β-Catenin expression in benign and malignant salivary gland tumors

Unique Cohorts of Salivary Gland Cancer Cells as an in-vitro Model of Circulating Tumor Cells

Introduction

The characterization of circulating tumor cells (CTC) and circulating tumor microemboli (CTM) has emerged as both a challenge to the standard view of metastasis, and as a valuable means for understanding genotypic and phenotypic variability shown even within the same cancer type. However, in the case of salivary gland neoplasms, limited data are available for the role that CTCs and CTMs play in metastasis and secondary tumor formation.ru.AQ1 In response to this, we propose that similarities between in vitro clusters of cultured salivary gland cancer cells may act as a surrogate model for in vivo CTCs and CTMs isolated from patients.

Materials and Methods

Using techniques in immunofluorescence, immunoblotting, and 2-dimensional migration, we isolated and characterized a group of cohort cells from a commercially available cell line (HTB-41). Results: Here, cells exhibited a hybrid phenotype with simultaneous expression of both epithelial and mesenchymal markers (E-cadherin, vimentin, and α-SMA). Cohort cells also exhibited increased migration in comparison to parental cells.

Conclusion

Data suggest that these isolated cell clusters may fucntion as a potential in vitro model of CTCs and CTMs.

Diagnostic role of DOG-1, GFAP and B-catenin in Basal cell Adenoma and Cellular Pleomorphic Adenoma of the Salivary Gland

BACKGROUND

Pleomorphic Adenoma (PA) and Basal cell adenoma (BCA) are benign salivary gland tumors that may pose a diagnostic challenge if typical features are not present. Due to the increased relapse and malignant transformation rate of the former, a correct diagnosis carries relevant prognostic information. Even though immunohistochemistry (IHC) plays a limited role in the diagnosis of these tumors, the use of IHC panels could increase diagnostic accuracy. In the present work, we aimed to demonstrate that the use of an IHC panel consisting of Glial Fibrillary Acid Protein (GFAP), B-Catenin and Discovered On GIST 1 (DOG-1) can aid in the differential diagnosis between PA and BCA.

METHODS

We analyzed 18 cases of benign salivary gland tumors (Pleomorphic adenomas and Basal cell adenomas) with overlapping histologic features. First, a head and neck pathologist diagnosed the cases relying on morphology alone. Afterwards, cases were re-evaluated considering the IHC panel results. Inter-observer IHC scoring concordance was evaluated with pre-defined marker cut-off points using Cohen's Kappa scores.

RESULTS

Based on morphology alone, 9 cases were classified as PA while the remaining tumors were considered to be BCA. Five out of nine BCA cases showed GFAP staining and absent nuclear B-catenin and DOG-1 positivity. Conversely, 2 PA cases showed absent GFAP and positive nuclear B-catenin with concurrent DOG-1 expression. Therefore, after IHC evaluation, up to 40% of morphologic diagnoses were reconsidered. Overall, the inter-observer concordance for IHC evaluation was good (resulting Kappa Scores between 0.78 and 1).

CONCLUSION

Our work supports the use of a concise IHC panel to improve the diagnostic accuracy of benign salivary gland tumors with overlapping histologic features.

Basal Cell Adenoma and Basal Cell Adenocarcinoma

Basal cell adenoma (BCA) and basal cell adenocarcinoma (BCAC) are uncommon biphasic salivary gland tumors having morphologic similarities to other biphasic salivary gland neoplasms having differentiation toward the intercalated ducts of the salivary gland. Both tumors show mixtures of trabecular, tubular, solid, and membranous solid patterns. BCAC is separated from BCA primarily by the presence of invasion in the former. The diagnosis of BCA and BCAC is best carried out with hematoxylin and eosin-stained sections and careful attention to detail of tumors in the differential diagnosis, including adenoid cystic carcinoma, pleomorphic adenoma, and epithelial myoepithelial carcinoma.

