Front. Oncol. Frontiers in Oncology Front. Oncol. 2234-943X Frontiers Media S.A. 10.3389/fonc.2026.1798367 Retraction Retraction: A phase II, single-arm study of apatinib and oral etoposide in heavily pre-treated metastatic breast cancer Frontiers Editorial Office * Correspondence: Frontiers Editorial Office, research.integrity@frontiersin.org 10 02 2026 2026 16 1798367 28 01 2026 28 01 2026 Copyright © 2026 Frontiers Editorial Office. 2026 Frontiers Editorial Office https://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. A Retraction of the Clinical Trial Article A phase II, single-arm study of apatinib and oral etoposide in heavily pre-treated metastatic breast cancer By Hu N, Zhu A, Si Y, Yue J, Wang X, Wang J, Ma F, Xu B and Yuan P (2021) Front. Oncol. 10:565384. doi: 10.3389/fonc.2020.565384 section-at-acceptance Women's Cancer

Following publication, significant concerns were raised regarding the integrity of the patient data and reporting within the manuscript. An investigation was conducted in accordance with Frontiers’ policies, and it was determined that the conclusions and assertions were not sufficiently supported by the findings from the material provided; therefore, the article has been retracted.

This retraction was approved by the Chief Editors of Frontiers in Oncology and the Chief Executive Editor of Frontiers. The authors agree to this retraction.

Approved by: Sharon R. Pine, University of Colorado Anschutz Medical Campus, United States