Intensity of vascular endothelial growth factor expression is associated with increased risk of recurrence and decreased disease-free survival in papillary thyroid cancer.

BACKGROUND

Vascular endothelial growth factor (VEGF) induces proliferation of endothelial cells, stimulates angiogenesis, and increases vascular permeability. Increased VEGF expression has been associated with poor clinical outcomes in many malignancies. Several recent reports have documented over expression of VEGF in papillary thyroid cancer. We hypothesized that increased expression of VEGF would be associated with either an increased risk of recurrence or a decreased recurrence-free survival in papillary thyroid cancer.

METHODS

Immunohistochemistry was used to detect VEGF expression in archival paraffin-embedded surgical thyroid specimens from 96 subjects with papillary thyroid cancer.

RESULTS

VEGF expression was detected in 98% (94/96) of the samples, predominantly of slight-to-moderate intensity in the majority of malignant cells. However, the specific finding of a diffuse pattern of intense immunostaining for VEGF was detected significantly more often than less intense, patchy immunostaining patterns in subjects with distant metastasis at diagnosis (63% versus 15%, P =.005), local recurrence (58% versus 13%, P =.001), and distant recurrence (83% versus 14%, P =.001). Furthermore, this specific pattern of diffuse, intense VEGF expression was associated with a significantly shorter recurrence-free survival than other staining patterns (P =.007).

CONCLUSIONS

These data demonstrate that the immunohistochemical pattern of VEGF staining in the initial surgical specimen is strongly associated with the incidence of local and distant metastasis in papillary thyroid cancer.