Fact is that most of us don't even notice what's going on inside our mouth. Even professionals like dentists and hygenists (who are paid to look in there) miss things. Once you begin to notice then all of the stuff that Brian mentioned in his post comes into play. Once you've had a good scare then the health of your mouth takes on a whole new meaning. I freaked out once at a salivary gland - I thought for sure it a new tumor - turned out to be a normal part of the anatomy. I'll bet the head & neck guy had a good laugh at that one. Then the stains from fillings and other normal anomolies.

I can certainly understand your fear in light of your mother but I have not heard or read anywhere that oral cancer is genetic. The vast majority of the time (80%) it is environmentally caused by tobacco and/or alcohol. Considering the high incidence of cancer in general - 1 in 2 males and 1 in 3 females. I guess just having a bag of bones makes us all genetically disposed to cancer.

Since early detection is key to better odds of survival you are wise to seek an accurate diagnosis.