PD-L1 immunohistochemistry for non-small cell lung carcinoma: which strategy should be adopted?

ABSTRACT

Introduction: PD-L1 detection with immunohistochemistry (IHC) is the only predictive biomarker available to date for PD-L1/PD1 immunotherapy in thoracic oncology. While many studies have been published on this biomarker, they raise a number of questions concerning mainly, (i) the type of antibody for use and its condition of utilization, (ii) the threshold to be used, (iii) the message and information to communicate to the thoracic oncologist and, (iv) the adoption of this methodology as part of the daily practices of a pathology laboratory.

Areas covered: This review provides an update on the use of the different PD-L1 antibodies for IHC in the context of metastatic non-small cell lung cancer (NSCLC) and discusses their use as companion or complementary diagnostic tests. The limits of PD-L1 IHC as a predictive test, the precautions to be adopted as well as some perspectives will then be considered.

Expert commentary: IHC for PD-L1 can be considered as a theranostic test, which implies providing an extremely reliable result that avoids any false positive and negative results. PD-L1 IHC requires considerable expertise and specific training of pathologists. PD-L1 IHC can be a companion or complementary diagnostic test depending on the clone employed, the molecular therapy prescribed and the indication of use.

KEYWORDS:

• Companion diagnostic test
• complementary diagnostic test
• immunohistochemistry
• non-small cell lung cancer
• PD-L1
• strategy

Acknowledgments

The author thanks the “association de la recherche contre le cancer”, the “ligue départementale 06 de lutte contre le cancer”, the “conseil départemental 06”, and the “cancéropôle PACA” for their support.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.