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Bladder Cancer and Genes

What do your genes do?

Genes are short pieces of DNA that carry your traits—those things your parents pass on to you. Your genes have instructions that tell your cells what to do. Your genes can change over time, as you age.

A change in the DNA of a gene is a mutation. Mutations are due to mistakes that occur when the cells divide and make copies of the DNA. Mutations may be inherited from your parents or occur because of contact with things in your environment. This can include exposure to smoking or certain chemicals. With some mutations, you may be more likely to get bladder cancer and/or other cancers.

Bladder cancer cells have a high number of genetic mutations compared to other cancers.  Many of these mutations are random. Their effect on tumor growth is unknown. Some mutations affect genes that are important for cell growth, survival, and DNA damage repair. Your doctor may want to find out if you inherited a mutation especially if you are young or have a family history of cancers or if your cancer has certain mutations.

How do your genes relate to bladder cancer treatments?

Researchers have found that specific medicines work well on certain mutations in bladder cancer cells. Some of these mutations help your bladder cancer tumor(s) to grow and survive. There may be drugs or combinations of medications that specifically target these mutation pathways that can slow a tumor’s growth, which has the potential to improve survival.

A gene, called FGFR3, sometimes undergoes changes (mutations) in bladder cancer. These mutations are not very common, but they are crucial for treatment decisions. About 13% of muscle invasive bladder cancers have mutations in this gene. If a person with bladder cancer has a mutation in the FGFR3 gene and the cancer has advanced, certain drugs called FGFR inhibitors can be very helpful in treating the disease effectively. To figure out if a bladder cancer has genetic mutations like FGFR3, doctors can look at two things:

  1. They can examine a sample of the tumor itself.
  2. They can also study DNA that’s floating freely in the blood. This DNA can come from the tumor and gives clues about its genetic makeup.

When the decision is made to check if you inherited a mutation, DNA from white blood cells circulating in the blood or cells in the saliva are studied.

Does my bladder tumor have the same genes wherever it grows in my body?

Bladder cancer tumors can be different from one another, even within the same tumor. If the cancer has spread beyond the bladder, the mutations might vary between different parts of the cancer. And sometimes, even if you take samples from the same tumor at different times, you might find important differences in the mutations. So, it’s not just one-size-fits-all with bladder cancer genes—they can be quite varied and change over time.

If you have a tumor in your bladder, ureter, or renal pelvis, doctors might use a biopsy or surgically removed tumor from before to study it. This includes samples taken during procedures like transurethral resection of the tumor (TURBT), radical cystectomy, or needle biopsies from other sites if the cancer has spread. However, if it’s been a while since the tumor was removed, or if you’ve had treatments since then, or if the previous sample wasn’t enough for DNA analysis, they might need to take another biopsy to make sure they get good quality tissue for accurate mutation analysis. If getting a new biopsy isn’t possible or safe, they might use a blood sample instead. The DNA floating in your blood can also give important clues about the tumor’s genetic makeup, which can help with the analysis.

Can I pass my gene mutations to my children?

In about 15% of patients, there are mutations in their genes that could be important. These mutations can be passed down from parents to their children. Genetic testing helps find these “germline” mutations, which can raise the risk of urinary tract cancers, like bladder cancer. Examples of these mutations include BRCA1, BRCA2, MSH2, CHEK2, and others. These mutations aren’t just important for the person with bladder cancer but also for their brothers, sisters, and kids. Doctors might recommend genetic testing for people who are younger, have a personal or family history of cancer, or have cancers in the upper urinary tract to see if they have these mutations.

The Bladder Cancer Genome Atlas

The National Cancer Institute published an updated comprehensive description of 412 patients with Stage II or greater muscle invasive bladder cancer (MIBC) in 2017. This genetic analysis created a molecular atlas or blueprint of bladder cancer called the “bladder cancer genome atlas,” and is free and publicly available for researchers, physicians and patients.

The Bladder Cancer Genomics Consortium

In an effort to further advance bladder cancer research, BCAN has launched the Bladder Cancer Genomics Consortium (BCGC). Learn more here.

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