PD-L1 is a potential predictive biomarker for cancers that utilise this pathway to inhibit the immune response

TUMOUR CELLS AND TUMOUR-INFILTRATING IMMUNE CELLS BOTH EXPRESS PD-L11,2

PD-L1 expression detected in immunohistochemistry staining of lung cancer tumour3

PD-L1 on tumour cells
Tumour

PD-L1 on tumour cells may lead to the inhibition of activated T cells.1

PD-L1 on tumour infiltrating immune cells
Tumour-infiltrating immune cell

PD-L1on tumour-infiltrating immune cells may also inhibit T cell activation and function.1,4

PD-L1 EXPRESSION ON TUMOUR-INFILTRATING IMMUNE CELLS

With their potential ability to inhibit T-cell function when expressing PD-L1, tumour-infiltrating immune cells are an emerging focus of cancer immunotherapy research.1,4 Different immune cells have been shown to express PD-L1.3

PD-L1 expression on macrophages detected in immunofluorescence staining of lung cancer tumour3

PD-L1 expression on macrophages

Arrows indicate macrophages (green; CD163) that express PD-L1 (red)Cell nuclei are stained in blue.

PD-L1 expression on macrophages

Arrows indicate macrophages (green; CD68) that express PD-L1 (red)Cell nuclei are stained in blue.

UNDERSTANDING PD-L1 EXPRESSION ON TUMOUR CELLS AND TUMOUR-INFILTRATING IMMUNE CELLS MAY IMPACT PERSONALISED CANCER IMMUNOTHERAPY RESEARCH1,5

As a primary immunosuppressive driver, high expression levels of PD-L1 may be an important facilitator for tumour growth and metastasis. PD-L1 has been detected in up to 50% of human cancers, making the PD-L1 pathway a focus of cancer research.1,4-6

The presence of tumour-infiltrating immune cells has also been reported in many of these cancer types.7-21 Because these immune cells can also express PD-L1, the assessment of PD-L1 on tumour cells and tumour-infiltrating immune cells may be an important consideration for cancer immunotherapy research.

CANCER TYPE PERCENTAGE POSITIVE 
FOR PD-L1 EXPRESSION1*
PRESENCE OF TUMOUR-
INFILTRATING IMMUNE 
CELLS 7-21
Melanoma 40%–100% 7,8
Non-small cell lung cancer 35%–95% 9
Nasopharyngeal 68%–100% 10
Glioblastoma/mixed glioma 100% 11
Colon adenocarcinoma 53% 12
Hepatocellular carcinoma 45%-93% 13
Urothelial/bladder 28%–100% 14
Multiple myeloma 93% 15
Ovarian 33%–80% 16
Gastric carcinoma 42% 17
Esophageal 42% 18
Pancreatic 39% 19
Renal cell carcinoma 15%–24% 20
Breast 31%–34% 19
Lymphomas 17%–94% 21
Leukemias 11%–42% -
  • *Table modified according to Chen DS, et al, a review of current literature on PD-L1 expression. 1
  • † Percentage of PD-L1 expression is unknown.
  • ‡ Includes peripheral T cell lymphomas, diffuse large cell lymphoma, or small lymphocytic lymphoma.

PD-L1 IS A POTENTIAL PREDICTIVE BIOMARKER UNDER INVESTIGATION

Based on clinical studies, PD-L1 expression has been associated with response to PD-L1/PD-1 inhibition, suggesting that cancers with high PD-L1 expression are more likely to respond to immunotherapies that target the PD-L1 pathway.1,6

Roche is actively investigating PD-L1 as a potential predictive biomarker in cancer research and is committed to pursuing the potential of personalised cancer immunotherapy for cancer patients.