Sialadenoma papilliferum-like intraductal papillary tumour: an emerging entity with intercalated duct differentiation showing MAPK pathway activation in both ductal and myoepithelial cells.

Sialadenoma papilliferum-like intraductal papillary tumour (SP-IPT) is a recently described salivary gland tumour that shows identical morphology to sialadenoma papilliferum (SP) except for the lack of an exophytic papillary component. However, the immunohistochemical phenotypes and molecular profiles of SP-IPT remain unclear. This study aims to report new cases of SP-IPT and to determine its cellular differentiation and molecular basis. After histopathological review, four cases of SP-IPT were retrieved. Immunohistochemical staining was performed to analyse the expression patterns of cytokeratin 7 (CK7), p63, smooth muscle actin (SMA), vimentin, S100, mammaglobin, androgen receptor, SOX10, BRAF V600E-mutated protein, and phosphorylated ERK. Sanger sequencing was performed to determine the mutation status of the BRAF, KRAS, NRAS, and HRAS genes. All four cases affected the posterior mandible with a mean age of 62 years and a male-to-female ratio of 3:1. Histologically, all cases consisted of multiple tubular and cystic structures with varying sizes and shapes. The tubulocystic components were lined by a double or few-layered epithelium frequently showing a micropapillary pattern. The outer layer consisted of a rim of myoepithelial cells, which were CK7+/p63+/SMA+/vimentin+/S100+/SOX10+. The inner ductal cells were CK7+/S100+/SOX10+, consistent with intercalated duct differentiation. All cases harboured BRAF V600E mutations, but no other mutations were detected. The BRAF V600E-mutated protein and phosphorylated ERK were expressed in both ductal and myoepithelial cells. These findings demonstrate the immunohistochemical and molecular similarities between SP-IPT and SP and the role and extent of MAPK pathway activation in the pathogenesis of SP-IPT.

Study of the Immunohistochemical Expression of p63 in Benign Lesions and Carcinoma of the Breast at a Tertiary Hospital in South India.

BACKGROUND: Invasive breast carcinoma is among the most common female cancers worldwide, causing high morbidity and mortality. Considerable disagreement in the interpretation of diagnostically challenging breast lesions based on histology alone has been documented. One of the essential histopathological findings that help distinguish benign from malignant lesions is the presence of the myoepithelial cell layer. Myoepithelial markers such as tumor protein 63 (p63) help distinguish invasive carcinoma from benign proliferations. p63 antibody is superior to other myoepithelial markers as it selectively stains the nuclei and is negative in stromal cells. OBJECTIVE: To study the expression of p63 in various histological subtypes and grades of breast carcinomas. METHODS: After routine hematoxylin and eosin stain, 65 cases of breast lesions were subjected to immunohistochemistry for p63 antigen using Novacastra ready-to-use monoclonal antibody p6. All cases were analyzed for p63 expression, and its staining arrangement was interpreted. RESULTS: In all benign lesions, immunoreactivity was noted in the myoepithelial cells, forming a continuous layer surrounding the luminal epithelial cells. The benign papillary lesions showed p63 staining in the fibrovascular core of the papillary fronds and at the periphery. A few single myoepithelial cells stained by p63 were also seen scattered discontinuously in ductal carcinoma in situ (DCIS). All invasive carcinomas and encapsulated papillary carcinomas were completely devoid of peripheral p63 staining of myoepithelial cells. CONCLUSION: p63 is a specific nuclear marker of myoepithelial cells in the breast and can, therefore, aid in distinguishing invasive ductal carcinoma from DCIS or rare questionable hyperplastic lesions. They also play a significant role in distinguishing various papillary lesions of the breast and, hence, can be incorporated into routine reporting for definitive diagnosis and accurate treatment.

Encapsulated papillary carcinoma of the breast: A single institution experience.

