Lung cancer cells with blebs, coloured scanning electron micrograph (SEM). Lung cancer occurs when abnormal cells divide in a chaotic and uncontrolled manner resulting in the formation of a tumour in the lungs. Lung cancer is the most common cause of cancer death in the UK. In terms of survival, approximately 5% will survive 10 years or more and 10% will survive 5 years or more. These cells are displaying a process known as blebbing. Blebbing is a bulge or protrusion of the plasma membrane of the cell which is visible on the cell surface. Blebbing is often seen during programmed cell death (apoptosis) or may be seen when a cell is undergoing physical or chemical stresses. It also has important functions in cellular processes like cell locomotion playing a role in cell migration. Magnification: x3000 when printed at 10 cm wide.