Predictive factor for photodynamic therapy effects on oral squamous cell carcinoma and oral epithelial dysplasia

The aim of this study was to investigate the correlation between the immunohistochemical expression of proliferating cell nuclear antigen (PCNA), factor VIII, and CD34 (markers of endothelial cells), and vascular endothelial growth factor (VEGF) and the recurrence of oral squamous cell carcinoma (OSCC) and oral epithelial dysplasia (OED) subjected to photodynamic therapy (PDT).

Twenty-one biopsy specimens (14 cases of OSCC and 7 cases of OED) before PDT were immunohistochemically investigated in terms of their expressions of PCNA, factor VIII, CD34 and VEGF. The percentages of the total sample area that were immunopositive for factor VIII (percentage factor VIII immunopositive area: PFIA) CD34 (PCIA) and VEGF (PVIA) were calculated using computer-assisted image analysis for quantitative assessment of endothelial cells or VEGF expression in the lesions. The PCNA labelling index (LI) was evaluated as a proliferation marker.

Five cases of OSCC and one case of OED recurred 4 to 30 months after PDT. We found that the average PVIA was 14.5% in the no-recurrence group and 1.7% in the recurrence group. The difference between these values was statistically significant (P=0.0483). On the other hand, the average PCNA LI was 30.3% in the no-recurrence group and 24.3% in the recurrence group; the average PFIA was 3.7% in the no-recurrence group and 1.6% in the recurrence group; and the average PCIA was 2.0% in the no-recurrence group and 1.4% in the recurrence group. There were no significant differences between the two groups for any of these markers (P=0.3379, P=0.1195, P=0.4835, respectively).

These results provide clinical data indicating that VEGF expression may be a useful predictive marker for the effects of PDT in OSCC and OED.