Unknown

Dataset Information

0

Phosphorylated p-70S6K predicts tamoxifen resistance in postmenopausal breast cancer patients randomized between adjuvant tamoxifen versus no systemic treatment.


ABSTRACT: INTRODUCTION: Activation of the phosphatidylinositol-3-kinase (PI3K) and/or mitogen-activated protein kinase (MAPK) pathways results in anti-estrogen resistance in vitro, but a biomarker with clinical validity to predict intrinsic resistance has not been identified. In metastatic breast cancer patients with previous exposure to endocrine therapy, the addition of a mammalian target of rapamycine (mTOR) inhibitor has been shown to be beneficial. Whether or not patients on adjuvant endocrine treatment might benefit from these drugs is currently unclear. A biomarker that predicts intrinsic resistance could potentially be used as companion diagnostic in this setting. We tested the clinical validity of different downstream-activated proteins in the PI3K and/or MAPK pathways to predict intrinsic tamoxifen resistance in postmenopausal primary breast cancer patients. METHODS: We recollected primary tumor tissue from patients who participated in a randomized trial of adjuvant tamoxifen (1-3 years) versus observation. After constructing a tissue micro-array, cores from 563 estrogen receptor ? positive were immunostained for p-AKT(Thr308), p-AKT(Ser473), p-mTOR, p-p706SK and p-ERK1/2. Cox proportional hazard models for recurrence free interval were used to assess hazard ratios and interactions between these markers and tamoxifen treatment efficacy. RESULTS: Interactions were identified between tamoxifen and p-AKT(Thr308), p-mTOR, p-p70S6K and p-ERK1/2. Applying a conservative level of significance, p-p70S6K remained significantly associated with tamoxifen resistance. Patients with p-p70S6K negative tumors derived significant benefit from tamoxifen (HR 0.24, P?

SUBMITTER: Beelen K 

PROVIDER: S-EPMC3979131 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

altmetric image

Publications

Phosphorylated p-70S6K predicts tamoxifen resistance in postmenopausal breast cancer patients randomized between adjuvant tamoxifen versus no systemic treatment.

Beelen Karin K   Opdam Mark M   Severson Tesa M TM   Koornstra Rutger H T RH   Vincent Andrew D AD   Wesseling Jelle J   Muris Jettie J JJ   Berns Els M J J EM   Vermorken Jan B JB   van Diest Paul J PJ   Linn Sabine C SC  

Breast cancer research : BCR 20140121 1


<h4>Introduction</h4>Activation of the phosphatidylinositol-3-kinase (PI3K) and/or mitogen-activated protein kinase (MAPK) pathways results in anti-estrogen resistance in vitro, but a biomarker with clinical validity to predict intrinsic resistance has not been identified. In metastatic breast cancer patients with previous exposure to endocrine therapy, the addition of a mammalian target of rapamycine (mTOR) inhibitor has been shown to be beneficial. Whether or not patients on adjuvant endocrine  ...[more]

Similar Datasets

| S-EPMC3695326 | biostudies-literature
| S-EPMC3776368 | biostudies-literature
| S-EPMC7043945 | biostudies-literature
| S-EPMC3677838 | biostudies-literature
| S-EPMC3556260 | biostudies-literature
| S-EPMC3588857 | biostudies-literature
| S-EPMC4969219 | biostudies-literature
| S-EPMC10358080 | biostudies-literature
| S-EPMC3978618 | biostudies-literature
| S-EPMC3132953 | biostudies-other