Neural cell adhesion molecule expression in human pituitary adenomas

Prognostic Factors for Invasiveness and Recurrence of Pituitary Adenomas: A Series of 94 Patients

(1) Background: The aim of the current study is to evaluate the immunohistochemical expression of Ki-67, CD-56, Cyclin-D1 and E-Cadherin in the tissues samples of pituitary adenomas (PAs) and its association with PAs clinical manifestation tumor size, invasiveness and the risk of recurrence. (2) Materials and Methods: Ninety-four patients who underwent endoscope transsphenoidal excision of PAs were included in our study. The immunohistochemical expression of the Cyclin-D1, CD-56, E-Cadherin and Ki-67 markers was analyzed in paraffin-embedded tissue samples. (3) Results: The expression of Cyclin-D1 and Ki-67 index levels was positively correlated with the size (p < 0.001, r = 0.56 and p < 0.001, r = 0.43, respectively), the recurrence (p < 0.001, r = 0.46 and p = 0.007 r = 0.3, respectively), the extrasellar extension (p < 0.001, r = 0.48 and p < 0.001, r = 0.4, respectively) and the cavernous sinus invasion of (p < 0.001, r = 0.39 and p < 0.001, r = 0.3, respectively). No correlation was found between CD-56 and E-Cadherin expression with the size, the invasiveness and the recurrence of PAs. (4) Conclusion: Cyclin-D1 and Ki-67 are promising immunohistochemical markers in predicting the invasive behavior and recurrence of PAs in contrast to E-Cadherin and CD-56 which did not seem to be associated with PAs behavior post-surgery. However, larger studies are required in order to establish their role in the routine evaluation of PAs.

The expression of neural cell adhesion molecule and the microenvironment of pituitary neuroendocrine tumours

The neural cell adhesion molecule (NCAM) has previously been studied in pituitary neuroendocrine tumours (PitNETs), but its role in tumour biology and aggressiveness remains controversial, and its relationship with the tumour microenvironment remains unknown. We aimed to characterise NCAM expression in PitNETs, to correlate this with clinico-pathological features, and to assess the role of various microenvironment components on NCAM expression. NCAM and immune cells were investigated by immunohistochemistry in 16 human non-functioning-PitNETs (NF-PitNETs) and eight somatotrophinomas, including macrophages (CD68, CD163, HLA-DR), cytotoxic (CD8) and T helper (CD4) lymphocytes, regulatory T cells (FOXP3), B cells (CD20), and neutrophils (neutrophil elastase). Five normal pituitaries were included for comparison. The cytokine secretome from these PitNETs and from PitNET-derived tumour-associated fibroblasts (TAFs) were assessed on culture supernatants using a multiplex immunoassay panel. There were no significant NCAM expression differences between PitNETs and normal pituitary, and no difference between types of pituitary tumours (NF-PitNETs vs. somatotrophinomas). There was no association between NCAM expression and different clinico-pathological features, including cavernous sinus invasion and Ki-67, nor with serum hormone levels. NCAM immunoreactivity correlated negatively with PitNET-derived CXCL10 (rho = -0.417; p = .042) and CX3CL1 (rho = -0.423; p = .040) levels. NCAM immunoreactivity was negatively correlated with TAF-derived fibroblast growth factor (FGF)-2 (rho = -0.632; p = .009), but not with other TAF-derived cytokines. Within the PitNET cohort, there were no correlations between NCAM immunoreactivity and immune infiltrates or ratios, although, within NF-PitNETs, NCAM expression was higher in tumours with more FOXP3+ cells. NCAM expression does not differ between PitNETs and normal pituitary, and does not appear to relate to tumour invasiveness or proliferation. However, our data suggest a possible role for cytokines in the modulation of NCAM expression in PitNETs, particularly CXCL10, CX3CL1 and FGF-2, but not for immune cell infiltrates.

Gene and protein expression of E-cadherin and NCAM markers in non-functioning pituitary adenomas

Non-functioning pituitary adenomas (NFPA) are classified as benign tumors of slow growth, but 40% of them present local invasion, a characteristic of behavior still unpredictable with the use of current tumor markers. This work aims to evaluate the tissue markers E-cadherin and NCAM, which act on cell adhesion, in tumor tissue samples of NFPA and its relationship with the degree of local invasiveness. Gene expression of E-cadherin (CDH1) and NCAM (NCAM1) was assessed by real-time PCR and tissue expression by immunohistochemistry. Fifty-three patients with macroadenomas were submitted to transsphenoidal surgery, presented grade II invasive adenomas in 16 cases (30.2%), grade III in 7 (13.2%) and grade IV in 30 (56.6%). In the immunohistochemistry, one case was negative for E-cadherin, 7 showed weak immunostaining, 17 moderate and 28 strong, whereas for NCAM, 5 showed negative, 28 weakly, 14 moderate and 6 strong. Regarding gene expression, 43.3% showed expression for CDH1 (mean of 2.12) and 50% for NCAM1 (mean of 1.86). There was no significant correlation between the immunohistochemical expression of the markers, as well as the gene expression, the degree of invasiveness and clinical data. The results suggest that E-cadherin and NCAM markers are not directly related to the invasiveness in NFPA.

