Oral Cancers start in a part of the mouth : the lips, gums, tongue, cheeks, floor of mouth, or roof of the mouth (the palate). As they grow, they can come to involve the bones of the upper or lower jaw, they can spread to lymph nodes in the neck, or they can spread elsewhere in the body. Most oral cancers are squamous cell carcinomas, which is a cancer that comes from the lining on the inside of the mouth.