Clinicopathologic implications of Myb and Beta-catenin expression in adenoid cystic carcinoma

Background

Adenoid cystic carcinoma (ACC) is the second most common malignancy of the salivary glands, accounting for ~ 1% of malignant tumors of the head and neck region and 10% of salivary gland neoplasms. Predicting the long-term outcomes of patients with ACC is still challenging, as reliable prognostic biomarkers are not available. Among salivary gland tumors, Myb overexpression is highly specific for ACC. In addition, the MYB-NF1B fusion translocation is a hallmark of ACC, and although the detection of this translocation does not appear to impact prognosis, the MYB-NF1B fusion is also implicated in MYB upregulation. Myb has recently been identified as an activator of the Wnt/β-catenin signaling pathway, and aberrant cytoplasmic expression of β-catenin has been observed in many salivary gland malignancies. In this study, we aim to analyze the impact of Myb and β-catenin expression on prognosis in ACC.

Methods

A tissue microarray constructed from archival tissue from 64 patients with ACC was stained for Myb and β-catenin; both localization and intensity were evaluated. In parallel, we abstracted demographic data, tumor characteristics, survival data, and outcomes, including local recurrence, regional recurrence, and distant metastasis from the medical record. Statistical analysis was performed.

Results

Our analysis supports that ACC patients negative for Myb by immunohistochemical methods have a higher risk of developing metastasis than patients with Myb staining (HR: 4.06, 95% CI: 1.02–14.96, p-value: 0.03). Although not statistically significant, cytoplasmic localization of β-catenin is may suggest a diminished rate of relapse-free survival (HR 2.45, 95%CI: 0.9–6.7, p = 0.08). Furthermore, Myb expression correlated with β-catenin expression, increasing 1.69 in staining intensity units with each increase in β-catenin staining intensity (p-value: 0.04).

Conclusions

Our study suggests that Myb expression is protective; Myb positive patients have diminished risk of distant metastasis. In contrast, there is a trend towards increased hazard of death in ACC patients with cytoplasmic β-catenin expression. Additional analyses will be necessary to establish Myb and β-catenin as independent protective and adverse biomarkers, respectively.

Abnormal activation of the Akt signaling pathway in adenoid cystic carcinoma

PURPOSE

Adenoid cystic carcinoma (ACC) is an intriguing lesion because it shows a slow growth in the beginning, but a late poor prognosis due to perineural invasion, metastasis and recurrence. This study aimed to investigate whether Akt signaling would be deregulated in adenoid cystic carcinoma and its consequence in the expression of associated proteins.

METHODS

The expression of the Akt, p-Akt, NFκB, β-catenin, cyclin D1 and COX-2 was assessed by immunohistochemistry in 10 cases of ACC, 17 cases of pleomorphic adenoma (PA), and 7 cases of normal salivary gland (NSG).

RESULTS

p-Akt was overexpressed in ACC when compared to NSG. NFκB, β-catenin, and COX-2 were overexpressed in ACC and PA when compared to NSG. Most proteins were slightly higher expressed in ACC than in PA, but they never reached significance. p-Akt expression positively correlated with NFκB, β-catenin, cyclin D1 and COX-2 in ACC and PA, while this correlation trended to be negative in for these proteins (except for NFκB) in NSG using Person's correlation analysis, but without reaching significance.

CONCLUSIONS

Our results indicate an abnormal activation of Akt signaling pathway, which can be an important regulator of tumor biology in ACC. Activated Akt correlated with the expression of NFκB, β-catenin and COX-2, which can potentially influence cell survival in ACC.

A Review of Selected Factors of Salivary Gland Tumour Formation and Malignant Transformation

Salivary gland tumours represent about 6% of head and neck neoplasms and about 0.5% of all malignancies in humans. Tumour growth and malignant transformation are complex processes involving various actions of molecules. Furthermore, some malignant salivary gland tumours are deemed to be caused by dedifferentiation or malignant transformation of benign tumours. The mechanisms of this transformation depend on a variety of different elements, such as cell cycle regulators, oncogenes, proteins, angiogenesis factors, and adipocytokines. The authors used PubMed, Medline, and Google websites to find and review the most significant papers related to malignant transformation in benign salivary gland tumours.

