Immunohistochemical expression of human chorionic gonadotropin and P-glycoprotein in human pituitary glands and craniopharyngiomas

P-glycoprotein and cancer: what do we currently know?

Acquired resistance during cancer treatment is unfortunately a frequent event. There are several reasons for this, including the ability of the ATP-binding cassette transporters (ABC transporters), which are integral membrane proteins, to export chemotherapeutic molecules from the interior of the tumor cells. One important member of this family is the protein known as Permeability Glycoprotein (P-Glycoprotein, P-gp or ABCB1). Its clinical relevance relies mainly on the fact that the inhibition of P-gp and other ABC transporters could result in the reversal of the multidrug resistance (MDR) phenotype in some patients. Recently, other roles apart from being a key player in MDR, have emerged for P-gp. Therefore, this review discusses the relationship between P-gp and MDR, in addition to the possible role of this protein as a biomarker in cancer.

Prolactin levels: sex differences in the effects of risperidone, 9-hydroxyrisperidone levels, CYP2D6 and ABCB1 variants

AIM

The role of sex on the association of plasma prolactin levels with risperidone (R) and 9-hydroxyrisperidone (9-OHR) concentrations is investigated.

METHODS

Plasma R and prolactin concentrations, CYP2D6 and exon 21 and 26 ABCB1 gene variants were studied in 110 patients.

RESULTS

In females, a 1 ng/ml increase in R levels was associated with a significant 1.02% increase in prolactin levels. In males, a 1 ng/ml increase in 9-OHR levels was associated with a significant 1.18% increase in prolactin levels. ABCB1 haplotype 12 had significant but opposite effects in males and females. In the combined sample, 9-OHR, but not R levels had significant effects on prolactin levels.

CONCLUSION

Genes had sex-specific effects on risperidone-associated prolactin elevations.

Solitary Langerhans cell histiocytosis located in the neurohypophysis with a positive titer HCG-β in the cerebrospinal fluid

INTRODUCTION

Beta-human chorionic gonadotropin (HCG-β) is considered to be a useful tumor marker for germ cell tumors (GCTs); however, various tumors other than GCTs, including cystic pituitary adenomas, Rathke's cleft cysts, and craniopharyngiomas, were reported to express HCG-β.

CASE REPORT

We herein present the case of a 5-year-old boy who presented with polyuria and had a solitary lesion in the neurohypophysis with a positive HCG-β titer in the cerebrospinal fluid. Under a preoperative diagnosis of germinoma, a biopsy was performed from the posterior pituitary lobe via the transsphenoidal endoscopic approach and the histological diagnosis was revealed to be Langerhans cell histiocytosis (LCH).

CONCLUSIONS

The finding of a slightly positive HCG-β titer in the cerebrospinal fluid (CSF) cannot exclude the possibility of LCH, and we strongly recommend a histological diagnosis for the diagnosis of a solitary neurohypophysial lesion.

The Role of Human Chorionic Gonadotropin as Tumor Marker: Biochemical and Clinical Aspects

Tumor markers are biological substances that are produced/released mainly by malignant tumor cells, enter the circulation in detectable amounts and are potential indicators of the presence of a tumor. The most useful biochemical markers are the tumor-specific molecules, i.e., receptors, enzymes, hormones, growth factors or biological response modifiers that are specifically produced by tumor cells and not, or minimally, by the normal counterpart (Richard et al. Principles and practice of gynecologic oncology. Wolters Kluwer Health, Philadelphia, 2009). Based on their specificity and sensitivity in each malignancy, biomarkers are used for screening, diagnosis, disease monitoring and therapeutic response assessment in clinical management of cancer patients.This chapter is focused on human chorionic gonadotropin (hCG), a hormone with a variety of functions and widely used as a tumor biomarker in selected tumors. Indeed, hCG is expressed by both trophoblastic and non-trophoblastic human malignancies and plays a role in cell transformation, angiogenesis, metastatization, and immune escape, all process central to cancer progression. Of note, hCG testing is crucial for the clinical management of placental trophoblastic malignancies and germ cell tumors of the testis and the ovary. Furthermore, the production of hCG by tumor cells is accompanied by varying degrees of release of the free subunits into the circulation, and this is relevant for the management of cancer patients (Triozzi PL, Stevens VC, Oncol Rep 6(1):7-17, 1999).The name chorionic gonadotropin was conceived: chorion derives from the latin chordate meaning afterbirth, gonadotropin indicates that the hormone is a gonadotropic molecule, acting on the ovaries and promoting steroid production (Cole LA, Int J Endocrinol Metab 9(2):335-352, 2011). The function, the mechanism of action and the interaction between hCG and its receptor continue to be the subject of intensive investigation, even though many issues about hCG have been well documented (Tegoni M et al., J Mol Biol 289(5):1375-1385, 1999).

