Vascular endothelial growth factor expression in invasive papillary thyroid carcinoma

The vascular endothelial growth factor (VEGF) is a major promoter of endothelial growth and migration. Some studies have shown a correlation between expression of this growth factor and prognosis in several cancers, including well-differentiated thyroid cancer.

We studied VEGF expression, local invasiveness, and other prognostic factors in papillary thyroid carcinoma (PTC) to test the hypothesis that the expression of VEGF is correlated with the degree of invasion of PTC.

Clinical and pathological data of 76 patients with PTC were retrospectively reviewed. Group 1 consisted of patients with gross locally invasive tumors, group 2 consisted of patients with only invasion of the thyroid capsule, and group 3 consisted of patients with noninvasive PTC.

VEGF expression was noted within the tumor in all groups of PTC patients but was absent in the surrounding normal tissue. Older patients had higher expression of VEGF than younger patients. The age of patients with strong reaction to VEGF was 46 +/- 14 (mean +/- standard deviation), and that in patients with a weaker reaction was 39 +/- 16 (p < 0.05). Only 20% of patients with a follicular variant of PTC had a strong reaction to VEGF compared with 68% of patients with classical PTC (p < 0.01).

VEGF expression appears to be an early event in the development of PTC. Whether VEGF expression promotes the progression of PTC is not known, but the answer to this question may be important in view of its greater expression in older patients, a group whose prognosis in PTC is worse.