title: Increased epidermal growth factor receptor (EGFR) expression in malignant mammary phyllodes tumors.
abstract: Mammary phyllodes tumors are uncommon stromal-epithelial neoplasms, and are divided into benign, borderline malignant and frankly malignant groups on the basis of their histological features. Accumulating evidence shows that epidermal growth factor receptor (EGFR) is involved in the pathogenesis and progression of many malignancies. This study investigated 453 phyllodes tumors (296 benign, 98 borderline, 59 malignant) for EGFR expression using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) for gene amplification. The staining was correlated to tumor margin status, degree of malignancy, stromal cellularity, mitotic activity, nuclear pleomorphism and stromal overgrowth. Cases with strong positive IHC staining were selected for FISH. The overall positive rate for EGFR was 16.2% (48/296), 30.6% (30/98) and 56% (33/59) for benign, borderline malignant and frankly malignant phyllodes tumors, respectively. FISH demonstrated egfr gene amplification in 8% of immunohistochemically positive cases. The results of this study provide strong evidence that EGFR overexpression is involved in the pathogenesis of phyllodes tumors, although gene amplification may not be the major underlying mechanism for overexpression.
authors.affiliation: Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, 30-32 Ngan Shing Street, Shatin, NT, Hong Kong SAR, China. garytse@cuhk.edu.hk
authors.forename: Gary M K
authors.initials: GM
authors.lastname: Tse
authors.forename: Philip C W
authors.initials: PC
authors.lastname: Lui
authors.forename: Joaquim S L
authors.initials: JS
authors.lastname: Vong
authors.forename: Kin-Mang
authors.initials: KM
authors.lastname: Lau
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Putti
authors.forename: Rooshdiya
authors.initials: R
authors.lastname: Karim
authors.forename: Richard A
authors.initials: RA
authors.lastname: Scolyer
authors.forename: C-Soon
authors.initials: CS
authors.lastname: Lee
authors.forename: Alex M C
authors.initials: AM
authors.lastname: Yu
authors.forename: David C H
authors.initials: DC
authors.lastname: Ng
authors.forename: Agnes K Y
authors.initials: AK
authors.lastname: Tse
authors.forename: Puay-Hoon
authors.initials: PH
authors.lastname: Tan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor; D001943:Breast Neoplasms / Q000378:metabolism*; D049109:Cell Proliferation; D066246:ErbB Receptors / Q000096:biosynthesis*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D017404:In Situ Hybridization, Fluorescence; D008024:Ligands; D008875:Middle Aged; D003557:Phyllodes Tumor / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D008024:Ligands; D066246:ErbB Receptors