Original Article p16INK4a expression in basal-like breast carcinoma
Olga L. Bohn, Mariana Fuertes-Camilo, Leticia Navarro, Jesus Saldivar, Sergio Sanchez-Sosa
Departments of Pathology, MetroHealth Medical Center-Case Western Reserve University, Cleveland, OH, USA; Department of Pathology, UPAEP University Hospital-Grupo Christus Muguerza, Puebla, Mexico.
Received June 7, 2010, accepted June, 2010, available online June, 2010
Abstract: BLBC represents a distinctive group of invasive breast carcinomas with specific genotype and immunoprofile. BLBC is usually defined by gene expression profiling and is currently associated with poor outcome. BLBCs are estrogen receptor (ER) negative, progesterone receptor (PgR) negative, HER2 negative, and usually show a variable expression of basal cytokeratins (CKs), EGFR and CD117. p16 INK4a is a tumor suppressor protein, encoded by the CDKN2A gene, which regulates cell cycle. The reported association of abnormalities in the p16/Rb pathway with increased risk of malignancy prompted us to determine the expression of p16INK4a in a group of BLBC; the results were compared with a group of high-grade invasive carcinoma (HG-IC) of breast. Tissue microarrays (TMA) were constructed in triplicate including 18 BLBC and 18 HG-IC. All BLBC cases were ER-/PgR-/HER2-. Seventeen (94%) BLBC were CK 5/6+/CK 14+; 14 (78%) BLCB showed EGFR expression and 13 (72%) were CD117 positive. BLBCs showed a strong positive reaction with p16 INK4a antibody in 16 of 18 (89%) cases. Although the significance of p16 INK4a expression in breast cancer is not fully understood, we have shown that p16INK4a is strongly expressed in breast cancers with basal-like phenotype. Since it is known that p16INK4a is associated with aggressive behavior in human carcinomas, these data suggest that p16INK4a play a role in the poor prognosis of BLBC. (IJCEP1006002).
Address all correspondence to: Olga L. Bohn, MD Department of Pathology, MetroHealth Medical Center Case Western Reserve University 2500 MetroHealth Drive, Cleveland, OH 44109 E-mail: firstname.lastname@example.org