Causes of laryngeal cancer. Laryngeal cancer is caused by changes in the cells of the larynx, although it's not clear exactly why this happens. All cancers begin with a change in a cell's DNA. DNA provides our cells with a basic set of instructions, such as when to grow and reproduce.his causes the cells to reproduce in an uncontrollable manner, producing a growth of tissue called a tumour. It's not known why the DNA inside the cells of the larynx is affected in cases of laryngeal cancer.