Dear Scott,
Here is some information from another part of the OCF web site:

Malignancies arising from the mucosa of the oral cavity are epithelial in origin and are, therefore,(23,24)classified as squamous cell carcinomas more than 90% of the time. According to the degree of differentiation, three subtypes are defined: (1) well-differentiated squamous cell carcinoma showing more than 75% keratinization; (2) moderately differentiated squamous cell carcinoma with 25-75% keratinization; and (3) poorly differentiated squamous cell carcinoma with less than 25%(1,2)keratinization. The majority of cases are of moderate differentiation. A clear relationship between histologic differentiation and clinical prognosis has not been established, although a lack of differentiation has been associated with more rapid growth and spread. The morphologic classification of squamous cell carcinoma by degree of differentiation is used in the description of the histopathologic specimen.

You can read more information at:
http://www.oralcancerfoundation.org/cdc/cdc_chapter2.htm

Hope this is of some help. Best of luck with the treatments. - Sheldon