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Intratumor heterogeneity of PD-L1 expression in head and neck squamous cell carcinoma

Research output: Contribution to journalArticle

Jacob H Rasmussen, Giedrius Lelkaitis, Katrin Håkansson, Ivan R Vogelius, Helle H Johannesen, Barbara M Fischer, Søren M Bentzen, Lena Specht, Claus A Kristensen, Christian von Buchwald, Irene Wessel, Jeppe Friborg

Original languageEnglish
Pages (from-to)1003-1006
Number of pages4
JournalBritish Journal of Cancer
Volume120
Issue number10
Early online date10 Apr 2019
DOIs
E-pub ahead of print10 Apr 2019
Published14 May 2019

King's Authors

Abstract

Intratumor heterogeneity may contribute to the ambiguous clinical results on PD-L1 status as a predictor for immunotherapy response in patients with HNSCC. This decreases the utility of PD-L1 expression from single tumour biopsies as a predictive biomarker. In this prospective study, intratumor heterogeneity of PD-L1 expression in HNSCC was investigated with both Tumour Proportion Score (TPS) and Combined Positive Score (CPS). Thirty-three whole surgical specimens from 28 patients with HNSCC were included. PD-L1 expression in six random core biopsies from each surgical specimen was used to assess the concordance between multiple biopsies and the negative predictive value of a single negative core biopsy. With 1% cut off, 36% of the specimens were concordant with TPS and 52% with CPS. With a 50% cut-off value the concordance was 70% with TPS and 55% with CPS. Defining a tumour as positive if just a single-one of the biopsies was positive, the negative predictive value (NPV) of a single negative core biopsy was 38.9 and 0% (1% cut off), and 79.9% and 62.8% (50% cut off) for TPS and CPS, respectively. In conclusion, PD-L1 positivity varies markedly within the tumour, both with TPS and CPS, challenging the utility of this biomarker.

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