PROGNOSTIC VALUE OF BCL-2 IMMUNOREACTIVITY IN MEDULLARY-THYROID CARCINOMA

Bcl-2 expression has been evaluated immunocytochemically in a series o f 33 medullary thyroid carcinomas (MTC) with long-term (mean, 10.3 yea rs) follow-up. Twenty-six of 33 cases showed intense bcl-2 immunoreact ivity in more than 25% neoplastic cells. Bcl-2 immunoreactivity did no t correlate with several clinicopathologic parameters including sex an d age of the patients, sporadic or familial disease, tumor size and st age, amount of amyloid stroma, and immunoreactivity for calcitonin, ch romogranin A, proliferating cell nuclear antigen (PCNA), N-myc, and p5 3. Lack of bcl-2 immunoreactivity, however, correlated significantly ( P = .0001) with a shorter survival. Indeed, the seven patients with tu mors devoid of bcl-2 immunoreactivity all died of disease within 8 yea rs from the diagnosis. In multivariate analysis, lack of bcl-2 immunor eactivity was an independent predictor of worse prognosis (P = .001 fo r disease-free survival and P = .0001 for overall survival). None of t he other clinicopathologic variables investigated proved to be an inde pendent prognostic parameter. It is concluded that down-regulation of bcl-2 expression in MTC may identify a subset of tumors with a more ag gressive clinical course. Copyright (C) 1995 by W.B. Saunders Company