title: Novel molecular markers of malignancy in histologically normal and benign breast.
abstract: To detect the molecular changes of malignancy in histologically normal breast (HNB) tissues, we recently developed a novel 117-gene-malignancy-signature. Here we report validation of our leading malignancy-risk-genes, topoisomerase-2-alpha (TOP2A), minichromosome-maintenance-protein-2 (MCM2) and "budding-uninhibited-by-benzimidazoles-1-homolog-beta" (BUB1B) at the protein level. Using our 117-gene malignancy-signature, we classified 18 fresh-frozen HNB tissues from 18 adult female breast cancer patients into HNB-tissues with low-grade (HNB-LGMA; N = 9) and high-grade molecular abnormality (HNB-HGMA; N = 9). Archival sections of additional HNB tissues from these patients, and invasive ductal carcinoma (IDC) tissues from six other patients were immunostained for these biomarkers. TOP2A/MCM2 expression was assessed as staining index (%) and BUB1B expression as H-scores (0-300). Increasing TOP2A, MCM2, and BUB1B protein expression from HNB-LGMA to HNB-HGMA tissues to IDCs validated our microarray-based molecular classification of HNB tissues by immunohistochemistry. We also demonstrated an increasing expression of TOP2A protein on an independent test set of HNB/benign/reductionmammoplasties, atypical-ductal-hyperplasia with and without synchronous breast cancer, DCIS and IDC tissues using a custom tissue microarray (TMA). In conclusion, TOP2A, MCM2, and BUB1B proteins are potential molecular biomarkers of malignancy in histologically normal and benign breast tissues. Larger-scale clinical validation studies are needed to further evaluate the clinical utility of these molecular biomarkers.
authors.affiliation: Department of Anatomic Pathology, Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA.
authors.forename: Aejaz
authors.initials: A
authors.lastname: Nasir
authors.forename: Dung-Tsa
authors.initials: DT
authors.lastname: Chen
authors.forename: Mike
authors.initials: M
authors.lastname: Gruidl
authors.forename: Evita B
authors.initials: EB
authors.lastname: Henderson-Jackson
authors.forename: Chinnambally
authors.initials: C
authors.lastname: Venkataramu
authors.forename: Susan M
authors.initials: SM
authors.lastname: McCarthy
authors.forename: Heyoung L
authors.initials: HL
authors.lastname: McBride
authors.forename: Eleanor
authors.initials: E
authors.lastname: Harris
authors.forename: Nazanin
authors.initials: N
authors.lastname: Khakpour
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Yeatman