The gene GSK3β, which encodes glycogen synthase kinase 3 (GSK3), was originally identified in 1980.

This is a serine/threonine kinase, and is highly conserved, from yeast to mammals. Deletion of GSK3β leads to embryonic lethality at E16 caused by hepatocyte apoptosis. This shows that the functions of GSK3β are not compensated by the presence of GSK3α.

In cancer cell lines, GSK3β modulation, particularly using pharmacological inhibitors, decreases cell proliferation and survival, and induction of apoptosis.

PTEN is a tumor suppressor gene that encodes a dual-specificity phosphatase with both protein phosphatase and lipid phosphatase activity. This lipid phosphatase activity is critical for its tumor suppressor function. The complete loss of PTEN is extremely common in tumor cell lines. PTEN loss of function is observed in many types of cancer including breast, prostate, and endometrial cancer. Around 5-14% of colorectal cancers show PTEN mutations.

The mitogen-activated protein kinase (MAPK) pathway is one of the most important mechanisms for the cytoplasmic transduction of extracellular signals. The classical MAPK signaling cascade consists of RAS, RAF, MEK and ERK. The cascade relays proliferative signals from the cell surface receptor into the nucleus. MAP kinases are major components of pathways controlling embryogenesis, cell differentiation, cell proliferation, and cell death.

DNA can be damaged through environmental attacks such as tobacco smoke or UV light, or through error introduced as part of the normal DNA replication processes. These can cause up to one million changes to the DNA each day. These changes to the DNA, and therefor any resulting proteins, increase the risk of cancer. To maintain the integrity and stability of the DNA, the cell has its own in-built DNA repair mechanisms that correct the errors, by chemically reversing the damage, or by removing and replacing the damaged bases.

The RPS6K family is involved in numerous pathways, many of which are central to carcinogenesis.

RPS6KB1 and B2, also known as p70-beta or p54, share 80% homology and many of the same functions. They are involved in cell growth, cell proliferation and regulation based on their activation by growth factors such as EGF, PDGF and insulin; and promote protein synthesis in response to mTOR (mammalian target of rapamycin) signaling. RPS6KB1 and B2 are also involved in the regulation of insulin.