Encapsulated papillary carcinoma (EPC) is a relatively rare form of breast cancer. To date, no evidence-based guidelines for the treatment of EPC have been established. Between January 2015 and December 2021, patients with histologically confirmed EPC of the breast were recorded in a database by The Third Hospital of Nanchang City (Nanchang, China). A total of 46 patients with EPC were retrieved from the database. Age at diagnosis ranged from 41-88 years (median age, 62 years). A total of 21 of these patients had pure EPC, 6 patients had EPC associated with ductal carcinoma in situ and 19 patients had EPC associated with invasive carcinoma. The majority of EPC cases were low nuclear grade, hormone receptor-positive and human epidermal growth factor receptor-2-negative. Additionally, myoepithelial cells were always absent in the papillae of the EPC. All patients underwent lumpectomy or mastectomy with sentinel lymph node biopsy, and almost all of the patients received adjuvant hormonal therapy. Adjuvant chemotherapy was only suggested to 4 patients who were diagnosed with axillary lymph node involvement. Subsequently, the clinicopathological features of non-invasive EPC were compared with invasive EPC. The results indicated that larger tumor sizes and axillary lymph node metastases were more common in invasive tumors. During the follow-up, only 2 patients with invasive EPC experienced recurrence or metastasis. In conclusion, a substantial proportion of invasive EPC cases display aggressive characteristics and metastatic potential, despite it being considered a subtype of carcinoma in situ with excellent prognosis, and local surgical resection is the initial method of treatment. Therefore, adjuvant endocrine therapy, radiotherapy and chemotherapy should be considered in select patients, especially in those diagnosed with invasive EPC tumors.

Cancer stem cells as the source of tumor associated myoepithelial cells in the tumor microenvironment developing ductal carcinoma in situ.

The heterogeneous cell population in the stromal microenvironment is considered to be attributed to the multiple sources from which the cells originate. Tumor associated myoepithelial cells (TAMEs) are one of the most important populations in the tumor microenvironment (TME) especially in breast cancer. On the other hand, cancer stem cells (CSCs) have previously been described to be the origin of tumor-associated cellular components in the TME. We prepared a cancer stem cell model converting mouse-induced pluripotent stem cells (miPSCs) in the presence of conditioned medium of breast cancer cell line MDA-MB-231 cells. The converted cells developed tumors progressing into invasive carcinoma with ductal carcinoma in situ (DCIS) like structure when transplanted into mouse mammary fat pads. The primary cultured cells from the tumor further exhibited markers of CSC such as Sox2, Oct3/4, - CD133 and EpCAM, and mammary gland-related TAME markers such as α-smooth muscle actin, cytokeratin 8, whey acidic protein, prolactin receptor and progesterone receptor as well. These results indicated that the CSCs could be an origin of TAMEs contributing to mammary gland epithelial cell differentiation and the progression to invasive carcinoma during tumor development. The gene expression profiles confirmed the enhanced signaling pathways of PI3K/AKT and MAPK, which have been demonstrated to be enriched in the CSC models, together with the estrogen receptor signaling which was peculiar to mammary gland-derived character.

Role of the adenylate cyclase/cyclic AMP pathway in oxytocin-induced lacrimal gland myoepithelial cells contraction.

The aim of these studies was to investigate the involvement of the second messenger 3',5'-cyclic adenosine monophosphate (cAMP) and its downstream effectors in oxytocin (OXT)-mediated lacrimal gland myoepithelial cell (MEC) contraction. Lacrimal gland MEC were isolated and propagated from alpha-smooth muscle actin (SMA)-GFP mice. RNA and protein samples were prepared to analyze G protein expression by RT-PCR and western blotting; respectively. Changes in intracellular cAMP concentration were measured using a competitive ELISA kit. To increase intracellular cAMP concentration, the following agents were used: forskolin (FKN, a direct activator of adenylate cyclase), 3-isobutyl-1-methylxanthine (IBMX, an inhibitor of the phosphodiesterase that hydrolyzes cAMP), or a cell permeant cAMP analog, dibutyryl (db)-cAMP. In addition, inhibitors and selective agonists were used to investigate the role of cAMP effector molecules, protein kinase A (PKA) and exchange protein activated by cAMP (EPAC) in OXT-induced MEC contraction. MEC contraction was monitored in real time and changes in cell size were quantified using ImageJ software. The adenylate cyclase coupling G proteins, Gαs, Gαo, and Gαi, are expressed in lacrimal gland MEC at both the mRNA and protein levels. OXT increased intracellular cAMP in a concentration-dependent manner. FKN, IBMX and db-cAMP significantly stimulated MEC contraction. Preincubation of cells with either Myr-PKI, a specific PKA inhibitor or ESI09, an EPAC inhibitor, resulted in almost complete inhibition of both FKN- as well as OXT-stimulated MEC contraction. Finally, direct activation of PKA or EPAC using selective agonists triggered MEC contraction. We conclude that cAMP agonists modulate lacrimal gland MEC contraction via PKA and EPAC activation which also play a major role in OXT induced MEC contraction.

