As revealed on the Today show, Valerie Harper’s initial bleak diagnosis of terminal brain cancer may now be a brighter one, as her doctor says she is “close to remission.”

Harper, 74, announced in March that she was diagnosed with leptomeningeal carcinomatosis, a kind of cancer that attacks the membranes around the brain. But a recent MRI showed signs of hope for the actress who played Rhoda Morgenstern, the titular character’s best friend on The Mary Tyler Moore Show.

In the Today interview with host Meredith Viera, Harper’s neuro-oncologist Dr. Jeremy Rudnick said her remission “defies the odds.”

But Rudnick cautioned that “the problem is any time this can change.”

“They develop resistance to the therapy. And it’s not a matter of if, it’s a matter of when,” he added.

The Today interview, “Valerie’s Story – a Meredith Viera Special” will air Sept. 19 at 10 p.m. on NBC.