"Sorry to eff you around with gigs," Brand Tweeted after cancelling the shows. "My mum ain't well. Tix will be honoured or refunded."
"My mother has currently got breast cancer," Brand said in a video blog he posted Wednesday, adding that she's attending support groups.
The Mirror notes that Brand's mother survived uterine cancer when he was 8 years old. The comic is very close with his mother, who raised him alone after divorcing Brand's father when he was just 6 months old; he has mentioned her strength in his autobiographies.