Open AccessPrevalence Study of PD-L1 SP142 Assay in Metastatic Triple-negative Breast Cancer
Author(s) -
Yijin Li,
Bharathi Vennapusa,
ChingWei Chang,
David Tran,
Rin Nakamura,
Teiko Sumiyoshi,
Priti S. Hegde,
Luciana Molinero
Publication year - 2020
Publication title -
applied immunohistochemistry and molecular morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.868
H-Index - 60
eISSN - 1541-2016
pISSN - 1533-4058
DOI - 10.1097/pai.0000000000000857
Subject(s) - atezolizumab , triple negative breast cancer , breast cancer , medicine , immunohistochemistry , cancer , pd l1 , metastatic breast cancer , oncology , immunostaining , pathology , immunotherapy , pembrolizumab
Metastatic triple-negative breast cancer (mTNBC) is the most aggressive breast cancer subtype. Programmed death ligand 1 (PD-L1) on immune cells (IC) using the VENTANA SP142 assay is linked to improved clinical outcome in atezolizumab plus nab-paclitaxel-treated patients with mTNBC in the IMpassion130 study. The goal of the current study was to evaluate prevalence of VENTANA SP142 PD-L1 assay by anatomic location in 670 histologically confirmed TNBC cases from subjects with metastatic disease screened for the phase 1 study PCD4989g (NCT01375842). PD-L1 immunohistochemistry was centrally tested on tumor cells (TC) and on tumor infiltrating IC, following manufacturer's instructions. At a 1% cutoff, tumor PD-L1 was more prevalent in IC than TC: 46% were PD-L1 IC+/TC-, 3% were PD-L1 IC-/TC+, and 10% were PD-L1 IC+/TC+. PD-L1 IC and TC immunostaining correlated with CD274 RNA expression, as assessed by fluidigm. Analyses of anatomic locations suggest that prevalence of PD-L1 IC+ was highest in lymph nodes (65.0%), lowest in liver metastases (26.9%), while breast tissue was intermediate (57.1%). Matched paired samples from the same subject collected synchronously or asynchronously showed a PD-L1 IC status agreement of 80% (8/10) and 75% (15/20), respectively. Our results suggest that the anatomic location of metastases and time of collection may influence the detection of PD-L1.