P53 OVER-EXPRESSION IN LARYNGEAL CARCINOMA IS NOT PREDICTIVE OF RESPONSE TO RADIOTHERAPY

It has been suggested that alterations involving the p53 gene may infl uence tumour response to radiotherapy. If this were so, then p53 overe xpression (which is usually associated with p53 mutation and readily d etectable in routine diagnostic pathology) may help determine the most appropriate form of cancer therapy. p53 expression was assessed in 90 formalin-fixed paraffin-embedded laryngeal carcinomas that were subse quently treated with radiotherapy. The polyclonal antibody DO1 (1 in 5 0 dilution) was used, together with an avidin-biotin immunoperoxidase technique, but in the absence of any additional antigen retrieval tech niques. p53 expression was assessed and correlated with various clinic opathological parameters. Using Chi square analysis, no significant di fference between p53 positive and p53 negative lesions was found for r esponse to radiotherapy, as measured by survival and recurrence rates. Furthermore, no correlation with p53 expression was found for tumour size, nodal metastasis, sex, age, alcohol intake, tobacco habit and hi stological grade. This absence of correlation may in part be explained by discrepancies between immunohistochemical detection of p53 and p53 mutation, although the lack of predictive response to radiotherapy mi mics that recently found for irradiated head and neck cancer cell line s. (C) 1997 Elsevier Science Ltd.