From biological mechanisms to clinical implications: the role of mineral dust-induced gene in lung cancers

While lung cancer has been a leading cause of death for humans with highest morbidity among all types of cancers, air pollution poses an increasing impact on the incidence of this catastrophe (1-3). Mineral dust-induced gene (Mdig ) is a lung cancer-related gene found in alveolar macrophages from coal miners exposed to mineral dusts in 2005 (4). It was later confirmed to be the same gene as the myc-induced nuclear antigen with an estimated molecular weight of 53 kDa (mina53) (5) and also the nuclear protein 52 (NO52) (6). Mdig/mina53 is located on chromosome 3 within a single open reading frame of 465 amino acids (4,5), and chiefly expressed in the cellular nuclei with part of the protein condensed in the nucleolus (5-7). However, the intracellular distribution of Mdig/mina53 may vary with cell cycle phases and different extracellular environments (8). In normal individuals, Mdig/mina53 is expressed in the liver, skeletal muscle, heart, pancreas and placenta, but not in lungs (4). When localized in lungs, therefore, Mdig/mina53 might represent a potential target for future therapy. Below we present an update on understanding of biological behaviors of Mdig/mina53 related to lung cancers.