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Histopathology Jan 2023Myoepithelial cells (MECs) constitute a continuous layer of cells surrounding the breast glands, localised between the epithelial cells (ECs) and the basal membrane.... (Review)
Review
Myoepithelial cells (MECs) constitute a continuous layer of cells surrounding the breast glands, localised between the epithelial cells (ECs) and the basal membrane. MECs play important roles in normal mammary gland as they produce basal membrane and stimulate secretion. During neoplastic transformation, MECs act as a barrier preventing stromal invasion. MECs themselves can undergo a great variety of changes, ranging from hyperplastic to metaplastic, to neoplastic, and giving rise to a wide spectrum of morphological pictures sometimes difficult to interpret on routine diagnoses. Several benign and malignant breast tumours can present features of MECs differentiation. As these latter tumours are quite infrequent, the purpose of the present study is to offer a review of the morphological spectrum of MECs lesions, with correlations to prognosis.
PubMed: 36482278
DOI: 10.1111/his.14826 -
The American Journal of Dermatopathology Jul 2021Eosinophilic hyaline inclusions (EHIs) or globules have been reported in various cutaneous tumors including vascular lesions, myoepithelial neoplasms, and basal cell...
Eosinophilic hyaline inclusions (EHIs) or globules have been reported in various cutaneous tumors including vascular lesions, myoepithelial neoplasms, and basal cell carcinoma. In basal cell carcinoma, the presence of intracytoplasmic inclusions is reportedly associated with myoepithelial differentiation. In this regard, EHI has not been conclusively documented in a cutaneous lesion of genuine squamous cell lineage without aberrant differentiation. In the current case, a biopsy from the right thigh of a 71-year-old male patient demonstrated a relatively well-demarcated intraepidermal squamous lesion featured an admixture of predominantly enlarged keratinocytes harboring distinct eccentric intracytoplasmic EHI and a smaller population of keratinocytes displaying pale cytoplasm. Cytologic atypia, mitotic activity, and inflammatory cells were not identified. The intracytoplasmic EHI stained red with Masson's trichrome and were negative with periodic-acid Schiff with and without diastase. Immunologically, the lesion was strongly and diffusely positive for various cytokeratins but negative for ubiquitin and myoepithelial markers. Only cytokeratin AE1 revealed a differential staining pattern as the suprabasal lesional cells displayed significantly stronger immunoreactivity in comparison with the adjacent normal keratinocytes. Polymerase chain reaction for low-risk and high-risk human papillomavirus was negative. Molecular studies did not reveal any mutations commonly encountered in seborrheic or lichenoid keratoses. As an analogous lesion has not previously reported in the literature, the term hyaline inclusion acanthoma is proposed for this peculiar lesion.
Topics: Acanthoma; Aged; Biomarkers, Tumor; Biopsy; Humans; Hyalin; Immunohistochemistry; Keratinocytes; Male; Skin Neoplasms
PubMed: 33606370
DOI: 10.1097/DAD.0000000000001927 -
Advances in Experimental Medicine and... 2019Epithelial stem cells reside within multiple regions of the lung where they renew various region-specific cells. In addition, there are multiple routes of regeneration... (Review)
Review
Epithelial stem cells reside within multiple regions of the lung where they renew various region-specific cells. In addition, there are multiple routes of regeneration after injury through built-in heterogeneity within stem cell populations and through a capacity for cellular plasticity among differentiated cells. These processes are important facets of respiratory tissue resiliency and organism survival. However, this regenerative capacity is not limitless, and repetitive or chronic injuries, environmental stresses, or underlying factors of disease may ultimately lead to or contribute to tissue remodeling and end-stage lung disease. This chapter will review stem cell heterogeneity among pulmonary epithelia in the lower respiratory system, discuss recent findings that may challenge long-held scientific paradigms, and identify several clinically relevant research opportunities for regenerative medicine.
Topics: Animals; Cell Differentiation; Humans; Lung; Stem Cells
PubMed: 31487021
DOI: 10.1007/978-3-030-24108-7_6 -
Surgical Pathology Clinics Mar 2021Basal cell adenoma (BCA) and basal cell adenocarcinoma (BCAC) are uncommon biphasic salivary gland tumors having morphologic similarities to other biphasic salivary... (Review)
Review
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.
