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The aim of the study was to determine the incidence of p53 alterations by mutation, deletion or inactivation by mdm2 or human papillomavirus (HPV) infection in recurrent squamous cell cancer

of the head and neck (SCCHN) refractory to radiotherapy. Twenty-two tumours were studied. The p53 status of each tumour was analysed by sequencing of exons 4–9 and by immunohistochemistry.

Mdm2 expression was assessed by immunohistochemistry and HPV infection was assessed by polymerase chain reaction of tumour DNA for HPV 16, 18 and 33. Fifteen (68%) of the 22 tumours studied

had p53 mutations, while seven had wild-type p53 sequence. p53 immunohistochemistry correlated with the type of mutation. HPV DNA was detected in 8 (36%) tumours and all were of serotype HPV

16. Of these, five were in tumours with mutant p53 and three were in tumours with wild-type p53. Mdm2 overexpression was detected in 11 (50%) tumours. Of these, seven were in tumours with

mutant p53 and four were in tumours with wild-type p53. Overall, 21 of the 22 tumours had p53 alterations either by mutation, deletion or inactivation by mdm2 or HPV. In this study, the

overall incidence of p53 inactivation in recurrent head and neck cancer was very high at 95%. The main mechanism of inactivation was gene mutation or deletion which occurred in 15 of the 22

tumours studied. In addition, six of the seven tumours with wild-type p53 sequence had either HPV 16 DNA, overexpression of mdm2 or both which suggested that these tumours had p53

inactivation by these mechanisms. This high incidence of p53 dysfunction is one factor which could account for the poor response of these tumours to radiotherapy and chemotherapy. Therefore,

new therapies for recurrent SCCHN which either act in a p53 independent pathway, or which restore p53 function may be beneficial in this disease. © 2000 Cancer Research Campaign

This paper was modified 12 months after initial publication to switch to Creative Commons licence terms, as noted at publication

Bischoff JR, Kirn DH, Williams A, Heise C, Horn S and Muna M (1996) A mutant adenovirus which selectively replicates in tumour cells with nonfunctional p53. Science 274: 373–376

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