DOG1: a novel marker of salivary acinar and intercalated duct differentiation

Clinicopathologic and molecular characterization of mammary analogue secretory carcinoma of salivary gland origin

BACKGROUND

Mammary analogue secretory carcinoma (MASC) is a newly recognized salivary gland tumor that harbors a characteristic balanced chromosomal translocation t (12; 15) (p13; q25) resulting in an ETV6-NTRK3 fusion gene.

METHODS

Retrospective study of 111 salivary gland carcinomas revealed 37 cases with secretory features and growth patterns resembling secretory carcinoma of breast. These 37 cases were originally diagnosed as acinic cell carcinoma, adenocarcinoma not otherwise specified and cystadenocarcinoma. Positive immunostaining for S-100 protein and mammaglobin, followed by detection of ETV6 gene rearrangement by FISH and/or ETV6-NTRK3 fusion transcript by RT-PCR were used to identify MASCs.

RESULTS

In the cohort of 37 salivary carcinomas with secretory features we have identified 10 cases of MASC. All 10 MASCs were positive for mammaglobin, S-100 protein and SOX10, while staining for DOG1 and p63 protein were mostly absent. In 7/10 cases, both FISH and RT-PCR were positive while three remaining cases showed break of ETV6 gene by FISH analysis and the RT-PCR was negative. Clinical follow-up data were obtained in 6 out of 10 patients with MASC. In 3 patients cervical lymph node metastases developed, one patient with high grade transformed MASC died with multiple distant bone metastases, and local recurrence was observed in three patients.

CONCLUSION

Our clinicopathological data are in keeping with previous studies; in most cases, MASC is a low-grade malignancy with overall favorable prognosis. In rare cases, however, MASC with high-grade transformation may behave aggressively, and these patients could benefit from targeted biological treatment using tyrosine kinase inhibitors.

Minor Salivary Gland Acinic Cell Carcinoma With Orbital Extension

An 80-year-old male presented with painless blurred vision from the right eye following endoscopic biopsy of a right maxillary sinus mass with the otolaryngology service. The patient admitted to progressive right-sided proptosis over the past few weeks. Past medical history was significant for acinic cell adenocarcinoma of buccal space origin with resection 3 years prior. Orbital CT revealed a large, poorly circumscribed destructive mass in the right masticator space with extension to the paranasal sinuses, inferior and medial orbit, and middle cranial fossa. Histopathology confirmed the mass to represent a recurrent acinic cell carcinoma. The patient was treated with chemotherapy, and at last follow-up 2 years after presentation had stable painless globe dystopia and visual acuity. The authors describe a very rare case of a recurrent minor salivary gland acinic cell carcinoma with secondary orbital extension.

Salivary Gland Tumors: Current Concepts and Controversies

This current review focuses on current concepts and controversies for select key salivary gland epithelial neoplasms. Rather than the traditional organization of benign and malignant tumors, this review is structured around select key topics: biphasic tumors, mammary analogue secretory carcinoma, and the controversy surrounding polymorphous low-grade adenocarcinoma and cribriform adenocarcinoma of (minor) salivary gland origin.

Utility of Immunohistochemistry and ETV6 (12p13) Gene Rearrangement in Identifying Secretory Carcinoma of Salivary Gland among Previously Diagnosed Cases of Acinic Cell Carcinoma

Objective. Secretory carcinoma is a recently described entity with characteristic immunoprofile and ETV6 (12p13) rearrangement. Before its initial description, it was generally diagnosed as acinic cell carcinoma (ACCi). We evaluated immunoprofile and ETV6 rearrangement in cytological and surgical cases of previously diagnosed ACCi, in an attempt to identify any misclassified SC. Methods. Fifteen cytology and surgical cases of ACCi diagnosed over a 13-year period were retrieved and subjected to immunohistochemistry for S-100, mammaglobin, GATA-3 and DOG-1 as well as FISH for ETV6 (12p13). Results. Of the 8 cytology cases, only 1 was positive for S100, GATA-3, and mammaglobin, and negative for DOG-1. It also demonstrated ETV6 rearrangement and was reclassified as SC. The same immunoprofile was present in 2 of the 13 surgical cases. ETV6 rearrangement characterized by 3′ interstitial deletion was detected in one of these cases and was reclassified as SC. Immunohistochemistry and ETV6 rearrangement were useful in identifying 2 (13.3%) cases misclassified as ACCi. Conclusions. Characteristic immunoprofile and ETV6 gene rearrangement may prove useful in identifying cases of SC. The presence of ETV6 3′ interstitial deletion in one of our cases suggests that there may be additional ETV6 related genetic alterations contributing to the pathogenesis of SC.

Combined DOG1 and Mammaglobin Immunohistochemistry Is Comparable to ETV6-breakapart Analysis for Differentiating Between Papillary Cystic Variants of Acinic Cell Carcinoma and Mammary Analogue Secretory Carcinoma

BACKGROUND

We investigated the reliability of combined DOG1 and mammaglobin immunohistochemistry compared with ETV6 fluorescence in situ hybridization (FISH) in the assessment of salivary tumors previously diagnosed as acinic cell carcinoma (ACC). Ultrastructural features of cases reclassified as mammary analogue secretory carcinoma (MASC) were assessed by transmission electron microscopy (TEM).

METHODS

Immunohistochemical (IHC) reactivity to DOG1 and mammaglobin was validated against FISH targeting the ETV6 gene in all 14 cases.

RESULTS

Three cases with papillary cystic histomorphology previously diagnosed as ACC were revised to MASC. TEM features of the ETV6 rearrangement-positive MASC cases showed large numbers of secretory granules with extrusion into the intercellular spaces, well-developed endoplasmic reticulum, lipid-laden vacuoles, well-formed microvilli, and large lining cystic spaces.

CONCLUSIONS

Combined DOG1 and mammaglobin immunohistochemistry is comparable to ETV6 -breakapart analysis for differentiating between papillary cystic variants of ACC and MASC.

