[169] Morphologic and Immunohistochemistry (IHC) Profile of Luminal A Subtype Breast Cancer Patients with Recurrence and Non-Recurrence: A Single Institution Retrospective Review Study with 10 Year Follow-Up.

Shveta Hooda, Gloria Carter, Adam Brufsky, Rachel Jankowitz, Preeti Badve, Mamatha Chivukula. University of Pittsburgh Medical Center, PA

Background: Breast cancer was classified into five subtypes by Perou et al using cDNA microarray into luminal A and B, HER2, basal and normal subtypes. Gene expression profiling of breast cancers has also further identified two biologically distinct estrogen receptor positive (ER+) subtypes of breast cancer namely luminal A and luminal B. Studies to distinguish luminal B from luminal A tumors by immunohistochemistry are evolving. We undertook the study to perform immunohistochemistry in a large cohort of luminal A tumors and to further define this group in terms of non-recurrence and recurrence.
Design: 268 patients with ER (+), lymph node negative (LN -) from 1990-2003 were selected. Hematoxylin and eosin (H&E) slides were reviewed and representative tumor blocks were retrieved from our pathology files. Immunohistochemistry staining were performed on formalin fixed, paraffin-embedded tissue blocks using ER, Ki-67 and HER 2.
Results: Of the 268 patients, 212 were Non-recurrence group, 56 patients presented with recurrence {distant recurrence (DR) (44/56); loco regional recurrence (LRR) (12/56)} with a median follow-up of 10.1 years. Majority of non-recurrence cases (88%) had a nottingham grade of 1 or 2 and only 12% of the cases were grade 3. All of the LRR cases were nottingham grade 2. Majority of DR cases(94%) had a grade of 2 or 3. Other results in the non-recurrence group and all cases of recurrence to date are shown in Table 1 and Table 2.

HER 2 expression in all three groups

	HER 2 { % (n)}
	Negative(0-1)	Equivocal(2)	Strong(3)
NR (80)	86% (69)	3% (2)	11%(9)
DR (27)	74% (20)	7% (2)	19% (5)
LRR (14)	64% (9)	14% (2)	21% (3)

Ki-67 index expression in all three groups

	Ki-67 Index { % (n)
	Low(0-10)	Moderate(11-25)	High (26-50)	Very High(>51)
NR (145)	58% (83)	15% (22)	14% (21)	13% (19)
DR (40)	40% (16)	20% (8)	20% (8)	20% (8)
LRR (14)	57% (8)	29% (4)	14% (2)	0

Conclusions: The non-recurrence (ER +) tumors show low-moderate nuclear grade in contrast to recurrence (ER+) group which showed moderate-high nuclear grade.
We found that the non-recurrence group showed lower proliferation index in comparison to recurrence group ( p= 0.0168)
HER 2 tends to be strongly expressed in the recurrence group (both DR, LRR) compared to the non recurrence group (p=1.000).
Expression of HER2 and Ki67 and Nottingham grade appears to distinguish the luminal A breast cancers which can present with recurrence versus the non-recurrence.
Category: Breast

Monday, February 28, 2011 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 43, Monday Morning