Solid Tumors

PD-L1 IHC 22C3 is a qualitative immunohistochemical assay using Monoclonal Mouse Anti-PD-L1, Clone 22C3 intended for use in the detection of PD-L1 protein. PD-L1 IHC 22C3 is indicated as an aid in identifying NSCLC patients for treatment with KEYTRUDA® (pembrolizumab).

disease state indication(s)
Non-Small Cell Lung Cancer (NSCLC), gastric/gastroesophageal (GEJ) adenocarcinoma

clinical use
PD-L1 is the protein product of the CD274 gene, and is expressed on the plasma membrane of a variety of both hematopoietic and solid tissue cells. PD-L1 interacts with the PD-1 receptor, which is found on the surface of leukocytes, including T- and B-lymphocytes and some myeloid cells. PD-L1/PD-1 binding triggers signal transduction cascades that ultimately result in self-tolerance and immune system suppression, which normally serves as an immune checkpoint that prevents overstimulation and autoimmunity. Research has shown that tumor infiltrating lymphocytes often exhibit upregulation of PD-1 expression; correspondingly, enhanced PD-L1 expression can be found on many tumor cells, and it is thought that this represents a possible mechanism of escape from immune-mediated tumor destruction. Blockade of PD-L1 stimulation of PD-1 impedes immune inhibition and allows for recognition of tumor as abnormal, with ensuing cytotoxicity. Clinical trials have demonstrated that PD-L1 status may predict benefit from treatment with immune modulators. Pembrolizumab (also called lambrolizumab or MK-3475) is a humanized monoclonal antibody targeting PD-1 that has been FDA-approved for advanced non-small cell lung carcinoma (NSCLC) with increased PD-L1 expression on the basis of data showing increased objective response rate and improved progression free and overall survival in these patients. Studies of other PD-1 inhibitors and anti-PD-L1 agents are ongoing in NSCLC as well as other tumor types.

methodology/product platform
Immunohistochemistry (IHC)

specimen type and requirements
Formalin-fixed, paraffin-embedded (FFPE) tissue containing sufficient tissue containing sufficient tumor cells for analysis. A single, best representative specimen will be tested. Specimens should be fixed in 10% neutral buffered formalin for 12 to 72 hours for PD-L1 testing.
Acceptable alternative:
At least 4 unstained slides cut at 4-5 µm thickness containing sufficient tumor cells, plus accompanying H&E stained slide. If an H&E slide is not available, 5 unstained slides cut at 4-5 µm thickness. Slides should be received at Genoptix within 5 weeks of being sectioned. Date of sectioning must be specified.
Use refrigerated cold pack for transport. Make sure cold pack is not in direct contact with specimen.

turnaround time
Tech-only (TC): 2 days
Global (TC & PC): 3 days

cpt code(s)
88360 (x1)

medicare moldx cpt code
Not applicable

regulatory classification
FDA approved/cleared

ordering option
Global (TC & PC) or Tech-only (TC)