New Developments in Salivary Gland Pathology: Clinically Useful Ancillary Testing and New Potentially Targetable Molecular Alterations

Accurate diagnosis of salivary gland tumors can be challenging because of the many diagnostic entities, the sometimes extensive morphologic overlap, and the rarity of most tumor types. Ancillary testing is beginning to ameliorate some of these challenges through access to newer immunohistochemical stains and fluorescence in situ hybridization probes, which can limit differential diagnostic considerations in some cases. These ancillary testing strategies are especially useful in small biopsy samples, including aspiration cytology. Molecular techniques are also expanding our understanding of salivary gland tumor pathology and are helping to identify potential targets that may improve treatment for some of these tumors. Here, we summarize the clinical use of new immunohistochemical markers in our practice and review the current understanding of chromosomal rearrangements in salivary gland tumor pathology, emphasizing the prospects for exploiting molecular alterations in salivary gland tumors for diagnosis and targeted therapy. We find that immunohistochemistry and fluorescence in situ hybridization are powerful tools toward the diagnosis of salivary gland tumors, especially when used in a systematic manner based on morphologic differential-diagnostic considerations. As new targeted therapies emerge, it will become increasingly vital to incorporate appropriate molecular testing into the pathologic evaluation of salivary gland cancers.

Mammary Analogue Secretory Carcinoma

Mammary analogue secretory carcinoma (MASC) is a recently described salivary gland tumor that shares the same histologic appearance and ETV6 gene (12p13) rearrangement as secretory carcinoma of the breast. Prior to its recognition, MASC cases were commonly labeled acinic cell carcinoma and adenocarcinoma, not otherwise specified. Despite distinctive histologic features, MASC may be difficult to distinguish from other salivary gland tumors, in particular zymogen-poor acinic cell carcinoma and low-grade salivary duct carcinoma. Although characteristic morphologic and immunohistochemical features form the basis of a diagnosis of MASC, the presence of an ETV6-NTRK3 gene fusion is confirmatory. Given its recent recognition the true prognostic import of MASC is not yet clearly defined.

Update from the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Tumors of the Salivary Gland

The salivary gland section in the 4th edition of the World Health Organization classification of head and neck tumors features the description and inclusion of several entities, the most significant of which is represented by (mammary analogue) secretory carcinoma. This entity was extracted mainly from acinic cell carcinoma based on recapitulation of breast secretory carcinoma and a shared ETV6-NTRK3 gene fusion. Also new is the subsection of "Other epithelial lesions," for which key entities include sclerosing polycystic adenosis and intercalated duct hyperplasia. Many entities have been compressed into their broader categories given clinical and morphologic similarities, or transitioned to a different grouping as was the case with low-grade cribriform cystadenocarcinoma reclassified as intraductal carcinoma (with the applied qualifier of low-grade). Specific grade has been removed from the names of the salivary gland entities such as polymorphous adenocarcinoma, providing pathologists flexibility in assigning grade and allowing for recognition of a broader spectrum within an entity. Cribriform adenocarcinoma of (minor) salivary gland origin continues to be divisive in terms of whether it should be recognized as a distinct category. This chapter also features new key concepts such as high-grade transformation. The new paradigm of translocations and gene fusions being common in salivary gland tumors is featured heavily in this chapter.

Diagnosis and Management of Malignant Salivary Gland Tumors of the Parotid Gland

Malignant parotid tumors are heterogeneous and diverse. Accurate diagnosis requires a pathologist familiar with the various histologic subtypes, immunohistochemistry stains, and common translocations. Clinical course varies according to tumor subtype, ranging from indolent, slow-growing adenoid cystic carcinoma to rapidly progressive, possibly fatal, salivary ductal carcinoma. Histologic grade is important in prognosis and therapy. Surgery remains the mainstay of treatment when negative margins can be achieved. Radiation improves locoregional control of tumors with high-risk features. Chemotherapy for parotid tumors can be disappointing. Studies of new targeted therapies have not offered significant benefits.

Newly described salivary gland tumors

This review concentrates on three salivary gland tumors that have been accepted in the recent literature as new neoplastic entities: mammary analog secretory carcinoma (MASC), sclerosing polycystic adenoma (SPA) and cribriform adenocarcinoma of tongue and other minor salivary glands (CAMSGs). MASC is a distinctive low-grade malignant salivary cancer that harbors a characteristic chromosomal translocation, t(12;15) (p13;q25) resulting in an ETV6-NTRK3 fusion. SPA is a rare lesion often mistaken histologically for low-grade salivary carcinoma. Previously thought to be a reactive fibroinflammatory process, but recent evidence of clonality, recurrences in up 30%, and dysplastic foci suggest it may be truly neoplastic. CAMSG is a distinct tumor entity that differs from polymorphous low-grade adenocarcinoma (PLGA) by location (ie, most often arising on the tongue), by prominent nuclear clearing, alterations of the PRKD gene family and clinical behavior with frequent metastases at the time of presentation of the primary tumor. Early metastatic disease seen in most cases of CAMSG associated with indolent behavior makes it a unique neoplasm among all low-grade salivary gland tumors. Salivary glands may give rise to a wide spectrum of different tumors. They are often diagnostically challenging as morphological features often overlap between different entities. Although conventional morphology in combination with immunohistochemical findings still provide the most important clues for diagnosis, recent advances in molecular pathology offer new diagnostic tools in investigating the differential diagnosis, as well as providing potentially valuable prognostic indicators. In the last two decades, several new salivary gland tumor entities have been described, namely MASC, SPA and CAMSGs.

Sinonasal Renal Cell-Like Carcinoma: Case Report and Review of the Literature

The differential diagnosis for clear cell neoplasms of the sinonasal tract is wide but critical to understand. In this paper, we describe a case of renal cell-like adenocarcinoma (SNRCLA) presenting as a paranasal sinus mass with clear cell morphology. The relevant literature is reviewed and the workup for clear cell neoplasms described. SNRCLA is a rarely encountered low grade glandular malignancy of the paranasal sinuses. Despite its morphologic mimicry of renal cell carcinoma, SNRCLA demonstrates a seromucinous phenotype and is associated with a favorable prognosis and low recurrence rates after surgical resection.

Is DOG1 Immunoreactivity Specific to Gastrointestinal Stromal Tumor?

