Total hemolytic complement (CH50) and its fractions (C3 and C4) in the sera of patients with premalignant and malignant lesions of the oral cavity.

Total hemolytic complement (CH50) and its fractions (C3 and C4) were estimated in the sera of 50 patients with oral leukoplakia, 50 patients with oral submucous fibrosis and 50 oral cancer patients. The values were compared with that of 50 normal controls. No significant alterations in the values of CH50, C3 or C4 were observed in the sera of patients with either leukoplakia or oral submucous fibrosis whereas the values were found to be altered significantly in oral cancer (P less than 0.001). In the case of oral submucous fibrosis the mean complement levels were slightly lower than those of normal controls and leukoplakia. Age and sex had no influence either on the total complement activity or its fractions (C3 and C4). The serum complement levels may be useful as a biological marker for the early detection of tissue dysplasia.