The present invention aims to provide a method for rapidly, simply, and reliably identifying patients with nontuberculous mycobacterial
lung disease (pulmonary NTM
disease) compared to
lung cancer patients, healthy controls, or chronic
airway inflammatory diseases other than pulmonary NTM
disease, as well as a marker to be used in this method. [Solution] According to the present invention, it is possible to provide a biomarker consisting of the SLC26A4
gene, the SLC26A4
protein, or the SLC26A4-AS1
gene for distinguishing between subjects with pulmonary NTM disease and
lung cancer patients or healthy controls or chronic
airway inflammatory diseases other than pulmonary NTM disease, a method of identification using the
gene or
protein, and a kit containing the gene.