[242] Comparison of Prognostic Receptors in Primary Breast Cancer and Nodal Metastases

Shannon K Rathke, Zainab Basir, Alexander C MacKinnon. Medical College of Wisconsin, Milwaukee, WI

Background: Breast cancer treatment is guided by assessment of estrogen receptors (ER), progesterone receptors (PR), and human epidermal growth factor receptor 2 (HER2). There is limited research on comparison of these receptors in primary tumors versus their lymph node metastases. If receptor expression were different, it could guide changes in therapy. Our aim is to determine if there is a significant change in receptor expression in lymph node metastases compared to primary tumors.
Design: All patients having breast cancer with lymph node metastases at our institution between January 2008 and June 2011 were identified. Tissue microarrays (TMAs) were constructed when possible and remaining cases were stained individually. Immunohistochemistry (IHC) for ER, PR and HER2, and FISH for HER2 were performed on lymph node metastases. HER2 IHC was scored from 0 to 3+. HER2 FISH was positive if the ratio was >2.2. Results were compared with those of the primary tumors.
Results:

Prognostic Receptors in Primary Tumor and Lymph Node Metastasis

Primary Tumor Receptors	Lymph Node Metastasis Receptors
	Discordant with primary tumor	Concordant with primary tumor
	% (n)	% (n)
ER pos, n=99	ER neg 5 (5)	ER pos 95 (94)
ER neg, n=23	ER pos 4 (1)	ER neg 96 (22)
ER total, n=122	5 (6)	95 (116)
PR pos, n=87	PR neg 18 (16)	PR pos 82 (71)
PR neg, n=35	PR pos 11 (4)	PR neg 89 (31)
PR total, n=122	16 (20)	84 (102)
HER2 neg, n=96	HER2 pos 0 (0); HER2 equivocal 6 (6)	HER2 neg 94 (90)
HER2 pos, n=19	HER2 neg 5 (1); HER2 equivocal 0 (0)	HER2 pos 95 (18)
HER2 equivocal, n=3	HER2 neg 67 (2); HER2 pos 33 (1)	HER2 equivocal 0 (0)
HER2 total n=118*	8 (10)	92 (108)

*3 cases were excluded from HER2 evaluation because there was no HER2 results on the primary tumor. 1 case showed 3+ HER2 IHC on primary tumor and metastasis but had non-amplified FISH on metastasis.

122 casees of breast cancer with lymph node metastases were obtained; 30 cases (25%) showed receptor changes. 4 cases (3.3%) showed expression changes in more than one receptor, 2 with PR and HER2 changes and 2 with ER and PR changes.
Conclusions: Changes in receptor expression in lymph node metastases when compared to the primary tumors do occur. The percentage of cases with changes in prognostic receptor expression warrants attention. This phenomenon may indicate that repeat testing for ER, PR and HER2 on lymph node metastases is indicated to guide treatment and to explain therapy failure in patients with metastatic disease.
Category: Breast

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 35, Monday Morning