Hi there and welcome - I too am not familiar with the test you mentioned - but the biopsy is an old friend and not one I like particularly, but they take so long because they resect the tissue and go through it thoroughly. Try not to worry until you get the results but do educate yourself in the mean time. Find out what the treatment is, what to prepare for etc. That way If you do get a cancer dx you will be prepared to ask the important questions and know what to expect - for the most part . Knowledge is power, and advocacy for yourself is important.
Also if you don't get a cancer dx, you will be prepared and know what to keep an eye out for if the situation persists.

I'm not as young as you but I am a vegetarian (almost vegan) and don't smoke, drink, or do drugs... In fact Im not even a coffee drinker. And I had my ulceration. For 6 years - with one negative biopsy. So it can happen. I'm not trying to scare you - just trying to tell you to educate yourself. The knowledge will never go to waste. Hugs and take care.