Bladder cancer characterized by mutations of the STAG2 gene appears to be less likely to recur than bladder cancer with no such mutations, researchers have learned.

STAG2 mutations have been seen in a number of cancers, but when Todd Waldman, MD, PhD, of the Georgetown Lombardi Comprehensive Cancer Center in Washington, DC, and associates examined 2,214 human tumors from various body sites, they found that STAG2 was most commonly inactivated in bladder cancer. As the team members reported in Nature Genetics, truncated mutations of the STAG2 gene occurred in 36% of the papillary noninvasive urothelial carcinomas and in 16% of the invasive urothelial carcinomas of the bladder.

“These findings identify STAG2 as one of the most commonly mutated genes in bladder cancer,” particularly in tumors that do not metastasize, noted the authors.

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Most bladder cancers are superficial tumors that have not metastasized, explained Waldman in a statement from Georgetown University Medical Center. “However,” he added, “a small fraction of these superficial tumors will recur and metastasize even after treatment.”

Because there has been no way to identify those potentially lethal cancers, all persons with bladder cancer typically must undergo frequent cystoscopy examinations to check for signs of recurrence. Now, a positive STAG2 mutation could mean that the patient is at lower risk of recurrence, according to Waldman.

Waldman and his co-investigators have developed what he describes as a simple test that will allow pathologists to assess easily the STAG2 status of superficial bladder tumors. The group is now conducting a larger study to determine whether the test should enter routine clinical use for predicting the likelihood of recurrence of superficial bladder cancer.