title: Immunohistochemical and molecular profiling of histologically defined apocrine carcinomas of the breast.
abstract: Despite the marked improvement in the understanding of molecular mechanisms and classification of apocrine carcinoma, little is known about its specific molecular genetic alterations and potentially targetable biomarkers. In this study, we explored immunohistochemical and molecular genetic characteristics of 37 invasive apocrine carcinomas using immunohistochemistry (IHC), fluorescent in situ hybridization (FISH), multiplex ligation-dependent probe amplification (MLPA), and next-generation sequencing (NGS) assays. IHC revealed frequent E-cadherin expression (89%), moderate (16%) proliferation activity [Ki-67, phosphohistone H3], infrequent (~10%) expression of basal cell markers [CK5/6, CK14, p63, caveolin-1], loss of PTEN (83%), and overexpression of HER2 (32%), EGFR (41%), cyclin D1 (50%), and MUC-1 (88%). MLPA assay revealed gene copy gains of MYC, CCND1, ZNF703, CDH1, and TRAF4 in 50% or greater of the apocrine carcinomas, whereas gene copy losses frequently affected BRCA2 (75%), ADAM9 (54%), and BRCA1 (46%). HER2 gain, detected by MLPA in 38% of the cases, was in excellent concordance with HER2 results obtained by IHC/FISH (κ = 0.915, P < .001). TOP2A gain was observed in one case, while five cases (21%) exhibited TOP2A loss. Unsupervised hierarchical cluster analysis revealed two distinct clusters: HER2-positive and HER2-negative (P = .03 and .04, respectively). NGS assay revealed mutations of the TP53 (2 of 7, 29%), BRAF/KRAS (2 of 7, 29%), and PI3KCA/PTEN genes (7 of 7, 100%). We conclude that morphologically defined apocrine carcinomas exhibit complex molecular genetic alterations that are consistent with the "luminal-complex" phenotype. Some of the identified molecular targets are promising biomarkers; however, functional studies are needed to prove these observations.
authors.affiliation: Department of Medical Sciences, University of Turin, Turin 10126, Italy; Department of Pathology, Clinical Center, University of Sarajevo, Sarajevo 71000, Bosnia and Herzegovina. Electronic address: semir.vranic@bosnianpathology.org.
authors.forename: Semir
authors.initials: S
authors.lastname: Vranic
authors.affiliation: Department of Medical Sciences, University of Turin, Turin 10126, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Marchiò
authors.affiliation: Department of Medical Sciences, University of Turin, Turin 10126, Italy.
authors.forename: Isabella
authors.initials: I
authors.lastname: Castellano
authors.affiliation: Department of Medical Sciences, University of Turin, Turin 10126, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Botta
authors.affiliation: Department of Medical Sciences, University of Turin, Turin 10126, Italy.
authors.forename: Maria Stella
authors.initials: MS
authors.lastname: Scalzo
authors.affiliation: Caris Life Sciences, Phoenix, AZ 85040, USA.
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Bender
authors.affiliation: Medical Genetics Center, Department of Cell Biology and Genetics, Center of Biomedical Genetics, Erasmus MC, Rotterdam 3015, the Netherlands; Facultad de Ciencias Naturales y Matemáticas, Universidad del Rosario, Bogotá 110010, Colombia.
authors.forename: Cesar
authors.initials: C
authors.lastname: Payan-Gomez
authors.affiliation: Department of Medical Sciences, University of Turin, Turin 10126, Italy.
authors.forename: Ludovica Verdun
authors.initials: LV
authors.lastname: di Cantogno
authors.affiliation: Department of Medical Sciences, University of Turin, Turin 10126, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Gugliotta
authors.affiliation: Center for Experimental Research and Medical Studies, San Giovanni Battista Hospital, Turin 10100, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Tondat
authors.affiliation: Center for Experimental Research and Medical Studies, San Giovanni Battista Hospital, Turin 10100, Italy.
authors.forename: Paola Francia
authors.initials: PF
authors.lastname: di Celle
authors.affiliation: Center for Experimental Research and Medical Studies, San Giovanni Battista Hospital, Turin 10100, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Mariani
authors.affiliation: Caris Life Sciences, Phoenix, AZ 85040, USA.
authors.forename: Zoran
authors.initials: Z
authors.lastname: Gatalica
authors.affiliation: Department of Medical Sciences, University of Turin, Turin 10126, Italy. Electronic address: anna.sapino@unito.it.
authors.forename: Anna
authors.initials: A
authors.lastname: Sapino
mesh_terms: D001050:Apocrine Glands / Q000737:chemistry* / Q000473:pathology; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000235:genetics*; D001943:Breast Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D002277:Carcinoma / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D016000:Cluster Analysis; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D020022:Genetic Predisposition to Disease; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D025202:Molecular Diagnostic Techniques; D060885:Multiplex Polymerase Chain Reaction; D010641:Phenotype; D011237:Predictive Value of Tests; D013544:Sweat Gland Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor
keywords: Androgen receptor; Breast carcinoma–apocrine carcinoma; Fluorescent in situ hybridization; Immunohistochemistry; Multiplex ligation-dependent probe amplification; Next-generation sequencing