BACKGROUND

DOG1 is a novel gene on gastrointestinal stromal tumors (GISTs) that encodes the chloride channel protein anoctamin 1, also known as discovered on GIST-1 (DOG1) protein. DOG1 antibodies are a sensitive and specific marker against GIST positive for CD117 and CD34 and negative for CD117 and CD34. DOG1 is also independent of KIT or PDGFRA mutation status and considered specific for GIST when it was first discovered in 2004.

METHODS

The previous 10 years of literature was searched for articles relating to DOG1. We critically reviewed 12 studies that showed DOG1 was positive in 250 cases of 2,360 tested non-GIST neoplasms (10.6%) at different anatomical sites using monoclonal, polyclonal, or nonspecified antibodies. Criteria for positivity varied between the studies.

RESULTS

Monoclonal and polyclonal DOG1 antibodies were reactive in various different non-GIST tumor types spanning 9 organ systems in addition to normal salivary and pancreatic tissues. The tumors included were renal oncocytoma (100%), renal cell carcinoma chromophobe type (86%), solid pseudopapillary neoplasm of the pancreas (51%), neoplastic salivary tissue (17%), synovial sarcoma (15%), leiomyoma (10%), pancreatic adenocarcinoma (7%), and leiomyosarcoma (4%).

CONCLUSIONS

By contrast to the original concept that DOG1 antibodies are specific to GIST neoplasms, the studies reviewed showed that the data suggest DOG1 positivity in select non-GIST tumors. Only in the appropriate clinical and pathological context is DOG1 positivity specific and helpful in the diagnosis of GIST.

Interleukin-13 stimulates MUC5AC expression via a STAT6-TMEM16A-ERK1/2 pathway in human airway epithelial cells

Transmembrane protein 16A (TMEM16A), a channel underlying the calcium-activated chloride channel (CaCC) currents, has been shown to be a key regulator of mucus overproduction in airway epithelial cells. However, the precise molecular mechanism involved in the TMEM16A-mediated mucus secretion remains unclear. In the present study, we inquired into a novel signaling mechanism for TMEM16A driving mucin 5AC (MUC5AC) production in human airway epithelial cells. Following treatment for 24-48h with type 13 interleukin (IL-13), an upregulation of TMEM16A expression in both mRNA and protein levels was observed in human bronchial epithelial cell line (HBE16), while signal transducer and activator of transcription 6 (STAT6) inhibition could decrease this elevated expression, suggesting that the regulation of TMEM16A expression by IL-13 was via a STAT6-based transcriptional mechanism. Further investigation of the HBE16 cells revealed that TMEM16A knockdown or specific chloride channel inhibitor T16Ainh-A01 could suppress the CaCC currents and consequently reduce the extracellular regulated kinase (ERK1/2) phosphorylation, accompanying a dramatical decrease in MUC5AC expression. Moreover, pretreated with PD98059, an inhibitor of ERK1/2, the HB16 cells showed a remarkable diminution in TMEM16A-mediated MUC5AC expression. Altogether, STAT6-TMEM16A-ERK1/2 signal pathway and TMEM16A channel activity are required for the IL-13-induced TMEM16A mediated mucus production.

Cytology of the Salivary Glands

Common usage of fine-needle aspirate (FNA) for salivary gland lesions is the preoperative determination of whether a lesion is neoplastic, its lineage, and if neoplastic, whether it is low grade/benign, or high grade. Immunohistochemical stains can be performed on cell blocks to determine lineage and help refine diagnosis, although their performance is not always equivalent to that seen in surgical specimens. Several characteristic translocations have been described in various entities in these categories, and these can be evaluated using fluorescence in situ hybridization. In the future, high-throughput next-generation sequencing panels may further refine cytologic diagnosis in salivary tumors.

Lysozyme Expression Can be Useful to Distinguish Mammary Analog Secretory Carcinoma from Acinic Cell Carcinoma of Salivary Glands

Lysozyme is an enzymatic marker of acinar and intercalated duct cells of normal salivary glands. The aim of this study was to verify whether lysozyme expression could be useful to distinguish acinic cell carcinoma (ACC) from its main mimic, mammary analog secretory carcinoma (MASC). For comparison, DOG1 expression was analyzed as well. Seventeen cases of ACC, 15 MASC, and 125 other salivary tumors were studied. Lysozyme expression was found in tumor cells as well as in secreted material of MASC (86.6 % of cases) and in ductal cells of epithelial-myoepithelial carcinoma (EMC-53.8 %), pleomorphic adenoma (PA-29.1 %) and polymorphous low-grade adenocarcinoma (PLGA-23.8 %). However, in ACC, lysozyme was not expressed. Three patterns of DOG1 staining were seen: apical-luminal, cytoplasmic, and mixed cytoplasmic/membranous. The apical-luminal pattern was detected in ductal cells of ACC (58.8 % of cases), EMC (38.4 %), adenoid-cystic carcinoma (AdCC-35.3 %), PA (8.3 %), and PLGA (4.8 %). These tumors also showed mixed membranous/cytoplasmic staining for DOG1. MASC, mucoepidermoid, and salivary duct carcinomas exhibited only DOG1 cytoplasmic staining. In conclusion, lysozyme cannot be used as a marker of acinar differentiation in salivary tumors. However, lysozyme expression can be helpful to distinguish MASC from ACC due to its high frequency in the former and absence in ACC. It is likely that in MASC, lysozyme expression may reflect a lactational-like secretory differentiation since lysozyme belongs to breast milk proteins. Regarding DOG1 expression, the apical-luminal pattern is related to acinar and intercalated duct differentiation whereas the cytoplasmic staining does not seem to be associated with a specific cellular phenotype.

Mammary analogue secretory carcinoma of parotid: Is preoperative cytological diagnosis possible?

