Endocrine Abstracts

Introduction: Despite low mortality rates of patients with papillary thyroid carcinoma (PTC), disease progression in PTC occurs in up to 20% of patients. Currently, recurrence risk stratification is accomplished by using clinicopathologic factors, despite their limited prognostic value. Some data suggest that patient age at disease onset and primary tumor size may predict the risk of disease progression. Identification of possible associations of traditional clinicopathological parameters of disease recurrence with molecular biomarkers of PTC may help better understanding the carcinogenesis and improving the clinical management of patients with PTC

Objectives: The aim of this study was to evaluate miRNA expression profiles in different age groups of patients with PTC and to compare the expression levels of miRNA in differently sized PTC tumors.

Methods: We selected 3 miRNA (miRNA-146b, -222 and -21) and measured the expression levels of these miRNAs in three patients groups according to age at disease onset (60 years and older, 40–60 years, and less than 40 years) and in patients with different PTC tumor size (2 cm or less and greater than 2 cm).

Results: The levels of miRNA (miRNR-146b, miRNR-222, miRNR-21) expression significantly differed between PTC patients with tumor size 2 cm or less (n=99) and greater than 2 cm (n=84). Higher expression levels of miRNAs (miRNR-146b P<0.001; miRNR-222 P<0.001; miRNR-21 P<0.001) were observed in patients with tumor size greater than 2 cm. The expression levels of all three miRNA did not significantly differ in patients of different age groups (P>0,05).

Conclusion: The levels of miRNA-146b, -222 and -21 expression in PTC were strongly associated with tumour size. Such difference in the expression levels could be due to the fact that in larger thyroid tumors there is a higher percentage of altered tumor cells in which the miRNA expression is severely disturbed. Selected miRNAs did not show age-related differences in expression, suggesting that mechanisms other than age may influence the expression of these miRNA.