RETINOBLASTOMA PROTEIN AND PROLIFERATING-CELL NUCLEAR ANTIGEN EXPRESSION AS PREDICTORS OF RECURRENCE IN WELL-DIFFERENTIATED PAPILLARY THYROID-CARCINOMA

Purpose: We analyzed retinoblastoma protein (pRB) and proliferating-ce ll nuclear antigen (PCNA) expression in primary tumors and recurrent l esions of well-differentiated papillary thyroid carcinoma (PTC) to cla rify the relationship between their expression and recurrent disease, Patients and Methods: The study included 93 patients with PTC. No recu rrent disease had developed in 60 patients within 10 years after surge ry (group N), Thirty patients in whom recurrent disease had developed after surgery were enrolled in group R. Levels of pRB and PCNA express ion were quantified using the CAS 200 system (Cell Analysis Systems, E lmhurst, IL) following immunohistochemical staining, Results: Mean pRB expression level in the primary tumors in group R was significantly l ower than that in group N (P < .0001). pRB expression in the rumors wi th ct diameter vp to 20 mm was significantly lower than that in tumors larger than 20 mm in group R (P < .01). There were no significant dif ferences in the levels of expression of PCNA in the primary tumors bet ween group N and group R, Univariate analysis demonstrated that the di sease-free survival was significantly correlated with pN category, pRB , and PCNA expression level, The subgroup with high-level expression o f pRB (> 25%) showed significantly long disease-free survival (P < .00 1). Furthermore, the subgroup with low level expression of PCNA (< 35% ) showed significantly longer disease-free survival (P < .05), Multiva riate analysis showed pRB expression and pN category to be independent prognostic factors for disease free survival in PTC, Conclusion: pRB expression level can be used as a reliable predictor for recurrence of PTC. (C) 1997 by American Society of Clinical Oncology.