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Alkhayyat R, Abbas A, Quinn CM, Rakha EA. Tumour 63 protein (p63) in breast pathology: biology, immunohistochemistry, diagnostic applications, and pitfalls. Histopathology 2024; 84:723-741. [PMID: 38012539 DOI: 10.1111/his.15101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 10/16/2023] [Accepted: 11/06/2023] [Indexed: 11/29/2023]
Abstract
Tumour protein 63 (p63) is a transcription factor of the p53 gene family, encoded by the TP63 gene located at chromosome 3q28, which regulates the activity of genes involved in growth and development of the ectoderm and derived tissues. p63 protein is normally expressed in the nuclei of the basal cell layer of glandular organs, including breast, in squamous epithelium and in urothelium. p63 immunohistochemical (IHC) staining has several applications in diagnostic breast pathology. It is commonly used to demonstrate myoepithelial cells at the epithelial stromal interface to differentiate benign and in situ lesions from invasive carcinoma and to characterize and classify papillary lesions including the distinction of breast intraduct papilloma from skin hidradenoma. p63 IHC is also used to identify and profile lesions showing myoepithelial cell and/or squamous differentiation, e.g. adenomyoepithelioma, salivary gland-like tumours including adenoid cystic carcinoma, and metaplastic breast carcinoma including low-grade adenosquamous carcinoma. This article reviews the applications of p63 IHC in diagnostic breast pathology and outlines a practical approach to the diagnosis and characterization of breast lesions through the identification of normal and abnormal p63 protein expression. The biology of p63, the range of available antibodies with emphasis on staining specificity and sensitivity, and pitfalls in interpretation are also discussed. The TP63 gene in humans, which shows a specific genomic structure, resulting in either TAp63 (p63) isoform or ΔNp63 (p40) isoform. As illustrated in the figure, both isoforms contain a DNA-binding domain (Orange box) and an oligomerization domain (Grey box). TAp63 contains an N-terminal transactivation (TA) domain (Green box), while ΔNp63 has an alternative terminus (Yellow box). Antibodies against conventional pan-p63 (TP63) bind to the DNA binding domain common to both isoforms (TAp63 and p40) and does not distinguish between them. Antibodies against TAp63 bind to the N-terminal TA domain, while antibodies specific to ΔNp63 (p40) bind to the alternative terminus. Each isoform has variant isotypes (α, β, γ, δ, and ε).
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Affiliation(s)
- Rabab Alkhayyat
- Department of Histopathology, Nottingham University Hospitals NHS Trust, Nottingham City Hospitals, Nottingham, UK
- Department of Pathology, Salmaniya Medical Complex, Government Hospitals, Manama, Kingdom of Bahrain
| | - Areeg Abbas
- Department of Histopathology, Nottingham University Hospitals NHS Trust, Nottingham City Hospitals, Nottingham, UK
| | - Cecily M Quinn
- Irish National Breast Screening Program, Department of Histopathology, St. Vincent's University Hospital, Dublin, School of Medicine, University College Dublin, Dublin, Ireland
| | - Emad A Rakha
- Department of Histopathology, Nottingham University Hospitals NHS Trust, Nottingham City Hospitals, Nottingham, UK
- Academic Unit for Translational Medical Sciences, School of Medicine, University of Nottingham, Nottingham, UK
- Department of Pathology, Hamad General Hospital, Hamad Medical Corporation, Doha, Qatar
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Lerwill MF, Lee AHS, Tan PH. Fibroepithelial tumours of the breast-a review. Virchows Arch 2021; 480:45-63. [PMID: 34505197 DOI: 10.1007/s00428-021-03175-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/08/2021] [Accepted: 07/25/2021] [Indexed: 12/24/2022]
Abstract
Fibroepithelial tumours of the breast are biphasic neoplasms composed of both epithelial and stromal elements, including the common fibroadenoma and the infrequent phyllodes tumour. The admixture of epithelium and stroma in the fibroadenoma shows intra- and pericanalicular patterns, and may display a variety of histological changes. Fibroadenoma variants include the cellular, juvenile, myxoid and complex forms. The cellular fibroadenoma may be difficult to distinguish from the benign phyllodes tumour. Stromal mitotic activity can be increased in fibroadenomas in the young and pregnant patients. Phyllodes tumours, neoplasms with the potential for recurrence, show an exaggerated intracanalicular growth pattern with broad stromal fronded architecture and stromal hypercellularity. They are graded into benign, borderline and malignant forms based on histological assessment of stromal features of hypercellularity, atypia, mitotic activity, overgrowth and the nature of the tumour borders. Classification of phyllodes tumours is imperfect, compounded by tumour heterogeneity with overlapping microscopic features among the different grades, especially in the borderline category. Malignant phyllodes tumours can metastasise and cause death. Determining which phyllodes tumours may behave aggressively has been difficult. The discovery of MED12 mutations in the pathogenesis of fibroepithelial tumours, together with other gene abnormalities in the progression pathway, has allowed refinements in diagnosis and prognosis.
