Lung cancer cells, 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. Here, the bottom cell is 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. The top cell has long extending filopodia like structures. Filopodia contain actin filaments and can have roles in numerous processes including cell-cell interactions, cell migration or as a sensory guide towards a chemoattractant (a chemical agent that induces a cell to migrate towards it). Magnification: x2300 when printed at 10 cm wide