Topics: Adenocarcinoma; Adenoma; Diagnosis, Differential; Epithelial Cells; Humans; Neoplasm Recurrence, Local; Prognosis; Salivary Gland Neoplasms; beta Catenin
PubMed: 33526221
DOI: 10.1016/j.path.2020.09.005 -
PloS One 2022The salivary gland can be permanently impaired by radiation treatment for head and neck cancers. Efforts at tissue regeneration have focused on saliva-producing acinar...
The salivary gland can be permanently impaired by radiation treatment for head and neck cancers. Efforts at tissue regeneration have focused on saliva-producing acinar cells. However, myoepithelial cells are also critical to gland function, but mechanisms that regulate their differentiation are poorly defined. To study myoepithelial differentiation, we employed mSG-PAC1 murine salivary gland epithelial cells. We demonstrate that mSG-PAC1 spheroids exhibit phenotypic plasticity between pro-acinar and myoepithelial cell fates. Increased expression of pro-acinar/acinar or myoepithelial RNAs was identified from spheroids cultured under different media conditions by microarray followed by gene-set enrichment analysis. Spheroids cultured with different medium components expressed proteins typical of either acinar or myoepithelial cells, as detected by immunocytochemistry. We demonstrate that the pattern of TAZ expression in the epithelial compartment of the differentiating murine salivary gland correlates with the expression of the myoepithelial marker alpha-SMA, as is the case for TAZ expression in mSG-PAC1 spheroids. Our analysis also indicates that YAP/TAZ target genes are upregulated together with myoepithelial markers. Importantly, siRNA targeting of TAZ expression in mSG-PAC1 spheroids diminished the expression of myoepithelial markers. Our results in this in vitro cell model implicate TAZ signaling in myoepithelial differentiation.
Topics: Animals; Mice; Acinar Cells; Cell Differentiation; Epithelial Cells; Salivary Glands
PubMed: 35617216
DOI: 10.1371/journal.pone.0268668 -
Ultrastructural Pathology 2018Salivary myoepithelial cells bear particular appendages and are involved in processes that have received incomplete attention in previous reviews. Here, cilia on... (Review)
Review
Salivary myoepithelial cells bear particular appendages and are involved in processes that have received incomplete attention in previous reviews. Here, cilia on myoepithelial cells are reviewed as regards substructure, occurrence, detection (electron microscopy, double immunofluorescence together with confocal microscopy), and roles (sensory reception, evolutionary homology, paracrine interaction). Attention is drawn to regressive changes affecting those cells (e.g. accumulation of lipofuscin), possible alterations of their cytoskeleton, internalization of apoptotic bodies and haemosiderin, and role in salivary microcalcification. The ability of differentiated salivary myoepithelial cells to divide is re-examined, particularly its increase in chronic inflammation and under experimental conditions. Caution with regard to histogenetic models of salivary neoplasia is re-emphasized; methodological deficiencies and areas of controversy are outlined; and lines of future research are suggested.
Topics: Cytoskeleton; Epithelial Cells; Epithelium; Fluorescent Antibody Technique; Humans; Muscle, Smooth; Salivary Gland Neoplasms
PubMed: 30526219
DOI: 10.1080/01913123.2018.1551259 -
Veterinary Journal (London, England :... Jan 2016Mammary tumours are the most common neoplasms of female dogs. Compared to mammary tumours of humans and cats, myoepithelial (ME) cell involvement is common in canine... (Review)
Review
Mammary tumours are the most common neoplasms of female dogs. Compared to mammary tumours of humans and cats, myoepithelial (ME) cell involvement is common in canine mammary tumours (CMT) of any subtype. Since ME cell involvement in CMT influences both histogenetic tumour classification and prognosis, correct identification of ME cells is important. This review describes immunohistochemical methods for identification of canine mammary ME cells used in vivo. In addition, phenotypic and genotypic methods to isolate ME cells for in vitro studies to analyse tumour-suppressor protein production and gene expression are discussed. The contribution of ME cells to both histogenetic classifications and the prognosis of CMT is compared with other species and the potential use of ME cells as a method to identify carcinoma in situ is discussed.