A craniopharyngioma with spontaneous involution of a gadolinium-enhanced region on magnetic resonance imaging

BACKGROUND

It has not been reported previously that the solid enhancing portion of a craniopharyngioma has involuted without a change in cyst size.

CASE DESCRIPTION

We herein report a case of a craniopharyngioma with spontaneous involution of a solid gadolinium (Gd)-enhanced region on magnetic resonance imaging (MRI). A 44-year-old female was referred to our department with a mass on MRI associated with headaches and polyuria. The images showed a suprasellar cystic lesion progressing from the posterior pituitary lobe to the right hypothalamus along the pituitary stalk. Examinations of the cerebrospinal fluid showed aseptic meningitis and a positive titer of beta-human chorionic gonadotropin (HCG-β) preoperatively. The hypothalamic lesion became enlarged over the following 3 weeks, and a biopsy of the posterior pituitary lobe was performed via the endonasal transsphenoidal approach under a preoperative diagnosis of a germ cell tumor (GCT). The histological diagnosis was a craniopharyngioma, and the patient's postoperative findings on MRI were atypical: The solid Gd-enhanced region in the hypothalamus had spontaneously decreased in size and the peritumoral edema had improved, although the biopsy site in the posterior pituitary lobe was distant from the area of shrinkage. We speculated that the involutional portion on MRI mimicking a tumor was actually the normal hypothalamus, which was abnormally enhanced due to a disruption of the blood-brain barrier caused by the craniopharyngioma.

CONCLUSION

Gd-enhanced regions of parenchyma neighboring the cysts of craniopharyngioma should be carefully managed, taking into consideration the possibility of the enhancement of normal tissue.

Infundibulo-tuberal or not strictly intraventricular craniopharyngioma: evidence for a major topographical category

PURPOSE

This study investigates retrospectively the clinical, neuroradiological, pathological and surgical evidence verifying the infundibulo-tuberal topography for craniopharyngiomas (CPs). Infundibulo-tuberal CPs represent a surgical challenge due to their close anatomical relationships with the hypothalamus. An accurate definition of this topographical category is essential in order to prevent any undue injury to vital diencephalic centres.

METHODS

A systematic review of all scientific reports involving pathological, neuroradiological or surgical descriptions of either well-described individual cases or large series of CPs published in official journals and text books from 1892 to 2011 was carried out. A total of 1,232 documents providing pathological, surgical and/or neuroradiological evidence for the infundibulo-tuberal or hypothalamic location of CPs were finally analysed in this study.

FINDINGS

For a total of 3,571 CPs included in 67 pathological, surgical or neuroradiological series, 1,494 CPs (42%) were classified as infundibulo-tuberal lesions. This topography was proved in the autopsy of 122 non-operated cases. The crucial morphological finding characterizing the tubero-infundibular topography was the replacement of the third ventricle floor by a lesion with a predominant intraventricular growth. This type of CP usually presents a circumferential band of tight adherence to the third ventricle floor remnants, formed by a functionless layer of rective gliosis of a variable thickness. After complete surgical removal of an infundibulo-tuberal CP, a wide defect or breach at the floor of the third ventricle is regularly observed both in the surgical field and on postoperative magnetic resonance imaging studies.

CONCLUSIONS

Infundibulo-tuberal CPs represent a major topographical category of lesions with a primary subpial development at the floor of the third ventricle. These lesions expand within the hypothalamus itself and subsequently occupy the third ventricle; consequently, they can be classified as not strictly intraventricular CPs. A tight attachment to the hypothalamus and remnants of the third ventricle floor is the pathological landmark of infundibulo-tuberal CPs.