Mammary analogue secretory carcinoma is a recently recognized tumor of salivary gland with characteristic t(12;15)(q13;q25) that results in ETV6-NTRK3 fusion product. Distinguishing mammary analogue secretory carcinoma from other salivary gland tumors is important. Present study highlights cytologic findings in three cases of mammary analogue secretory carcinoma of parotid which facilitate preoperative diagnosis with the aid of ancillary diagnostic techniques. Fine needle aspiration cytology of parotid was performed on three cases after clinical examination. Immunocytochemistry for mammoglobin and S100 were performed. Parotidectomy was done in all cases. The corresponding hematoxylin and eosin stained slides and blocks of all cases were studied. Molecular analysis was done in one of the cases. Cases 1 and 3 revealed uniform atypical epithelial cells arranged in branching papillary pattern with few cells in microcystic pattern. Case 2 showed atypical cells arranged mainly in loose clusters and few singly dissociated. Individual cells revealed round nuclei, vesicular chromatin, prominent nucleoli and abundant finely vacuolated cytoplasm with metachromasia prominent in May-Grunwald-Giemsa smear (case 3). Characteristic hob-nail cells covering papillae were observed in cases 1 and 3. Immunocytochemistry showed strong positivity for mammoglobin and S100 thereby confirming the diagnosis of mammary analogue secretory carcinoma preoperatively. The diagnosis was in concordance with surgical specimen. Also, characteristic ETV6-NTRK3 translocation was confirmed in case 1. Increased awareness and high index of suspicion is necessary for the upfront diagnosis, more so for the papillary variant of mammary analogue secretory carcinoma. Immunocytochemistry aids in confirming this preoperative diagnosis, based on which treatment can be planned. Diagn. Cytopathol. 2016;44:519-525. © 2016 Wiley Periodicals, Inc.

Novel Use for DOG1 in Discriminating Breast Invasive Carcinoma from Noninvasive Breast Lesions

Aims. DOG1 has proven to be a useful marker of gastrointestinal stromal tumors (GISTs). Recently, DOG1 expression has also been reported in some non-GIST malignant tumors, but the details related to DOG1 expression in breast tissue remain unclear. The aim of this study was to detect the expression of DOG1 in the human breast and to evaluate the feasibility of using DOG1 to discriminate between invasive breast carcinoma and noninvasive breast lesions. Methods and Results. A total of 210 cases, including both invasive and noninvasive breast lesions, were collected to assess DOG1 expression immunohistochemically. DOG1 expression was consistently positive in breast myoepithelial cells (MECs), which was similar to the results obtained for three other MEC markers: calponin, smooth muscle myosin heavy chain (SMMHC), and P63 (P > 0.05 in all). Importantly, DOG1 was useful in discriminating invasive breast carcinoma from noninvasive breast lesions (P < 0.05). Conclusions. DOG1 is a useful marker of breast MECs, and adding DOG1 to the MEC identification panel will provide more sophisticated information when diagnosing uncertain cases in the breast.

Cellular functions of TMEM16/anoctamin

Ca²⁺-activated Cl⁻ channels (CaCCs) are a class of Cl⁻ channels activated by intracellular Ca²⁺ that are known to mediate numerous physiological functions. In 2008, the molecular identity of CaCCs was found to be anoctamin 1 (ANO1/TMEM16A). Its roles have been studied in electrophysiological, histological, and genetic aspects. ANO1 is known to mediate Cl⁻ secretion in secretory epithelia such as airways, salivary glands, intestines, renal tubules, and sweat glands. ANO1 is a heat sensor activated by noxious heat in somatosensory neurons and mediates acute pain sensation as well as chronic pain. ANO1 is also observed in vascular as well as airway smooth muscles, controlling vascular tone as well as airway hypersensitivity. ANO1 is upregulated in numerous types of cancers and thus thought to be involved in tumorigenesis. ANO1 is also found in proliferating cells. In addition to ANO1, involvement of its paralogs in pathophysiological conditions was also reported. ANO2 is involved in olfaction, whereas ANO6 works as a scramblase whose mutation causes a rare bleeding disorder, the Scott syndrome. ANO5 is associated with muscle and bone diseases. Recently, an X-ray crystal structure of a fungal TMEM16 was reported, which explains a precise molecular gating mechanism as well as ion conduction or phospholipid transport across the plasma membrane.

Salivary acinic cell carcinoma: reappraisal and update

Epidemiologic and clinicopathologic features, therapeutic strategies, and prognosis for acinic cell carcinoma of the major and minor salivary glands are critically reviewed. We explore histopathologic, histochemical, electron microscopic and immunohistochemical aspects and discuss histologic grading, histogenesis, animal models, and genetic events. In the context of possible diagnostic difficulties, the relationship to mammary analog secretory carcinoma is probed and a classification is suggested. Areas of controversy or uncertainty, which may benefit from further investigations, are also highlighted.

Expression of SOX10 in Salivary Gland Oncocytic Neoplasms: A Review and a Comparative Analysis with Other Immunohistochemical Markers

OBJECTIVES

We evaluated SOX10 (SRY-related HMG-box 10) in differentiating acinic cell carcinoma (AciCC) from other salivary gland neoplasms with oncocytic features on fine-needle aspiration cell blocks (FNA CB) and compared its performance to DOG1 (discovered on gastrointestinal stromal tumor 1).

MATERIAL AND METHODS

35 FNA CB of oncocytic salivary gland neoplasms, i.e. 13 cases of AciCC, 16 of Warthin tumor (WT), 3 of mucoepidermoid carcinoma (MEC) and 3 of oncocytoma (ONC), and 75 salivary gland resections, i.e. 26 AciCC, 7 WT, 36 MEC, 3 ONC, 2 mammary analog secretory carcinomas (MASC) and 1 papillary cystadenoma were stained for SOX10 and DOG1.

RESULTS

None of the benign oncocytic neoplasms were immunoreactive for SOX10 on CB or resection, similar to DOG1. On CB, 61.5 and 77% of AciCC were positive for SOX10 and DOG1, respectively. All surgically resected AciCC cases were positive for SOX10 and DOG1; other malignant oncocytic lesions such as MEC and MASC demonstrated variable SOX10 and DOG1 staining.

CONCLUSION

The use of SOX10 may increase the diagnostic accuracy of oncocytic lesions on FNA. In this context, SOX10 is equivalent to DOG1 in ruling out benign lesions such as WT and ONC; however, negative results for SOX10 as well as DOG1 do not favor a benign diagnosis since MEC is often negative for both markers.

