[Biological significance of DNA content in parotid carcinoma].

The DNA content was analysed by flow cytometry in 5 samples of normal salivary tissue, 36 cases of benign salivary gland tumors and 50 cases of parotid carcinoma. It was found that the difference in the DNA index (DI) and proliferative index (PI) in age, sex, tumor size and TNM staging were insignificant (P greater than 0.05). The DI and PI of poorly differentiated parotid carcinoma were much higher than those of well differentiated parotid carcinoma (P less than 0.05). The DI and PI were closely related to the presence of lymph node metastasis (P less than 0.001). The DI and PI of patients with facial nerve paralysis and with disease free period shorter than 5 years were remarkably higher than those with normal facial nerve and disease free survival for more than 5 years (P less than 0.01). The above results indicate that DI and PI, showing cell proliferative kinetic characteristics, can provide reliable and objective parameters for assessing the degree of differentiation, degree of malignancy, biological behavior and prognosis of parotid carcinomas.