343P - New immunohistochemical markers predictive of response to neoadjuvant chemotherapy plus trastuzumab in HER2-positive locally advanced breast cancer:...
|Date||29 September 2012|
|Event||ESMO Congress 2012|
|Session||Poster presentation I|
|Topics|| Breast Cancer, Locally Advanced
G. Faggioni1, C. Ghiotto1, E. Orvieto2, S. Valpione3
We present the results of a prospective pilot study aimed to investigate the value of new immunohistochemichal predictive markers of response to chemotherapy in locally advanced HER-2 breast cancer. pTEN loss, pAKT and HER-3 overexpression cause PI3K activation and induce resistance to trastuzumab in vitro and in vivo, with poorer clinical responses in patients with advanced disease. We studied the espression of EGFR, HER-3, pTEN and pAKT in 31 patients with locally advanced HER-2 positive breast cancer who received neoadjuvant chemotherapy plus trastuzumab. Mean age of patients was 55.7 years (median 55, 95% CI 44,2-63,5 years). Results of immunohistochemistral staining are reassumed in the table.
|Mean||Median||25% C.I.||75% C.I.|
|HER3 (% positive cells)||50,0||50,0||32,5||70,0|
|HER3 H score||82,6||70,0||32,5||115,0|
|PTEN (% positive cells)||48,9||70,0||2,5||70,0|
Patients were homogeneous for tumor burden at diagnosis and received anthraciclin-taxane and trastuzumab-based neoadjuvant treatment. 14 out of 31patients achieved pathological complete remission. Ki-67 and HER3 H score were significatively higher in patients who achieved complete remission (medians were 45.5% versus 25%, p = 0.022; 100% versus 50%, p = 0.045 respectively. We found a correlation between EGFR H score and HER3 Hscore (p = 0.02), and an inverse correlation between age and EGFR H score (p = 0.05) and between PgR and AKT intensity (p = 0.03). Ki-67 and HER3 H score maintained significatively different medians in the group of patients who experienced pathological complete response versus the group on incomplete responders with multivariate analysis (p < 0.01).Disclosure
All authors have declared no conflicts of interest.