THE ROLE OF IMMUNOHISTOCHEMICAL MARKERS IN PREDICTING RECURRENCE OR DEATH IN PATIENTS WITH MEDULAR THYROID CANCER

Abstract

Introduction. Medullary thyroid cancer (MTC) belongs to a class of rare neuroendocrine aggressive tumors and arises from parafollicular cells (C-cells). An important modern problem is the development of ways to predict the recurrence of this disease. The aim of the study is to determine the role of immunohistochemical tumor markers of medullary thyroid cancer in predicting recurrence or death. Materials and methods. The analysis of the prospective study included 22 patients with MTC, 5 of whom have developed a recurrence and 4 have died at the end of the 10-year (120 months) follow-up period. Immunohistochemical examinations were performed using monoclonal antibodies of tumor markers calcitonin, chromogranin A, vimentin and Ki-67. Results. The discrepancy between the data of histological and immunohistochemical examinations in MTC is 12.0%, which indicates the hyperdiagnosis of this nosology and argues the importance of performing immunohistochemical examinations to verify the diagnosis. Patients who had a recurrence of MTC had significantly (p <0.05) lower levels of calcitonin expression (5.00 [5.00; 5.00] points) compared with patients who did not relapse, where this figure was 6.00 [6.00; 7.00] points. In patients with MTC, an increase in calcitonin expression was significantly associated with an increase in chromogranin A expression (r = + 0.49, p = 0.02); a similar relationship was found for the proportions of immunopositive cells of these tumor markers: r = + 0.68, p = 0.001. At the same time, it was found that the increase in the level of calcitonin expression was apparently combined with the decrease in the level of Ki-67 expression (r = -0.52, p = 0.02). It was also found that the increase in the level of vimentin expression is combined with an increase in the expression (r = + 0.64, p = 0.001) and the proportion of immunopositive cells of chromogranin A (r = + 0.45, p = 0.038). Conclusions. Low levels of calcitonin expression are prognostically unfavorable markers for the recurrence of MTC. Specific tumor markers are important in the treatment process and for the dynamic monitoring of patients with MTC.