Is DOG1 really useful in the diagnosis of salivary gland acinic cell carcinoma? - A DOG1 (clone K9) analysis in fine needle aspiration cell blocks and the review of the literature

INTRODUCTION

DOG1 is a transmembrane protein originally "discovered on gastrointestinal stromal tumors," works as a calcium-activated chloride channel protein. There is a limited number of studies on the potential usage of this antibody in the diagnosis of salivary gland tumors on routine practice in cell blocks. The aim of this study was to search for the usefulness of K9 clone in oncocytic type tumors and review of the literature.

MATERIALS AND METHODS

Sixty-nine fine needle aspiration (FNA) cytologic materials of predominantly oncocytic morphology salivary gland tumors; acinic cell carcinoma (AciCC) (n = 8), adenoid cystic carcinoma (n = 2), pleomorphic adenoma (PA) (n = 22), Warthin tumor (WT) (n = 20), myoepithelioma (ME) (n = 5), benign oncocytoma (BeO) (n = 3), mucoepidermoid carcinoma (MEC) (n = 7), mammary analog salivary gland carcinoma (n = 2) were immunostained with DOG1 (clone K9) stain.

RESULTS

Of the 8 AciCCs, 7 were observed apical-luminal positive staining, demonstrating 1-3 + intensity, and involving 40-70% of the tumor cells. One MEC of 7 (14%), 1 ME of 5 (20%), and 4 PA of 22 (18%) showed weak (1+) cytoplasmic granular staining in 5-10% of the tumor cells. Pure oncocytic neoplasms (WT, BeO) showed no expression with DOG1-K9.

CONCLUSIONS

FNA is a common tool in the diagnosis and management of salivary gland tumors. DOG1-K9 clone was very useful with a unique staining pattern of apical-luminal positivity in the differential diagnosis of AciCC from other oncocytic salivary gland tumors.

Clinicopathologic and Immunophenotypic Characterization of 25 Cases of Acinic Cell Carcinoma with High-Grade Transformation

Acinic cell carcinoma (AiCC) with high-grade transformation is a rare variant of AiCC composed of both a conventional low-grade (LG) AiCC and a separate high-grade (HG) component. We describe here, the clinicopathologic and immunohistochemical features of 25 cases diagnosed between 1990 and 2015. Available tissue was analyzed and compared with a cohort of pure LG AiCC for the morphologic and immunophenotypic profile. Incidence was higher in females (1.8:1) than males with an overall mean age at presentation of 63.2 years. All tumors occurred in the parotid gland including 76% with facial nerve trunk and branches involvement. Most patients were treated with extensive resection and adjuvant therapy. Local recurrence or distant metastasis occurred in most patients, with 72.7% dead with disease (mean 2.9 years) and 3 patients alive with disease (mean 2.4 years). The majority of the tumors were composed of a LG microcystic AiCC and a HG component consisting of invasive lobules of undifferentiated cells with predominantly solid, cribriform, and glandular patterns. Acinic differentiation was still present in HG areas but aggressive features such as perineural invasion (76%), lymphovascular invasion (62%), positive margins (72%), high mitotic rate, atypical mitoses and/or comedonecrosis (86%) were easily identified. Compared to the pure LG AiCC, the cases with HG transformation showed significantly increased expression of cyclin-D1, p53 and Ki-67. Most HG areas of AiCC expressed membranous β-catenin (92%) and were negative for p63 (three cases were focally positive), S100, SMA, androgen, and estrogen receptors. DOG1 expression was present in all LG AiCC tested with retained expression in 91% of cases with HG transformation, supporting acinic differentiation in the HG foci. Recognition of AiCC with high-grade transformation is imperative as more aggressive clinical management is warranted.

Mammary analog secretory carcinoma, low-grade salivary duct carcinoma, and mimickers: a comparative study

Mammary analog secretory carcinoma (MASC) is a recently recognized low-grade salivary carcinoma characterized by a specific ETV6 rearrangement. We describe 14 new MASCs and examine their immunophenotypic and genetic profiles in the context of look-alikes, namely, low-and high-grade salivary duct carcinoma and acinic cell carcinoma. ETV6 rearrangement, and robust expression of mammaglobin and S100, were demonstrated in 11/11, 14/14, and 12/14 MASCs, respectively. All low-grade salivary duct carcinomas coexpressed S100/mammaglobin (6/6); none harbored ETV6 rearrangements (0/5). Given that S100/mammaglobin coexpression and absence of zymogen granules are features of both MASC and low-grade salivary duct carcinoma, these two are best distinguished histologically. The former is predominantly an extraductal neoplasm with bubbly pink cytoplasm, whereas the latter is a distinct intraductal micropapillary and cribriform process. Querying ETV6 gene status may be necessary for difficult cases. No acinic cell carcinoma expressed mammaglobin (0/13) or harbored an ETV6 rearrangement (0/7); only 1/13 acinic cell carcinomas weakly expressed S100. DOG1 expression was limited or absent among all tumor types, except acinic cell carcinoma which expressed DOG1 diffusely in a canalicular pattern. Therefore, histology and immunohistochemistry (mammaglobin, S100, DOG1) suffices in distinguishing acinic cell carcinoma from both MASC and low-grade salivary duct carcinoma. HER2 (ERBB2) amplification was detected in only 1/10 acinic cell carcinomas, but none of the MASCs or low-grade salivary duct carcinomas tested. High-grade salivary duct carcinomas frequently expressed mammaglobin (11/18) and harbored HER2 amplifications (13/15); none harbored ETV6 rearrangements (0/12). High-grade salivary duct carcinomas can easily be distinguished from these other entities by histology and HER2 amplification.

Oncocytic lipoadenoma: a rare case of parotid gland tumor and review of the literature

Oncocytic lipoadenoma is a rare tumor, with only 18 cases having been reported since the first in 1998. We encountered a case of oncocytic lipoadenoma presenting as a slowly growing parotid mass in a 71-year-old man. This tumor is characteristically comprised of a mixture of oncocytes and adipocytes. The present case is one of five reported cases of oncocytic lipoadenoma showing sebaceous differentiation. The results of immunohistochemical study with DOG1 antibody supported the origination of this tumor in the striated duct.

