The 49-year-old revealed his diagnosis on June 23 in a statement on his Twitter account, saying: "I have cancer. It sucks and I'm scared."
"At the same time I'm blessed with incredible doctors and family and friends to get me through this," Mark wrote.
He continued: "I still have months of treatment ahead of me but I'm trying to remain hopeful and positive. Can't wait to be cancer free and see you all at a concert in the near future."