Topics: Animals; Dog Diseases; Dogs; Epithelial Cells; Female; Humans; Mammary Glands, Animal; Mammary Neoplasms, Animal
PubMed: 26639832
DOI: 10.1016/j.tvjl.2015.10.035 -
Cell Reports Nov 2022Salivary adenoid cystic carcinoma (ACC) is a rare, biologically unique biphasic tumor that consists of malignant myoepithelial and luminal cells. MYB and Notch signaling...
Salivary adenoid cystic carcinoma (ACC) is a rare, biologically unique biphasic tumor that consists of malignant myoepithelial and luminal cells. MYB and Notch signaling have been implicated in ACC pathophysiology, but in vivo descriptions of these two programs in human tumors and investigation into their active coordination remain incomplete. We utilize single-cell RNA sequencing to profile human head and neck ACC, including a comparison of primary ACC with a matched local recurrence. We define expression heterogeneity in these rare tumors, uncovering diversity in myoepithelial and luminal cell expression. We find differential expression of Notch ligands DLL1, JAG1, and JAG2 in myoepithelial cells, suggesting a paracrine interaction that may support oncogenic Notch signaling. We validate this selective expression in three published cohorts of patients with ACC. Our data provide a potential explanation for the biphasic nature of low- and intermediate-grade ACC and may help direct new therapeutic strategies against these tumors.
Topics: Humans; Carcinoma, Adenoid Cystic; Oncogenes; Carcinogenesis; Exome Sequencing; Sequence Analysis, RNA
PubMed: 36450256
DOI: 10.1016/j.celrep.2022.111743 -
Cellular and Molecular Life Sciences :... Apr 2021The mammalian salivary gland develops as a highly branched structure designed to produce and secrete saliva. This review focuses on research conducted on mammalian... (Review)
Review
The mammalian salivary gland develops as a highly branched structure designed to produce and secrete saliva. This review focuses on research conducted on mammalian salivary gland development, particularly on the differentiation of acinar, ductal, and myoepithelial cells. We discuss recent studies that provide conceptual advances in the understanding of the molecular mechanisms of salivary gland development. In addition, we describe the organogenesis of submandibular glands (SMGs), model systems used for the study of SMG development, and the key signaling pathways as well as cellular processes involved in salivary gland development. The findings from the recent studies elucidating the identity of stem/progenitor cells in the SMGs, and the process by which they are directed along a series of cell fate decisions to form functional glands, are also discussed. Advances in genetic tools and tissue engineering strategies will significantly increase our knowledge about the mechanisms by which signaling pathways and cells establish tissue architecture and function during salivary gland development, which may also be conserved in the growth and development of other organ systems. An increased knowledge of organ development mechanisms will have profound implications in the design of therapies for the regrowth or repair of injured tissues. In addition, understanding how the processes of cell survival, expansion, specification, movement, and communication with neighboring cells are regulated under physiological and pathological conditions is critical to the development of future treatments.
Topics: Animals; Cell Differentiation; Humans; Organogenesis; Salivary Glands; Signal Transduction; Stem Cells
PubMed: 33449148
DOI: 10.1007/s00018-020-03741-2 -
Biochimica Et Biophysica Acta.... Jan 2022Nearly all mammals rely on lactation to support their young and to ensure the continued survival of their species. Despite its importance, relatively little is known... (Review)
Review
Nearly all mammals rely on lactation to support their young and to ensure the continued survival of their species. Despite its importance, relatively little is known about how milk is produced and how it is ejected from the lumen of mammary alveoli and ducts. This review focuses on the latter. We discuss how a relatively small number of basal cells, wrapping around each alveolar unit, contract to forcibly expel milk from the alveolar lumen. We consider how individual basal cells coordinate their activity, the fate of these cells at the end of lactation and avenues for future deliberation and exploration.
Topics: Animals; Cell Plasticity; Epithelial Cells; Female; Humans; Lactation; Mammary Glands, Human
PubMed: 34653580
DOI: 10.1016/j.bbamcr.2021.119159