- Chen, Yen-Lin;
- Huang, Wen-Chien;
- Lin, Feng-Ming;
- Hsieh, Huangpin;
- Hsieh, Chia-Hsun;
- Hsieh, Ruey;
- Chen, Kuo-Wei;
- Yen, Ming-Hong;
- Lee, James;
- Su, Stephen;
- Marfatia, Twinkal;
- Chang, Shih-En;
- Sundar, Padma;
- Patterson, Bruce;
- Watson, Drew;
- Mei, Rui;
- Javey, Manana
We evaluated the analytical and clinical performance of a novel circulating tumor cell (CTC)-based blood test for determination of programmed death ligand 1 (PD-L1) protein expression status in real time in treatment-naïve non-small cell lung cancer (NSCLC) patients. CTCs were detected in 86% of patients with NSCLC (I-IV) at the time of diagnosis, with a 67% PD-L1 positivity rate (≥ 1 PDL + CTC). Among 33 NSCLC patients with PD-L1 results available via both tissue immunohistochemistry (IHC) and CTC assays, 78.9% were positive according to both methods. The CTC test identified an additional ten cases that were positive for PD-L1 expression but that tested negative via IHC analysis. Detection of higher PD-L1 expression on CTCs compared to that in the corresponding tissue was concordant with data obtained using other platforms in previously treated patients. The concordance in PD-L1 expression between tissue and CTCs was approximately 57%, which is higher than that reported by others. In summary, evaluation of PD-L1 protein expression status on CTCs isolated from NSCLC patients is feasible. PD-L1 expression status on CTCs can be determined serially during the disease course, thus overcoming the myriad challenges associated with tissue analysis.