# Tumour proportion score (TPS)

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

## TL;DR

The PD-L1 score used in lung cancer: the percentage of tumour cells that stain positive.

## Summary

The tumour proportion score is the PD-L1 read-out used in non-small-cell lung cancer: the share of tumour cells that stain positive for PD-L1 on the 22C3 assay. A high score supports pembrolizumab or cemiplimab alone, an intermediate score favours chemo-immunotherapy, and a negative score still leaves room for chemo-immunotherapy or CTLA-4-containing regimens such as those tested in POSEIDON. Readers meet TPS in KEYNOTE-024 and KEYNOTE-189 and in the pairing of PD-1 blockade with chemotherapy in PD-L1-low disease. It differs from the combined positive score used in breast, gastric and head and neck cancer, which also counts immune cells. Its weakness as a predictor is why the biomarker-validation and immunotherapy-response bottlenecks link to it.

## Fields

- Kind: Term
- Last checked: 2026-09-06

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/PD-L1
- KEYNOTE-024: pembrolizumab versus chemotherapy for PD-L1-positive non-small-cell lung cancer (NEJM 2016): https://doi.org/10.1056/NEJMoa1606774

## Connected records

- cancers: [BRAF V600E-mutant non-small-cell lung cancer](https://onco.cc/cancers/braf-v600e-nsclc/), [KRAS G12C-mutant non-small-cell lung cancer](https://onco.cc/cancers/kras-g12c-nsclc/), [Lung cancer (all types)](https://onco.cc/cancers/lung-cancer/), [Non-small-cell lung cancer](https://onco.cc/cancers/nsclc/), [PD-L1-high non-small-cell lung cancer without a driver mutation](https://onco.cc/cancers/pdl1-high-nsclc/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- targets: [PD-L1](https://onco.cc/targets/pdl1/)
- drugs: [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/)
- terms: [Combined positive score (CPS)](https://onco.cc/terms/cps/), [Lung cancer: the failed and stopped programmes, and why](https://onco.cc/terms/lung-failed-programmes/)
- trials: [CheckMate 017](https://onco.cc/trials/checkmate-017/), [CheckMate 026](https://onco.cc/trials/checkmate-026/), [CheckMate 057](https://onco.cc/trials/checkmate-057/), [CheckMate 9LA](https://onco.cc/trials/checkmate-9la/), [EMPOWER-Lung 1](https://onco.cc/trials/empower-lung-1/), [IMpower110](https://onco.cc/trials/impower110/), [KEYNOTE-010](https://onco.cc/trials/keynote-010/), [KEYNOTE-024 & KEYNOTE-189](https://onco.cc/trials/keynote-024-189/), [KEYNOTE-042](https://onco.cc/trials/keynote-042/)
- pairings: [PD-1 blockade + chemotherapy in PD-L1-low NSCLC](https://onco.cc/pairings/pd1-plus-chemo-pdl1-low/)
- key papers: [Atezolizumab for first-line treatment of PD-L1-selected patients with NSCLC](https://onco.cc/key-papers/paper-herbst-impower110-atezolizumab-pd-l1-nejm-2020/), [KEYNOTE-001 (Garon 2015): pembrolizumab in non-small-cell lung cancer and the 50% PD-L1 cut-off](https://onco.cc/key-papers/paper-keynote-001-pembrolizumab-nsclc-nejm-2015/), [KEYNOTE-010 (Herbst 2016): pembrolizumab versus docetaxel in previously treated PD-L1-positive lung cancer](https://onco.cc/key-papers/paper-keynote-010-lancet-2016/), [KEYNOTE-024: pembrolizumab alone beats chemotherapy in PD-L1-high lung cancer](https://onco.cc/key-papers/paper-keynote-024-nejm-2016/)
- bottlenecks: [Biomarkers are not validated or standardised](https://onco.cc/bottlenecks/b-biomarker-validation/), [No one can predict who responds to immunotherapy](https://onco.cc/bottlenecks/b-immunotherapy-response/)
- ideas: [Pool every immunotherapy trial's biomarker data into one commons](https://onco.cc/ideas/idea-bio2-io-biomarker-data-commons/), [Turn the map of immune cells inside a tumour into a standardised test](https://onco.cc/ideas/idea-bio2-spatial-signature-cdx/)
- biomarkers: [PD-L1 TPS (tumour proportion score)](https://onco.cc/biomarkers/pd-l1-tps/)

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JSON: https://onco.cc/api/v1/entities/tps.json