (A103), suggests that it is a sensitive marker for SCTs, NOS. MART-1 (Ab3) immunostaining may be useful for cases in which melanoma is considered in the differential diagnosis.

Biomarkers, Tumor↗
PubMed2004

Adenomatoid tumors of the female and male genital tracts express WT1.

Adenomatoid tumors are benign proliferations most often encountered in the female and male genital tracts. The mesothelial phenotype of these unusual tumors has been established by a variety of ultrastructural and immunohistochemical studies, although their etiology is by no means certain. The expression of the Wilms' tumor suppressor gene, WT1, in normal, hyperplastic, and malignant mesothelial cells prompted us to analyze the expression pattern of WT1 in a series of 24 adenomatoid tumors occurring in the uterus, fallopian tube, ovary, epididymis, scrotum, and testis. Twenty-three of the tumors expressed WT1 protein and the same number expressed calretinin, another marker of mesothelial differentiation. The one tumor that failed to stain with calretinin was positive for WT1. These results provide further support for mesothelial differentiation of adenomatoid tumors and suggest that the presence of WT1 expression may be useful in the differential diagnosis of these uncommon neoplasms, especially when they present in unusual settings or expression of other mesothelial markers is absent.

Adenomatoid Tumor↗
PubMed2003

Calretinin expression in odontogenic cysts.

Calretinin is a calcium-binding protein with a possible role as a calcium buffer, calcium-sensor, or regulator of apoptosis. Calretinin is expressed in neural tissue, is a specific marker of mesothelial cells, and has been demonstrated in the odontogenic epithelium during odontogenesis in rat molar tooth germs. Moreover, it has been found to be expressed in a high proportion of solid, unicystic, and multicystic ameloblastomas, whereas, on the contrary, no positive staining has been found in odontogenic keratocysts, residual cysts, and dentigerous cysts. The purpose of this study was to evaluate calretinin expression in radicular cysts, follicular cysts, orthokeratinized keratocysts, and parakeratinized keratocysts. A total of 70 odontogenic cysts, 24 radicular cysts, 24 follicular cysts, and 22 odontogenic keratocysts (10 orthokeratinized keratocysts, 12 parakeratinized keratocysts) were evaluated. All the radicular cysts, follicular cysts, and orthokeratinized keratocysts were negative. However in 8 of 12 parakeratinized keratocysts, there was a positivity to calretinin in the parabasal-intermediate layers of the cyst epithelium. This positivity to calretinin in the parabasal layers in parakeratinized keratocysts, similar to that found for other markers like PCNA and p53, could point to an abnormal control of the cell cycle and could help to explain the differences in the clinical and pathologic behavior of odontogenic keratocysts, in particular the differences found between orthokeratinized keratocysts and parakeratinized keratocysts.

Basement Membrane↗
PubMed1995

Neurochemical profile of glioneuronal lesions from patients with pharmacoresistant focal epilepsies.

Gangliogliomas, dysembryoplastic neuroepithelial tumors (DNT) and glioneuronal malformations are frequently encountered in patients with pharmacoresistant focal epilepsies. In order to characterize the neurochemical profile of these neoplastic and malformative glioneuronal lesions, we have examined the presence of the alpha 1 subunit of the GABAA receptor, the N-methyl-D-aspartate receptor subunit 1 (NR1), glutamate decarboxylase, tyrosine hydroxylase, somatostatin, parvalbumin, and calretinin in 60 gangliogliomas, 11 DNT, 10 tuberous sclerosis-like lesions and 17 non-tuberous sclerosis-like glioneuronal malformations. All DNT and tuberous sclerosis-like lesions, 59 gangliogliomas (98%), and 13 non-tuberous sclerosis-like hamartias (76%) were positive for at least one of the markers. Despite a great variation between and within the different entities, the neurochemical profile was generally reminiscent of normal neocortex: glutamate decarboxylase, GABAA receptor and NR1 which are common in neocortical neurons were present in the great majority of the lesions and often showed high labeling indices. There were three tuberous sclerosis-like lesions (30%) that contained both NR1 and glutamate decarboxylase immunoreactive giant cells in addition to well-differentiated ganglion cells. This supports the idea that at least some of these giant cells are of neuronal origin. The oligodendroglia-like cells of DNT and glioneuronal hamartias did not show immunoreactivity for any of the markers. The very high incidence of ganglioglial lesions in patients with chronic focal epilepsies and the presence of neurotransmitter-producing enzymes, neurotransmitter receptors, neuropeptides, and calcium-binding proteins in many of these lesions suggests that they may play an active role in the pathogenesis of epileptic seizures.

