biomarkersBiomarker

PD-L1 TC score (tumour-cell score, SP263 and 28-8)

aka PD-L1 TC, TC score, tumor cell score, tumour cell score, TC >= 1%, TC >= 50%, PD-L1 >= 1% tumor cells, SP263 TC, 28-8 TC, TC≥1%, TC≥50%

The TC score is the percentage of tumour cells staining for PD-L1 on the SP263 or 28-8 assays. Atezolizumab uses 1 percent after lung surgery and 50 percent for first-line treatment alone; nivolumab with ipilimumab uses 1 percent in first-line lung cancer.

Tumour-cell scoring on the VENTANA SP263 and Dako 28-8 assays is arithmetically the same as TPS (percentage of tumour cells with membrane staining) but is tied to different drugs and assays, so labels write it as TC or as 'PD-L1 expression on >= 1% of tumor cells'. Atezolizumab's adjuvant NSCLC indication after resection and platinum chemotherapy requires PD-L1 on >= 1 percent of tumour cells (IMpower010, SP263), and its first-line single-agent indication uses TC >= 50 percent (or IC >= 10 percent). Nivolumab with ipilimumab in first-line metastatic NSCLC is approved for tumours expressing PD-L1 >= 1 percent on the 28-8 pharmDx (CheckMate 227). Blueprint phase 2 found SP263, 22C3 and 28-8 closely concordant for tumour-cell scoring, which is why the FDA has accepted each as a companion for several antibodies.

Part ofPD-L1· CD274Other readoutsPD-L1 CPS PD-L1 IC score PD-L1 TPS All readouts

PD-L1: what it is and how drugs act on it · animated schematic, not to scale

Target · the protein and the cell it sits on
Drug · antibody, small molecule, cell or radioligand
Effect · signal, damage or kill

In plain words · PD-L1 is the tumour's side of the PD-1 brake, and also the biomarker that decides who gets immunotherapy.

TC score 3 approval thresholds

What it means for a patient

A TC percentage is the share of tumour cells that stain. After lung cancer surgery, 1 percent or more is the label threshold for a year of atezolizumab; in metastatic lung cancer 50 percent or more allows atezolizumab on its own, and 1 percent or more allows nivolumab with ipilimumab. Ask which assay was used, because the drug the result applies to follows the assay.

Written only from the label or guideline text cited on this page. Not medical advice; your own report and the reading your team gives it come first.

Scoring rule

Percentage of tumour cells with membrane staining of any intensity on the SP263 or 28-8 assay; immune cells are not counted.

“PD-L1 protein expression (PD-L1 stained ≥ 1% of tumor cells [TC ≥ 1%])”
FDA: List of FDA-Authorized Companion Diagnostic Devices

Thresholds used in approvals

Threshold	Drug	Cancer	Regulator	Source
PD-L1 on >= 1% of tumour cells (adjuvant)	Atezolizumab	Non-small-cell lung cancer	FDA	label
TC >= 50% (or IC >= 10%)	Atezolizumab	Non-small-cell lung cancer	FDA	label
PD-L1 >= 1% tumour cells (28-8 pharmDx) FDA companion diagnostic row P150025/S013 (15 May 2020) for Opdivo in combination with Yervoy in NSCLC.	Nivolumab	Non-small-cell lung cancer	FDA	label

Drugs whose label names it

Atezolizumab Nivolumab

Companion diagnostics (FDA list)

Device	Maker	Indication and sample	Drug	PMA / 510(k)
Ventana PD-L1 (SP263) Assay	Ventana Medical Systems (Roche)	Non-Small Cell Lung Cancer (NSCLC) - Tissue	Atezolizumab	P160046/S010 (10/15/2021)
PD-L1 IHC 28-8 pharmDx	Agilent Technologies (Dako)	Non-small cell lung cancer (NSCLC) - Tissue	Nivolumab Ipilimumab	P150025/S013 (05/15/2020)