DICER1 and DGCR8 in thyroid tumorigenesis: miRNA biogenesis and histopathologic diversity

This review examines the emerging roles of DICER1 and DGCR8, key components of the miRNA biogenesis pathway, in thyroid pathogenesis, with a particular focus on their association with oncocytic morphology. Recent findings have expanded our understanding of DICER1 syndrome and DGCR8-related thyroid disorders, revealing a broader spectrum of thyroid lesions associated with mutations in these genes than previously recognised. We analyse the current literature on DICER1 and DGCR8 mutations in thyroid pathology, synthesising data from both basic science and pathological studies. The review explores recent findings on oncocytic features in some DICER1-mutated thyroid lesions, acknowledging that this association remains under investigation. The manuscript details the molecular mechanisms underlying DICER1 and DGCR8 mutations, including their impact on miRNA processing and subsequent effects on gene expression and cellular function. We discuss the diverse range of thyroid lesions associated with these mutations, from benign follicular nodular disease to aggressive carcinomas. The clinical implications of these findings are significant, as recognising DICER1 and DGCR8-related thyroid lesions can lead to improved patient management, including genetic counselling and surveillance for other associated malignancies. We propose an algorithm for identifying DICER1-related thyroid lesions, with a focus on oncocytic tumours, to aid clinicians and pathologists in recognising these entities. This emerging field promises to refine the diagnosis, management, and treatment of thyroid disorders associated with miRNA biogenesis pathway alterations, potentially leading to novel diagnostic and therapeutic approaches.