NBC News Special Correspondent and former “NBC Nightly News” anchor Tom Brokaw has been diagnosed with cancer, the network announced Tuesday night.

Brokaw, 74, was diagnosed with multiple myeloma, a cancer affecting blood cells in the bone marrow, at the Mayo Clinic in August.

But the journalist said he and his physicians are very encouraged with the progress he’s making.

"With the exceptional support of my family, medical team and friends, I am very optimistic about the future and look forward to continuing my life, my work and adventures still to come,” Brokaw said in a statement. "I remain the luckiest guy I know. I am very grateful for the interest in my condition but I also hope everyone understands I wish to keep this a private matter."

He's continued to work for NBC News throughout his treatments, including a two-hour documentary on the JFK assassination, as well as appearances on various NBC News programs. He has recently contributed to the network’s coverage of the Winter Olympics in Sochi.

Brokaw, who has worked for NBC since 1966, is best known for the “NBC Nightly News,” for which he served as managing editor and anchor from 1982 to 2004.