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Pigment Cell Melanoma Res. 2015 May;28(3):245-53. doi: 10.1111/pcmr.12340. Epub 2014 Dec 22.

PD-L1 expression in melanoma shows marked heterogeneity within and between patients: implications for anti-PD-1/PD-L1 clinical trials.

Author information

1
Melanoma Institute Australia, Sydney, NSW, Australia; Sydney Medical School, The University of Sydney, Sydney, NSW, Australia.

Abstract

This study evaluated the expression of PD-L1 in immunotherapy-naïve metastatic melanoma patients to determine longitudinal intrapatient concordance and correlate PD-L1 status with clinicopathologic characteristics and outcome. PD-L1 expression was assessed by immunohistochemistry in 58 patients (43 primary tumors, 96 metastases). Seventy-two percent of patients had at least one specimen expressing PD-L1 in ≥ 1% of tumor cells. Median positive tumor cell count overall was low (8% in nonzero specimens). PD-L1 expression was frequently discordant between primary tumors and metastases and between intrapatient metastases, such that 23/46 longitudinal patient specimens were discordant. PD-L1 was associated with higher TIL grade but not with other known prognostic features. There was a positive univariate association between PD-L1 expression in locoregional metastases and melanoma-specific survival, but the effect was not observed for primary melanoma. In locoregional lymph node metastasis, PD-L1+/TIL+ patients had the best outcome, and PD-L1+/TIL- patients had poor outcome.

KEYWORDS:

PD-1; PD-L1; biomarker; diagnosis; heterogeneity; immunotherapy; melanoma; metastasis; pathology; prognosis

PMID:
25477049
DOI:
10.1111/pcmr.12340
[Indexed for MEDLINE]

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