Expression of E-cadherin, Slug and NCAM and its relationship to tumor invasiveness in patients with acromegaly

Pituitary adenomas account for 10–15% of primary intracranial tumors. Growth hormone (GH)-secreting adenomas account for 13% of all pituitary adenomas and cause acromegaly. These tumors can be aggressive, invade surrounding structures and are highly recurrent. The objective of this study was to evaluate E-cadherin, Slug and neural cell adhesion molecule (NCAM) expression in GH-secreting pituitary adenomas and its relationship to tumor invasiveness. A cross–sectional study of patients who underwent hypophysectomy due to GH-secreting pituitary adenoma from April 2007 to December 2014 was carried out. The medical records were reviewed to collect clinical data. Immediately after surgery, tumor samples were frozen in liquid nitrogen and stored in a biofreezer at –80°C for assessment of E-cadherin 1 (CDH1), SLUG (SNAI2), and NCAM (NCAM1) by real-time PCR. The samples were fixed in formalin and embedded in paraffin for immunohistochemical analysis of E-cadherin and NCAM. Thirty-five patients with acromegaly were included in the study. Of these, 65.7% had invasive tumors. Immunohistochemically, E-cadherin was expressed in 96.7% of patients, and NCAM in 80% of patients. There was no statistically significant relationship between tumor grade or invasiveness and immunohistochemical expression of these markers. Regarding gene expression, 50% of cases expressed CDH1, none expressed SNAI2, and 53.3% expressed NCAM1. There was no statistically significant relationship between tumor grade or invasiveness and gene expression of CDH1, SNAI2, and NCAM1. The absence of Slug overexpression and of E-cadherin and NCAM suppression suggests that expression of these markers is not associated with tumor invasiveness in GH-secreting pituitary adenomas.

Neural adhesion molecule (N-CAM) in pleomorphic adenoma and carcinoma ex-pleomorphic adenoma

BACKGROUND

The neural cell adhesion molecule (N-CAM) has been implicated in the behaviour of the adenoid cystic carcinoma. In vitro, it was demonstrated that N-CAM inhibits cell invasion. The aim of this study was to search for N-CAM in the most common salivary gland tumour that has a malignant counterpart.

METHODS

We investigated the presence of N-CAM in pleomorphic adenoma and its malignant counterpart, the carcinoma ex-pleomorphic adenoma, using the immunohistochemistry technique.

RESULTS

Neural cell adhesion molecule was expressed in all cases of pleomorphic adenoma, strongly labelling the luminal cells of the double-layered ductform structures. This expression was weaker in neoplastic myoepithelial cells and progressively diminished at a distance from the luminal cells. In carcinoma, ex-pleomorphic adenoma N-CAM was either totally absent or faintly present at the apical pole of the few luminal cells.

CONCLUSIONS

As a result of the peculiar distribution of N-CAM in pleomorphic adenoma, we speculated that N-CAM behaves as a tumour-suppressor molecule, which is expressed in the benign neoplasm and which is down-regulated after malignancy, when the tumour assumes an invasive behaviour.

Polysialylated neural cell adhesion molecules expressed in human pituitary tumors and related to extrasellar invasion

OBJECT

Pituitary adenomas are usually benign tumors; however, some behave aggressively and metastasize. Until now, no specific marker of aggressive behavior or malignancy has been found. The polysialylated neural cell adhesion molecule (NCAM), which is highly expressed in embryonic tissues such as the brain and pituitary, is detected in some and neuroendocrine tumors. Because polysialylation has been implicated in the regulation of cell growth and migration, polysialylated NCAM expression has been considered as a prognostic marker in such tumors.

METHODS

In the present study, the authors analyzed polysialylated NCAM expression in 82 pituitary tumors from humans: 49 secreting adenomas, 32 nonfunctioning adenomas, and one growth hormone and prolactin-secreting carcinoma associated with acromegaly and spinal and liver metastases. Based on immunohistochemical analyses, the tumors were classified as somatotropic (22 tumors), prolactinoma (14 tumors), corticotropic (17 tumors), and gonadotropic or so-called null cell adenomas (28 tumors). Assessment of polysialylated NCAM was performed using three different methods (immunohistochemical analysis, Western blot analysis, and enzyme-linked immunosorbent assay) with a specific mouse monoclonal immunoglobulin M (Men B) that recognizes polysialic acid on NCAM. Tumoral NCAM expression was also evaluated with the aid of immunohistochemical analysis. Using this method, NCAM and polysialylated NCAM were studied in six healthy pituitaries. In addition, correlations were investigated using three statistical methods (chi-square test, nonparametric Mann-Whitney U-test, and principal component analysis) to compare tumoral polysialylated NCAM expression and seven parameters (tumor size and type, intrasphenoidal or cavernous sinus invasion, Ki-67 index, mitoses, and patient age and sex). Neural cell adhesion molecules were expressed in the healthy anterior pituitary and in all tumors. In contrast, polysialylated NCAM was not found in the healthy pituitary gland, but was expressed in 46.3% of typical pituitary tumors and 85% of the tumors selected as highly aggressive, including one carcinoma and three tumors with histological characteristics that raised suspicion of malignancy. There was no significant correlation between polysialylated NCAM expression and tumor size, tumor type, Ki-67 index, mitoses, or patient age and sex. In contrast, the expression of polysialylated NCAM, which was sensitive to endoneuraminidase-N treatment, was strongly correlated with tumor invasion (p < 0.0001).

