Test Catalog

Test ID: SP142    
Programmed Death-Ligand 1 (PD-L1) (SP142), Semi-Quantitative Immunohistochemistry, Manual

Useful For Suggests clinical disorders or settings where the test may be helpful

Identification of neoplasms expressing programmed cell death 1-ligand 1 (clone SP142)

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Programmed cell death 1-ligand 1 (PD-L1), also known as B7 homolog 1 (B7-H1) or CD274, is a transmembrane protein involved in the regulation of cell-mediated immune responses through interaction with the receptor programmed death protein-1. PD-L1 has been identified as both a prognostic and theranostic marker in a variety of neoplasms. Overexpression of PD-L1 has been observed in carcinomas of the urinary bladder, lung, thymus, colon, pancreas, ovary, breast, kidney, and in melanoma and glioblastoma.

Interpretation Provides information to assist in interpretation of the test results

The results of the test will be reported in form of scores. The scoring system is based on type and origin of tumor. If additional interpretation or analysis is needed, order PATHC / Pathology Consultation along with this test.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Preclinical studies suggest that positive programmed cell death 1-ligand 1 (PD-L1) immunohistochemistry in tumor cells may predict tumor response to therapy with immune checkpoint inhibitors. This result should not be used as the sole factor in determining treatment, as other factors (eg, tumor mutation burden and microsatellite instability) have also been studied as predictive markers.


This test has been validated for nondecalcified paraffin-embedded tissue specimens fixed in 10% neutral-buffered formalin. This assay has not been validated on tissues subjected to the decalcification process or use of alternative fixatives for bone and bone marrow specimens or cell blocks.


Age of a cut paraffin section can affect immunoreactivity. Stability thresholds vary widely among published literature and are antigen dependent. Best practice is for paraffin sections to be cut within 6 weeks.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Rimm DL, Han G, Taube JM, et al: A prospective, multi-institutional, pathologist-based assessment of 4 immunohistochemistry assay for PD-L1 expression in non-small cell lung cancer. JAMA Oncol. 2017 Aug 1;3(8):1051-1058. doi: 10.1001/jamaoncol.2017.0013

2. Gaule P, Smithy JW, Toki M, et al: A quantitative comparison of antibodies to programmed cell death 1 Ligand 1. JAMA Oncol. 2017 Feb;3(2):256-259. doi: 10.1001/jamaoncol.2016.3015

3. Sunshine JC, Nguyen P, Kaunitz G, et al: PD-L1 expression in melanoma: A quantitative immunohistochemical antibody comparison. Clin Can Res. 2017 Aug;23(16):4938-4944. doi: 10.1158/1078-0432.CCR-16-1821

4. D'Incecco A, Andreozzi M, Ludovini V, et al: PD-1 and PD-L1 expression in molecularly selected non-small-cell lung cancer patients. Br J Cancer. 2015 Jan;112(1):95-102. doi: 10.1038/bjc.2014.555

5. Mansfield AS, Roden AC, Peikert T, et al: B7-H1 expression in malignant pleural mesothelioma is associated with sarcomatoid histology and poor prognosis. J Thorac Oncol. 2014 Jul;9(7):1036-1040. doi: 10.1097/JTO.0000000000000177

Special Instructions Library of PDFs including pertinent information and forms related to the test