EXPRESSION OF BCL-2 AND P53 IN ONCOCYTIC (HURTHLE CELL) TUMORS OF THETHYROID - AN IMMUNOHISTOCHEMICAL STUDY

Previous studies have established that thyroid follicular neoplasms of higher malignant potential show a high p53 and low bcl-2 expression. This however has not been well studied in Oncocytic (Hurthle cell) neo plasms, the management of which remains controversial. We therefore st udied the expression of p53 and bcl-2 in 18 Hurthle cell adenomas (HCA ) and 8 Hurthle cell carcinomas (HCC) and compared them with their ben ign and malignant counterparts, respectively, including 16 follicular adenomas (FA) and 68 papillary carcinomas (PC). All 16 FA were bcl-2 p ositive, 4 were 2+, and 12 were 3+. On the other hand, 14/18 (78%) HCA showed bcl-2 expression, 5 were 1+, 6 were 2+, and only 3 were 3+. Si milarly, HCC showed a weaker bcl-2 staining pattern compared to PC. On ly 1 FA showed grade 1, p53 staining, the remaining 15 were negative, and 15/18 HCA showed p53 expression of varying grades. This difference in p53 staining was statistically significant (p = 0.005). A signific ant p53 overexpression was also seen in HCC compared to PC (p = 0.005) . In conclusion, there appears to be an inverse relationship between p 53 and bcl-2 expression in thyroid follicular neoplasms. A higher expr ession of p53 and lower levels bcl-2 in Hurthle cell neoplasms may hav e biological and clinical implications. This may support a more aggres sive surgical treatment for HCA compared to FA.