An international research team led by scientists from Georgetown Lombardi Comprehensive Cancer Center has discovered a genetic mutation linked to low-risk bladder cancer. The findings, published in Nature Genetics, identified STAG2 as one of the most commonly mutated genes in bladder cancer, particularly in tumors that do not spread. According to the study’s senior investigator, cancer geneticist Todd Waldman, MD, PhD, Professor of Oncology at Georgetown Lombardi, checking the status of the gene may help identify patients who might do unusually well following cancer treatment.
“Most bladder cancers are superficial tumors that have not spread to other parts of the body, and can therefore be easily treated and cured. However, a small fraction of these superficial tumors will recur and metastasize even after treatment,” Dr. Waldman said.
Because clinicians have been unable to definitively identify those potentially lethal cancers, after surgery all bladder cancers patients must undergo frequent endoscopic examinations of their bladder to look for signs of recurrence, said Dr. Waldman. This procedure, cystoscopy, can be uncomfortable and is expensive.
“Our data show that STAG2 is one of the earliest initiating gene mutations in 30% to 40% of superficial or ‘papillary-type’ bladder tumors, and that these tumors are unlikely to recur,” said lead author David Solomon, MD, PhD, a pathology resident at the University of California, San Francisco.
“We have developed a simple test for pathologists to easily assess the STAG2 status of these tumors, and are currently performing a larger study to determine if this test should enter routine clinical use for predicting the likelihood that a superficial bladder cancer will recur,” Dr. Solomon said.
For the study, the researchers examined 2,214 human tumors from virtually all sites of the human body for STAG2 inactivation and found that STAG2 was most commonly inactivated in bladder cancer, the fifth most common human cancer. In follow-up work, they found that 36% of low-risk bladder cancers had mutated STAG2, suggesting that testing the STAG2 status of the cancer could help guide clinical care. “A positive STAG2 mutation could mean that patient is at lower risk of recurrence,” Dr. Waldman said.
The researchers also found that 16% of invasive bladder cancers had mutated STAG2.
This work was supported by National Institutes of Health grants and the MD Anderson Cancer Center Bladder Cancer SPORE grant (P50CA091846).
A provisional patent application has been filed by Georgetown University for the technology described in this paper.
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