# Mitch Dowsett

Source: https://onco.cc/people/mitch-dowsett/  
OnCo record `mitch-dowsett` (Person). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The translational scientist behind the aromatase inhibitor era and the Ki67 response test used in POETIC.

## Summary

Mitch Dowsett's laboratory established the pharmacology of aromatase inhibitors and the biomarker work that supported the ATAC trial, and defined Ki67 change after two weeks of endocrine therapy as a predictor of outcome (POETIC). He chaired the International Ki67 Working Group and led the IMPACT and POETIC trials with Ian Smith. His current work focuses on endocrine resistance biology and biomarker standardisation.

## Fields

- Kind: Person
- Last checked: 2026-09-10
- Tags: breast; biomarkers; translational
- Role: Professor of Biochemical Endocrinology, Institute of Cancer Research and Royal Marsden
- Specialisms: Endocrine therapy biology; Ki67 and biomarkers; Aromatase inhibitors; Translational breast research

## Sources

- PubMed: https://pubmed.ncbi.nlm.nih.gov/?term=Dowsett%20M%5BAuthor%5D%20Ki67%20endocrine

## Connected records

- cancers: [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/)
- technologies: [Endocrine therapy (SERMs, AIs, SERDs)](https://onco.cc/technologies/endocrine-therapy/), [Histopathology & immunohistochemistry](https://onco.cc/technologies/histopathology-ihc/)
- targets: [Estrogen receptor (ERα)](https://onco.cc/targets/estrogen-receptor/)
- institutions: [The Institute of Cancer Research](https://onco.cc/institutions/icr-london/), [The Royal Marsden](https://onco.cc/institutions/royal-marsden/)

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