CONCLUSIONS

In pituitary tumors in humans, expression of polysialylated NCAM is strongly related to tumor invasion and confirms the clinical diagnosis of aggressiveness.

Expression and secretion of neural cell adhesion molecules by human pituitary adenomas

Neural cell adhesion molecules (NCAMs) are found predominantly in neural, muscle and endocrine cells. Recent interest has focused on their potential role in tumorigenesis. We have analysed the expression and secretion of NCAM in a series of 48 human pituitary adenomas. Immunocytochemical analysis of 19 adenomas demonstrated NCAM expression in all tumours with, in each case, diffuse cytoplasmic staining being found with variable membrane accentuation. There were no apparent differences in the expression of immunoreactivity seen on sections between individual tumours. Cell culture media from 43 dispersed human pituitary tumours were analysed by immunoassay for the secretion of soluble NCAM and all the pituitary hormones. In contrast to the immunocytochemical studies, soluble NCAM was released from only 27% of human pituitary tumours, but this was not related to tumour type nor was the amount of soluble NCAM released correlated with the amount of pituitary hormone secreted by each adenoma. NCAM expression is common to all human pituitary adenoma types and the observed differences in release of soluble NCAM between individual tumours may reflect different molecular mechanisms, altering adhesive interactions between normal and adenomatous tissue.

Paucity of retinoic acid receptor alpha (RAR alpha) nuclear immunostaining in gliomas and inability of retinoic acid to influence neural cell adhesion molecule (NCAM) expression

Neural cell adhesion molecule (NCAM) is down-regulated during periods of embryological cell migration and may be important in local tumor migration or metastases. Conflicting information exists in the literature about NCAM expression in human glial tumors and little is known about its expression in human brain metastases. We immunohistochemically stained a panel of 43 primary human brain tumors and their cultured counterparts for NCAM including glioblastoma multiformes, anaplastic astrocytomas, oligodendrogliomas, and contrasted their staining with a panel of 3 meningiomas, 11 brain metastases, and 5 normal brain samples utilizing the monoclonal antibody NKH-1. Most gliomas and metastatic melanomas and lung carcinomas showed a high percentage of cells positive for NCAM expression while NCAM staining was negative for other carcinomas. No difference was seen between intensity or percentage of cells that were NCAM positive, based on tumor grade or type. In glioma cell lines, NCAM expression was lost upon passage. In 15 glioma cell lines we also determined NCAM isoform expression by reverse transcription/polymerase chain reaction (RT/PCR) and found that 6 of 15 had message for NCAM 180, 8 of 15 for NCAM 140, and only 3 of 15 had message for NCAM 120. Normal brains always contained message for the 180 isoform and usually had mRNA for all 3 isoforms. Using monoclonal antibodies for retinoic acid receptor alpha (RAR alpha), we found nuclear staining in melanomas and lung carcinomas metastatic to brain and only rarely in gliomas. Neither the relative antigen density of NCAM nor the percent of NCAM-positive cells appreciably changed upon incubation with retinoic acid (RA), as measured by flow cytometry. RAR alpha was not found at a level measurable by immunohistochemistry in nuclei of most glial tumors, providing an explanation for why RA might not induce NCAM expression. Whether paucity of RAR alpha on primary gliomas might also correlate with results from clinical trials showing limited efficacy of RA in treatment of human gliomas awaits further study.

Expression of epithelial cadherin and cavernous sinus invasion in human pituitary adenomas

Pituitary adenomas generally are regarded as benign tumors, although some invade the cavernous sinus and recur. We examined the epithelial cadherin (E-CD) expression in 30 pituitary adenomas (6 with cavernous sinus invasion and 24 without). Immunoreactivity of E-CD were found in all pituitary adenomas but they were very various. The presence of an association between E-CD expression and cavernous sinus invasion was assessed. There were no significant differences in E-CD expression between invasive and noninvasive adenomas. These results suggest that E-CD expression is not associated with cavernous sinus invasion in pituitary adenomas.