Topoisomerase IIα gene status and prediction of pathological complete remission after anthracycline-based neoadjuvant chemotherapy in endocrine non-responsive Her2/neu-positive breast cancer

Purpose: Topoisomerase II alpha (Topo II) is a potential marker of responsiveness to anthracycline-based therapy. We analyzed the role of Topo II gene status in the prediction of pathological complete remission (pCR) after primary anthracycline-based chemotherapy in non-endocrine responsive breast cancers overexpressing Her2/neu. Methods: Twenty-three patients, with T2-T4, ER and PgR absent, overexpressing Her2/neu breast cancers treated with anthracycline-based chemotherapy were evaluated. Topo II gene status was assessed by FISH in pre-treatment tumor specimens and the results were correlated to pathological and clinical responses. Results: Overall, six patients had a pCR (26%). Topo II was amplified in 5 (22%) of the tumors. In all patients with Topo II amplification, Her2/neu gene amplification was also detected. Among patients without amplification, one had polysomia of chromosome (Cr) 17 and four patients had deletion of the Topo II gene. A higher probability of pCR was observed when Topo II amplification and Cr 17 polysomy were present: pCR was reported in 3 of 5 amplified tumors (60%). in the polysomic tumor (amplified plus polysomic 67%) and in only 2 out of 13 tumors without alteration of Topo II status (15%). If we compare the frequency of pCR in tumors with amplification or polysomy versus the frequency of tumors with not amplification (deletion or no modification), a significant difference was detected (p = 0.02). One progressive disease (PD) was reported in one tumor with Topo II deletion (1/4, 25%) and one in tumor without any modification of Topo II gene status (1/13, 8%). Conclusions: In patient, with endocrine unresponsive and Her2 overexpressing tumors, Topo II amplification or the presence of chromosome 17 polysomy correlate with a significantly high probability of achieving pCR after ncoadjuvant, anthracycline-based chemotherapy. Further prospective studies in order to more clearly define the predictive role of Topo II status in this subgroup of patients are warranted. (C) 2008 Elsevier Ltd. All rights reserved.