Salivary duct carcinomas can be classified into luminal androgen receptor‐positive, HER2 and basal‐like phenotypes*

• DOI: 10.1111/j.1365-2559.2012.04252.x
• Publication Date: 2012-08-09T10:39:13Z
• Authors: Silvana Di Palma; Roderick H W Simpson; Caterina Marchiò; Alena Skálová; Marco Ungari; Ann Sandison; Stephen Whitaker; Suzanne Parry; Jorge S Reis‐Filho
• Keywords: Adult; Male; Receptor, ErbB-2; 03 medical and health sciences; 0302 clinical medicine; 616; Biomarkers, Tumor; Humans; Salivary Ducts; In Situ Hybridization; Aged; Oligonucleotide Array Sequence Analysis; Aged, 80 and over; Carcinoma; androgen receptor; basal cytokeratins; basal-like phenotype; HER2; molecular subtypes; salivary duct carcinoma; Middle Aged; Salivary Gland Neoplasms; Immunohistochemistry; 3. Good health; Carcinoma, Ductal; Phenotype; Receptors, Androgen; Tissue Array Analysis; Female; Carcinoma in Situ

Di Palma S, Simpson R H W, Marchiò C, Skálová A, Ungari M, Sandison A, Whitaker S, Parry S & Reis‐Filho J S (2012) Histopathology 61, 629–643Salivary duct carcinomas can be classified into luminal androgen receptor‐positive, HER2 and basal‐like phenotypesAims: The aim of this study was to devise a molecular classification for salivary duct carcinomas (SDCs) based on the similarities between SDCs and breast carcinomas and on characteristics of the microarray‐based gene expression profiling‐defined molecular subtypes of breast cancer.Methods and results: Forty‐two pure salivary duct carcinomas, 35 of which contained an in‐situ component as defined by histological review and/or immunohistochemical analysis, were stained with antibodies for oestrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR), human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor (EGFR) and cytokeratin (CK) 5/6. Based on these markers, tumours were classified into HER2, luminal androgen receptor‐positive, basal‐like, luminal and indeterminate phenotype. Analysis revealed that 16.7%, 69%, 4.8%, 9.5% and 0% were of HER2, luminal androgen receptor‐positive, basal‐like, indeterminate and luminal phenotype, respectively. The in‐situ and invasive components displayed the same molecular subtype in all but one case.Conclusions: Salivary duct carcinomas can be classified into molecular subgroups approximately equivalent to those in the breast. We also report on the existence of a subgroup of bona fide pure salivary duct carcinomas that have a ‘basal‐like’ phenotype. Understanding the phenotypic complexity of SDCs may help to expedite the identification of novel therapeutic targets for these aggressive tumours.