What is cancer?

Cancer is uncontrolled cell growth.

Life cycle of a cell is tightly controlled. Orderly cell death is called apoptosis (second p is silent).

Cancer has been often categorized according to the tissue where it’s found. This is why you may often hear about:

  • ovarian cancer
  • lung cancer
  • breast cancer
  • testicular cancer
  • prostate cancer
  • esophageal cancer
  • intestinal cancer

It may be better to define it by the cancer driver mutations.

A distinction is also made between solid tumors (which can be benign or malignant) and leukemias (blood cancers), and between carcinomas (cancer of epithelial tissues that lines the organs) and sarcomas (cancer of connective tissue).

A table with half-lives of cells from several human tissues.


Find answers in Cell Biology by the numbers

  1. How many individual cells are there in our body?
  2. How often do they die?
  3. How long do they live?
  4. What is the turnover frequency of cells?
  5. Do all cells reproduce?
  6. How may reproduction frequency affect development of cancer?