[1125] The HistoRx AQUAnalysis Platform Is the More Discriminatory Method To Quantify ER/PR Expression: The Example of Low-Grade Serous Carcinoma

Jorge Escobar, Michelle Dean, Alexander Klimowicz, Pamela Chu, Jill Nation, Gregg Nelson, Prafull Ghathage, Steve Kalloger, Martin Kobel. University of Calgary, CLS, Calgary, Canada; Tom Baker Cancer Centre, Calgary, Canada; University of British Columbia, Vancouver, Canada

Background: Case reports suggest that hormonal therapy may be an option for low-grade serous carcinomas (LGSC) but data on quantitative hormone receptor expression in LGSC are lacking.
Design: We assessed ER/PR expression on 25 LGSC, 66 high-grade serous carcinomas (HGSC), 31 serous borderline tumours (SBOT), and five normal fallopian tubes (FT) on TMAs using two DAB platforms (Lecia/Bond (SP1, 1E2 antibodies) and DAKO with PharmDx antibodies) and evaluating with the Allred score. Quantitative fluorescent immunohistochemistry, using the DAKO PharmDx antibodies, was performed using the HistoRx AQUAnalysis platform. Mean values were calculated and Anova analysis applied to calculate the 95 CI.

DAB Allred and AQUA scores
DiagnosisER Leica AllredER DAKO AllredER AQUA scorePR Leica AllredPR DAKO AllredPR AQUA score
FT8.0 (5.9-8.0)8.0 (6.1-8.0)402 (318-486)7.3 (5.0-8.0)7.8 (5.4-8.0)474 (361-586)
SBOT7.7 (7.0-8.0)7.7 (7.0-8.0)411 (376-445)7.3 (6.6-8.0)7.1 (6.1-8.0)364 (322-405)
LGSC7.0 (6.2-7.8)7.0 (6.1-7.8)267 (229-304)5.2 (4.4-6.0)3.6 (2.5-4.6)163 (118-209)
HGSC6.3 (5.8-6.8)5.8 (5.3-6.3)195 (171-218)5.0 (4.5-5.5)2.5 (1.8-3.1)111 (81-142)
Means and 95% CI are displayed

ER level of LGSC are significantly lower than FT and SBOT but higher than HGSC, a finding only seen in the HistoRX analysis. LGSC and HGSC do not differ with respect to PR expression; both show a significantly lower PR expression than FT and SBOT.

Nonparametric bivariate density analysis (Figure) revealed two populations with respect to hormone receptor expression within LGSC only when using the ER and PR AQUA data.
Conclusions: Immunohistochemical assays do not distinguish the hormone receptor expression level between LGSC and HGSC, while the HistoRx AQUAnalysis platform showed a significant higher ER expression in LGSC. HistoRx AQUAnalysis reveals two distinct populations with respect to hormone receptor expression within LGSC, which may be useful as a predictive marker for hormonal therapy, assuming that only double high expressors benefit from hormonal treatment.
Category: Gynecologic & Obstetrics

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 211, Wednesday Afternoon


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