TMEM16A mediates the hypersecretion of mucus induced by Interleukin-13

Previous studies showed that the Ca(2+)-activated Cl(-) channel (CaCC) was involved in the pathogenesis of mucus hypersecretion induced by Interleukin-13 (IL-13). However, the mechanisms underlying the process were unknown. Recently, transmembrane protein 16A (TMEM16A) was identified as the channel underlying the CaCC current. The aim of the current study was to investigate whether the TMEM16A channel is part of the mechanism underlying IL-13-induced mucus hypersecretion. We observed that both TMEM16A mRNA and protein expression were significantly up-regulated after treatment with IL-13 in human bronchial epithelial 16 (HBE 16) cells, which correlated with an increase in mucus production. Additionally, mucus hypersecretion in rat airways was induced by intratracheal instillation of IL-13 and similar increases were observed in the expression of TMEM16A mRNA and protein in the bronchial epithelium. Niflumic acid (NA), a selective antagonist of CaCC, markedly blocked IL-13-induced mucin (MUC) 5AC mRNA and protein production in vivo and in vitro. Further investigation with HBE16 cells revealed that TMEM16A overexpression clearly promoted mucus production, IκBα phosphorylation, and p65 accumulation in the nucleus. The loss of TMEM16A resulted in inhibition of mucus production, and the TMEM16A-mediated production of MUC5AC was significantly blocked by a nuclear factor-kappa B (NF-κB) inhibitor. Therefore, the TMEM16A channel acts upstream of NF-κB in the regulation of mucus production. This is the first demonstration that the TMEM16A-NF-κB pathway is positively involved in IL-13-induced mucus production, which provides novel insight into the molecular mechanism of mucin overproduction.

A Subset of Sinonasal Non-Intestinal Type Adenocarcinomas are Truly Seromucinous Adenocarcinomas: A Morphologic and Immunophenotypic Assessment and Description of a Novel Pitfall

While sinonasal intestinal type adenocarcinoma (ITAC) is defined by an intestinal phenotype, non-intestinal type adenocarcinoma (non-ITAC) is traditionally viewed as a diagnosis of exclusion, despite previous implication of a seromucinous phenotype and similarity to sinonasal seromucinous hamartomas (SSH). We performed a comparison of clinicopathologic and immunophenotypic features of ITAC, non-ITAC and SSH using traditional discriminatory markers and new markers of seromucinous differentiation. Twenty-three non-ITAC, 17 ITAC, and 5 SSH were retrieved (1987-2014). As expected, ITAC occurred predominantly in the nasal cavity in elderly patients (mean age 65 years) with a striking male predilection (15:2). Regardless of grade/subtype, all ITAC were invariably CK20 and CDX2 positive, and many (11/15) showed some CK7 positivity. Non-ITAC occurred in younger individuals (mean age 51 years) with a slight female predilection (male to female ratio: 10:13) and showed diverse morphologic patterns and grades, some with morphologic similarity to SSH. SSH occurred in younger individuals (mean age 33 years). Non-ITAC and SSH were invariably CK7 positive and CK20 negative, however, 4/22 non-ITAC and 2/5 SSH showed squamoid morular metaplasia that aberrantly expressed CDX2 and co-expressed nuclear β-catenin. Markers of seromucinous differentiation (S100, DOG1, and SOX10) were essentially absent in ITAC, but present to varying degrees in the majority of non-ITAC and all SSH. Thus, the term 'seromucinous adenocarcinoma' is the more appropriate designation for non-ITAC. Squamoid morules in non-ITAC and SSH may be an immunophenotypic pitfall given the aberrant CDX2 expression.

Relationship of endothelial area with VEGF-A, COX-2, maspin, c-KIT, and DOG-1 immunoreactivity in liposarcomas versus non-lipomatous soft tissue tumors

Soft tissue tumors are rare tumors that show a heterogeneous structure; thus far, their molecular behavior has not been elucidated. The aim of our study was to define the relationship between microvessel density (MVD), evaluated with CD31, and other immunohistochemical markers, such as vascular endothelial growth factor (VEGF), cyclooxygenase-2 (COX-2), CD34, maspin, DOG-1, and c-KIT. Immunostains were done in 55 cases consisting of benign and malignant tumors, such as liposarcomas, dermatofibrosarcomas, and tumors with histiocytic differentiation. Renal tubes were used as external control for VEGF, maspin, and DOG-1. Although DOG-1 is considered a specific marker for gastrointestinal tumors (GISTs), its positivity, correlated with c-KIT and VEGF immunoexpression, was also shown by dermatofibrosarcomas and tumors with histiocytic and lipomatous differentiation, suggesting its possible pro-angiogenic role. Maspin expression was observed in adipose tissue tumors only. Regarding angiogenesis, 31 of the 55 cases were VEGF-positive, such positivity being directly correlated with COX-2 and CD34 positivity as evaluated in the tumor cells and also with MVD. Although no significant differences in angiogenic activity were found between benign and malignant non-lipomatous tumors, the MVD was directly correlated with the histological type/grade of liposarcomas. Based on these aspects, we conclude that VEGF/COX-2-induced angiogenesis is specific for non-lipomatous tumors, whereas liposarcomas are dependent on the VEGF/maspin angiogenic pathway. The DOG-1/c-KIT/VEGF target may be used for further personalized therapy of soft tissue sarcomas. No data about DOG-1 and maspin positivity in liposarcomas have been published to date.

Review and Updates of Immunohistochemistry in Selected Salivary Gland and Head and Neck Tumors

Context

Immunohistochemistry is a useful tool for diagnosing salivary gland and head and neck tumors.

Objective

To review immunohistochemical markers, which can aid in the diagnosis of selected salivary gland and head and neck tumors.

Data Sources

Literature review and authors' personal practice experience.

Conclusions

Salivary gland and head and neck tumors include a large diverse group of tumors with complex and overlapping histologic features. Immunohistochemistry plays an important role in resolving the differential diagnosis of some salivary gland and head and neck tumors and can provide information for the prognosis of certain tumors.

