173P - Expression of programmed death-ligand 1 and EGFR on circulating tumour cells in advanced lung cancer patients

Background

Targeted molecular therapy and immunotherapy have revolutionized the treatment of advanced lung cancer (ALC). Although therapeutically significant, the outcome of ICI or TKI is dependent on the presence of their respective targets in tumor cells. Evaluating targets based on solid biopsy may be often misleading, particularly in progressive patients despite therapy administration. Additionally, tissue biopsy provides a static signature of a target protein expression from the evolving tumor. The unmet need for dynamic detection and monitoring of actionable targets could be addressed by circulating tumor cells (CTCs). Here we report on the utility of CTCs to detect actionable targets from advanced lung cancer (ALCs) patients.

Methods

We retrospectively analyzed 193 ALC patients for Programmed Death - Ligand 1 (PD-L1) and EGFR expression on CTCs from. CTCs were isolated from Drug Controller General of India-approved OncoDiscover technology based on immunomagnetic targeting using anti EpCAM antibody, and immuno-staining with anti EGFR and PD-L1 antibodies. CTCs were detected based on the expression of CKs, absence of CD45, and prominent DAPI-stained nuclei. The presence or absence of EGFR and PD-L1 was determined with automated immunofluorescence microscopy.

Results

Among the evaluated cohort, 67 % patients showed the presence of CTCs with a mean value of 4.2 (Range: 1 to 62, SD =10.65). The absence of CTCs from the remaining 33 % of patients could be due to the therapy response of the clinically stable disease. From all patients showing the presence of CTCs, 66 % showed the detectable expression of PD-L1, while 42 % showed a strong expression of EGFR. The presence of PD-L1 was a significant association with CTCs. Similarly, the expression of EGFR among the detected CTCs showed high significance compared to the reported data on tissue biopsy from the literature.

Conclusions

Detection of therapeutic targets on CTCs obtained from ALC strongly indicate these patients qualify for anti-EGFR and PD-L1 therapies. Systematic studies with larger samples are required to strengthen the liquid biopsy-based detection of actionable targets. This could immensely help ALC patients showing progressive disease on chemo/radiotherapy.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Actorius Innovations and Research.

Funding

Actorius Innovations and Research.

Disclosure

All authors have declared no conflicts of interest.