What Are the Main Signs of Cancer?

The main signs of cancer include a persistent sore throat, changes in bladder or bowel habits, difficulty swallowing, indigestion and unusual discharge or bleeding, according to WebMD. Other signs include the formation of a lump or thickening in the testicles or breast, and changes in the shape, thickness, color or size of a mole, wart or sore in the mouth. Additionally, hoarseness and a nagging cough may indicate the presence of cancer.