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STK11 gene

Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

STK11 gene

The STK11 gene provides instructions for making an enzyme that acts as a tumor suppressor, helping to regulate cell growth and division.

Normal Function

The STK11 gene (also called LKB1) 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. 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. In addition to its role as a tumor suppressor, serine/threonine kinase 11 function appears to be required for normal development before birth.

Health Conditions Related to Genetic Changes

Breast cancer

Inherited changes in the STK11 gene greatly increase the risk of developing breast cancer, as well as other types of cancer, as part of Peutz-Jeghers syndrome. These mutations are thought to account for only a small fraction of all breast cancer cases.

Peutz-Jeghers syndrome

Inherited mutations in the STK11 gene cause Peutz-Jeghers syndrome, a condition characterized by the development of noncancerous growths called hamartomatous polyps in the gastrointestinal tract and a greatly increased risk of developing several types of cancer. More than 340 STK11 gene mutations have been identified in people with this condition. Many of these mutations result in the production of an abnormally short, nonfunctional version of the serine/threonine kinase 11 enzyme. Mutations in the STK11 gene impair the enzyme's tumor suppressor function, allowing cells to grow and divide without control or order.

Other cancers

Noninherited (somatic) mutations in the STK11 gene have been found in various forms of cancer, including:

  • Non-small cell lung carcinoma
  • Cervical cancer
  • Colorectal cancer
  • Melanoma
  • Pancreatic cancer

These somatic mutations impair the function of serine/threonine kinase 11, which can allow cells to grow and divide uncontrollably and contribute to the formation of a cancerous tumor.

Other Names for This Gene

  • LKB1
  • PJS
  • serine/threonine kinase 11 (Peutz-Jeghers syndrome)
  • Serine/threonine-protein kinase 11
  • STK11_HUMAN

Genomic Location

The STK11 gene is found on chromosome 19.

Frequently Asked Questions

People with germline STK11 mutations (Peutz‑Jeghers syndrome) have markedly increased risks for gastrointestinal, breast, pancreatic, lung, and gynecologic cancers. Guidelines suggest annual breast MRI (starting age 25) and mammography (starting age 30), colonoscopy every 2–3 years beginning at age 18, upper endoscopy every 2–3 years, pancreatic imaging (MRI/MRCP or endoscopic ultrasound) every 1–2 years after age 30, and regular skin examinations. Tailor the schedule to personal and family history.
STK11 mutations are autosomal dominant; each child has a 50% chance of inheriting the variant. Options for family planning include prenatal diagnostic testing (chorionic villus sampling or amniocentesis) if the specific familial mutation is known, or pre‑implantation genetic testing for monogenic disorders (PGT‑M) with in‑vitro fertilization to select embryos without the mutation. Genetic counseling is strongly recommended before making decisions.
Even when polyps are benign, individuals with Peutz‑Jeghers syndrome remain at elevated risk for malignancies throughout the gastrointestinal tract and elsewhere. Polyps can also cause bleeding or obstruction, so regular surveillance and polyp removal are essential. Ongoing cancer screening as outlined above should continue regardless of current polyp pathology.
While the genetic risk cannot be eliminated, adopting a healthy lifestyle may modestly reduce overall cancer risk. Recommendations include maintaining a healthy weight, regular aerobic exercise, limiting alcohol, avoiding tobacco, eating a diet rich in fruits, vegetables, and fiber, and limiting processed red meat. Some clinicians also suggest low‑dose aspirin for colorectal cancer prevention, but this should be discussed with your physician due to bleeding risk.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.