Central nervous system (CNS) delivery of glucocorticoids is fine-tuned by saturable transporters at the blood-CNS barriers and nonbarrier regions

Proper functioning of the hypothalamic-pituitary-adrenal axis depends on the ability of glucocorticoids (GCs), mainly cortisol in humans and corticosterone in rodents, to access brain targets and regulate their own secretion. Being highly lipophilic, GCs have been assumed to passively diffuse through the cell membrane. However, the access of these GCs to the brain may be a more complicated process, because the free movement of molecules into the central nervous system (CNS) is restricted by the presence of the blood-brain and blood-cerebrospinal fluid barriers. GCs do interact with some transporter systems, including the efflux transporter, P-glycoprotein, and members of the organic anion transporter polypeptide (oatp) family, both of which have been found at the blood-CNS barriers. Using an in situ brain/choroid plexus perfusion, P-glycoprotein was shown to not majorly regulate the access of [(3)H]cortisol and [(3)H]corticosterone to the choroid plexus or pituitary gland. Interactions of [(3)H]cortisol and [(3)H]corticosterone with saturable influx transporters were detected at the hypothalamus, cerebellum, choroid plexus, and pituitary gland. Oatp2 seems to have some role in the influx of [(3)H]cortisol and [(3)H]corticosterone to the choroid plexus and the pituitary gland and other transporters, unlikely to be oatp2, may play a very minor role in the access of [(3)H]cortisol and [(3)H]corticosterone to the brain, as well as having a significant effect on [(3)H]glucocorticoid receptor accumulation in the pituitary gland. Overall, these data suggest that the majority of cortisol and corticosterone present in the plasma diffuse into the CNS and that transporters do not play a major role in the accumulation of these GCs in the brain.

P-glycoprotein and breast cancer resistance protein expression in human placentae of various gestational ages

Placental efflux transporters such as P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) protect the developing fetus from exposure to potentially toxic xenobiotics. However, little is known about the expression of these transporters in human placentae of different gestational ages. Therefore, we quantified the expression of P-gp and BCRP in human placentae of different gestational ages. We also measured the expression of various nuclear regulatory factors such as the pregnane xenobiotic factor to determine whether their expression also changes with gestational age. Syncitial microvillous plasma membranes were isolated from human placentae of various gestational ages (60–90 days, 90–120 days, and full-term C-section placentae). P-gp and BCRP expression (protein) in these preparations were measured by Western blot analysis followed by an ELISA. Expression (mRNA) of P-gp, BCRP, and nuclear regulatory factors in the placentae were quantified by quantitative real-time PCR. P-gp expression (relative to that of alkaline phosphatase) was significantly ( P < 0.05) higher (44.8-fold as protein; 6.5-fold as mRNA) in early gestational age human placentae (60–90 days) vs. term placentae. In contrast, BCRP (protein and mRNA) and nuclear regulatory factors (mRNA) expression in placental tissue did not change significantly with gestational age. However, placental expression of P-gp and human chorionic gonadotropin-β (hCG-β) transcripts was highly correlated ( r = 0.73; P < 0.0001; Spearman rank correlation). Expression of P-gp, but not BCRP, decreases dramatically with gestational age in human placentae. This decrease in P-gp expression is not caused by a change in expression of nuclear receptor transcripts but appears to be related to hCG-β expression. The placental P-gp expression appears to be upregulated in early pregnancy to protect the fetus from xenobiotic toxicity at a time when it is most vulnerable to such toxicity.

Transport of somatostatin and substance P by human P-glycoprotein

P-glycoprotein is an efflux pump for a broad spectrum of hydrophobic agents. We found that bioactive peptides including somatostatin and substance P inhibit ATP-dependent vincristine binding to P-glycoprotein-overexpressing K562/ADM membrane vesicles. Some of these bioactive peptides including somatostatin stimulate basal ATPase activity of P-glycoprotein; in contrast, other peptides including substance P inhibit it. The K562/ADM membrane vesicles showed an ATP-dependent, osmotically sensitive uptake of somatostatin and substance P, which was inhibited by valspodar, an inhibitor of P-glycoprotein. These findings suggested that certain bioactive peptides such as somatostatin and substance P directly interact with human P-glycoprotein as endogenous substrates for P-glycoprotein-mediated transport.

Human chorionic gonadotropin in cancer

Human chorionic gonadotropin (hCG) is mainly used for detection and monitoring of pregnancy and pregnancy-related disorders but it is also an extremely sensitive and specific marker for trophoblastic tumors of placental and germ cell origin. Thus treatment of relapsing choriocarcinomas and testicular germ cell tumors is often initiated on the basis of rising hCG levels even in the absence of clinical or histological evidence of a relapse. While these tumors mostly produce the intact heterodimeric hormone consisting of an alpha (hCGalpha), and a beta subunit (hCGbeta), many nontrophoblastic tumors produce only hCGbeta This is usually a sign of aggressive disease and elevated serum levels of hCGbeta are strongly associated with poor prognosis. Elevated serum levels are observed in 45-60% of patients with biliary and pancreatic cancer and in 10-30% of most other cancers. Methods that detect hCG and hCGbeta together are mainly used for measurement of hCG-like immunoreactivity in serum. However, the reference range for hCG is 5-8 fold higher than that for hCGbeta and thus moderately elevated levels can be identified only with a specific and sensitive hCGbeta assay.