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Affiliation(s)
- Melinda F Lerwill
- Department of Pathology, Massachusetts General Hospital, Boston, MA, USA
| | - Andrew H S Lee
- Department of Histopathology, Nottingham University Hospitals, Nottingham, UK
| | - Puay Hoon Tan
- Division of Pathology, Singapore General Hospital, Singapore, Singapore.
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Best Practice (Efficient) Immunohistologic Panel for Diagnosing Metaplastic Breast Carcinoma. Appl Immunohistochem Mol Morphol 2020; 29:265-269. [PMID: 32858538 DOI: 10.1097/pai.0000000000000873] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 07/27/2020] [Indexed: 11/26/2022]
Abstract
Immunohistochemistry (IHC) plays a key role in the diagnosis of metaplastic breast carcinomas (MBCs), particularly the spindle cell variant. The most efficient immunopanel has yet to be developed. We studied the immunoprofile of 45 MBCs including 23 matrix-producing MBCs, 11 squamous cell carcinomas, 6 spindle cell carcinomas, and 5 mixed-subtypes (2 cases including spindle cell components). Representative sections from mastectomy or core biopsy specimens were subject to IHC using a list of antibodies including OSCAR, a recently developed antibody against pooled cytokeratins. The staining was interpreted as positive when >1% of tumor cells demonstrated unequivocal staining. As a result, OSCAR showed similar sensitivity to AE1/AE3 and CAM 5.2 (89.1% vs. 89.4% vs. 89.4%) for MBCs, but the former showed more diffuse pattern of staining, particularly in spindle cell carcinomas. High molecular weight cytokeratin CK14, CK5, and CK17 were positive in 91.3%, 87.2%, and 73.3% of MBCs, respectively. CK7 was much less likely to be positive in spindle cell carcinomas (37.5%) than in other variants of MBCs (97.4%). P63 and CK14 were the most useful markers for spindle cell carcinomas, positive in 87.5% and 85.7% of cases, respectively. GATA 3 was positive in 63% MBCs, and nonspecific staining for vimentin and smooth muscle actin were common. Random combination of up to 3 antibodies against keratins including p63 showed sensitivities ranging from 80.9% to 97.9%. Our results suggested the combination of OSCAR, CK14 and p63 is the most efficient panel (sensitivity 97.9%) for diagnosing MBCs.
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An Algorithmic Immunohistochemical Approach to Define Tumor Type and Assign Site of Origin. Adv Anat Pathol 2020; 27:114-163. [PMID: 32205473 DOI: 10.1097/pap.0000000000000256] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Immunohistochemistry represents an indispensable complement to an epidemiology and morphology-driven approach to tumor diagnosis and site of origin assignment. This review reflects the state of my current practice, based on 15-years' experience in Pathology and a deep-dive into the literature, always striving to be better equipped to answer the age old questions, "What is it, and where is it from?" The tables and figures in this manuscript are the ones I "pull up on the computer" when I am teaching at the microscope and turn to myself when I am (frequently) stuck. This field is so exciting because I firmly believe that, through the application of next-generation immunohistochemistry, we can provide better answers than ever before. Specific topics covered in this review include (1) broad tumor classification and associated screening markers; (2) the role of cancer epidemiology in determining pretest probability; (3) broad-spectrum epithelial markers; (4) noncanonical expression of broad tumor class screening markers; (5) a morphologic pattern-based approach to poorly to undifferentiated malignant neoplasms; (6) a morphologic and immunohistochemical approach to define 4 main carcinoma types; (7) CK7/CK20 coordinate expression; (8) added value of semiquantitative immunohistochemical stain assessment; algorithmic immunohistochemical approaches to (9) "garden variety" adenocarcinomas presenting in the liver, (10) large polygonal cell adenocarcinomas, (11) the distinction of primary surface ovarian epithelial tumors with mucinous features from metastasis, (12) tumors presenting at alternative anatomic sites, (13) squamous cell carcinoma versus urothelial carcinoma, and neuroendocrine neoplasms, including (14) the distinction of pheochromocytoma/paraganglioma from well-differentiated neuroendocrine tumor, site of origin assignment in (15) well-differentiated neuroendocrine tumor and (16) poorly differentiated neuroendocrine carcinoma, and (17) the distinction of well-differentiated neuroendocrine tumor G3 from poorly differentiated neuroendocrine carcinoma; it concludes with (18) a discussion of diagnostic considerations in the broad-spectrum keratin/CD45/S-100-"triple-negative" neoplasm.