Biomarkers↗
PubMed1996

Preservation of calretinin-immunoreactive neurons in the hippocampus of epilepsy patients with Ammon's horn sclerosis.

Selective neuronal vulnerability and aberrant axonal reorganization in the hippocampus may play an important role for the pathogenesis of pharmaco-resistant temporal lobe epilepsy (TLE). Interneurons containing calcium-binding proteins (CaBPs) are candidates for pathogenetically relevant neurons in the hippocampus of patients with TLE. Here we have examined the cellular localization and distribution of calretinin (CR), a recently discovered CaBP, in the hippocampus of 35 patients with TLE. There was a striking preservation of CR-immunoreactive neurons in TLE patients with Ammon's horn sclerosis (AHS). No significant differences in the distribution of CR-immunoreactive neurons were observed between patients with lesion-associated TLE and control patients without epilepsy. However, a subpopulation of CR-immunoreactive interneurons with morphological features of Cajal-Retzius-like cells, which are only transiently detectable in the normally developing hippocampus, was markedly increased in epilepsy patients with AHS. This increase did not correlate with the duration of the epileptic disorder. Another significant finding was a striking increase and reorganization of CR-immunoreactive neuropil throughout the entire molecular layer of the dentate gyrus (DG-ML) in patients with AHS as compared to patients with focal lesions and control specimens. Ultrastructural analysis identified the CR-immunoreactive axonal profiles as components of an inhibitory, intrinsic neuronal system. The presence of a CR-positive, aberrant cell population, in combination with sprouting of CR-positive axonal processes may significantly alter the gating function of the dentate gyrus and thereby increase hippocampal epileptogenicity in epilepsy patients with AHS.

Adolescent↗
PubMed2002

Calretinin and inhibin are useful in separating adrenocortical neoplasms from pheochromocytomas.

Most adrenocortical neoplasms and pheochromocytomas can be diagnosed by a combination of clinical findings and morphologic features. Occasionally, however, this histologic differential diagnosis requires ancillary tests, such as immunohistochemistry. Both tumors are generally negative for epithelial markers but express synaptophysin. Inhibin and chromogranin are used for the diagnosis of adrenocortical neoplasms and pheochromocytomas, respectively. Both antigens, however, are expressed focally and may be completely negative, particularly in small biopsies. The authors investigated the potential value of adding calretinin to inhibin in the differential diagnosis of these tumors. Fifty-five primary adrenal neoplasms including 33 adrenocortical tumors (21 adenomas and 12 carcinomas), 22 pheochromocytomas, and 7 healthy adrenal glands were examined immunohistochemically for the expression of calretinin and inhibin. Inhibin was demonstrated in 24 (73%) adrenocortical neoplasms. When calretinin was added, the number of tumors staining positively for the two markers alone or in combination increased to 31 (94%). Both antigens showed a focal pattern of distribution in many cases. None of the pheochromocytomas reacted for any of these two markers. Healthy adrenal gland showed a distinct positive and negative pattern of immunoreactivity for both antigens in cortex and medulla, respectively. There were no differences between staining patterns of calretinin and inhibin in healthy adrenal cortex, adrenocortical adenomas, and adrenocortical carcinomas. The authors conclude that the addition of calretinin to inhibin increases the sensitivity of the diagnosis of adrenocortical neoplasms. When used together, they are highly specific and sensitive for the differential diagnosis of these tumors from pheochromocytomas. These markers, however, do not distinguish between benign and malignant adrenocortical neoplasms.

Adrenal Cortex Neoplasms↗
PubMed2002

Calretinin: a valuable marker of normal and neoplastic Leydig cells of the testis.

Sex cord-stromal tumors represent approximately 4% of all testicular neoplasms. Leydig cell tumor (LCT) is the most common entity, followed by Sertoli cell tumor (SCT). Leydig cell tumor histologic diagnosis is usually easy, but occasional forms of LCT could mimic others neoplasms, especially SCT or variants of yolk sac tumor. The aim of this study was to investigate calretinin expression in LCT and SCT of the testis. We evaluated calretinin reactivity in formalin-fixed, paraffin-embedded sections of 10 LCT, three SCT, five Leydig cell hyperplasia, two Sertoli cell adenomas, eight seminomatous tumors, five nonseminomatous germ cell tumors (mixed tumor), one adenomatoid tumor, and two normal testes using a standard immunohistochemical technique with a microwave-mediated epitope retrieval. All cases of LCT showed a positive staining that was diffuse and intense, constantly cytoplasmic, and sometimes nuclear. A positive strong and diffuse cytoplasmic and sometimes nuclear staining was also observed in Leydig cell hyperplasia and in normal Leydig cells. No staining was seen in two of three cases of SCT, and focal staining was observed in the third case. Only rare scattered cells were weakly immunostained in the Sertoli cell nodules. Seminomatous and nonseminomatous germ cell tumors were negative. Calretinin is an interesting marker of normal and neoplastic Leydig cells of the testis and may be of value in the diagnosis of atypical LCT.

