Projectile vomiting and weight loss

I took my 9year old cat sneakers to vet yesterday and they have no idea what's wrong. Ran a bunch of tests and still clueless. He's been projectile vomiting with no wreching and lost 6 pounds. I had another cat that was younger than him and she died from brain cancer last year. He doesn't have all the symtoms (symptoms) but some of them. Could he have stomach cancer? They gave him steroids yesterday and a steroid shot and nothing. Projectiled 3 times today. I just don't know what to do.

[Aleda M Cheng, D.V.M., C.V.A]

Could you please tell me what tests they have performed?

Did they do blood work for hyperthyroidism?  Did they perform abdominal X-Rays?  If you really suspect stomach cancer, (and it is a cause of chronic vomiting), than you can ask to have a abdominal ultrasound or barium study performed on your cat.  These should be able to give you a definitive diagnosis.  

Diagnosis of brain cancer would require a CT Scan or MRI of the brain.

[valv6ford]

They said that his white blood is elevated and his red blood is elevated. Tested everything but MRI. On the cat that died from brain cancer we did both ct and mri. He hasn't eaten in 2 days now.