Thanks for your question on HCM. There are few causes for white patches on tongue. The common causes are 1. Fungal infection due to improper hygiene. 2. Vitamin b12 deficiency 3. Riboflavin, pyridoxine and niacin deficiency. 4. Leukoplakia due to tobacco use or dental problems. In my opinion you are having vitamins deficiency. So get done vitamin b 12 level. If deficient, start supplements. Also give multi vitamin tablets containing folic acid, niacin and pyridoxine. Do take proper care of oral hygiene. So very less likely due to cancer in your case.