Bcl-2 Expression in Different Mammary Carcinoma Subtypes. Correlation with Nottingham Histologic Grade.
Mercedes Lioni, Rekha Bhat, Sharon Cavone, Fernando Garcia. Drexel University College of Medicine, Philadelphia, PA
Background: Bcl-2 expression in mammary carcinoma (BCa) is emerging as a favorable prognostic marker and tool to further prognosticate BCa. Aim: To compare the Bcl-2 expression in relation to Nottingham histologic grade (NHG) and its components in different BCa subtypes (Luminal A, Luminal B, Triple negative and HER2+).
Design: A total of 410 consecutive de-identified primary BCa without adjuvant therapy in the University Hospital pathology database from 1997-2010, were included in the study. These were further classified into 235 Luminal A (ER+, and/or PR+, HER2–), 45 Luminal B (ER+, and/or PR+, HER2+), 89 Triple negative (ER–, PR–, HER2–), and 41 HER2+/ER– (ER–, PR–, and HER2+). Expression of Bcl-2 (quantified with Immuno score (IS)= Intensity + 1 x % positive cells) in relation to NHG was evaluated for each group. Further correlation was done with all three components of the NHG and Ki67 (quantified with image analysis). Statistical analysis was done with SPSS software using Chi-square test and Spearman's correlation (P≤0.05).
When analyzing the individual components of the NHG by subtype, only Luminal A and triple negative BCa showed significant correlation (p=0.01) with mitotic count and/or nuclear grade in two of the grading categories (Grade I and II). Grade II Luminal A BCa when divided into high Ki-67 (>20%) and low Ki-67 <20%) had significant inverse correlation with Bcl-2 IS (P≤0.01).
Conclusions: 1) Bcl-2 correlates with all NHG in Luminal A and Triple negative BCa and does not with Luminal B and HER2 sub-types. 2) Of all three components of NHG mitotic count and nuclear grade have significant correlation in these two BCa sub-types, and tubule formation does not. 3) NHG Grade II Luminal A BCa can be further categorized by Bcl-2 and Ki-67 expression.
Wednesday, March 2, 2011 1:00 PM
Poster Session VI # 14, Wednesday Afternoon