Diem Brown Diem Brown

Diem Brown, who competed on MTV's long-running show The Challenge, lost her battle with cancer on Friday, People reports. She was 34.

The reality star was diagnosed with cancer for a third time over the summer. She received her first diagnosis shortly after competing on her first season of Real World/Road Rules Challenge in 2006 and faced the disease again in 2012.

After beating ovarian cancer twice, Brown revealed in October that cancer had been found in her stomach and colon before spreading to her liver and lymph nodes.

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Through everything, Brown kept up an active and positive presence on Twitter, even during her time in the hospital. "I NEED PRAyErs and advice my doctors are seemingly giving up but I won't & can't rollover. Whatever option I have to LIVE I'm grabbing," she wrote. Her last tweet, on Tuesday, urged her fans to contact E! News correspondent Alicia Quarles. "We know there is hope & help," she wrote.

In addition to competing on seven seasons of The Challenge, Brown founded MedGift, a charity organization that provides medical patients a platform to create a gift registry.

Brown is survived by her father, two sisters and a brother.