MIB-1 and p53 expression in radiotherapy-resistant T1aN0M0 glottic squamous cell carcinoma

Radiotherapy of T1aN0M0 glottic carcinoma results in a local control rate o f 80-94%. This homogenous group, which is the earliest recognisable invasiv e malignancy in the head and neck region, provides a 'unique model' for stu dying possible biological markers of radiosensitivity. p53 and MIB-1 were i nvestigated as possible markers of radiosensitivity in such a group. In all , 107 patients with T1aN0M0 glottic squamous cell carcinoma treated with ra diotherapy were identified. Cases not responsive to radiotherapy were compa red with matched radiosensitive controls by immunohistochemistry using mono clonal primary antibodies to MIB-1 (n = 18; controls = 10) and p53 (n = 6: controls = 11). No significant difference in p53 expression was noted betwe en the two groups (P = 0.73). A greater MIB-1 expression was found in the r adiosensitive group but only a trend towards significance was observed (P = 0.06). MIB-1 is a potential marker of radiosensitivity. A larger multicent re study is required for a more definitive answer.