Abstract 4429: An exhaled microRNA panel interrogation and validation as risk biomarkers for lung cancer

Abstract

Abstract Background: There is a need for non-invasive airway-based biomarkers in lung carcinogenesis for both risk assessment of the ex-smoker, and earlier diagnosis. Recent studies have revealed that microRNAs play important regulatory roles in carcinogenesis. Exhaled breath condensate (EBC) contains airway lining fluid molecules, including nucleic acids, presumably in part from epithelial cellular origins. Here we further develop and begin validation of the detection of microRNAs in EBC from lung cancer patients and controls. Methods: Exhaled breath condensate (EBC) was collected non-invasively, using a handheld device in ambulatory subjects. MicroRNA expression profiling using RNA-specific RT-qPCR was performed in EBC in an initial batch (E) of 88 individuals (41 lung cancer cases, 47 controls), and a second batch D of 88 individuals (41, cases and 47 controls). We generated a 39 miR panel based on literature-derived microRNAs, combined with a lung tissue-based discovery effort we have performed using microRNA-seq on lung tumors and surrounding non-tumor tissue. The qPCR primers were designed using our previously published RNA-specific realtime RT-PCR technique. All samples were run twice with positive and negative controls. Results: Qualitative analyses of the first donor batch E was performed on 39 microRNAs measured in 41 cases and 47 controls. Chi-square analysis (univariate) within the training set (batch E) revealed that exhaled miR-31, 33, 105, 200b, 944, 1269a were significantly different between the initial set of cases and controls; their absence marked the cases. In the validation batch (D) preliminary analysis, exhaled miRs 200b (this time present in cases, p=0.044) and 944 (again absent in cases, p=0.052) were case-control discriminant. In addition, test set batch D showed case-control discrimination for additional miRs 130b-3p (present in cases, p=0.035), 212 (absent in cases, p=0.009), 1910a (absent in cases, p=0.006) and other microRNAs that were not seen in the qualitative training set (batch E). Importantly, multi-miR discriminant signatures, quantitative analysis, and risk ROC/modelling analyses are pending as of this AACR abstract deadline. Conclusion: This new exhaled biomarker platform can yield case-control discriminant microRNA sets, including a subset of miRs that can validate in test sets. Once further distilled and validated, our goal is to apply this non-invasive biomarker approach to prospective cohorts for non-invasive lung cancer risk assessment, in order to better select higher risk individuals who should undergo CT screening. Note: This abstract was not presented at the meeting. Citation Format: Simon D. Spivack. An exhaled microRNA panel interrogation and validation as risk biomarkers for lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4429. doi:10.1158/1538-7445.AM2017-4429