Cancer cells reproduce without restraint and colonize other tissues
Cancer cells reproduce in defiance of normal restraints of cell growth/division.
They invade and colonize territories normally occupied by other cells.
A tumor is benign if it is not invasive.
Tumor = cancer when it is malignant (invades surrounding tissue and forms metastases)
Common types of cancer in the United States
Carcinomas: from epithelial cells
Sarcomas: from connective tissue or muscle cells
Leukemias and lymphomas: from white blood cells and precursors, as well as from
Most cancers derive from a single abnormal cell
Cancer cells are a clone.
Can be demonstrated by molecular analysis of chromosomes (same abnormality in all
A single mutation is not enough to cause cancer
Cancer occurs by progressive accumulation of random mutations in a single lineage of
Relationship with age
People exposed to carcinogens develop cancer many years later.
Tumor progression involves clonal evolution
Development of cancer requires gradual accumulation of mutations.
Usually 5 or more genes need to be mutated for developed cancer. Epigenetic changes contribute to tumor progression
In addition to DNA mut