Oncologists in the not too distant future may have a urine test to screen for bladder cancer.
Colorado investigators reported at the American Association for Cancer Research (AACR) Annual Meeting 2015 that specific gene alterations happen early in the development of bladder cancer and so it may be possible to develop a genetic test that examines urine as a way to screen for the disease.
The researchers examined bladder cancer tumors from 54 patients and found that telomerase (TERT) is the gene most frequently altered by somatic sequence changes.
This was found to occur in 37 out of the 54 tumors (69%). TERT was also altered by rare and common germline variants in 30 out of the 54 tumors (56%).
The researchers reported that TERT germline variants were novel in 19 out of 20 tumors and three variants were confirmed as both somatic and germline in distinct tumors.
“We are moving into a new era,” said senior study author Dan Theodorescu, MD, PhD, who is the director of the Colorado University Cancer Center in Denver, CO. Gene sequencing for bladder cancer is expanding rapidly and Dr. Theodorescu and his colleagues found that TERT alterations frequently co-occur with alterations in recently identified bladder cancer genes such as the stromal antigen 2 (STAG2) and the lysine-specific demethylase 6A (KDM6A).
The researchers found that somatic alterations occurred in 15% of tumors in the BRCA1-associated protein-1 (BAP1) gene, a gene recently characterized in the development of bladder cancer.
The BAP1 alterations co-occurred with KDM6A mutations and contributed to a high frequency of BRCA pathway defects due to germline and somatic alteration of BRCA1, BRCA2, ATM, and PALB2.
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Prior studies have shown that BRCA1- and BRCA2-mutant breast, ovarian, and prostate cancers are responsive to the class of drugs known as poly (ADP-ribose) polymerase (PARP) inhibitors.
Study co-author Michael Nickerson, PhD, who is a staff scientist the National Cancer Institute (NCI) in Bethesda, MD, said it is hoped that U.S. Food and Drug Administration (FDA)-approved drugs such as PARP inhibitors that are currently being developed to treat BRCA-mutant cancers may be effective in treating the potentially large number of patients with bladder cancer with BRCA DNA repair pathway defects.