Malignant Adenomyoepithelial Tumour of the Breast - a Rare Diagnosis - Case Report.

Breast adenomyoepithelioma is an unusual tumour characterized by a biphasic proliferation of epithelial and myoepithelial cells. Most of the breast adenomyoepitheliomas are considered to be benign and characterized by propensity for local recurrence. Malignant change can occur rarely in one or both cellular components. We here present a case of a 70-year-old previously healthy female who initially presented with a painless breast lump. The patient underwent wide local excision in view of suspicion of malignancy and sent for frozen section regarding the diagnosis and margins which surprisingly came as adenomyoepithelioma. Final histopathology came as low-grade malignant adenomyoepithelioma. The patient shows no sign of tumour recurrence in the follow up.

Growth of a Nipple Adenoma After Estrogen Replacement Therapy.

A nipple adenoma is an epithelial tumor of the lactiferous ducts, typically affecting women aged 50-60 years old. This case report discusses a 52-year-old woman who developed a papillary adenoma of the right nipple after initiating oral estrogen replacement therapy (ERT) for perimenopausal symptoms. A 4 mm punch biopsy and subsequent immunohistochemistry stain revealed the proliferation of ductal structures consistent with a papillary adenoma and tumor cells expressing estrogen receptors (ER) and progesterone receptors (PR). Despite their benign nature, nipple adenomas may exhibit alterations in immunophenotype, including ER and PR expression, which could lead to potential tumor growth in women undergoing these treatments. This case describes the first reported growth of a nipple adenoma in the context of estrogen replacement therapy, highlighting a potential risk of hormone therapy in promoting hyperproliferation of benign tumors such as nipple adenomas. When utilizing ERT, it is important to weigh the potential advantages and risks, as its application in the management of vasomotor symptoms during menopause may increase the risk of both breast cancer and benign proliferative breast diseases. These considerations underscore the need for individualized therapy when approaching perimenopausal and postmenopausal care.

Re-evaluation of the myoepithelial cells roles in the breast cancer progression.

Over the past decades, luminal epithelial cell lineage has gained considerable attraction as the functionally milk-secreting units and as the most fruitful acreage for breast cancer launching. Recognition of the effective involvement of the myoepithelial cells in mammary gland development and in hampering tumorigenesis has renewed the interest in investigating the biological roles of this second main mammary lineage. The human breast is made up of an extensively branching ductal system intervening by copious lobular units. The ductal system is coated by a chain of luminal epithelial cells (LECs) situated on a layer of myoepithelial cells (MECs) and encompassed by a distinguished basement membrane. Ductal contractility during lactation is a well-known function delivered by the MECs however this is not the only assignment mediated by these cellular populations. It has been well appreciated that the MECs exhibit a natural paracrine power in defeating cancer development and advancement. MECs were found to express numerous proteinase inhibitors, anti-angiogenic factors, and tumour suppressors proteins. Additionally, MECs contributed effectively to maintaining the right luminal cells' polarization and further separating them from the adjacent stroma by making an integrated fence. Indeed, disruption of the MECs layer was reported to facilitate the invasion of the cancer cells to the surrounding stroma. Nonetheless, MECs were also found to exhibit cancer-promoting effects and provoke tumour invasion and dissemination by displaying distinct cancer chemokines. Herein in this review, we aimed to address the roles delivered by MECs in breast cancer progression and decipher the molecular mechanisms regulating proper MECs' physiology, integrity, and terminal differentiation.

Effects of proinflammatory cytokines on lacrimal gland myoepithelial cells contraction.

