Diagnostic Utility of PD-L1 and TP-53 mRNA As Well As microRNAs Expression in Liquid Biopsy of NSCLC Patients – Pilot Study

Abstract Introduction The expression of PD-L1 (programed cell death ligand 1) protein on neoplastic cells is a factor qualifying cancer patients for immunotherapy. However, the status of PD-L1 mRNA expression in plasma or serum has not been well studied in cancer patients. TP-53 (Tumor Protein p53) as tumor suppressor affects the expression of many genes, including microRNAs that regulate PD-L1 expression. Purpose of our study was to evaluate usefulness of analysis of PD-L1 mRNA, microRNAs and TP-53 mRNA expression in liquid biopsy in non-invasive diagnosis of non-small cell lung cancer patients (NSCLC).Material and methods We examined the expression the expression of TP-53 and PD-L1 mRNA as well as seven microRNAs (miR-17, miR-93, miR-142, miR-519, miR-526, miR-34a-5p and miR-34a-3p) in plasma obtained from 80 NSCLC patients and 39 healthy volunteers. We used quantitative PCR preceded by reverse transcription method.Results We observed PD-L1 mRNA expression only in 6 (7.5%) NSCLC patients. We showed that expression of TP-53 mRNA and each tested microRNAs were significantly higher in healthy person than in NSCLC patients. Based on the Receiver Operating Characteristic (ROC) analysis, we found that TP-53 mRNA and each of examined microRNAs expression were good diagnostic markers for non-invasive diagnosis of NSCLC. We found a significant, negative correlation between TP-53 mRNA and miR-17 (R=-045, p=0.0005) as well as miR-34a-5p (R=-0.32, p=0.04) expression in patients with advanced NSCLC.Conclusion The decreased expression of TP-53 mRNA may influence the disruption of microRNAs which could be involved in the regulation of PD-L1 expression in NSCLC patients