Sorry to hear about your cat. After one of my dogs died in February 2013, fluid came from her nose which was suspected to be lung fluid, and it is now pondered to be something cancer related.
A long time back one of my cats has Feline Leukemia. He disappeared (ran away, presumably) before he contracted anything lethal from it. His fate remains unknown :c
My mom had a cat before she moved out named Baxter. After a while, he ended up living with her after I was born. He was declawed and went to the bathroom on the floor, and I started crawling towards it (yummy). My mom sent him to live with my dad's friend who loves animals, but the cat ran away.
His fate remains unknown :c