# Thomas Helleday

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

## TL;DR

Co-discovered that PARP inhibitors kill BRCA-deficient cells, the synthetic lethality behind olaparib and its successors.

## Summary

Thomas Helleday's laboratory published, back-to-back with Alan Ashworth's, the 2005 Nature paper showing that BRCA2-deficient cells are exquisitely sensitive to PARP inhibition, the discovery that led to olaparib, niraparib, rucaparib and talazoparib and established synthetic lethality as a drug-discovery strategy. He later developed the MTH1 inhibitor concept and continues to work on DNA repair targets.

## Fields

- Kind: Person
- Last checked: 2026-09-10
- Tags: parp; synthetic-lethality; discovery
- Role: Professor of Chemical Biology, Karolinska Institutet; Professor, University of Sheffield
- Specialisms: DNA damage response; Synthetic lethality; PARP inhibitors; Drug discovery

## Sources

- PubMed: https://pubmed.ncbi.nlm.nih.gov/?term=Helleday%20T%5BAuthor%5D%20PARP%20synthetic%20lethality

## Connected records

- technologies: [PARP inhibitors](https://onco.cc/technologies/parp-inhibitor/), [Synthetic lethality approaches](https://onco.cc/technologies/synthetic-lethality-approaches/)
- targets: [BRCA1 / BRCA2 (HRD)](https://onco.cc/targets/brca/), [PARP](https://onco.cc/targets/parp/)
- drugs: [Olaparib](https://onco.cc/drugs/olaparib/)
- institutions: [Karolinska University Hospital](https://onco.cc/institutions/karolinska/)
- journals: [Molecular oncology](https://onco.cc/journals/molecular-oncology/)

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