ΔNp63, also known as p40, regulates stemness of normal mammary gland epithelium and provides stem cell characteristics in basal and HER2-driven murine breast cancer models. Whilst ΔNp63/p40 is a characteristic feature of normal basal cells and basal-type triple-negative breast cancer, some receptor-positive breast cancers express ΔNp63/p40 and its overexpression imparts cancer stem cell-like properties in ER+ cell lines. However, the incidence of ER+ and HER2+ tumours that express ΔNp63/p40 is unclear and the phenotype of ΔNp63/p40+ cells in these tumours remains uncertain. Using immunohistochemistry with p63 isoform-specific antibodies, we identified a ΔNp63/p40+ tumour cell subpopulation in 100 of 173 (58%) non-triple negative breast cancers and the presence of this population associated with improved survival in patients with ER- /HER2+ tumours (p = 0.006). Furthermore, 41% of ER+ /PR+ and/or HER2+ locally metastatic breast cancers expressed ΔNp63/p40, and these cells commonly accounted for <1% of the metastatic tumour cell population that localised to the tumour/stroma interface, exhibited an undifferentiated phenotype and were CD44+ /ALDH- . In vitro studies revealed that MCF7 and T47D (ER+ ) and BT-474 (HER2+ ) breast cancer cell lines similarly contained a small subpopulation of ΔNp63/p40+ cells that increased in mammospheres. In vivo, MCF7 xenografts contained ΔNp63/p40+ cells with a similar phenotype to primary ER+ cancers. Consistent with tumour samples, these cells also showed a distinct location at the tumour/stroma interface, suggesting a role for paracrine factors in the induction or maintenance of ΔNp63/p40. Thus, ΔNp63/p40 is commonly present in a small population of tumour cells with a distinct phenotype and location in ER+ and/or HER2+ human breast cancers.

Advanced Data Analysis Centre University of Nottingham Nottingham UK

Department of Pathology Ninewells Hospital and Medical School Dundee UK

Division of Surgical Oncology Dan L Duncan Comprehensive Cancer Center Baylor College of Medicine Houston TX USA

Dundee Cancer Centre University of Dundee Ninewells Hospital and Medical School Dundee UK

NCRC University of Michigan Ann Arbor MI USA

Regional Centre for Applied Molecular Oncology Masaryk Memorial Cancer Institute Brno Czech Republic

Zobrazit více v PubMed

Crum CP, McKeon FD. p63 in epithelial survival, germ cell surveillance, and neoplasia. Annu Rev Pathol 2010; 5: 349–371. PubMed

Nekulova M, Holcakova J, Coates P, et al The role of p63 in cancer, stem cells and cancer stem cells. Cell Mol Biol Lett 2011; 16: 296–327. PubMed PMC

Melino G, Memmi EM, Pelicci PG, et al Maintaining epithelial stemness with p63. Sci Signal 2015; 8: re9. PubMed

Barbareschi M, Pecciarini L, Cangi MG, et al p63, a p53 homologue, is a selective nuclear marker of myoepithelial cells of the human breast. Am J Surg Pathol 2001; 25: 1054–1060. PubMed

Ribeiro‐Silva A, Zambelli Ramalho LN, Britto Garcia S, et al The relationship between p63 and p53 expression in normal and neoplastic breast tissue. Arch Pathol Lab Med 2003; 127: 336–340. PubMed

Wang X, Mori I, Tang W, et al p63 expression in normal, hyperplastic and malignant breast tissues. Breast Cancer 2002; 9: 216–219. PubMed

Koker MM, Kleer CG. p63 expression in breast cancer: a highly sensitive and specific marker of metaplastic carcinoma. Am J Surg Pathol 2004; 28: 1506–1512. PubMed

Ali HR, Dawson S‐J, Blows FM, et al Cancer stem cell markers in breast cancer: pathological, clinical and prognostic significance. Breast Cancer Res 2011; 13: R118. PubMed PMC

Kim J, Villadsen R, Sørlie T, et al Tumor initiating but differentiated luminal‐like breast cancer cells are highly invasive in the absence of basal‐like activity. Proc Natl Acad Sci U S A 2012; 109: 6124–6129. PubMed PMC

Liu S, Cong Y, Wang D, et al Breast cancer stem cells transition between epithelial and mesenchymal states reflective of their normal counterparts. Stem Cell Reports 2014; 2: 78–91. PubMed PMC

