Are Luminal A Breast Tumors as Good as They Sound?
R Bhat, FU Garcia, S Soundararajan. Drexel University College of Medicine, Philadelphia, PA
Background: Among the molecular subtypes of invasive breast carcinomas (BCa), luminal A subtype (ER positive, Her2/neu negative) tumors are associated with a good prognosis, while luminal B (ER positive, Her2/neu positive) tumors are associated with an intermediate prognosis. Aim: To compare the Nottingham Prognostic Index (NPI) in luminal type A and B BCa and determine the role of positive Ki-67 (>20%) and p53 (>20%) in these subtypes.
Design: A total of 223 BCa (187 luminal A (ER+, and/or PR+, HER2-); 36 luminal B (ER+, and/or PR+, HER2+) out of 1094 cases from DUCOM Pathology from 1997-2008, with nodal status information and prognostic panel performed and read by image analysis, were included in the study. These were further classified into prognostic groups using the NPI (<3.4, 3.4 5.4, and >5.4). Values of Ki67 and p53 for each prognostic group as well NPI component were evaluated. Statistical analysis was done with Student's t test (p<0.05).
Ki67 and p53 in Prognostic Subgroups of Luminal A and Luminal B Breast Carcinomasstudent's t test, **p<0.001; *p<0.05 (Luminal A vs Luminal B)
|NPI < 3.4||NPI < 3.4||NPI 3.4 -5.4||NPI 3.4 - 5.4||NPI > 5.4||NPI > 5.4|
|Number of cases (%)||Luminal A N= 69 (36.8%)||Luminal B N= 7 (19.4%)||Luminal A N= 82 (43.8%)||Luminal B N=15 (41.6%)||Luminal A N= 36 (19.3%)||Luminal B N= 14 (38.8%)|
Conclusions: 1. Luminal A type BCa is associated with better prognosis (NPI >5.4) when compared with Luminal B type BCa (38 vs 19%). 2. In the intermediate prognostic group NPI 3.4 to 5.4, the number of Ki-67 and p53 positive tumors is significantly higher in luminal B type (p<0.05) than type A BCa (data not shown). 3. The Her2 status of luminal A type BCa with high Ki-67 and p53 should be reconsidered.
Tuesday, March 10, 2009 1:00 PM
Poster Session IV # 38, Tuesday Afternoon