Most lung cancers are simultaneously stimulated by several autocrine and paracrine growth factors. Diseases resulting in excessive production of these factors and/or changes in the receptors, second messengers, or genes comprising their signal transduction pathways can thus result in the stimulation of continuous cell proliferation characteristic of cancer. Some carcinogenic N-nitrosamines mimic the stimulatory effect of cell-type-specific growth factors by binding to their receptors, and in this way mediate their selective carcinogenic effects. In this review I discuss the significance of receptor-mediated mitogenic signal transduction pathways for the initiation and progression of lung cancer, and describe novel lung cancer therapeutics that target components of these pathways.