Elevated levels of human chorionic gonadotropin-beta, a marker of active neurohypophyseal germinoma, detected by immune complex transfer enzyme immunoassay

We report the usefulness of a highly sensitive immune complex transfer enzyme immunoassay (ICT-EIA) to detect human chorionic gonadotropin (HCG)-beta and thereby the onset of neurohypophyseal germinoma in its active phase. A 14-year-old girl exhibiting arrested puberty was diagnosed with neurohypophyseal germinoma following observation for two years. This patient initially showed no signs of diabetes insipidus (DI). While ICT-EIA indicated concentrations of HCG-beta higher than normal in cerebrospinal fluid (CSF) and serum, the results obtained with conventional methods were negative. ICT-EIA was also useful to assess the efficacy of treatment.

Characterization of the levels of expression of retinoic acid receptors, galectin-3, macrophage migration inhibiting factor, and p53 in 51 adamantinomatous craniopharyngiomas

OBJECT

Craniopharyngiomas are histopathologically defined as benign tumors that can behave very aggressively at the clinical level. They can originate from different types of embryonal epithelial tissue in which correct spatiotemporal regulation has been disrupted at the effector production level. The goal of this study was to determine the efficacy of using selected biological markers to distinguish between recurring and nonrecurring craniopharyngiomas.

METHODS

The authors used computer-assisted microscopy to determine quantitatively the immunohistochemical levels of expression of selected markers, including retinoic acid receptors (RARs), as response elements to retinoic acid in a series of 51 adamantinomatous craniopharyngiomas. These tumors may also originate as the result of physiological defects in the apoptosis-mediated elimination of embryological remnants of epithelial tissue. Galectin-3, p53, and the macrophage migration inhibiting factor (MIF) are known to play crucial roles in these processes. The authors quantitatively determined the levels of expression of these substances in this series of 51 craniopharyngiomas. The data show that all craniopharyngiomas were immunoreactive for RARalpha, whereas their immunoreactivity for RARbeta and RARgamma varied dramatically from one case to another. Craniopharyngiomas with low levels of RARbeta and high levels of RARgamma are more likely to recur than those with higher levels of RARbeta and lower levels of RARgamma. Rapidly recurring craniopharyngiomas also show significantly lower levels of expression of galectin-3 and MIF than nonrecurring or slowly recurring cases. Few tumors exhibited p53 immunopositivity.

CONCLUSIONS

The data indicate that even in the so-called adamantinomatous group of craniopharyngiomas, several subgroups with different clinical behavior patterns can be identified on the basis of differentiation markers relating mainly to the presence or absence of RARbeta and RARgamma.

Markers of function and proliferation in non-invasive and invasive bi- and plurihormonal adenomas of patients with acromegaly: an immunohistochemical study

Twenty-seven plurihormonal and 21 growth hormone- prolactin- (GH- PRL-) mixed cell adenomas obtained from patients with acromegaly undergoing transnasal-transsphenoidal surgery were investigated immunohistochemically for expression of Epidermal Growth Factor (EGF), Transforming Growth Factor alpha (TGF alpha), Insulin-like Growth Factor-1 (IGF-1), Estrogen Receptor-Related Protein (ERRP), Multidrug Resistance Marker (MDRM), Protein Kinase C (PKC), Gs alpha,. Cathepsin D and p53. Five plurihormonal adenomas grew invasively. The panel of markers used in this study represents a selection of functional and proliferative markers thought to be associated with the function and development of pituitary adenomas. Our results imply that the growth factors (EGF, TGF alpha, IGF-1), the cell signalling protein Gs alpha and the MDRM are expressed by both types of pituitary adenomas in a similar pattern. Non-invasive GH-PRL-mixed cell adenomas showed an increased expression of IGF-1, TGF alpha and MDRM compared to non-invasive plurihormonal adenomas. No factor was found which would reliably distinguish between invasive and non-invasive adenomas. We failed to confirm the findings of others that p53 and cathepsin D might be indicators of tumor aggressiveness. A participation of ERRP and PKC in the development of bi- and plurihormonal adenomas with acromegaly appears unlikely, as the immunostains were all negative.