Liu Y, Nenutil R, Appleyard MV, et al Lack of correlation of stem cell markers in breast cancer stem cells. Br J Cancer 2014; 110: 2063–2071. PubMed PMC

Brooks MD, Burness ML, Wicha MS. Therapeutic implications of cellular heterogeneity and plasticity in breast cancer. Cell Stem Cell 2015; 17: 260–271. PubMed PMC

Plaks V, Kong N, Werb Z. The cancer stem cell niche: how essential is the niche in regulating stemness of tumor cells? Cell Stem Cell 2015; 16: 225–238. PubMed PMC

Balboni AL, Hutchinson JA, DeCastro AJ, et al ΔNp63α‐mediated activation of bone morphogenetic protein signaling governs stem cell activity and plasticity in normal and malignant mammary epithelial cells. Cancer Res 2013; 73: 1020–1030. PubMed PMC

Chakrabarti R, Wei Y, Hwang J, et al ΔNp63 promotes stem cell activity in mammary gland development and basal‐like breast cancer by enhancing Fzd7 expression and Wnt signalling. Nat Cell Biol 2014; 16: 1004–1015. PubMed PMC

Memmi EM, Sanarico AG, Giacobbe A, et al p63 sustains self‐renewal of mammary cancer stem cells through regulation of sonic hedgehog signaling. Proc Natl Acad Sci U S A 2015; 112: 3499–3504. PubMed PMC

Du Z, Li J, Wang L, et al Overexpression of ΔNp63α induces a stem cell phenotype in MCF7 breast carcinoma cell line through the Notch pathway. Cancer Sci 2010; 101: 2417–2424. PubMed PMC

Amin R, Morita‐Fujimura Y, Tawarayama H, et al ΔNp63α induces quiescence and downregulates the BRCA1 pathway in estrogen receptor‐positive luminal breast cancer cell line MCF7 but not in other breast cancer cell lines. Mol Oncol 2016; 10: 575–593. PubMed PMC

Matos I, Dufloth R, Alvarenga M, et al p63, cytokeratin 5, and P‐cadherin: three molecular markers to distinguish basal phenotype in breast carcinomas. Virchows Arch 2005; 447: 688–694. PubMed

Kumar S, Wilkes DW, Samuel N, et al ΔNp63‐driven recruitment of myeloid‐derived suppressor cells promotes metastasis in triple‐negative breast cancer. J Clin Invest 2018; 128: 5095–5109. PubMed PMC

Orzol P, Nekulova M, Holcakova J, et al ΔNp63 regulates cell proliferation, differentiation, adhesion, and migration in the BL2 subtype of basal‐like breast cancer. Tumour Biol 2016; 37: 10133–10140. PubMed

Nekulova M, Holcakova J, Gu X, et al ΔNp63α expression induces loss of cell adhesion in triple‐negative breast cancer cells. BMC Cancer 2016; 16: 782. PubMed PMC

Holcakova J, Nekulova M, Orzol P, et al ΔNp63 activates EGFR signaling to induce loss of adhesion in triple‐negative basal‐like breast cancer cells. Breast Cancer Res Treat 2017; 163: 475–484. PubMed

Coates PJ, Nenutil R, Holcakova J, et al p63 isoforms in triple‐negative breast cancer: ΔNp63 associates with the basal phenotype whereas TAp63 associates with androgen receptor, lack of BRCA mutation, PTEN and improved survival. Virchows Arch 2018; 472: 351–359. PubMed

Hilson JB, Schnitt SJ, Collins LC. Phenotypic alterations in ductal carcinoma in situ‐associated myoepithelial cells: biologic and diagnostic implications. Am J Surg Pathol 2009; 33: 227–232. PubMed

Lee AHS. Use of immunohistochemistry in the diagnosis of problematic breast lesions. J Clin Pathol 2013; 66: 471–477. PubMed

Baker L, Quinlan PR, Patten N, et al p53 mutation, deprivation and poor prognosis in primary breast cancer. Br J Cancer 2010; 102: 719–726. PubMed PMC

Bouchalova P, Nenutil R, Muller P, et al Mutant p53 accumulation in human breast cancer is not an intrinsic property or dependent on structural or functional disruption but is regulated by exogenous stress and receptor status. J Pathol 2014; 233: 238–246. PubMed