Biomarkers, Tumor↗
PubMed2005

Age-dependent alterations of striatal calretinin interneuron density in a genetic animal model of primary paroxysmal dystonia.

Various types of hereditary dystonia are regarded as a basal ganglia disorder, but the underlying mechanisms are still unknown. In the dt hamster, a genetic animal model of age-dependent paroxysmal dystonia, recent studies demonstrated a reduced density of striatal parvalbumin-immunoreactive (PV) GABAergic interneurons at an age of maximum severity of dystonia in comparison with age-matched nondystonic controls. So far, alterations of other types of striatal interneurons in dt hamsters cannot be excluded. Therefore, we determined the density of calretinin-immunoreactive (CR) interneurons in the dt mutant at an age of maximum severity and after spontaneous remission of dystonia in comparison with age-matched nondystonic controls using an image analysis system and a stereologic counting method in a blinded fashion. At an age of maximum severity of dystonia, CR interneuron density was significantly lower in dt hamsters in comparison with controls (-20%), whereas no significant differences between the animal groups could be detected after spontaneous remission of dystonia. The comparison of CR interneuron density between young hamsters with those at an age of > 90 days revealed a significant ontogenetic decrease of CR interneurons in both animal groups (dt hamsters: -38%, controls: -54%). These results demonstrate that alterations of striatal interneuron density in dt mutants are not restricted to PV ones. A deficit of CR interneurons that coexpress GABA may contribute to previous findings of disinhibition of striatal projection neurons in the dt mutant at an age of maximum expression of dystonia.

Age Factors↗
PubMed2003

Ovarian sex cord-stromal tumors: an immunohistochemical study including a comparison of calretinin and inhibin.

Because ovarian sex cord-stromal tumors (SCST) are morphologically heterogeneous neoplasms that are relatively infrequently encountered, their diagnosis can be difficult. Immunohistochemical staining may be useful for establishing the diagnosis in problematic cases. We studied 53 ovarian SCSTs to characterize their immunohistochemical staining pattern: 17 adult granulosa cell tumors (AGCTs), 4 juvenile granulosa cell tumors (JGCTs), 3 sex cord tumors with annular tubules (SCTATs), 9 Sertoli-Leydig cell tumors (SLCTs), 10 fibromas, 5 fibrothecomas (FTs), and 5 thecomas. In 8 of the 53 cases, the tissue studied was from a metastatic site. The immunopanel included calretinin, inhibin, WT1, cytokeratin cocktail, epithelial membrane antigen (EMA), and cytokeratin 5/6 (CK5/6). The fibromas and FTs were also tested with CD10. The extent of staining was assessed in a semiquantitative fashion and ranked on a scale of 0 through 4+. All of the tumors, except for 1 metastatic SLCT, were positive for calretinin. Forty-five of the cases (85%) stained for inhibin; 1 metastatic AGCT, 3 fibromas, and 4 FTs were negative. WT1 was present in 39 tumors (74%), with expression most prominent in the SLCTs. The cytokeratin cocktail stained 23 of the 53 tumors (43%), whereas just 1 tumor was positive for EMA (1+ in a JGCT). All tumors were negative for CK5/6, and the 15 fibromas and FTs were negative for CD10. We conclude that because cytokeratin is frequently expressed by SCSTs, in particular by granulosa cell tumors, SLCTs, and SCTATs, the inclusion of EMA in a panel may help to exclude epithelial neoplasms. In addition, WT1, present in normal granulosa cells, is expressed by a majority of SCSTs. Finally, these results demonstrate that calretinin is at least as sensitive as inhibin for ovarian SCSTs overall and that it is more sensitive than inhibin for fibromas and FTs.

Biomarkers, Tumor↗
PubMed2003

The role of calretinin, inhibin, melan-A, BCL-2, and C-kit in differentiating adrenal cortical and medullary tumors: an immunohistochemical study.

