NBC correspondent Tom Brokaw says he has been diagnosed with cancer but is encouraged with his progress against the disease. Brokaw said he has multiple myeloma, a cancer that affects blood cells in the bone marrow. He was diagnosed at the Mayo Clinic in August. While under treatment, Brokaw has continued to work as a correspondent for NBC on several special projects. He has worked for the network since 1966. Brokaw released the following statement with the news of his cancer: "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. "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." Brokaw turned 72 on Feb. 6.