Metalloproteinase-9 immunoexpression and angiogenesis in thyroid follicular neoplasms: Relation to clinical and histopathologic features

Background. Thyroid follicular neoplasms (adenoma and carcinoma) may pose c onsiderable difficulties to the differential diagnosis. Because such a dist inction is not possible at fine-needle aspiration, surgery is often necessa ry. Clinical information such as age, sex, and node size is important in ca se of suspected carcinoma. Follicular carcinoma is characterized by capsula r invasion, vascular invasion, and metastatic dissemination mainly by the h ematogenic pathway. This invasion depends on collagen degradation in capsul e and in subendothelial basement membrane. Collagen degradation has been wi dely researched in the angiogenesis process and in the hematogenic dissemin ation mechanism. In this study, we performed clinical and histopathologic a ssessment of 74 follicular neoplasms, as well as immunohistochemical reacti ons for CD-34 protein to estimate angiogenesis and for metalloproteinase-g, an enzyme that degrades type IV collagen. Methods. The research was carried out retrospectively in 74 patients who ha d surgery and were followed up at HC-FMUSP and IBCC. Clinical, histologic, and immunohistochemical variables were compared among the groups of follicu lar neoplasms and a control group of 36 patients with colloid goiter. Results. No significant statistical difference was found between patients w ith follicular adenoma and thyroid follicular carcinoma concerning sex (p = .092), age (p = .098), thyroid node size (p = .426), vascularization (p = .388), and immunostaining intensity for metalloproteinase-g (p = .055). The proportion of immunoreactive cells for metalloproteinase-g in follicular c arcinoma cases was higher than that observed in follicular adenoma cases (p < .001). Patients in more advanced stages of carcinoma were more than 45 y ears old (p = .006), presented extensive invasion (p < .001), had less vasc ularization (p = .046), and a had higher proportion of immunoreactive cells for metalloproteinase-9 (p < .001). Conclusions. The proportion of immunoreactive cells for metalloproteinase-9 in follicular carcinoma was higher than that observed in follicular adenom a, with a significant statistical difference (p < .001). This method must b e developed to apply in material obtained by fine-needle aspiration to diff erentiate follicular adenoma from carcinoma. (C) 2000 John Wiley & Sons, In c.