Morphologic distinction between adrenal cortical and medullary tumors can be difficult. Previous studies have shown inhibin, melan-A, and BCL-2 to be useful markers for adrenal cortical tumors. We have recently observed a high level of calretinin expression in normal adrenal cortex but not the medulla and therefore evaluated its diagnostic application for adrenal tumors in comparison with inhibin, melan-A, and BCL-2. C-kit is a transmembrane tyrosine kinase receptor. Immunodetection of c-kit expression has been recently used for tumor diagnosis, and c-kit-positive tumors can potentially benefit from kit kinase inhibitor treatment. Although c-kit expression was reported in adrenal medulla and pheochromocytoma, it has not been evaluated in adrenal cortical tumors. In this study, 28 adrenal cortical tumors (12 carcinomas, 16 adenomas), 20 pheochromocytomas, and 20 extraadrenal paragangliomas were evaluated for calretinin, inhibin, melan-A, BCL-2, and c-kit expression by standard immunohistochemical assays on paraffin sections. The percentage of immunoreactivity in adrenal cortical tumors was as follows: calretinin, 96%; melan-A, 89%; inhibin, 92%; BCL-2, 20%; and c-kit, 5%. Normal adrenal medulla did not stain for c-kit but was positive for BCL-2. Eighty-six percent of pheochromocytomas stained for BCL-2 and none for calretinin, with the exception of the ganglioneuromatous areas in composite pheochromocytomas (n = 5). Extraadrenal paragangliomas showed reactivity with calretinin in 25%, melan-A in 5%, inhibin in 16%, BCL-2 in 38%, and c-kit in 8% of the cases. Our results indicate that calretinin is the most sensitive among all the adrenal markers tested. Like melan-A and inhibin, calretinin is also a very specific marker in differentiating cortical from medullary adrenal tumors. In addition, calretinin can be used to confirm a composite pheochromocytoma. BCL-2 does not appear to be useful in differentiating adrenal cortical from medullary tumors. C-kit is not useful in the diagnosis of adrenal tumors, and kit kinase inhibitor might have a limited role in the treatment of adrenal tumors and paraganglioma because of the low frequency of c-kit expression in these tumors.

Adrenal Cortex Neoplasms↗
PubMed2006

Value of immunohistochemistry in distinguishing peritoneal mesothelioma from serous carcinoma of the ovary and peritoneum: a review and update.

At present, a large number of immunohistochemical markers that can be used in the differential diagnosis between epithelioid peritoneal mesotheliomas and serous carcinomas are available. However, great differences of opinion exist regarding the individual value of some of these markers. This article provides a critical review of all of the information that is currently available on those markers that have the greatest potential for assisting in distinguishing between peritoneal mesotheliomas and serous carcinomas. The conclusion of this review indicates that the positive serous carcinoma markers, by and large, have a higher degree of sensitivity and specificity in assisting in discriminating between these malignancies than the positive mesothelioma markers. From a practical point of view, a combination of MOC-31 (or Ber-EP4), estrogen receptors, and calretinin immunostaining should allow a clear distinction to be made between epithelioid peritoneal mesotheliomas and serous carcinomas in most cases.

Biomarkers, Tumor↗
PubMed2003

Uterine tumor resembling ovarian sex-cord tumor: report of a case mimicking cervical adenocarcinoma.

Uterine tumors resembling ovarian sex-cord tumors (UTROSCTs) are unusual neoplasms with histologic features that resemble those within ovarian Sertoli and granulosa cell tumors. We report the case of a 24-year-old woman with a UTROSCT presenting as a cervical mass, which on initial evaluation was thought to represent cervical adenocarcinoma. The patient's cervical biopsy specimen contained epithelioid cells arranged in tubules and anastomosing cords, without significant cellular atypia or mitotic activity. Because this morphology elicited a broad differential diagnosis, immunohistochemical studies were performed. The tumor was found to be diffusely positive for cytokeratin cocktail, calretinin, and desmin, focally positive for CK7 and SMA, and negative for EMA, CEA, inhibin, CD10, CK20, chromogranin, and synaptophysin. Ultrastructural examination revealed occasional gland-like lumens with cells joined by desmosomes and a continuous basal lamina. UTROSCTs have features that may cause them to be confused with more common tumors, especially in limited biopsy samples, and should be included in the differential diagnosis when a gland-forming neoplasm with an unusual appearance is identified in a cervical or endometrial biopsy specimen.

Actins↗
PubMed2005

Uterine retiform sertoli-leydig cell tumor: report of a case providing additional evidence that uterine tumors resembling ovarian sex cord tumors have a histologic and immunohistochemical phenotype of genuine sex cord tumors.

