Prognostic value of PCNA and cytokeratins for radiation therapy of oral squamous cell carcinoma.

In a retrospective pilot study we compared morphologically the first biopsies of 20 patients suffering from oral squamous cell carcinoma (OSCC) where preoperatively performed radiation therapy [gamma rays (cobalt-60)] was successful with 20 patients who underwent the same therapy without the expected success. All specimens were formalin fixed and paraffin embedded. We performed haematoxylin and eosin staining and immunohistochemistry (ABC-method) applying broad spectrum cytokeratin, cytokeratin (CK) 1 + 2, 3 + 6, 13 and anti-proliferating cell nuclear antigen (PCNA, PC10). The specimens of the patients with success of the radiotherapy showed statistically higher levels of PCNA positive tumour cells, measured by a computerised morphometric analysis system (VIDAS). These specimens showed significantly less CK 3-6 positive tumour cells than the specimens of the patients with failure of this therapy. The difference in the content of proliferating cell nuclear antigen might explain the different results of the performed radiation therapy. The difference in cytokeratin 3 + 6 expression might be linked with the different amount of benign hyperproliferation. Prospective studies are planned to prove the results.