In the lacrimal gland, myoepithelial cells (MEC) express muscle contractile proteins such as alpha smooth muscle actin (SMA) and calponin and therefore can contract to help expel lacrimal fluid. In a previous study, we demonstrated that lacrimal gland MEC express the oxytocin receptor (OXTR) and they contract under oxytocin (OXT) stimulation. Using NOD and MRL/lpr mice (animal models of Sjogren's syndrome), we reported a decrease in SMA and calponin protein levels plus a decline in acini contraction after stimulation with OXT. It is known that proinflammatory cytokines, such as interleukin-1ß (IL-1ß), tumor necrosis factor alpha (TNF-α) or interferon gamma (IFN-γ), can affect OXTR expression and signaling capacity and inhibit MEC contraction. The aim of the current study was to investigate if proinflammatory cytokines are implicated in the loss of MEC contractile ability. Thus, lacrimal gland MEC from a SMA-GFP transgenic mouse were treated with IL-1ß (10 ng/ml) for a total of 7 days. At days 0, 2, 4 and 7, GFP intensity, cell size/area, contractile proteins amounts and MEC contraction were assessed. At day 0, control and treated cells showed no differences in GFP intensity and cell size. GFP intensity started to decrease in treated MEC at day 2 (20%; p=0.02), continuing after day 4 (25%; p=0.007) and 7 (30%; p=0.0001). Mean cell area was also reduced at day 2 (34%; p=0.0005), and after 4 (51%; p<0.0001) and 7 days (30%; p=0.0015). The contraction assay at day 2 showed a 70% decrease of contraction in treated MEC (p<0.0001), 73% (p<0.0001) at day 4 and 82% (p=0.0015) at day 7 when compared to control. Levels of contractile proteins were measured on day 7 showing a decrease in SMA and calponin amount in treated MEC compared with the control group (around 30%; p=0.0016 and p=0.0206; respectively). Similar results were observed when TNF-α and IFN-γ were added along with IL-1ß. Taken together the present data and those from our previous studies with Sjogren's syndrome mouse models, they strongly suggest that proinflammatory cytokines affect lacrimal gland MEC contractile ability that may account for the reduced tear secretion associated with Sjogren's syndrome dry eye disease.

Postmenopausal Tubular Adenoma of the Breast: A Case Report.

Tubular adenoma (TA) of the breast is a rare, benign proliferative breast lesion that is predominantly composed of closely compacted tubules with an inner layer of epithelial cells and an outer layer of myoepithelial cells. They are regarded as residing on the opposite end of a spectrum of proliferative breast lesions from fibroadenomas, which are predominantly stromal. The majority of TAs are found in premenopausal women and the reason for this demographic predilection is not yet known. It is generally not possible to distinguish between TA and other, higher-risk breast lesions prior to biopsy or resection because the clinical and radiographic findings overlap. In this article, we present the case of a TA in a postmenopausal patient and review the epidemiology, histology, carcinogenic potential, and management of such lesions.

Nipple Adenoma: Case Report of a Rare Entity.

A nipple adenoma is a rare benign breast tumor. The commonest presentation of this rare entity is nipple erosion, serosanguinous discharge, induration, or tumor formation at the nipple. It often mimics malignant breast lesions or nipple eczema and is mistaken for Paget's disease of the nipple or dermatological pathology. It may be misdiagnosed pathologically as ductal carcinoma of the breast. This may cause a diagnostic delay or a faulty diagnosis. Treatment is the excision of the tumor with or without nipple excision. Here, we report a case of nipple adenoma that projected out of the nipple along with nipple erosion, serosanguinous discharge, and occasional bleeding from the adenoma. A 37- year-old woman presented with a tumor on her right nipple for eight months, with the erosion of the nipple and serosanguinous discharge. The patient gave a history of a small amount of bleeding occasionally. Axilla was normal. The patient was advised to have a mammosonography. It showed an oval-shaped, well-demarcated, hypoechoic, uniformly solid nodule in the right nipple. There was no microcalcification seen on mammography. A punch biopsy was done to establish the diagnosis. It showed ductal hyperplasia and papillary proliferation of glandular structures suggestive of nipple adenoma. Complete resection of the tumor with partial excision of the nipple was done with a satisfactory cosmetic result. Though very uncommon, the possibility of nipple adenoma should be thought of when a patient presents with nipple erosion and discharge with or without a clinically obvious tumor. Timely diagnosis with histopathological correlation is important since it allows for less invasive surgical methods. In our case, we could attain a cosmetically satisfactory outcome without a remnant tumor. Paget's disease of the nipple also has a similar clinical presentation, and it is a premalignant condition. The objective of presenting this case is to highlight the possibility of this rare benign condition, which may be easily missed clinically and also demands careful histopathological examination for its correct diagnosis.