Appleyard MVCL, Murray KE, Coates PJ, et al Phenformin as prophylaxis and therapy in breast cancer xenografts. Br J Cancer 2012; 106: 1117–1122. PubMed PMC

Nylander K, Vojtesek B, Nenutil R, et al Differential expression of p63 isoforms in normal tissues and neoplastic cells. J Pathol 2002; 198: 417–427. PubMed

Nekulova M, Holcakova J, Nenutil R, et al Characterization of specific p63 and p63‐N‐terminal isoform antibodies and their application for immunohistochemistry. Virchows Arch 2013; 463: 415–425. PubMed

Detre S, Saclani Jotti G, Dowsett MA. ‘QuickScore’ method for immunohistochemical semiquantitation: validation for oestrogen receptor in breast carcinomas. J Clin Pathol 1995; 48: 876–878. PubMed PMC

Buckley NE, Conlon SJ, Jirstrom K, et al The DeltaNp63 proteins are key allies of BRCA1 in the prevention of basal‐like breast cancer. Cancer Res 2011; 71: 1933–1944. PubMed

Hanker L, Karn T, Ruckhaeberle E, et al Clinical relevance of the putative stem cell marker p63 in breast cancer. Breast Cancer Res Treat 2010; 122: 765–775. PubMed

de Biase D, Morandi L, Degli Esposti R, et al p63 short isoforms are found in invasive carcinomas only and not in benign breast conditions. Virchows Arch 2010; 456: 395–401. PubMed

Stingl J. Detection and analysis of mammary gland stem cells. J Pathol 2009; 217: 229–241. PubMed

Al‐Hajj M, Wicha MS, Benito‐Hernandez A, et al Prospective identification of tumorigenic breast cancer cells. Proc Natl Acad Sci U S A 2003; 100: 3983–3988. PubMed PMC

Abraham BK, Fritz P, McClellan M, et al Prevalence of CD44+/CD24−/low cells in breast cancer may not be associated with clinical outcome but may favor distant metastasis. Clin Cancer Res 2005; 11: 1154–1159. PubMed

Dontu G, Abdallah WM, Foley JM, et al In vitro propagation and transcriptional profiling of human mammary stem/progenitor cells. Genes Dev 2003; 17: 1253–1270. PubMed PMC

Yallowitz AR, Alexandrova EM, Talos F, et al p63 is a prosurvival factor in the adult mammary gland during post‐lactational involution, affecting PI‐MECs and ErbB2 tumorigenesis. Cell Death Differ 2014; 21: 645–654. PubMed PMC

Hu L, Liang S, Chen H, et al ΔNp63α is a common inhibitory target in oncogenic PI3K/Ras/Her2‐induced cell motility and tumor metastasis. Proc Natl Acad Sci U S A 2017; 114: E3964–E3973. PubMed PMC

Fichter CD, Przypadlo CM, Buck A, et al A new model system identifies epidermal growth factor receptor‐human epidermal growth factor receptor 2 (HER2) and HER2‐human epidermal growth factor receptor 3 heterodimers as potent inducers of oesophageal epithelial cell invasion. J Pathol 2017; 243: 481–495. PubMed PMC

McCart Reed AE, Kalita‐De Croft P, Kutasovic JE, et al Recent advances in breast cancer research impacting clinical diagnostic practice. J Pathol 2019; 247: 552–562. PubMed

Gerdes MJ, Gökmen‐Polar Y, Sui Y, et al Single‐cell heterogeneity in ductal carcinoma in situ of breast. Mod Pathol 2018; 31: 406–417. PubMed PMC

Heterogeneous protein dynamics links to mitochondrial activity, glucose transporter, and ALDH cancer stem cell properties

Stat3 Tyrosine 705 and Serine 727 Phosphorylation Associate With Clinicopathological Characteristics and Distinct Tumor Cell Phenotypes in Triple-Negative Breast Cancer

DNA Demethylation Switches Oncogenic ΔNp63 to Tumor Suppressive TAp63 in Squamous Cell Carcinoma

Identifying pathways regulating the oncogenic p53 family member ΔNp63 provides therapeutic avenues for squamous cell carcinoma

TAp63 and ΔNp63 (p40) in prostate adenocarcinomas: ΔNp63 associates with a basal-like cancer stem cell population but not with metastasis