PIK3CA Gene Mutation Ultimate Guide
The PIK3CA gene holds the instructions for making a protein called p110a. This protein is important for many cell functions, including telling your cells when to grow and divide.
Certain people may have mutations in this gene. PIK3CA gene mutations cause cells to grow uncontrollably, which can lead to cancer.
The PIK3CA gene provides instructions to the body to make a protein that helps control the signaling of other proteins. This protein helps many processes occur at the correct times including cell growth and division, cell movement, and cell survival.
PIK3CA gene mutations can contribute to the growth of many kinds of cancer, including metastatic breast cancer. PIK3CA mutations are present in about 30 to 40 percent of breast cancers.
What Is the Function of the PIK3CA Gene?
PIK3 mutations are referred to as “driver mutations” because the proteins created fuel the cell’s growth.
A cancer cell’s genetic changes can also help it avoid death (apoptosis), change its metabolism, and improve its ability to break away and move to other areas of the body (metastasize).
For those familiar with some of the signaling pathways involved in cancer growth, PIK3CA is a component of the P13K/AKT/mTOR pathway, which is involved in a variety of cell growth processes.
PIK3CA Mutation Related Cancers
PIK3CA mutations have been found in a dozen different cancers, including uterine cancer, bladder cancer, colon cancer, and head and neck cancers, in addition to breast cancer.
Somatic PIK3CA mutations can cause a variety of uncommon illnesses defined by tissue overgrowth when they occur during early development (embryonic development). The type of overgrowth condition is determined by the timing of the mutation; disorders can be minor or severe and range from an enlarged finger to an enlarged leg, as well as huge enlargement of big blood vessels.
Surprisingly, the risk of cancer is not enhanced in patients with these overgrowth conditions. Some benign skin disorders, such as seborrheic keratoses, have been linked to PIK3CA mutations.
How Common Is the PIK3CA Mutation?
PIK3CA gene mutations are genetic alterations that appear to increase tumor growth in some breast cancers (as well as other cancers). The protein generated by this gene, PIK3 (phosphoinositide 3-kinase), is part of a signaling system that has been widely investigated in the hopes of slowing the progression of metastatic breast cancer.
These gene mutations are widespread, occurring in 30-40 percent of tumors, and are most commonly discovered in estrogen receptor-positive breast cancer.
What Causes PIK3CA Mutations?
Mosaicism is the term for a mixture of cells with and without a genetic abnormality. Klippel-Trenaunay syndrome is caused by PIK3CA gene mutations that alter single protein building blocks (amino acids) in the p110a protein. As a result of these alterations, an altered p110 subunit is produced, causing PIK3CA to become abnormally active.
What Is the PIK3CA Mutation Test?
The doctor who treats your cancer may test you for the PIK3CA gene mutation if you have an ER-positive, HER2-negative breast cancer. The FDA authorized a test for detecting mutations in the PIK3CA gene in 2019, called therascreen.
A sample of your blood or breast tissue is used in this test. The blood test is performed in the same way as any other blood test. A needle will be used to draw blood from your arm by a nurse or technician.
After that, the blood sample is sent to a facility for analysis. Breast tumors release modest amounts of DNA into the bloodstream. Your blood sample will be tested for the PIK3CA gene.
If you get a negative result on the blood test, you should have a biopsy to confirm it. Your doctor will remove a sample of tissue from your breast during a minor surgical procedure. The tissue sample then goes to a lab, where technicians test it for the PIK3CA gene mutation.
How Is the PIK3CA Mutation Treated?
If you have the PIK3CA mutation, your cancer may not react as effectively to hormone therapy for metastatic breast cancer. It also suggests you’re a candidate for alpelisib, a new medicine.
The medicine alpelisib (Piqray), a targeted therapy known as a PI3K inhibitor, is used to treat PIK3CA mutations. Alpelisib (Piqray) is a drug used to treat postmenopausal women and men with advanced breast cancer who have a PIK3CA mutation and tumors that are hormone receptor (HR) positive but HER2 negative.
Alpelisib (Piqray) is intended to be used in conjunction with fulvestrant (Faslodex), a hormone therapy that has already received FDA approval.
PIK3CA Clinical Trials
Clinical trials for PIK3CA Positive Tumors are research studies intended to evaluate the effectiveness and safety of new cancer treatments for patients who are positive for the PIK3CA gene mutation. Similar to other gene mutations, PIK3CA is involved in multiple signaling pathways associated with cell growth and division. Tumors that are associated with PIK3CA are often more aggressive, have a worse overall prognosis, and an Increased rate of recurrence.