Notably, Clara and AT2 cells are relatively abundant in lung epithelium, inconsistent with previous observations that only a very limited number of lung epithelial cells are susceptible to oncogenic K-Ras-induced lung tumorigenesis.44 In addition, a simple calculation based on the rate of specific point mutations per cell and the number of cells in the body suggests that several thousand new point-mutated RAS oncogenes are created every day in every human being.7 However, humans do not suffer from cancer as frequently as this calculated rate would predict. The gene discussed is KRAS; the disease is cancer.