Are myoepithelial cells confined to genital coelomic sinus in the gonads of sea stars?

An ultrastructural study of the gonadal wall in 10 sea star species from the orders Forcipulatida, Paxillosida, Spinulosida, Valvatida and Velatida has shown variations in the presence of myoepithelial cells in the visceral peritoneal epithelium. These cells have only been found in the peritoneal epithelium of the gonads in Aphelasterias japonica (Forcipulatida: Asteriidae), Asterias amurensis (Forcipulatida: Asteriidae), Distolasterias nipon (Forcipulatida: Asteriidae), Diplopteraster multipes (Velatida: Pterasteridae), Luidia quinaria (Paxillosida: Ctenodiscidae), and Pteraster sp. (Velatida: Pterasteridae). Our results may shed light on the evolution of peritoneal epithelium of sea star gonads. It is probable that, initially sea stars had myoepithelial cells in visceral peritoneal epithelium of the gonads. The species from the orders Forcipulatida and Velatida have retained this plesiomorphic state, while many species from the orders Paxillosida, Spinulosida and Valvatida have lost myoepithelial cells from visceral peritoneal epithelium of their gonads.

Cytodiagnosis of chondroid syringoma-Series of three cases.

Chondroid syringoma is a rare, benign, appendegeal neoplasm. It was initially termed as mixed tumor as it comprises both epithelial cells and chondromyxoid stroma. It usually presents as a slow growing, solitary, painless, subcutaneous, or intracutaneous mass, frequently in the head and neck region. Cytological features usually include the presence of both components, similar to histology but aspiration of only one component or atypical features can pose challenges in diagnosis. According to literature, only a few single case reports describing the cytological features of chondroid syringoma has been published. We report three cases of chondroid syringoma and its differential diagnosis on cytology.

Perfil do componente mioepitelial em neoplasias de glândulas salivares / Myoepithelial component profiling in salivary gland tumors

As neoplasias de glândulas salivares são um grupo heterogêneo de lesões que correspondem aproximadamente a 3-6% dos casos de neoplasias de cabeça e pescoço e apresentam características histológicas distintas. A grande variação no padrão histológico das lesões de glândulas salivares tem sido atribuída à presença de células mioepiteliais, que apresentam padrões distintos em cada neoplasia. O objetivo deste trabalho é avaliar a expressão de um painel de proteínas do citoesqueleto, adesão e proliferação celular, sendo elas: actina de músculo liso (AML), calponina, caldesmon, citoceratina 14 (CK14), E-caderina, vimentina, beta-catenina, Ki-67 e p63 em neoplasias malignas das glândulas salivares utilizando a técnica de imunoistoquímica (IHQ). Foram selecionadas retrospectivamente, um total de 15 amostras, sendo 08 amostras de carcinoma ex-adenoma pleomórfico, 04 de carcinoma mioepitelial, 03 de adenocarcinoma de células basais. Os casos foram analisados e os resultados, obtidos através da imumoistoquímica, comparados com os dados demográficos, clínicos e patológicos. A expressão das proteínas foi analisada qualitativamente e semi-quantitativamente, sendo classificada em negativo, positivo focal, positivo difuso ou positivo abundante. A actina de músculo liso (AML) foi observada em dois casos de adenocarcinoma de células basais (ACCB), três de carcinoma mioepitelial (CAME) e três de carcinoma ex-adenoma pleomórfico (CXAP). A calponina foi expressa em dois casos, tanto de ACCB quanto de CAME e em três casos de CXAP. A proteína caldesmon foi observada em dois casos de ACCB, os quatros casos de CAME e sete casos de CXAP. Três casos de ACCB e de CAME e cinco de CXAP apresentaram expressão de CK14. A E-caderina foi observada em todos os casos dos três tipos tumorais, assim como a beta-catenina. A proteína vimentina foi expressa em todos os casos de ACCB e CAME, e predominantemente nos casos de CXAP. Poucos casos, tanto de ACCB, CAME e CXAP apresentaram positividade para Ki-67. A proteína p63 foi observada em todos os casos de ACCB e CAME, sendo pouco expressa em CXAP. A análise de clusterização hierárquica demonstrou a formação de dois clusters, sendo um deles predominantemente composto por CXAP. A comparação da expressão das proteínas com as características demográficas, clínicas e patológicas demonstrou associação entre a perda de expressão das proteínas CK14 e p63 e a ocorrência de metástase. Os resultados sugerem que a expressão das proteínas beta-catenina, E-caderina, caldesmon e vimentina apresentou-se de forma muito similar, sugerindo um perfil equivalente de expressão entre essas neoplasias derivadas do ducto intercalar. Já a ausência de expressão de AML e calponina parece estar associada à separação dos grupos na análise de clusterização, sugerindo que deve ser considerada como um fator na diferenciação tumoral.

