Squamous cell carcinomas arising from different types of oral epithelia differ in their tumor and patient characteristics and survival.

A hypothesis that OSCCs originating from different types of oral epithelia may have different patient and tumor characteristics was evaluated in this retrospective analysis of 188 patients with primary OSCC treated at Turku University Central Hospital, Turku, Finland in 1988-1997. The tumors were categorized according to the type of oral epithelium from which they have originated: (1) specialized epithelium (dorsal tongue) (2) keratinized (masticatory) epithelium, (3) non-keratinized (lining) epithelium, and (4) tongue epithelium (epithelium on the lateral border of the tongue). The relevant clinical data, including age, sex, social status, and risk behavior of the patients and clinical presentation, histopathological grading, and treatment of the tumors, as well as the follow-up information, were collected from the patient charts of the hospital. In general, tumor and patient characteristics of OSCCs and survival rates were found to be in line with those of recent analyses reported from other industrialized countries. However, OSCCs in young patients (4.8%) seemed to be clinically at a lower stage and histologically more highly differentiated than those of the other patients. Eight out of 9 (89%) OSCCs in the young patients were located on the lateral tongue. The 5-year recurrence-free rates of the patients according to the epithelial origin of the tumors were as follows: masticatory epithelium 42%, lining epithelium 57%, and epithelium of the lateral border of the tongue 61%. In conclusion, the tumors originating from different types of oral epithelia may have distinct properties with regard to their clinical behavior and responsiveness to the different treatment modalities. It would seem to be meaningful to investigate the molecular characteristics of the different types of oral epithelium in order to elucidate possible differences in their susceptibility to malignant transformation.