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Mitch Dowsett, FMedSci, PhD

Head, Department of Biochemistry and Centre for Molecular Pathology
Professor of Biochemical Endocrinology,
Breakthrough Research Centre
Professor of Translational Research
The Royal Marsden Hospital
Institute of Cancer Research
London, United Kingdom

Current Research

  • Seeking to reduce recurrence of ER-positive breast cancer with new strategies to prevent resistance to anti-estrogen drugs.

  • A novel clinical trial platform is used to identify markers of drug resistance in individual patients following aromatase inhibitor treatment.

  • These studies will lead to better outcomes in early stage breast cancer by identifying biomarkers that can be therapeutically targeted to prevent tumors from coming back.

Estrogen receptor-positive (ER+) breast cancer makes up more than two-thirds of all breast cancer cases, particularly those that occur after menopause. Although a variety of successful anti-estrogen drugs are available to treat ER+ cancer, resistance to these therapies remains a significant clinical challenge.

Drs. Dowsett and Smith are using a new clinical trial platform called POETIC-2 (PeriOperative Endocrine Therapy for Individualized Care-2) to identify potential combinations of anti-estrogen drugs and other drugs that target anticipated resistance mechanisms in individual patients. Patients who are diagnosed with early-stage ER+ breast cancer are asked to take an aromatase inhibitor (AI) for four weeks. If after that time, their tumor continues to show signs of growth, another drug is administered to block that growth.

This year, the team is conducting four separate associated studies within the POETIC-2 cohort  (i) confirm that  gene expression signatures of endocrine resistance are enriched in residual disease after neoadjuvant AI treatment;  (ii) investigate if tumor DNA alterations are contributing to this resistance; (iii) separate proliferative (actively growing) from non-proliferative breast cancers and compare the DNA alterations between the two groups; (iv) validate the robustness of the proliferation marker that is used as an entry criterion for POETIC-2 and to assess tumor response to treatment.

These studies will improve our knowledge of the characteristics of an individual's tumor and offer the potential for individualized therapy and new drug development.


Professor Mitch Dowsett, FMedSci, PhD, is Head of the Academic Department of Biochemistry and Head of the Centre for Molecular Pathology at the Royal Marsden Hospital; Professor of Biochemical Endocrinology at the Institute of Cancer Research; and Professor of Translational Research in the Breakthrough Breast Cancer Centre, London.

Professor Dowsett’s research focuses almost exclusively on breast cancer and predominantly on hormonal aspects of the disease and biomarkers of response with a research team of about 24 investigators. He was closely involved with the clinical development of aromatase inhibitors and in the creation of national and international standards for steroid receptor and HER2 analysis (ASCO/CAP Guidelines Steering Committees). He co-chairs the International Working Party for Ki67 in Breast Cancer. He was the founding chairman of the UK NCRI Translational Research (subsequently Biomarker and Imaging) Clinical Study Group. In 2004 he founded and continues to chair the Aromatase Inhibitor Overview Group.

He has authored nearly 600 published papers related to breast cancer, and given numerous named lectures including the 2007 William L McGuire Memorial Lecture. He recently rotated off the Executive Board of the Breast International Group (BIG) after seven years, and sits on the Executive/Steering Committees of several clinical trials. He has been a NCRI Senior Clinical Investigator since 2009. In 2013 he was appointed as a Fellow of the Academy of Medical Sciences.

BCRF Investigator Since


Donor Recognition

The Estée Lauder Companies' Brands Award in honor of Elizabeth Hurley

Area(s) of Focus

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