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Taskin OC, Akkas G, Memis B, Seven IE, Basturk O, Jang KT, Roa JC, Araya JC, Bellolio E, Losada H, Sarmiento J, Balci S, Pehlivanoglu B, Reid MD, Koshiol J, Adsay V. Sarcomatoid carcinomas of the gallbladder: clinicopathologic characteristics. Virchows Arch 2019; 475:59-66. [PMID: 31177317 DOI: 10.1007/s00428-019-02583-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 04/16/2019] [Accepted: 05/07/2019] [Indexed: 11/28/2022]
Abstract
Sarcomatoid carcinomas recently came into the spotlight through genetic profiling studies and also as a distinct model of epithelial-mesenchymal transition. The literature on sarcomatoid carcinomas of gallbladder is limited. In this study, 656 gallbladder carcinomas (GBC) were reviewed. Eleven (1.7%) with a sarcomatoid component were identified and analyzed in comparison with ordinary GBC (O-GBC). Patients included 9 females and 2 males (F/M = 4.5 vs. 3.9) with a mean age-at-diagnosis of 71 (vs. 64). The median tumor size was 4.6 cm (vs. 2.5; P = 0.01). Nine patients (84%) presented with advanced stage (pT3/4) tumor (vs. 48%). An adenocarcinoma component constituting 1-75% of the tumor was present in nine, and eight had surface dysplasia/CIS; either in situ or invasive carcinoma was present in all cases. An intracholecystic papillary-tubular neoplasm was identified in one. Seven showed pleomorphic-sarcomatoid pattern, and four showed subtle/bland elongated spindle cells. Three had an angiosarcomatoid pattern. Two had heterologous elements. One showed few osteoclast-like giant cells, only adjacent to osteoid. Immunohistochemically, vimentin, was positive in six of six; P53 expression was > 60% in six of six, keratins in six of seven, and p63 in two of six. Actin, desmin, and S100 were negative. The median Ki67 index was 40%. In the follow-up, one died peri-operatively, eight died of disease within 3 to 8 months (vs. 26 months median survival for O-GBC), and two were alive at 9 and 15 months. The behavior overall was worse than ordinary adenocarcinomas in general but was not different when grade and stage were matched. In summary, sarcomatoid component is identified in < 2% of GBC. Unlike sarcomatoid carcinomas in the remainder of pancreatobiliary tract, these are seldom of the "osteoclastic" type and patients present with large/advanced stage tumors. Limited data suggests that these tumors are aggressive with rapid mortality unlike pancreatic osteoclastic ones which often have indolent behavior.
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Affiliation(s)
- Orhun Cig Taskin
- Department of Pathology, Koç University Hospital, Istanbul, Turkey
| | - Gizem Akkas
- Department of Pathology, Kutahya Evliya Celebi Research and Training Hospital, Kutahya, Turkey
| | - Bahar Memis
- Emory University, Atlanta, GA, USA.,TC.SBU, Sanliurfa Mehmet Akif Inan Training and Research Hospital, Sanlıurfa, Turkey
| | - Ipek Erbarut Seven
- Department of Pathology, Marmara University Pendik Research and Training Hospital, Istanbul, Turkey
| | - Olca Basturk
- Wayne State University, Detroit, MI, USA.,Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Kee-Taek Jang
- Department of Pathology and Translational Genomics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Juan C Roa
- Department of Pathology, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Juan Carlos Araya
- Department of Pathology, Hospital Dr. Hernan Henriquez Aravena, Temuco, Chile
| | - Enrique Bellolio
- Anatomic Pathology Department, Universidad de La Frontera, Claro Solar 115, Temuco, Chile
| | - Hector Losada
- Department of Surgery and Traumatology, Universidad de La Frontera, Temuco, Chile
| | | | | | | | | | - Jill Koshiol
- Division of Cancer Epidemiology & Genetics, National Cancer Institute, Infections and Immunoepidemiology Branch, NCI, NIH, Rockville, MD, USA
| | - Volkan Adsay
- Department of Pathology, Koç University Hospital, Istanbul, Turkey.
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