My family's dog was recently diagnosed with colon cancer... in his case it isn't treatable - it's too far along since we didn't catch it, the symptoms led the vet to believe he just had an infection. After 2 rounds of antibiotics didn't work, we learned the truth.
So for right now, we're just doing our best to keep him comfortable.
So I'm really feeling for Ayu right now
Marron had cancer years ago too, but it got treated at the time, so perhaps Pino will be alright.
Having purebred dogs, there's always the risk of this kind of thing happening, sadly. My dog is a purebred Sheltie and he's only about 11 or 12 years old... Pino is still so young though! My WoW character is only a few years old, and I named her after Pino & Papiko because they were her newest furbabies at the time.