Neuregulin 1 Gene (NRG1). A Potentially New Targetable Alteration for the Treatment of Lung Cancer.

Oncogenic gene fusions are hybrid genes that result from structural DNA rearrangements, leading to unregulated cell proliferation by different mechanisms in a wide variety of cancer. This has led to the development of directed therapies to antagonize a variety of mechanisms that lead to cell growth or proliferation. Multiple oncogene fusions are currently targeted in lung cancer treatment, such as those involving ALK, RET, NTRK and ROS1 among many others. Neuregulin (NRG) gene fusion has been described in the development of normal tissue as well as in a variety of diseases, such as schizophrenia, Hirschsprung's disease, atrial fibrillation and, most recently, the development of various types of solid tumors, such as renal, gastric, pancreatic, breast, colorectal and, more recently, lung cancer. The mechanism for this is that the NRG1 chimeric ligand leads to aberrant activation of ERBB2 signaling via PI3K-AKT and MAPK cellular cascades, leading to cell division and proliferation. Details regarding the incidence of these gene rearrangements are lacking. Limited case reports and case series have evaluated their clinicopathologic features and prognostic significance in the lung cancer population. Taking this into account, NRG1 could become a targetable alteration in selected patients. This review highlights how the knowledge of new molecular mechanisms of NRG1 fusion may help in gaining new insights into the molecular status of lung cancer patients and unveil a novel targetable molecular marker.