Received: 15 June 2020
Accepted: 8 December 2020
First Online: 7 January 2021
Ethics approval and consent to participate
: Approval of the use of human primary breast cancer samples and metastatic tissue was obtained from the official ethical authorities of the Canton Zurich, Switzerland (ethical approval KEK-2012-553) according to the Declaration of Helsinki.
: Not applicable.
: The authors declare that they have no competing interests.