# PD-L1 expression testing (22C3, SP142, SP263)

Source: https://onco.cc/terms/pd-l1-testing/  
OnCo record `pd-l1-testing` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A stain on the tumour biopsy that measures how much of the PD-L1 'don't attack me' protein is present, scored as a tumour proportion or combined positive score. Higher levels usually mean checkpoint inhibitors work better, and approvals in lung, triple-negative breast, gastric and head and neck cancer set minimum scores; yet PD-L1-negative tumours sometimes respond.

## Summary

Several antibody clones (22C3 for pembrolizumab, SP142 for atezolizumab, SP263 for durvalumab, 28-8 for nivolumab) and scoring systems (tumour proportion score, combined positive score, immune cell score) are in use and are only partly interchangeable (Blueprint project), which complicates practice. PD-L1 ≥50% TPS in lung cancer permits pembrolizumab alone; CPS ≥10 gates pembrolizumab in triple-negative breast and CPS ≥1 or ≥5 in gastric and head and neck cancer. It is an imperfect biomarker: PD-L1-negative tumours sometimes respond and expression is heterogeneous and changes with treatment.

## Fields

- Kind: Term
- Last checked: 2026-09-09
- Also known as: PD-L1 expression; PD-L1-positive; PD-L1 positive; PD-L1-negative; PD-L1 negative; PD-L1-high; PD-L1 high; PD-L1-low; PD-L1 status; PD-L1 IHC; 22C3; SP142; SP263; 28-8; PD-L1 ≥50%; PD-L1 ≥1%

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/PD-L1
- Wikipedia: https://en.wikipedia.org/wiki/PD-L1

## Connected records

- terms: [Combined positive score (CPS)](https://onco.cc/terms/cps/), [Immuno-oncology (IO) and checkpoint blockade](https://onco.cc/terms/immuno-oncology/), [Interferon-gamma gene signature (T-cell-inflamed signature)](https://onco.cc/terms/interferon-gamma-signature/), [Lung cancer trials open today (registry snapshot)](https://onco.cc/terms/lung-trials-open-today/), [Lung cancer: the failed and stopped programmes, and why](https://onco.cc/terms/lung-failed-programmes/), [STK11 / KEAP1 co-mutations](https://onco.cc/terms/stk11-keap1/), [Subgroup analysis (forest plots)](https://onco.cc/terms/subgroup-analysis/), [Tumour mutational burden (TMB)](https://onco.cc/terms/tmb/)
- fronts: [Diagnostics & Biomarkers](https://onco.cc/fronts/diagnostics/), [Immunotherapy](https://onco.cc/fronts/immunotherapy/)
- technologies: [Companion diagnostics](https://onco.cc/technologies/companion-diagnostic/), [Histopathology & immunohistochemistry](https://onco.cc/technologies/histopathology-ihc/), [Immune checkpoint inhibitors](https://onco.cc/technologies/checkpoint-inhibitor/)
- targets: [PD-L1](https://onco.cc/targets/pdl1/)
- 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/), [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-042](https://onco.cc/trials/keynote-042/), [OAK](https://onco.cc/trials/oak/)
- key papers: [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/)
- drugs: [PD-L1 IHC 22C3 pharmDx](https://onco.cc/drugs/dako-pd-l1-22c3-pharmdx/), [VENTANA PD-L1 (SP142) Assay](https://onco.cc/drugs/ventana-pd-l1-sp142/), [VENTANA PD-L1 (SP263) Assay](https://onco.cc/drugs/ventana-pd-l1-sp263/)
- biomarkers: [PD-L1 CPS (combined positive score)](https://onco.cc/biomarkers/pd-l1-cps/), [PD-L1 IC score (immune-cell score, SP142)](https://onco.cc/biomarkers/pd-l1-ic-score/), [PD-L1 TC score (tumour-cell score, SP263 and 28-8)](https://onco.cc/biomarkers/pd-l1-tc-score/), [PD-L1 TPS (tumour proportion score)](https://onco.cc/biomarkers/pd-l1-tps/)
- cancers: [HPV-negative head and neck squamous cell carcinoma (including HPV-negative oropharyngeal cancer)](https://onco.cc/cancers/hpv-negative-head-and-neck-cancer/), [Lung cancer (all types)](https://onco.cc/cancers/lung-cancer/), [Mucoepidermoid carcinoma](https://onco.cc/cancers/mucoepidermoid-carcinoma/), [PD-L1-high non-small-cell lung cancer without a driver mutation](https://onco.cc/cancers/pdl1-high-nsclc/), [Recurrent or metastatic head and neck squamous cell carcinoma](https://onco.cc/cancers/recurrent-metastatic-hnscc/)

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