Ovarian cancer expression of ER, PgR, EGFR, and Her2 in Irish women may predict for targeted therapies: A single institution experience

Abstract

22179 Background: To help select for targeted agents (e.g. erlotinib or trastuzumab), and to determine patients who would best benefit from hormonal manipulation, we estimated by immunohistochemistry (IHC), the expression of oestrogen-receptor (ER), progesterone-receptor (PgR), epidermal growthfactor receptor I (EGFR I) and c-erb-2 receptors (Her2; EGFR-2) in ovarian cancer tissue in Ireland. Methods: Tissue samples from 96 sequential patients with histologically proven ovarian cancer were studied. The receptors were determined by IHC using kits by DAKO - Denmark, Novocastra - UK, NeoMarkers Labvision - UK. ER and PgR stained slides were scored as strong, moderate, weak or negative, EGFR-1 was stained as either positive or negative and Her2 was scored either 0, 1+, 2+ or 3+. Any ER, PgR positivity, EGFR-1 positivity, and Her2 2+ and 3+ are reported. FISH analysis of Her2 2+ and 3+ samples was undertaken. Results: 96 patient samples were studied, mean age: 56 years (Range 19–82). Histology was either serous (53%) or mucinous (24%) in the majority. 60/96 (62%) were positive for at least 1 receptor, 29% were positive for 2 receptors, 4% were positive for 3 and 1% were positive for all 4. 21/96 (22%) were positive for ER/PgR. 13/96 (13%) were 2+ and 3+ for Her2. 20/96 (21%) were positive for EGFR-1, and 4/96 (4%) were positive for both EGFR I and Her2. Approximately 50% of 13 patient samples expressing 2+ and 3+ Her2 were poorly differentiated tumours, 33% of 21 EGFR positive tumours were poorly differentiated. Conclusions: Measurement of ER, PgR, EGFR-1 and Her2 receptor expression could lead to a rationale for using targeted agents (e.g. erlotinib, trastuzumab etc) and also endocrine therapies in ovarian cancer. Growth factor receptor expression may modulate response to targeted therapies and thus growth factor and hormone receptors should be determined in patients, allowing for more precise treatments. No significant financial relationships to disclose.