I have oral trush. .. Is that mean that I have HIV or cancer.

Not necessarily. Oral thrush can occur in healthy people, but is more common with immune deficiency, some endocrine disorders like diabetes, antibiotic treatment and HIV and cancer. Please consult this site for more information. http://www.mayoclinic.org/diseases-conditions/oral-thrush/basics/definition/con-20022381.
Oral thrush-Candida. People can develop oral candida for many reasons and it doesn't mean you have HIV or cancer. Any medication that suppresses the immune system can increase the risk. In particular, people using cortisone meds are at more risk. You should see your doctor to find out the potential cause and get treated. Typically it's treated with oral anti-fungal medication ( Nystatin or clotrimazole).