A bioluminescence reporter mouse that monitors expression of constitutively active β-catenin

This short technical report describes the generation and characterization of a bioluminescence reporter mouse that is engineered to detect and longitudinally monitor the expression of doxycycline-induced constitutively active β-catenin. The new responder transgenic mouse contains the TetO-ΔN89β-CatTMILA transgene, which consists of the tet-operator followed by a bicistronic sequence encoding a stabilized form of active β-catenin (ΔN89β-catenin), an internal ribosome entry site, and the firefly luciferase gene. To confirm that the transgene operates as designed, TetO-ΔN89β-CatTMILA transgenic mouse lines were crossed with an effector mouse that harbors the mouse mammary tumor virus-reverse tetracycline transactivator (MMTV-rtTA) transgene (termed MTB hereon), which primarily targets rtTA expression to the mammary epithelium. Following doxycycline administration, the resultant MTB/CatTMILA bigenic reporter exhibited precocious lobuloalveologenesis, ductal hyperplasia, and mammary adenocarcinomas, which were visualized and monitored by in vivo bioluminescence detection. Therefore, we predict that the TetO-ΔN89β-CatTMILA transgenic responder mouse-when crossed with the appropriate effector transgenic-will have wide-applicability to non-invasively monitor the influence of constitutively active β-catenin expression on cell-fate specification, proliferation, differentiation, and neoplastic transformation in a broad spectrum of target tissues.

Epithelial-Mesenchymal Transition Protein Expression in Basal Cell Adenomas and Basal Cell Adenocarcinomas

Basal cell adenomas and basal cell adenocarcinomas show marked histomorphologic similarity and are separated microscopically primarily by the invasive characteristics of the adenocarcinomas. We wished to explore potential differences in the expression of epithelial-mesenchymal transition associated proteins in these two tumor types. A tissue microarray was constructed utilizing 29 basal cell adenomas and 16 basal cell adenocarcinomas. Immunohistochemical expression of E-cadherin, beta-catenin, Twist 1 and vimentin were investigated. Both tumors expressed all proteins in a relatively similar manner. Nuclear beta-catenin was essentially limited to the abluminal cell populations in both tumor types. E-cadherin was limited largely to luminal locations but was more prevalent in the adenocarcinomas as compared to the adenomas. Primarily abluminal expression for vimentin was seen, sometimes present in an apical dot-like pattern. Distinct populations of cellular expression of these four markers of epithelial mesenchymal transition were present but were similar in locations in both tumors with no patterns discerned to separate basal cell adenoma from basal cell adenocarcinoma. Given these findings, the mechanisms by which basal cell adenocarcinoma is able to invade while its counterpart, basal cell adenoma can not, may be more complex than in other tumor types.

Selected case from the Arkadi M. Rywlin International Pathology Slide Club: carcinoma of the transverse colon in a young girl

We report a case of a 14-year-old female with primary adenocarcinoma of the transverse colon. She was hospitalized after presenting with abdominal pain and signs of intestinal obstruction. There was no health antecedent or family history of neoplasia. Physical examination revealed a distended abdomen. Tenderness was elicited to palpation of the right lower quadrant. Magnetic resonance imaging of the abdomen revealed obstructive signs, with a constricting lesion in the mid-transverse colon of probable neoplastic nature. Laparoscopic segmental resection of the colon was followed by standard right hemicolectomy. A circumferential mid-transverse tumor was diagnosed as primary colorectal carcinoma (CRC) of signet-ring cell type, AJCC stage IIIC, Dukes' C stage. On the basis of immunohistochemistry and clinical data, hereditary nonpolyposis and hamartomatous colorectal cancer syndromes were excluded. Involvement of either the p53, BRAF, or K-RAS genes was ruled out by immunohistochemistry profiling and genetic testing. The neoplasm was categorized as sporadic. The possibility of activation of the Wnt signaling pathway was suspected, because of a defective turnover of the β-catenin protein. Postoperatively, the patient was treated with both systemic and intra-abdominal adjuvant chemotherapy, including oxaliplatin. Between 18 and 24 months after diagnosis, intra-abdominal tumor recurrences were detected. The patient underwent bilateral oophorectomies for Krukenberg tumors and received salvage chemotherapy. Recently, additional recurrent metastatic retroperitoneal disease caused hydronephrosis. The retroperitoneal mass was debulked and a ureteric stent was placed. At the time of this writing, 43 months after diagnosis, the patient is receiving FOLFOX chemotherapy combined with panitumumab. CRC of childhood is exceedingly rare, generally develops in the setting of unrecognized genetic predisposing factors to cancer, presents with advanced disease, is high grade, and tends to have dismal prognosis.

