STK11

The STK11 gene provides instructions for making an enzyme called serine/threonine kinase 11. This enzyme is a tumor suppressor, which means that it helps keep cells from growing and dividing too fast or in an uncontrolled way. In addition to its role in regulating cell division, this enzyme helps certain types of cells correctly orient themselves within tissues (polarization) and assists in determining the amount of energy a cell uses. This kinase also promotes a type of programmed cell death known as apoptosis. Through a combination of these mechanisms, serine/threonine kinase 11 aids in the prevention of tumors, especially in the gastrointestinal tract, pancreas, cervix, ovaries, and breasts. Serine/threonine kinase 11 function is also required for normal development before birth.

Peutz-Jeghers syndrome - caused by mutations in the STK11 gene

Researchers have identified more than 140 mutations in the STK11 gene that are responsible for Peutz-Jeghers syndrome. Many of these mutations result in the production of an abnormally short, nonfunctional version of the serine/threonine kinase 11 enzyme. Other mutations change a single protein building block (amino acid) used to build the enzyme. Research has shown that the loss of this enzyme's function allows cells to divide too often, leading to the formation of polyps in the gastrointestinal tract. Sometimes these polyps develop into malignant (cancerous) tumors. The loss of the enzyme's tumor suppressor function likely underlies the increased risk of gastrointestinal tumors, breast cancer, and other forms of cancer in Peutz-Jeghers syndrome.

breast cancer - increased risk from variations of the STK11 gene

Changes in the STK11 gene increase the risk of developing breast cancer as part of a rare inherited cancer syndrome called Peutz-Jeghers syndrome. These inherited mutations are thought to account for only a small fraction of all breast cancer cases.

other cancers - associated with the STK11 gene

Some gene mutations are acquired during a person's lifetime and are present only in certain cells. These changes, which are called somatic mutations, are not inherited. Somatic mutations in the STK11 gene are uncommon in most types of cancer. These mutations have been found, however, in a form of lung cancer called non-small cell lung carcinoma, an aggressive type of skin cancer called melanoma, and some cases of pancreatic cancer. A loss of serine/threonine kinase 11 function can allow cells to grow and divide uncontrollably, leading to the formation of a cancerous tumor.