Fibroblast growth factor receptor 2 (FGFR2) mutations occur in several cancer types that cause the FGFR2 protein to be more active, leading to cancerous cells that grow and divide quickly. In normal cells, the FGFR2 proteins facilitate cell growth, division, maturation, and the development of bones and blood vessels. Growth factors interact with the FGFR2 protein and create chemical reactions that instruct the cell to carry out specific functions related to cells.
The FGFR family of tyrosine kinases consists of four members, FGFR1, FGFR2, FGFR3, and FGFR4. Each FGFR differs in the specific functions of cells they are responsible for; however, they all take part in the growth and division of cells. Therefore, cancers with FGFR mutations typically are more aggressive and have a worse prognosis.
Mutations in FGFR2 occur in 2 percent of all cancers with the most common occurrences listed as follows:
- Breast cancer
- Prostate cancer
- Bladder cancer
- Gastric cancer
- Ovarian cancer
- Cervical cancer
- Pancreatic cancer
- Lung cancer
- Head and neck cancers
To test cancer patients for the presence of a mutation in one of the FGFRs, there are tests available specific to FGFR, or tests that can detect mutations present in a wider subset of genes. These tests involve taking a sample of the tumor tissue and sending it to a laboratory to be analyzed. In most cases, mutations in any of the FGFRs are somatic and not hereditary. This means the mutation was not inherited from a family member but developed at some point during the patient’s lifetime from an unknown cause.
Treating Cancers With FGFR2 Mutations
To treat cancers positive for FGFR2 mutations, the receptor needs to be inhibited so cells can no longer function properly or reproduce. The treatment for FGFR2 mutated cancer depends on the specific cancer type among other factors like stage of disease and biomarker status.
There are therapies that have been developed through clinical trials to treat FGFR cancers. Targeted therapies are treatments that can locate cells with FGFR mutated proteins to target and attack them. By targeting mutated cancer cells, healthy cells are ignored, so some patients will experience less side effects compared to standard chemotherapies and other treatments. Patients with FGFR mutated cancer often still receive standard therapies on their own or in combination with targeted therapies and other treatments.
There are two FDA approved drugs to treat FGFR2 tumors including pemigatinib (Pemazyre) for cholangiocarcinoma, and erdafitinib (Balversa) for bladder cancer. However, there are other drugs targeting FGFR2 available in clinical trials for patients with other cancer types. There are 73 total clinical trials that include FGFR2 biomarker status as inclusion criteria. Some of these trials are for specific cancer types while others are for any patient with a mutation in FGFR2. Before drugs are approved to be widely used, they must go through several phases of clinical trials to ensure safety and efficacy. Talk with your doctor to see if clinical trials could benefit you.