We report a case of a retiform Sertoli-Leydig cell tumor of intermediate differentiation presenting as a uterine intracavity polypoid mass in a 63-year-old woman. In contrast to sertoliform endometrioid carcinoma and to hitherto reported uterine tumors resembling ovarian sex cord tumors (UTROSCTs), which are primarily characterized by tubular glands and solid tubules, this tumor, which most likely represents a UTROSCT, showed a large spectrum of histologic features typical of a genuine retiform Sertoli-Leydig cell tumor. The diagnosis was confirmed by a battery of immunohistochemical stains, which also served as a tool for differential diagnosis with other neoplasms. The tumor cells were positive for broad spectrum keratin (CK) CK18, vimentin, calretinin, and progesterone receptor. Only a few isolated cells stained for inhibin. The tumor cells were negative for CK7, CK5/6, epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), carbohydrate antigen 125 (CA125), thrombomodulin, 013 (CD99), melan A, alpha-fetoprotein (AFP), placental alkaline phosphatase (PLAP), alpha-1-antitrypsin, estrogen receptor, S100, neurone specific enolase (NSE), chromogranin, synaptophysin, desmin, caldesmon, and CD10. Divergent differentiation of uterine cells seems to be the most likely pathogenetic mechanism. To the best of our knowledge, no UTROSCT showing such a variety of histologic features indicative of a true sex cord tumor has been reported before.

Calbindin 2↗
PubMed2006

Ovarian serous cystadenofibroma with stromal sex cord elements: report of a unique case.

This report describes an ovarian serous cystadenofibroma, in a postmenopausal woman, which exhibited extensive sex cord differentiation, in the form of solid and hollow tubules resembling Sertoli cell elements, within the stroma. The sex cord elements, which were located just beneath the epithelium, were positive with both alpha inhibin and calretinin and negative with epithelial membrane antigen. They were also CD56 positive but negative with other neuroendocrine markers. True sex cord structures or sex cord-like elements have been described in ovarian adenosarcomas and pure stromal tumors, especially fibromas. However, as far as we are aware, these elements have not been reported in a serous cystadenofibroma. The endometrium exhibited simple hyperplasia, perhaps secondary to estrogenic activity of the sex cord elements. We discuss the significance of CD56 positivity of the sex cord elements.

Adenofibroma↗
PubMed2004

Irreversible loss of a subpopulation of cortical interneurons in the absence of glutamatergic network activity.

In the cerebral cortex of mammals, gamma-aminobutyric acid (GABA)ergic neurons represent 15-25% of all neurons, depending on the species and area being examined. Because converging evidence suggests that activity may play an important role in the neuritic maturation and synaptic function of GABAergic neurons, it is feasible that activity plays a role in the regulation of the proportion of GABAergic neurons. Here we provide direct evidence that early in cortical development activity blockade may deplete the network of a subpopulation of GABA immunoreactive neurons characterized by their small size and late generation in vitro. In a period of time coinciding with the emergence of synchronous network activity, the survival and morphological differentiation of GABAergic neurons was influenced by long-term blockade of synaptic activity. While GABA(A) receptor antagonists had a minor promoting effect on interneuronal survival during the second week in vitro, antagonists of ionotropic glutamate receptors strongly impaired survival and differentiation of immature GABAergic interneurons. Interneuronal loss was more severe when N-methyl-D-aspartate receptors were blocked than after blockade of alpha-amino-3-hydroxy-5-methylisoxazole-4-proprionic acid (AMPA)/kainate receptors. The decrease in the density of GABAergic neurons was irreversible, but could be prevented by the simultaneous addition of brain-derived neurotrophic factor (BDNF). These results suggest that there is a narrow time window during neocortical development when glutamatergic activity, and specially NMDA receptor stimulation, is crucial to assure survival and maturation of a subpopulation of late developing GABAergic interneurons.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed2005

The calcium-binding protein calretinin is a marker of the companion cell layer of the human hair follicle.

BACKGROUND: Ultrastructural studies of the hair follicle show that the outer root sheath (ORS) does not consist of a homogeneous cell population. The innermost cell layer of the ORS, also called the companion layer, is a single cell layer closely associated with the Henle layer of the inner root sheath. OBJECTIVES: To describe the immunohistochemical expression of calretinin, a calcium-binding protein, in the human hair follicle. METHODS: Immunohistochemical studies using two different antisera to calretinin were performed in paraffin-embedded and in frozen scalp specimens using standard techniques. RESULTS: Calretinin immunostaining was consistently and specifically found in the companion cell layer of hair follicles. CONCLUSIONS: These findings provide further evidence to support the notion that the companion layer is not only morphologically, but also immunohistochemically, different from the other cells of the ORS.

Aged↗