CE L1 - overview on the molecular basis of cancer Flashcards
What is cancer?
Cancer is a group of diseases characterized by inappropriate and unregulated cell growth and the invasion and spread of cells from the site of origin, or primary site, to other sites in the body. Found in tissues in high replication (turn over) or metabolism ie skin and lung but not heart.
What are the hallmarks of cancer?
Self-sufficiency in growth signals (e.g. oncogenes)
Insensitivity to antigrowth signals (mutations in tumor suppressor proteins)
Evasion of apoptosis
Limitless replicative potential - due to telomerases.
Tissue invasion and metastasis
Sustained angiogenesis - increased production of tumours that promote blood vessel formation.
Two additional hallmarks that have recently emerged include:
Reprogramming of energy metabolism
and
Avoiding immune destruction.
What are carcinomas?
Carcinomas are cancers which arise from epithelial cells. They acount for 90% of malignant cancers. This is because epithelial cells are regularly undergoing tissue repair and therefore proliferating more.
What are adenocarcinomas?
Cancers that arise from glandular tissue e.g. breast cancer
What are sarcomas?
Cancer of connective tissue and muscle.
What is meant by a benign tumor?
The cells in a benign tumor resemble normal wild-type cells (have the same morphology and properties). Usually easily treated, unless in a difficult to reach location e.g. brain.
How does a cell transform from being a normal, healthy cell to a malignant, cancerous cell?
Cancer is an accumulation of mutations - cells must acquire many mutations before they become cancerous, usually 3-7 mutations that tend to occur on different pathways.
What can cause mutations?
Chemical carcinogens - tobacco smoke, asbestos
Radiation - nuclear, UV
Viruses - largely cancer, is not caused by infectious agents, they do not directly affect the DNA but alter the funcitons of proteins.
Who does cancer affect?
1 in 2 people will develop cancer. 65% of cases are in people over the age of 65 - it is generally a disease classified of the elderly (as need to acquire the mutations over time).