[Craniopharyngioma: clinical, epidemiological and pathological findings in 25 cases]

We report the clinical and pathological findings of 25 cases of craniopharyngiomas. Fourteen patients were males and 11 were females. The ages ranged between 3 and 64 years, with a mean of 30.52 years. The symptoms reflected the growth and topography of the tumours; visual disorders (72%), headache (68%), vomits (40%) and papilledema (24%) were the most frequent symptoms. Twelve cases were suprasellar; 10 tumours arose from sellar region, from which 8 presented suprasellar extension; frontal lobe (n = 2) and ponto cererebellar angle (n = 1) were also affected. Eleven patients undergone total resection of the tumor and 14 were submitted to partial resection, from which 1 received adjuvant chemotherapy. The overall recurrence rate was 48%. Eight recurrences were observed in the patients submitted to partial resection and 4 in which total resection were performed. These results are similar with the literature, corroborating to the extension of residual tumour after the surgical resection as the main prognostic factor for this neoplasm.

Embryonal craniopharyngioma. Case report of the morphogenesis of a craniopharyngioma

BACKGROUND

Ordinary craniopharyngiomas affecting sellar regions of children and preadolescents are composed of ameloblastomatous and/or squamous constituents. The authors encountered an autopsy case of a stillborn infant with a large craniopharyngioma with unusual manifestations.

METHODS

The craniopharyngioma was analyzed using detailed histologic and immunohistochemical techniques.

RESULTS

An autopsy revealed a large tumor arising from the pituitary gland with associated severe hydrocephalus. Histologically, the cells of the tumor showed features of ameloblastoma and organoid structures simulating tooth buds and adenohypophyseal primordia in the stage of organogenesis. Cells of the latter were shown to be immunoreactive for chromogranin A and six adenohypophyseal hormones.

CONCLUSIONS

Because embryology of the adenohypophysis and the teeth indicated that all of the epithelia in this tumor emerged during the normal development of the stomodeum, it was believed that an "embryonal form of craniopharyngioma" would characterize this organoid neoplasm best. The possible morphogenesis of craniopharyngioma is also discussed.

Human chorionic gonadotrophin immunoactivity in cystic intracranial tumours

BACKGROUND AND OBJECTIVE

With regard to intracranial tumours, elevated hCG in CSF or serum has been considered to be specific for germ-cell tumours. Recently however, elevated hCG has also been shown to be present in cyst fluid and CSF of patients with craniopharyngiomas. While germ-cell tumours are generally non-cystic, the aim of our study was to determine the significance of hCG in cystic intracranial lesions.

DESIGN

In a prospective study, hCG immunoactivity and subunits of hCG were measured in cyst fluid, CSF, and serum of patients harbouring intracranial cyst lesions.

PATIENTS AND MEASUREMENTS

hCG immunoactivity was measured in cyst fluid and serum samples of 42 patients. CSF samples were available from 12 patients with craniopharyngiomas. In order to fully characterize the hCG immunoactivity, we used immunoradiometric assays for total hCG activity (measuring both intact hCG and the free beta-subunit of hCG), and those specific for intact, dimeric hCG (hCG), free beta-subunit of hCG (hCG beta) and free alpha-subunit. Furthermore, immunostaining of tumour tissue was performed using monoclonal antibodies directed against the free beta-subunit of hCG.

RESULTS

Total hCG immunoactivity was markedly elevated in cyst fluid of all 17 craniopharyngiomas (range 36.7-4558 IU/I; normal < 5 IU/I). Moderately elevated levels of hCG in cyst fluid were detected in three of four pituitary adenomas, in two metastases from lung cancer and in two arachnoid cysts. hCG beta was detected in cyst fluid from all hCG positive cysts, while specific determination of intact (dimer) hCG and alpha-subunit mostly yielded negative results. No hCG immunoactivity was found in cystic gliomas, meningiomas or haemangioblastomas. hCG was elevated in CSF of two patients with craniopharyngiomas, but no hCG immunoactivity was detected in any serum sample. Subtle immunostaining of epithelial cell groups was shown in five of ten craniopharyngiomas. Clear immunostaining for hCG beta was also found in scattered epithelial cells of one pituitary adenoma.

CONCLUSIONS

hCG immunoactivity in cystic intracranial lesions is due mainly to hCG beta. Measurement of hCG immunoactivity in cyst fluid can be helpful in the differential diagnosis of intracranial cystic lesions, if surgery is restricted to cyst decompression and no histology is available. High levels suggest a craniopharyngioma.