Germline NQO1c.559C>T as a biomarker of genetic susceptibility to immune checkpoint blockade resistance.

Abstract

8537 Background: Tobacco is the main risk factor for developing lung cancer. Yet, some heavy smokers do not develop cancer while others do at young ages. The study of cancer immunology has led to the surge of immune checkpoint blockade (ICB), which transformed the treatment landscape of cancer pts. NQO1 has been associated with extreme phenotypes of high risk for the development of tobacco-induced NSCLC and with poor survival outcomes for xerographs. Development of biomarkers for ICB has been mainly focused on tumor-related factors while genetic susceptibility of the host has been poorly explored to date and some evidence suggests that genetic dysregulation may enables immune escape. Methods: From June 2016 to January 2023, 326 NSCLC pts from two main University Hospitals of Malaga (Spain) receiving ICB were prospectively enrolled, blood samples were gathered. We selected a representative set of 60 consecutive pts for exome sequencing to characterize the germline contribution to resistance (progression within the first 6 months of treatment). PBMC DNA was extracted and prepared for exome sequencing. Raw sequencing data was processed and aligned to a reference genome using BWA. Base recalibration, germline variant calling and variant filtering was performed through GATK. Survival probabilities were estimated with the Kaplan-Meier method and compared using the log-rank test. We explored the lung cancer related genes among our results. Results: Median age at diagnosis of 64 (54-85). 76,6% were men. 44/60 (73,3%) were adenocarcinoma (ADC), PD-L1≥1% in 55% of patients, 22% shown PD-L≥50%. 78% had advanced disease at diagnosis. 65% received ICB in combination with chemotherapy. We found NQO1c.559C>T in 46,6% of pts (28/60). The variation was not associated with survival outcomes in the multivariant analysis (p>0.05) but with poor OS for non-ADC histology (19.7m vs 6m for mutated and WT, respectively; p<0.01). In addition, we found 26 germline variants associated with OS and PFS, and 52 variants with response to ICB. The variants were missense or involved a stop gain/loss. Conclusions: Exome sequencing analysis of germline variants could be a suitable methodology to identify subrogated biomarkers of immune resistance in NSCLC patients. NQO1c.559C>T might help to identify poor prognosis non-ADC pts in the ICB setting.