Inhibition of TMEM16A expression suppresses growth and invasion in human colorectal cancer cells

Metastasis leads to poor prognosis in colorectal cancer patients, and there is a growing need for new therapeutic targets. TMEM16A (ANO1, DOG1 or TAOS2) has recently been identified as a calcium-activated chloride channel (CaCC) and is reported to be overexpressed in several malignancies; however, its expression and function in colorectal cancer (CRC) remains unclear. In this study, we found expression of TMEM16A mRNA and protein in high-metastatic-potential SW620, HCT116 and LS174T cells, but not in primary HCT8 and SW480 cells, using RT-PCR, western blotting and immunofluorescence labeling. Patch-clamp recordings detected CaCC currents regulated by intracellular Ca(2+) and voltage in SW620 cells. Knockdown of TMEM16A by short hairpin RNAs (shRNA) resulted in the suppression of growth, migration and invasion of SW620 cells as detected by MTT, wound-healing and transwell assays. Mechanistically, TMEM16A depletion was accompanied by the dysregulation of phospho-MEK, phospho-ERK1/2 and cyclin D1 expression. Flow cytometry analysis showed that SW620 cells were inhibited from the G1 to S phase of the cell cycle in the TMEM16A shRNA group compared with the control group. In conclusion, our results indicate that TMEM16A CaCC is involved in growth, migration and invasion of metastatic CRC cells and provide evidence for TMEM16A as a potential drug target for treating metastatic colorectal carcinoma.

DOG1, p63, and S100 protein: a novel immunohistochemical panel in the differential diagnosis of oncocytic salivary gland neoplasms in fine-needle aspiration cell blocks

INTRODUCTION

DOG1 is a calcium-activated chloride channel protein that may have a potential role in secretory cells of salivary glands and tumors derived from them. Its role in cytologic specimens is not well documented. This study was performed to evaluate its utility in separating acinic cell carcinoma (AciCC) from other closely related differential diagnoses on cytologic samples. In addition, an immunohistochemical panel consisting of DOG1, p63, and S100 protein to assist in the subclassification of these salivary gland neoplasms with oncocytic differentiation was also investigated.

MATERIALS AND METHODS

Thirty-one fine-needle aspiration cell blocks (CBs) of oncocytic salivary gland neoplasms (16 Warthin tumors [WTs], 10 AciCCs, 3 mucoepidermoid carcinomas [MECs], and 2 oncocytomas [ONCs]), and 75 salivary gland resections (7 WTs, 27 AciCCs, 36 MECs, 2 high-grade adenocarcinomas, 2 ONCs, 1 papillary cystadenoma) were immunostained for DOG1, p63, and S100.

RESULTS

DOG1 and p63 were very useful in distinguishing AciCC from WT on CB, because 100% of WTs were DOG1-negative and 87.5% were p63-positive, whereas 70% of AciCCs were DOG1-positive and 100% were p63-negative. The resection results correlated with those on CBs: 100% of WTs were DOG1-negative and 86% were p63-positive, whereas 93% of AciCCs were DOG1-positive and 89% were p63-negative. S100 and DOG1 were negative in both WTs and ONCs, with <10% S100 positivity in AciCCs.

CONCLUSIONS

DOG1 was very helpful in separating AciCC from WT, MEC, and ONC. In summary, an immunohistochemical panel including DOG1, p63, and S100 can significantly improve the accuracy of diagnosing oncocytic salivary gland neoplasms on CBs.

Characterization of mammary analogue secretory carcinoma of the salivary gland: discrimination from its mimics by the presence of the ETV6-NTRK3 translocation and novel surrogate markers

Mammary analogue secretory carcinoma (MASC) is a recently recognized salivary gland tumor harboring an ETV6-NTRK3 translocation similar to secretory carcinoma of the breast. Histologically, MASC mimics papillary-cystic, microcystic, and follicular-type acinic cell carcinoma (AciCC) and low-grade cribriform cystadenocarcinoma (LGCCC) of the salivary gland. Using histology, immunohistochemistry (IHC), and molecular genetic techniques, we reevaluated 18 cases originally diagnosed as AciCC between 1993 and 2012. The last of these methods was used to detect the ETV6-NTRK3 translocation. The results reconfirmed 6 cases as AciCC (3 men; average age, 63 years) and helped us reclassify 10 cases as MASC (6 men; mean age, 46 years) and 2 as LGCCC (2 women; mean age, 48 years). Using IHC, we identified the 3 histologic types according to the expression patterns of vimentin, high-molecular-weight cytokeratin, cytokeratin 19, S-100, mammaglobin, MUC1, GATA-binding protein 3, adipophilin, α-amylase, DOG-1, SOX-10, and p63. The number of tumors diagnosed as MASC indicates that AciCC includes bona fide MASC cases. Because differential diagnosis among zymogen granule-poor AciCC, MASC, and LGCCC tumors is challenging, we recommend using molecular genetic tests for ETV6-NTRK3 for accurate diagnosis. Furthermore, detailed analyses of hematoxylin and eosin-stained tissues and IHC studies using the markers described here should be incorporated into routine practices.

Recent advances in the diagnostic pathology of salivary carcinomas

This review concentrates on the most important developments since the WHO classification of 2005. In particular, the identification of specific translocations is revolutionising the way salivary tumours are considered and will have a major impact on future diagnostic practice. This is true so far in four malignancies: mammary analogue secretory, mucoepidermoid, adenoid cystic and hyalinising clear cell carcinomas. In each, the gene rearrangement is found in 80 % or more of cases. Two 2014 publications have added further possible candidates with molecular abnormalities to the list (cribriform adenocarcinoma of the tongue and minor salivary glands and epithelial-myoepithelial carcinoma), but these findings have yet to be confirmed by other investigators. The advances in molecular pathology have also allowed re-evaluation of the morphology; for example, it is now realised that the histological spectrum of hyalinising clear cell carcinoma includes intracellular mucin in over half of cases, as well as tumours with only scanty clear cells. In a separate development, it is now proposed that salivary duct carcinoma can be subdivided along molecular lines, in ways analogous to breast cancer, suggesting new therapeutic prospects in an otherwise highly aggressive malignancy.

