Prediction of lung cancer development using chest X ray with microRNA samples in health screening of patients.

e22606 Background: Chest X ray (CXR) has been the most common screen test procedure for detection of lung cancer. Lung cancer progresses rapidly and a single missing small shadow on CXR in health check-ups can deprive the patient of the chance of cure. CXR has diagnostic limitations. For example, in the presence of lesions such as old pulmonary tuberculosis, it may be difficult to detect new abnormal shadows. Recently, microRNAs (miRNAs) have been shown to be involved in the exchange of information between cells via exosomes. The association between cancer and miRNAs has been reported. The hypothesis was that the combination of CXR and miRNAs during health check-ups could predict the development of lung cancer. Using the biobank for health check-ups, we conducted a study to look at changes in miRNAs in plasma samples between at the time of small nodule in CXR and after surgery. Methods: Our clinic “MedCity21” is a university outpatient clinic for health check-ups as a part of private health screening programs. At our facility, a biobank for accumulating health check-ups data and biological specimens has been established with the consent of health check-up patients. From 2016 to 2021, 14368 cases and 22602 specimens have been accumulated. As a retrospective cohort study using our biobank, we selected cases who had undergone health check-ups during that period, were diagnosed with lung cancer by CXR, and had it removed. A total of 2632 genes were evaluated in a comprehensive miRNA analysis (3D-Gene miRNA Oligo chip, Toray Industries Inc., Kamakura, Japan) from plasma samples before and after surgery. Candidate genes were narrowed down using genes with the lowest coefficient of variation as internal controls and subsequently validated by RT-PCR (TaqMan Advanced miRNA Assays). Results: A total of 15 patients were diagnosed with early-stage lung cancer and 4 of them continued to receive health check-ups after their surgeries. In the miRNA exhaustive analysis, there were 289 miRNAs that all showed a valid signal intensity.Eight genes (hsa-miR-4634, 744-5p, 24-3p,122-5p, 11181-3p, 1275, let-7a-5p, let-7b-5p) were identified as genes with a twofold or greater increase after surgery in two or more cases.Validation was performed by RT-PCR and 4 genes (hsa-miR-744-5p, 24-3p, 11181-3p and let-7a-5p) were identified as candidate genes.These genes have been reported to have cancer-suppressive effects, angiogenesis-suppressing and TGFβ1-regulating effects according to the database. Conclusions: In this study, we found that the expressions of 4 miRNAs in plasma were up regulated after surgery. It was suggested that these normal defense responses may be suppressed by malignant cells, even in early-stage cancer. In the future, combinations of these candidate genes will be investigated for the development of early lung cancer markers. Such markers may be able to differentiate whether the small nodule is malignant or benign.