Salivary gland neoplasms are a heterogeneous group of lesions that account for approximately 3-6% of head and neck tumors, with distinct histological characteristics. The variation in the histological pattern of salivary gland lesions has been attributed to the presence of myoepithelial cells, that present different patterns in each neoplasm. The aim of the study was to evaluate the expression of a panel of cytoskeletal, cell adhesion and cell proliferation proteins, namely: smooth muscle actin (SMA), calponin, caldesmon, cytokeratin 14 (CK14), E-cadherin, vimentin, beta- catenin, Ki-67 and p63 in salivary glands malignant neoplasms, using immunohistochemical technique (IHC). Fifteen samples werer etrospectively selected, being 08 carcinoma ex-pleomorphic adenoma samples, 04 myoepithelial carcinoma samples, 03 basal cell adenocarcinoma samples. The immunohistochemical results were analyzed and compared with demographic, clinical and pathological data. Protein expression were qualitatively and semi-quantitatively analyzed and classified as negative and positive (focal, diffuse, or abundant). Smooth muscle actin (SMA) was observed in two cases of basal cell adenocarcinoma (BCAC), three cases of myoepithelial carcinoma (MECA) and three cases of carcinoma ex-pleomorphic adenocarcinoma (CXPA). Calponin was expressed in two cases of BCAC, two cases of MECA, and three cases of CXPA. Caldesmon protein was observed in two cases of BCAC, four cases of MECA and seven cases of CXPA. Three cases of BCAC and MECA and five of CXPA presented CK14 expression. E-cadherin was observed in all cases of the three tumor types, as well as beta-catenin. Vimentin protein was expressed in all BCAC and MECA cases, and predominantly in CXPA cases. Few cases of BCAC, MECA and CXPA were positive for Ki-67. p63 protein was observed in all cases of BCAC and MECA, and present low expression in CXPA. The hierarchical clustering analysis demonstrated the formation of two clusters, one of them being predominantly composed of CXPA. Protein expression comparison with demographic, clinical and pathological characteristics demonstrated an association between loss of expression of CK14 and p63 proteins and the occurrence of metastasis. The results suggest that the expression of beta-catenin, E-cadherin, caldesmon and vimentin proteins was very similar, suggesting an equivalent expression profile among these neoplasms derived from the intercalated duct of the salivary gland. The absence of SMA and calponin expression seems to be associated with the separation of groups in the clustering analysis, suggesting that it should be considered as a factor in tumor differentiation

Aging-Associated Alterations in Mammary Epithelia and Stroma Revealed by Single-Cell RNA Sequencing.

Aging is closely associated with increased susceptibility to breast cancer, yet there have been limited systematic studies of aging-induced alterations in the mammary gland. Here, we leverage high-throughput single-cell RNA sequencing to generate a detailed transcriptomic atlas of young and aged murine mammary tissues. By analyzing epithelial, stromal, and immune cells, we identify age-dependent alterations in cell proportions and gene expression, providing evidence that suggests alveolar maturation and physiological decline. The analysis also uncovers potential pro-tumorigenic mechanisms coupled to the age-associated loss of tumor suppressor function and change in microenvironment. In addition, we identify a rare, age-dependent luminal population co-expressing hormone-sensing and secretory-alveolar lineage markers, as well as two macrophage populations expressing distinct gene signatures, underscoring the complex heterogeneity of the mammary epithelia and stroma. Collectively, this rich single-cell atlas reveals the effects of aging on mammary physiology and can serve as a useful resource for understanding aging-associated cancer risk.

