[245] Significance of Unamplified Chromosome 17 Monosomy in Breast Carcinoma

U Krishnamurti, FD Atem, JF Silverman. Western Pennsylvania Hospital, Pittsburgh, PA; Allegheny General Hospital, Pittsburgh, PA; University of Pittsburgh, Pittsburgh, PA

Background: HER2 gene amplification is a poor prognostic indicator in breast carcinoma. Some patients show chromosome 17 aneusomy with or without HER2 amplification. We have in an earlier study demonstrated the poor prognostic effect of unamplified polysomy 17 in breast carcinoma (Mod Pathol 22:1044; 2009). The aim of this study was to determine the effect of unamplified 17 monosomy on prognostic factors in invasive breast carcinoma.
Design: Monosomy 17 was defined as the presence of less than 1.5 chromosome 17 centromere copies/cell. Four groups: N (no polysomy or HER2 amplification, 36 cases), M (unamplified 17 monosomy, 23 cases), P (unamplified 17 polysomy, 44 cases) and A (HER2 amplification without 17 polysomy, 35 cases) were compared for the following: Nottingham score, nuclear grade, mitotic score, histologic grade, lymphvascular invasion, nodal metastases, T stage, estrogen receptor (ER) and progesterone receptor (PR) negativity. SAS 9.2 was used for statistical analysis.
Results: The percentage of prognostic factors is the different groups is given in the table.

% of Prognostic factors

Prognostic factors	% N	% M	% P	% A	N vs. M	N vs. P	N vs. A
Nottingham score 8	11	27	37	34	-	-	-
Nottingham score 9	11	11	14	34	-	-	p=0.05
Nuclear grade 3	26	44	61	74	p=0.001	-	p=0.012
Mitotic score 2	18	33	54	43	-	-	-
Mitotic score 3	18	11	26	40	-	-	p=0.04
Histoogic grade 3	20	37	44	69	-	-	p=0.03
T stage 2	18	11	31	30	-	p=0.03	p=0.03
Lymph vascular invasion present	17	38	19	34	-	-	-
Positive lymph nodes	38	40	42	45	-	-	-
ER negativity	11	17	30	50	-	-	p=0.02
PR negativity	24	48	35	34	p=0.02	-	-

- = not statistically significant


Conclusions: Invasive breast carcinoma with chromosome 17 monosomy is associated with a higher percentage of adverse prognostic indicators such as a higher Nottingham score, nuclear grade, mitotic activity, histologic grade, and lymphvascular invasion compared to cases with neither amplification or 17 aneusomy. However these differences are statistically significant only for nuclear grade 3 and progesterone receptor negativity. The incidence of adverse prognostic factors with unamplified 17 monosomy is less than that seen with unamplified 17 polysomy and even less than that seen with HER2 amplification. The percentage of cases with adverse prognostic factors is : A> P > M > N.
Category: Breast

Wednesday, March 24, 2010 1:00 PM

Poster Session VI # 18, Wednesday Afternoon