[Determination of cell proliferation using monoclonal antibodies. Studies of 21 squamous cell carcinomas of the head and neck area].

These tumours showed a correlation between Ki 67 labelling index and histological differentiation: poor differentiation resulted in a Ki 67 labelling index from 30 to 50%, high differentiation below 20%. Labelling index of moderately differentiated carcinomas ranged between these values. Pretreatment of tumours, i.e. chemotherapy and radiotherapy, resulted in a labelling index of less than 6%. The observed heterogeneity must be considered as a limitation for using the monoclonal antibody Ki 67 in these cases as a prognostic marker.