Understanding of tumourigenesis in canine mammary tumours based on cancer stem cell research.

Mammary tumours occur frequently in female dogs, where such tumours exhibit complexity when examined histologically. These tumours are composed not only of proliferative luminal epithelial cells, but also of myoepithelial cells and/or mesenchymal cells with cartilage and osseous tissues in a solitary mass. The origin of this complexed histogenesis remains speculative, but cancer stem cells (CSCs) are likely involved. CSCs possess self-renewing capacity, differentiation potential, high tumourigenicity in immunodeficient mice, and resistance to chemotherapy and radiation. These cells are at the apex of a hierarchy in cancer tissues and are involved in tumour initiation, recurrence, and metastasis. For these reasons, understanding the properties of CSCs is of paramount importance. Analysis of the characteristics of CSCs may contribute to the elucidation of the histogenesis underlying canine mammary tumours, formulation of novel CSC-targeted therapeutic strategies, and development of biomarkers for early diagnostic and prognostic applications. Here, we review research on CSCs in canine mammary tumours, focusing on: (1) identification and properties of CSCs; (2) hypotheses regarding hierarchal structures in simple type, complex type and mixed tumours of the canine mammary gland; and (3) current and prospective studies of CSC metabolism.

Myoepithelial cells and extracellular matrix in the cytologic differentiation of canine mammary tumors.

BACKGROUND: Mammary neoplasms are common tumors in intact female dogs. Fine-needle aspiration cytology (FNAC) is a valuable diagnostic tool and has gained some credibility in the diagnosis of mammary tumors in dogs. Prompt classification of canine mammary tumors using cytology would enhance feasibility as a prognostic tool and guide clinical and surgical management. OBJECTIVES: We aimed to examine background elements to differentiate mammary tumors using FNAC. We proposed to distinguish simple from complex and mixed tumors by identifying myoepithelial (ME) cells and different types of extracellular matrix. Additionally, we determined the accuracy of FNAC to differentiate benign from malignant tumors. METHODS: One hundred and one mammary tumors from female dogs were included in this study. We compared FNAC using histopathology as the gold standard. Cellular and background components were evaluated and identified. The cytologic accuracy, sensitivity (Se), specificity (Sp), positive predictive value (PPV), and negative predictive value (NPV) for diagnosing malignancy were determined, excluding inadequate samples. RESULTS: The cytologic-histologic agreement was 92.5% for simple carcinomas, 57.9% for complex-type carcinomas, 57.1% for mixed-type carcinomas, 27.3% for carcinosarcomas, and 100% for osteosarcomas. Myoepithelial cells were successfully identified using FNAC. Myxoid and chondroid/osteoid matrix were satisfactorily recognized. Cytologic accuracy, Se, Sp, PPV, and NPV for diagnosing malignancy were 99%, 100%, 83%, 99%, and 100%, respectively. CONCLUSIONS: Chondroid/osteoid matrix was noted in mixed tumors but not in complex tumors. Myxoid matrix, often associated with ME cells, was noted in complex and mixed tumors. Mesenchymal cells were differentiated from ME cells, allowing the distinction of simple carcinomas with scirrhous reaction from complex and mixed tumors.

[Expression of thymidylate synthase in salivary adenoid myoepithelial cells and its clinical significance].

