A comparison of cellular proliferation markers in squamous cell carcinoma of the head and neck

Abstract

Head and neck squamous cell carcinoma has a relatively good prognosis but treatment may be at the expense of function and quality of life. Various host and tumour parameters have been studied in an attempt to predict the course of the disease but without success. It has been hoped that laboratory based methods, particularly those based on molecular biology, may prove more useful. Cell kinetic parameters are studied in this paper. The present study includes 75 patients with a proven squamous cell carcinoma of the head and neck at various sites and undergoing various forms of treatment. The patient's mean age was 62 years and the median survival rate 45 months. Immunohistochemical techniques using Ki67 and PCNA were compared with flow cytometric analysis which included the BRDU labelling index, the duration of S phase, ploidy and potential doubling time. The median PCNA index was 560 and the Ki67 index 298. These indices varied between 980 and 150 for PCNA and 808 and 110 for Ki67. The BRDU labelling index measured by flow cytometry was 8.9 with a range from 25 to 1.6 and the duration of S phase was 14.8 hours. The PCNA index failed to correlate with any host or tumour factors and this failure was also seen in Ki67 indices and also in the flow cytometric parameters. There was a strong correlation between PCNA and Ki67 expression (p<0.0001). Neither PCNA nor Ki67 values were significantly different between irradiated and nonirradiated tissues nor in sites or in patients who later developed lymph node metastases. Neither PCNA nor any other cell kinetics parameter correlated with survival and multivariate analysis confirmed this lack of correlation. The PCNA labelling index like the Ki67 index and flow cytometric parameters does not appear to be of value in predicting the course of squamous cell carcinoma of the head and neck.