In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 37, No. 15_suppl ( 2019-05-20), p. e13162-e13162
Abstract:
e13162 Background: PD-L1 protein expression, tumor mutation burden (TMB) and microsatellite instability (MSI) are majorbiomarkers for PD-1/PD-L1 blockade therapy for solid tumors. We designed a study to evaluate the relevance of these biomarkers. Methods: From April 2018 to December 2018, 197 patients with lung cancer, colorectal cancer, andgastric cancer wereprospectivelyenrolled.Foreachpatient, afreshfrozentissuesampleor FFPE sample wascollected. Each sample was dividedinto3parts for next-generation sequencing (NGS), PD-L1 protein expression evaluation and MSI evaluation. The sequencing library was captured using a 605-gene panel and sequenced at~5,000×coverage.Mutationsinthe NGS datawereidentified,andTMB was then calculated. The PD-L1 protein expression was analyzedby immunohistochemistry, and the MSI was evaluated using a multiplex PCR comprising 5 loci(NR27, NR21, NR24, BAT25, and BAT26). Results: 18.78% (37/197) were detected with high PD-L1 expression (positive tumor cells ≥50%); 5.08% (10/197) ofpatientswere diagnosed as MSI-H; 4.06% (8/197) of patients had a TMB-H (TMB 〉 20 mutations/Mb). Among the 37 PD-L1 positive patients, only one patientwith TMB-Hwas detected, and 3patients were MSI-H. In contrast, among the 14 patients with PD-L1 expression less than 1%, 8patients (57.14%) were detected with TMB-H or MSI-H (3 with TMB-H only, 3 with MSI-H only, and 2 with both). In addition, among all the 10patients with MSI-H, 4patients had TMB-H, indicating that MSI-H may be partly associatedwith high TMB. Conclusions: From our preliminary result, PD-L1 protein expression negative patients tend to have higher rates of TMB-H and MSI-H. For patients with negative PD-L1 expression, it issuggested to evaluate its TMB level and MSI status. This study is ongoing, and more data will be collected to verify these findings.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/JCO.2019.37.15_suppl.e13162
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2019
detail.hit.zdb_id:
2005181-5
Permalink