A new imaging test may provide the ability to identify ovarian cancer patients who are candidates for an emerging treatment that targets a key enzyme cancer cells need to survive. Currently, epithelial ovarian cancer patients with BRCA1 mutations are considered candidates for the treatment, but there is no method to measure the enzyme levels to help guide treatment choices. Researchers from the Perelman School of Medicine at the University of Pennsylvania used a new type of imaging to do just that in hopes of finding patients who may benefit from treatment to block the enzyme, including patients without the BRCA mutation. Researchers will present their findings at the upcoming 2017 American Association for Cancer Research Annual Meeting in Washington, D.C. (Abstract 3716).

Researchers used the imaging to see Poly (ADP-ribose) Polymerase 1 (PARP-1), an enzyme that helps damaged cancer cells repair their DNA and survive, and found drugs that block that enzyme have an equal to or even greater impact on treatment than restoring the BRCA1 mutation. 

PARP-1 is already a target of emerging therapies for breast and ovarian cancer. By using a PARP inhibitor, doctors can trap the enzyme on cancer DNA, causing that cell to form poisonous lesions and die. This new research could help point the way towards identifying patients most likely to benefit from treatment with PARP inhibitors.

“Research exists that shows PARP inhibitors can be effective in the treatment of BRCA1 mutated cancer, but there are no good existing methods to explore how mutations within BRCA genes effect PARP-1 expression,” said the study’s lead author Mehran Makvandi, PharmD, RPh, ANP, an instructor of Radiology at Penn. “We wanted to validate our radiotracer technology as a quantitative biomarker for PARP-1 with the goal of selecting patients who could benefit from PARP inhibitor therapy.”

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