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Oncotarget. 2017 Oct 24;8(61):104149-104159. doi: 10.18632/oncotarget.22027. eCollection 2017 Nov 28.

Predictive value of quantitative HER2, HER3 and p95HER2 levels in HER2-positive advanced breast cancer patients treated with lapatinib following progression on trastuzumab.

Author information

1
Military Institute of Medicine, Warsaw, Poland.
2
Monogram Biosciences, Integrated Oncology, Laboratory Corporation of America Holdings, South San Francisco, CA, USA.
3
Białystok Oncology Center, Białystok, Poland.
4
Oncology Center, Zielona Góra, Poland.
5
Opole Oncology Center, Opole, Poland.
6
Masaryk Memorial Cancer Institute, Brno, Czech Republic.
7
Warmia and Masuria Oncology Center, Olsztyn, Poland.
8
Medical University of Gdańsk, Gdańsk, Poland.
9
National Institute of Oncology, Budapest, Hungary.
10
Regional Hospital, Wrocław, Poland.
11
Medical University of Łódź, Łódź, Poland.
12
Oncology Center, Kielce, Poland.
13
Oncology Institute, Kraków, Poland.

Abstract

Lapatinib is a HER1 and HER2 tyrosine kinase inhibitor (TKI) approved in second line treatment of advanced or metastatic breast cancer following progression on trastuzumab-containing therapy. Biomarkers for activity of lapatinib and other TKIs are lacking. Formalin-fixed, paraffin-embedded primary tumor samples were obtained from 189 HER2-positive patients treated with lapatinib plus capecitabine following progression on trastuzumab. The HERmark® Breast Cancer Assay was used to quantify HER2 protein expression. HER3 and p95HER2 protein expression was quantified using the VeraTag® technology. Overall survival (OS) was inversely correlated with HER2 (HR = 1.9/log; P = 0.009) for patients with tumors above the cut-off positivity level by the HERmark assay. OS was significantly shorter for those with above median HER2 levels (HR = 1.7; P = 0.015) and trended shorter for those below the cut-off level of positivity by the HERmark assay (HR = 1.7; P = 0.057) compared to cases with moderate HER2 overexpression. The relationship between HER2 protein expression and OS was best captured with a U-shaped parabolic function (P = 0.004), with the best prognosis at moderate levels of HER2 protein overexpression. In a multivariate model including HER2, increasing p95HER2 expression was associated with longer OS (HR = 0.35/log; P = 0.027). Continuous HER3 did not significantly correlate with OS. Patients with moderately overexpressed HER2 levels and high p95HER2 expression may have best outcomes while receiving lapatinib following progression on trastuzumab. Further study is warranted to explore the predictive utility of quantitative HER2 and p95HER2 in guiding HER2-directed therapies.

KEYWORDS:

HER2; breast cancer; lapatinib; p95HER2; trastuzumab

Conflict of interest statement

CONFLICTS OF INTEREST Jeff Sperinde, John Winslow, Christos Petropoulos and Weidong Huang are employees of Monogram Biosciences, Integrated Oncology, Laboratory Corporation of America® Holdings. All other authors have not declared a conflicts of interest.

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