The molecular genetic alterations underpinning lung cancer have been of great interest to researchers for many years. The discovery of small molecule inhibitors that target some of the key driver genetic alterations of lung cancer has fuelled this interest and catapulted genetic testing of tumours for somatic mutations into routine clinical practice. Successful and rapid translational lung cancer research has enabled patients of today to clinically benefit from these recent advances. It is therefore most fitting to dedicate a special issue on molecular genetics of lung cancer in Translational Lung Cancer Research (TLCR). In this issue, we bring together a range of original articles and reviews that summarise current clinical practice of molecular testing in lung cancer and preview exciting developments that may impact patient care in the future. We hope you will find our special issue on molecular genetics of lung cancer in TLCR both informative and stimulating as we endeavour to expand our understanding of lung cancer and ultimately improve patient outcomes.