Unfolding of Imminent Bio-Signatures in the Prognosis of Thyroid Cancer; The Emergence of Estrogen Related Receptor Gamma (ERRγ) as a Hurricane

Thyroid cancer’s incidence has increased by leaps and bounds over the last years and accounts for 2.8% of new cases of cancers. This increasing bar is partially assisted by enormous screening to understand the sub-clinical status. Advanced tumor growth is the leading cause of thyroid cancer-associated death. However, the complete understanding of the underlying cause is still to be disclosed. The updated clinical assessment evidenced a few major oncogenes viz. RAS, BRAF, and RET as key drivers in the development and progression of thyroid cancer. The BRAF mutation, a major cause of aggressive tumor type in papillary thyroid carcinoma, is frequently reported. The characteristic oncogenic changes imply thyroid cancer to be clinically an ideal model for targeted therapy against RET, RAS, and BRAF mutation. Though the sensitive biochemical marker assay has been improvised, the diagnosis of thyroid follicular neoplasms is still a big challenge as the biopsy aspiration cannot define the nature of the tumor in 30% of the cases. The main hurdle is assisted distinction between follicular thyroid lesions. The discrimination between follicular thyroid adenomas and carcinomas is histologically accomplished. This strictly necessitates the identification of sensitive diagnostic/prognostic markers to mitigate the risk of thyroid cancer and to avoid the unnecessary hurdles of biopsy and surgery. An array of prognostic biomarkers is being used for the diagnosis of thyroid cancer. However, Estrogen Related Receptor Gamma (ERRγ) is setting a new benchmark among the clinical biomarkers. The dramatic expression of ERRγ in thyroid cancer enables itself not only to serve as a characteristic diagnostic marker but also as a therapeutic target. Recently, we have reported that ERRγ is upregulated in 96 papillary thyroid cancer (PTC) and 26 poorly differentiated/ anaplastic thyroid cancer (ATC) samples. Various synthetic ERRγ inverse agonists viz. GSK5182, DN200434, and 24e are fully proved to modulate ERRγ expression in ATC to attain partial cure. If this finding can be assayed on a larger scale the evaluation of this marker may be warranted and informative. This review article highlights the ascending sheds of clinical biomarkers of thyroid cancer. This also reveals the clinical importance of ERRγ as an evolving diagnostic and therapeutic target in thyroid cancer.