OBJECTIVE: To evaluate the expression of thymidylate synthase (TS) in myoepithelial cells (MECs) of salivary adenoid tissues and explore its clinical significance. METHODS: Immunohistochemical staining EnVision method was used to detect the expression of TS, P63, Calponin, CK5/6 and S-100 in 32 salivary gland specimens, including 10 non-neoplastic and salivary inflammation specimens, 11 mixed tumor specimens, 5 basal cell carcinoma specimens and 6 adenoid cyst carcinoma specimens. The specificity and sensitivity of TS as a specific molecular marker of salivary muscle epithelial cells were evaluated in comparison with P63, Calponin, CK5/6 and S-100. RESULTS: The expression pattern of TS in all the salivary gland tissue specimens was identical with that of p63. TS and P63 both showed strong immunohistochemical expressions in MECs of salivary adenoid tissue specimens. Calponin, CK5/6, and S-100 showed cytoplasmic/membranous expressions in the MECs. In addition, TS exhibited weak or moderate cytoplasmic expression in a few salivary gland epithelial cells, cancer cells and scattered stromal cells, with negative expression in the cell nuclei. The expression of TS in the MECs of all the salivary adenoid specimens was highly consistent with those of P63, Calponin, CK5/6 and S-100 (P>0.05) Except for CK5/6 expression in Salivary inflammation and Salivary gland specimens. Kappa>0.75. The specificity and sensitivity of TS as a molecular marker of MECs were both 100%. CONCLUSIONS: TS is a new specific marker of MECs for differential diagnosis of salivary gland tumors.

Localized peripheral autonomous neuropathy and dysfunctional myoepithelial cells: A novel hypothesis for xerostomia in oral submucous fibrosis.

Oral submucous fibrosis (OSMF) is a potentially malignant disorder of the oral cavity characterized by submucosal deposition of dense collagen bundles leading to limited mouth opening. Besides, patients also complain about the burning sensation in the oral cavity and xerostomia. These symptoms have a major impact on the functional and psychological domains of oral health-related quality of life. However, the pathogenesis of xerostomia in OSMF is not yet well established. In our routine histopathology practice, we observed fibrosis surrounding minor salivary glands, distended acini, obliteration of acinar lumen and loss of interstitial spaces. Based on these features, we hypothesized that fibrosis in OSMF drives localized peripheral autonomous neuropathy in minor salivary glands, which leads to dysfunctional myoepithelial cells. These dysfunctional myoepithelial cells will unable to contract and expel saliva out of the salivary secretary unit, thus leading to xerostomia. In the present paper, experiments are recommended to prove this hypothesis, which can be exploited in the future for the development of appropriate drugs.

Interleukin-6-mediated epigenetic control of the VEGFR2 gene induces disorganized angiogenesis in human breast tumors.

Disorganized vessels in the tumor vasculature lead to impaired perfusion, resulting in reduced accessibility to immune cells and chemotherapeutic drugs. In the breast tumor-stroma interplay, paracrine factors such as interleukin-6 (IL-6) often facilitate disordered angiogenesis. We show here that epigenetic mechanisms regulate the crosstalk between IL-6 and vascular endothelial growth factor receptor 2 (VEGFR2) signaling pathways in myoepithelial (CD10+) and endothelial (CD31+, CD105+, CD146+, and CD133-) cells isolated from malignant and nonmalignant tissues of clinically characterized human breast tumors. Tumor endothelial (Endo-T) cells in 3D cultures exhibited higher VEGFR2 expression levels, accelerated migration, invasion, and disorganized sprout formation in response to elevated IL-6 levels secreted by tumor myoepithelial (Epi-T) cells. Constitutively, compared with normal endothelial (Endo-N) cells, Endo-T cells differentially expressed DNA methyltransferase isoforms and had increased levels of IL-6 signaling intermediates such as IL-6R and signal transducer and activator of transcription 3 (STAT3). Upon IL-6 treatment, Endo-N and Endo-T cells displayed altered expression of the DNA methyltransferase 1 (DNMT1) isoform. Mechanistic studies revealed that IL-6 induced proteasomal degradation of DNMT1, but not of DNMT3A and DNMT3B and subsequently led to promoter hypomethylation and expression/activation of VEGFR2. IL-6-induced VEGFR2 up-regulation was inhibited by overexpression of DNMT1. Transfection of a dominant-negative STAT3 mutant, but not of STAT1, abrogated VEGFR2 expression. Our results indicate that in the breast tumor microenvironment, IL-6 secreted from myoepithelial cells influences DNMT1 stability, induces the expression of VEGFR2 in endothelial cells via a promoter methylation-dependent mechanism, and leads to disordered angiogenesis.