Canalicular adenoma: a clinicopathologic and immunohistochemical analysis of 67 cases with a review of the literature

There is a lack of a comprehensive immunohistochemical (IHC) analysis of canalicular adenoma (CanAd), especially when combined with a description of the unique histologic features. Given the usual small biopsies, IHC may be useful in distinguishing CanAd from other tumors in the differential diagnosis. Retrospective. The patients included 54 females and 13 males (4.2:1), aged 43-90 years, with a mean age at presentation of 69.9 years. Clinical presentation was generally a mass (n = 61) slowly increasing in size (mean 38.5 months), affecting the upper lip (n = 46), buccal mucosa (n = 17) or palate (n = 4), involving the right (n = 29), left (n = 24) or midline (n = 9), without any major salivary gland tumors. The tumors ranged in size from 0.2 to 3 cm (mean 1.2 cm). Most tumors were multilobular or bosselated (76 %), often surrounded by a capsule. Histologically, the tumors were characterized by cystic spaces, tumor cords with beading, tubule formation, and by the presence of luminal squamous balls (n = 41). The cells were cuboidal to columnar with stippled chromatin. Mitoses were inconspicuous. A myxoid stroma (n = 64), sclerosis (n = 42), luminal hemorrhage (n = 51), and luminal microliths (calcifications) (n = 33) were characteristic. Nine (13.4 %) were multifocal. CanAd showed the following characteristic immunohistochemistry findings: CK-pan and S100 protein (strong, diffuse reaction); peripheral or luminal GFAP reaction; CK5/6 and p16 luminal squamous ball reaction; SOX10 nuclear reaction; cytoplasmic p63 reaction. CanAd are unique minor salivary gland tumors showing a distinct architecture and phenotype. They predilect to older women, with the majority multilobulated and affecting the upper lip, multifocal in 13 %; no major salivary gland tumors were identified. S100 protein, CK-pan, GFAP and SOX10 are positive, with luminal squamous balls highlighted by CK5/6 or p16.

Morphology in conjunction with immunohistochemistry is sufficient for the diagnosis of mammary analogue secretory carcinoma

The recently described mammary analogue secretory carcinoma (MASC) is a low-grade salivary gland malignancy that harbors the recurrent cytogenetic abnormality t(12;15) (p13;q25) ETV6-NTRK3. Confirmation of this is currently considered the gold standard for diagnosis. Some have postulated that morphology together with supporting immunohistochemistry is sufficient to diagnose MASC. In this study we retrospectively review a series of 19 MASCs diagnosed based on histology in conjunction with immunohistochemistry; subsequently we performed in situ hybridization using an ETV6 break-apart probe. Immunohistochemistry for S100 protein and mammaglobin as well as fluorescence in situ hybridization using the Vysis ETV6 Dual Color Break-Apart FISH Probe Kit were performed on all cases. The 19 cases were from 12 females and 7 males with ages ranging from 16 to 76 years (mean = 45 years). Sixteen cases were from the parotid gland, 1 case was from a periparotid lymph node and 2 cases were from the submandibular gland. All 19 cases demonstrated moderate to strong expression of S100 protein. Eighteen cases demonstrated strong, diffuse expression of mammaglobin, while one case had only rare tumor cells that strongly expressed mammaglobin. Eighteen of 19 cases (95 %) demonstrated the ETV6 rearrangement by fluorescence in situ hybridization. Given that morphology together with immunohistochemistry is highly correlated with the ETV6 gene rearrangement, we conclude that molecular confirmation is not required to diagnose MASC.

Role of anoctamins in cancer and apoptosis

Anoctamin 1 (TMEM16A, Ano1) is a recently identified Ca(2+)-activated chloride channel and a member of a large protein family comprising 10 paralogues. Before Ano1 was identified as a chloride channel protein, it was known as the cancer marker DOG1. DOG1/Ano1 is expressed in gastrointestinal stromal tumours (GIST) and particularly in head and neck squamous cell carcinoma, at very high levels never detected in other tissues. It is now emerging that Ano1 is part of the 11q13 locus, amplified in several types of tumour, where it is thought to augment cell proliferation, cell migration and metastasis. Notably, Ano1 is upregulated through histone deacetylase (HDAC), corresponding to the known role of HDAC in HNSCC. As Ano1 does not enhance proliferation in every cell type, its function is perhaps modulated by cell-specific factors, or by the abundance of other anoctamins. Thus Ano6, by regulating Ca(2+)-induced membrane phospholipid scrambling and annexin V binding, supports cellular apoptosis rather than proliferation. Current findings implicate other cellular functions of anoctamins, apart from their role as Ca(2+)-activated Cl(-) channels.

The Ca(2+) -activated Cl(-) channel, ANO1 (TMEM16A), is a double-edged sword in cell proliferation and tumorigenesis

Since anoctamin 1 ANO1 (TMEM16A) was found to be a molecular component of Ca²⁺-activated Cl⁻ channels, its role in tumorigenesis has gained attention at a fast pace. ANO1 overexpression frequently occurs in the cancer tissues along with 11q13 chromosome amplification. Poor prognosis of many types of cancers has been closely correlated with ANO1 gene amplification and protein overexpression. ANO1 is now considered an excellent biomarker for certain cancers. Recent research suggests that it is the channel function of ANO1 that is involved in the tumorigenesis. However, how the overexpression of the functional ANO1 causes malignant transformation of tissues via signaling pathways, for example, MAPK remains to be investigated. Clarification of the reasons in future will avail to make ANO1 as a target for cancer treatment.

A rare malignancy of the parotid gland in a 13-year-old Taiwanese boy: case report of a mammary analogue secretory carcinoma of the salivary gland with molecular study

Mammary analogue secretory carcinoma (MASC) is a recently described malignancy of the salivary glands characterized by an ETV6-NTRK3 (EN) fusion gene. Morphologically, MASC is sometimes difficult to distinguish from acinic cell carcinoma. Consequently, identifying the chromosomal translocation is essential for diagnosis. We present a case of parotid gland MASC in a 13-year-old boy. To the best of our knowledge, this is the youngest case reported in the literature. Histologic evaluation showed a tumor composed of microcysts, tubular structures, solid nests, or papillary architecture, with secretions within the lumens of the cysts or tubules. Immunohistochemically, tumor cells showed diffuse positive staining of S-100 protein, cytokeratin 19, and vimentin. ETV6 rearrangement was detected by fluorescence in situ hybridization and EN fusion transcripts were verified by reverse transcription (RT-PCR) assay.