Can you tell me how cancer cells differ from regular cells?

They invade : Cancer cells have mutations in what are called proto oncogenes that allow the cell to divide when there are abnormalities in their DNA that would normally be repaired. These mutations allow the metabolic pathway to be altered to use anaerobic glycolysis, produce invasive enzymes known as metalloproteinases and reach immortality by having the telomerase enzyme activated for immortality

Immortal: The cells in our bodies are "programmed" to grow, divide a certain number of times and then die. Cancer cells lose their ability to die, and become "immortal". They will continue growing as long as they receive oxygen and nutrients. HeLa cells used today are from a cervical cancer of a patient who died over 60 year ago!