What is a cancer?

On the medical science come from the malignant tumor of skin organization to be called a cancer.Such as the occurrence is at the scale-like in shape last skin cell of call scale-like in shape last skin cell cancer, call a scale cancer.Often the occurrence originally possessed the part that the scale-like in shape last skin overalies in the body, like skin, mouth cavity, lips, cervix, vagina, oesophagus, larynx, and penis...etc..The occurrence is on the gland skin cell of call gland cancer.It Be seen to stomach, bowel and mammary glands, liver and thyroid gland, saliva gland and bronchus and womb body etc. more.If the organs of human body have a malignant tumor growth, then is called skin cancer, stomach cancer, oesophagus cancer, and bowel cancer...etc. respectively.The cancer is seen to middle age and old people over 40 years of age more, from transfer path to see, the cancer is transfered by lymphoid way.