The prognostic significance of β-catenin, cyclin D1 and PIN1 in minor salivary gland carcinoma: β-catenin predicts overall survival

Minor salivary gland carcinoma is a rare and heterogeneous type of cancer. Molecular prognostic and predictive markers are sparse. The aim of this study was to identify new prognostic and predictive markers in minor salivary gland carcinoma. 50 tissue samples of carcinomas of the minor salivary glands (adenoid cystic carcinoma n = 23, mucoepidermoid carcinoma n = 12, adenocarcinoma n = 10, carcinoma ex pleomorphic adenoma n = 2, salivary duct carcinoma n = 1, clear cell carcinoma n = 1, basal cell carcinoma n = 1) were immunohistochemically stained for β-catenin, cyclin D1 and PIN1. Expression patterns were analyzed and correlated to clinical outcome of 37 patients with complete clinical data. High expression of membranous β-catenin was linked to significantly better overall survival in patients with adenoid cystic carcinoma (log rank test, χ (2) = 13.3, p = .00397, Bonferroni corrected p = .024). PIN1 and cyclin D1 did not show any significant correlation to patients' clinical outcome. Expression of β-catenin in adenoid cystic carcinoma of the minor salivary glands significantly correlates with better overall survival. Hence, evaluation of β-catenin might serve as a clinical prognostic marker.

Basal cell adenocarcinoma of the salivary gland: a morphological and immunohistochemical comparison with basal cell adenoma with and without capsular invasion

Background

It is often difficult to diagnose salivary gland tumors that exhibit basaloid features differentially. The aim of this study was to identify additional morphological and immunohistochemical characteristics that can aid the diagnosis of basal cell adenocarcinoma (BCAC) of the salivary gland.

Methods and results

In total, 29 basal cell neoplasms [eight BCACs, 11 basal cell adenomas (BCAs) with capsular invasion, and 10 BCAs without capsular invasion] and 10 cases of adenoid cystic carcinomas (ACCs) were subjected to histopathology and immunohistochemical analyses for CK7, CK5/6, SMA, p63, calponin, p53, c-erbB2, CD117, β-catenin, EGFR, VEGF, Ki-67, and S100P protein expression. Compared to BCA without capsular invasion, the BCACs and BCAs with capsular invasion were more likely to be larger and have solid or cribriform patterns. Most BCACs and BCAs exhibited nuclear β-catenin expression. In all basal cell neoplasm cases, the clinical course after surgery with or without radiotherapy was indolent. β-catenin, CK5/6, CD117, and S100P protein were helpful for differentiating basal cell neoplasms from ACC.

Conclusions

BCAs with capsular invasion shared several pathological features with BCACs, including a large size and frequent cribriform patterns but the malignant potential of these tumors seems highly limited and should be reexamined. β-catenin immunostaining may aid the differential diagnosis between basal cell neoplasms and ACCs.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/9637819101988153

CYLD regulates keratinocyte differentiation and skin cancer progression in humans

CYLD is a gene mutated in familial cylindromatosis and related diseases, leading to the development of skin appendages tumors. Although the deubiquitinase CYLD is a skin tumor suppressor, its role in skin physiology is unknown. Using skin organotypic cultures as experimental model to mimic human skin, we have found that CYLD acts as a regulator of epidermal differentiation in humans through the JNK signaling pathway. We have determined the requirement of CYLD for the maintenance of epidermal polarity, keratinocyte differentiation and apoptosis. We show that CYLD overexpression increases keratinocyte differentiation while CYLD loss of function impairs epidermal differentiation. In addition, we describe the important role of CYLD in the control of human non-melanoma skin cancer progression. Our results show the reversion of the malignancy of human squamous cell carcinomas that express increased levels of CYLD, while its functional inhibition enhances the aggressiveness of these tumors which progress toward spindle cell carcinomas. We have found that the mechanisms through which CYLD regulates skin cancer progression include the control of tumor differentiation, angiogenesis and cell survival. These findings of the role of CYLD in human skin cancer prognosis make our results relevant from a therapeutic point of view, and open new avenues for exploring novel cancer therapies.