The relationship of vascular endothelial growth factor and osteopontin expression with 3-year progression-free survival of locally advanced nasopharyngeal cancer patients treated with platinumbased chemoradiation

Introduction
The incidence of nasopharyngeal cancer (NPC) is high, with new cases accounting for 5.2% of all malignancies in Indonesia. Most cases are detected at an advanced stage, and recurrences are common. Vascular endothelial growth factor (VEGF) and osteopontin (OPN) are important markers in tumorigenesis that serve as prognostic predictors. This study aims to determine the correlation of VEGF and OPN expression with 3-year progression-free survival (PFS).

Material and methods
This retrospective cohort study analyzed 155 patients with locally advanced NPC. Data were obtained from medical records between 2015 and 2017. The locally advanced sample of this disease that met the inclusion criteria was stained with H&E before being prepared in a paraffin block. Furthermore, the immunohistochemistry staining results for VEGF and OPN were observed with ImageJ 1.50i and calculated semi-quantitatively using the histoscore.

Results
The 3-year PFS obtained was 39%, with a median of 23 months. Vascular endothelial growth factor expression was detected in 113 of 155 samples (72.9%), while positive OPN expression was discovered in 99 of 155 samples (63.8%). There was a correlation between VEGF (p = 0.747) and OPN expression (p = 0.584) and 3-year PFS. Positive VEGF and OPN expression in the subgroup of patients with stage IVB and N3 tumors was related to improved 3-year PFS (p < 0.05). This was similar to the positive VEGF expression in the subgroup of patients receiving neoadjuvant chemotherapy (p < 0.05).

Conclusions
Vascular endothelial growth factor and OPN remained potential prognostic predictors in NPC. Patients with positive VEGF and OPN expression in N3, IVB, and neoadjuvant treatment had significantly improved 3-year PFS.