# PD-L1 IC score (immune-cell score, SP142)

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

## TL;DR

The IC score measures how much of the tumour area is covered by PD-L1-stained immune cells rather than tumour cells. It belongs to the SP142 assay used with atezolizumab and is read differently from every other PD-L1 score.

## Summary

The VENTANA SP142 assay scores PD-L1 on tumour-infiltrating immune cells as the proportion of tumour area they occupy: IC0 (< 1 percent), IC1 (1 to < 5 percent), IC2 (5 to < 10 percent), IC3 (>= 10 percent). Atezolizumab's current US label uses IC >= 10 percent as one arm of the first-line NSCLC single-agent gate (the other being TC >= 50 percent). Earlier atezolizumab indications that used IC scores, IC >= 5 percent in cisplatin-ineligible urothelial cancer and IC >= 1 percent in triple-negative breast cancer (IMpassion130), were withdrawn in the United States in 2022 and 2021; the FDA companion diagnostic list still carries the urothelial SP142 approval of 2016. Blueprint comparison studies found SP142 stains fewer tumour cells than 22C3, 28-8 or SP263, so an SP142 result cannot be swapped for a TPS or CPS.

## Fields

- Kind: Biomarker
- Last checked: 2026-09-23
- Also known as: PD-L1 IC; IC score; immune cell score; tumor-infiltrating immune cell score; SP142 IC; IC >= 1%; IC >= 5%; IC >= 10%; IC≥1%; IC2/3
- Tags: biomarker; pd-l1

## Notes

- Triple-negative breast cancer: IMpassion130 defined PD-L1-positive as SP142 tumour-infiltrating immune cells covering 1% or more of the tumour area, 46.4% of 614 centrally scored samples (Rugo 2021) and 50.9% of 232 early tumours (Sigurjonsdottir 2023). SP263 and 22C3 call IC 1% in about 74% of the same samples, but the atezolizumab benefit was confined to SP142-positive cases, so a positive on another clone does not qualify (Rugo 2021). The US indication was withdrawn in 2021; the threshold remains in the European authorisation.
- Lung cancer: the immune-cell score is an area fraction, the percentage of the tumour area occupied by PD-L1-staining immune cells, and it is the least reproducible measurement in lung pathology. Agreement between pathologists on it is 0.18 to 0.19 against 0.86 to 0.93 for tumour cells (Tsao 2018) and interassay concordance is 0.277 against 0.813 (Rimm 2017). It nevertheless carries a threshold, since IMpower110 selected on tumour-cell 1% or more or immune-cell 1% or more, with the survival benefit confined to the highest expressers (Herbst 2020).

## Sources

- TECENTRIQ prescribing information (DailyMed): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=6fa682c9-a312-4932-9831-f286908660ee

## Connected records

- biomarkers: [PD-L1 CPS (combined positive score)](https://onco.cc/biomarkers/pd-l1-cps/), [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: [Bladder & urothelial cancer](https://onco.cc/cancers/urothelial/), [Metastatic triple-negative breast cancer](https://onco.cc/cancers/tnbc-metastatic/), [Non-small-cell lung cancer](https://onco.cc/cancers/nsclc/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- drugs: [Atezolizumab](https://onco.cc/drugs/atezolizumab/), [VENTANA PD-L1 (SP142) Assay](https://onco.cc/drugs/ventana-pd-l1-sp142/)
- terms: [Immunohistochemistry (IHC)](https://onco.cc/terms/ihc/), [PD-L1 expression testing (22C3, SP142, SP263)](https://onco.cc/terms/pd-l1-testing/), [Tumour-infiltrating lymphocytes (TILs)](https://onco.cc/terms/tils/)
- key papers: [A prospective, multi-institutional, pathologist-based assessment of 4 immunohistochemistry assays for PD-L1 expression in non-small cell lung cancer](https://onco.cc/key-papers/paper-rimm-pd-l1-assay-comparison-jama-oncol-2017/), [Atezolizumab and Nab-Paclitaxel in Advanced Triple-Negative Breast Cancer](https://onco.cc/key-papers/paper-impassion130-n-engl-j-med-2018/), [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/), [Comparison of SP142 and 22C3 PD-L1 assays in a population-based cohort of triple-negative breast cancer patients in the context of their clinically established scoring algorithms](https://onco.cc/key-papers/paper-sigurjonsdottir-sp142-22c3-tnbc-bcr-2023/), [PD-L1 Immunohistochemistry Assay Comparison in Atezolizumab Plus nab-Paclitaxel-Treated Advanced Triple-Negative Breast Cancer](https://onco.cc/key-papers/paper-rugo-pd-l1-assay-comparison-impassion130-jnci-2021/), [PD-L1 Immunohistochemistry Assays for Lung Cancer: Results from Phase 1 of the Blueprint PD-L1 IHC Assay Comparison Project](https://onco.cc/key-papers/paper-hirsch-j-thorac-oncol/), [PD-L1 immunohistochemistry comparability study in real-life clinical samples: results of Blueprint phase 2 project](https://onco.cc/key-papers/paper-blueprint-phase-2-pd-l1-assays-jto-2018/)
- targets: [PD-L1](https://onco.cc/targets/pdl1/)

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