Molecular pathology of lung cancer: current status and perspectives

In this article, we summarize the current knowledge on molecular alterations in lung cancer that are targets for therapy, and provide an outlook on the future development of molecular pathology in precision oncology.

Lung cancer has become a paradigm for the success of molecular targeted therapies in solid tumors. Tyrosine kinase inhibitors are effective treatment options in adenocarcinoma patients with an EGFR, ALK, ROS1 or B-Raf Proto-Oncogene, Serine/Threonine kinase mutation. Additional molecular targets that are addressed in clinical trials include ERBB2, MET, RET, NTRK1 and FGFR. Therapies with antibodies that block the interaction of PD-L1 with PD-1 and thereby liberate an antitumor immune response have introduced a new era in cancer therapy with impressive therapeutic benefits. The high financial burden, treatment failures and therapeutic side effects of immunotherapies have prompted a search for biomarkers beyond PD-L1 expression, for example, tumor mutation load or immune cell profiling, that might more reliably identify patients that are likely to respond.

The discoveries of cancer research have been translated into the clinical management of lung cancer patients. So far, the approach of targeted therapy that is directed towards certain molecular alterations in a given tumor has been successful for adenocarcinomas, but not yet for squamous or small cell carcinomas. Further clinical progress will require a better understanding of the molecular interactions within cancer cells that will subsequently enable innovative drug designs. Diagnostic molecular pathology will be a provider of information on a tumor's features and thus, navigate precision cancer therapy.