Patterns of blood-borne microRNA, or miRNA, have potential as circulating markers of the presence of lung cancer, according to researchers in Europe. As Dr. Andreas Keller told Reuters Health by email, "we identified microRNA signatures that allow us to distinguish lung-cancer patients with an accuracy of over 90% even when compared to patients diagnosed with non-tumorous lung diseases." In a paper in JAMA Oncology, Dr. Keller of Saarland University, in Saarbrcken, Germany, and colleagues note that "few tissue-based biomarkers and virtually no new blood-borne biomarkers are used in clinical practice." Their use "is largely hampered by the relatively small number of cases that have been analyzed in most preclinical studies. This limitation also applies to the studies of blood-borne miRNAs in patients with lung cancer," the team adds. The researchers conducted genome-wide microRNA profiling of blood samples from over 3,000 people. Machine-learning methods were used to evaluate samples from 606 patients with nonsmall-cell and small-cell lung cancer, 593 with nontumor lung diseases, 883 with diseases not affecting the lung, and 964 controls. Three classification scenarios were investigated by splitting the samples equally into training and validation sets. A 15-miRNA signature from the training set was used to distinguish patients diagnosed with lung cancer from all other individuals in the validation set with an accuracy of 91.4%, a sensitivity of 82.8% and a specificity of 93.5%. Corresponding proportions for a 14-miRNA signature comparing lung cancer with nontumor lung diseases were 92.5%, 96.4% and 88.6%. A further comparison of early-stage lung cancer vs absence of lung cancer had an accuracy of 95.9%, a sensitivity of 76.3% and a specificity of 97.5%. Dr. Keller added, "the identification of a microRNA signature for patients diagnosed with low lung-cancer stages represent a highly promising step towards early detection of lung cancer by a minimally invasive test that can complement imaging tests, sputum cytology and biopsies and can thereby contribute to a more efficient intervention of this deadly cancer type." The study was partly funded by Hummingbird Diagnostics, which is developing liquid biopsy diagnostics. Dr. Keller and three of his coauthors report financial ties to the company. —David Douglas Source
