THE PROGNOSIS OF ORAL MUCOSAL SQUAMOUS-CELL CARCINOMAS - A COMPARISONOF CLINICAL AND HISTOPATHOLOGICAL GRADING AND OF LAMININ AND TYPE-IV COLLAGEN STAINING

Changes in the distribution of basement membrane components have been described in dysplastic lesions and in oral mucosal squamous cell carc inomas (OMSCC). The purpose of this study was to determine if these ch anges were related to pathological grade and if so, whether this had p rognostic implications. Fifty formalin-fixed, paraffin-embedded specim ens of OMSCC, with five or more years clinical follow-up, were studied using an immunoperoxidase technique for the detection of the basement membrane components, laminin and type IV collagen. The immunoreactivi ty of each component was evaluated and semiquantitatively scored as mi nimal, moderate or extensive and the results compared with the tumour size, node involvement and metastasis (TNM) clinical staging system an d histopathological features. OMSCC were characterized by minimal or m oderate staining with small islands of neoplastic cells frequently lac king staining for laminin and type IV collagen. Deposition of these co mponents decreased with increased histopathological grade and absence of staining was more commonly associated with a poor prognosis. In par ticular the pattern of type IV collagen staining frequently differed f rom laminin staining. Neither of these parameters offered an advantage over TNM clinical staging with regard to prognosis. It was concluded that variations in laminin and type IV collagen immunoreactivity occur red in OMSCC and that high histopathological grade tumours with consid erably diminished staining with anti-laminin and anti-type IV collagen carried a poor prognosis.