MON-516 Quantitative Analysis of Differential Enigma/PDLIM7 Gene Expression in Thyroid Cancer vs. Benign Nodules

Thyroid cancer incidence is rising worldwide. Although fine-needle aspiration biopsy (FNAB) is an accurate modality for evaluating thyroid nodules, up to 25% of FNABs still yield indeterminate results. There is a considerable number of diagnostic thyroidectomies for benign disease as a result of indeterminate FNAB. A more accurate and time-efficient diagnostic approach for analyzing indeterminate thyroid nodules may reduce diagnostic thyroidectomy. Recently, the osteogenic protein, Enigma, has been associated with different cancer types, including thyroid cancer progression and calcification through its interaction with bone morphogenic protein-1 (BMP-1), and tyrosine kinases linked to mitogenic signaling pathways [1, 2]. Our published data on Enigma protein analysis with immunohistochemistry showed promising results in discriminating between malignant versus benign thyroid nodules and demonstrated a correlation with thyroid cancer staging [3]. In this study, we are investigating Enigma at a gene expression level by real-time (RT-qPCR), which is a quantitative and more time-efficient method that requires smaller samples (FNA) than immunohistochemistry. We analyzed Enigma mRNA expression levels to determine if Enigma-qPCR could be used as a diagnostic tool to improve the accuracy of FNAB in both malignant and benign thyroid tissues. We extracted mRNA/DNA/proteins from fresh malignant and benign thyroid nodules using a QIAGEN DNA/RNA/Protein Kit. We ran isolated pure mRNA through Enigma-qPCR. The results showed that the Enigma-mRNA expression was 3-fold higher in malignant as compared to benign thyroid tissues. This finding supports our previous Enigma immunohistochemistry data and shows a relative quantitative difference in Enigma-mRNA expression level between malignant and benign thyroid nodules. We conclude that Enigma-RT-qPCR can be used to effectively determine malignancies in FNAB samples derived from thyroid nodules. This method could potentially enhance the diagnostic accuracy of indeterminate nodules and decrease diagnostic thyroidectomies and associated morbidity. [1] C.R. Jung, J.H. Lim, Y. Choi, D.G. Kim, K.J. Kang, S.M. Noh, D.S. Im, Enigma negatively regulates p53 through MDM2 and promotes tumor cell survival in mice, The Journal of clinical investigation 120(12) (2010) 4493-506. [2] Y.J. Kim, H.J. Hwang, J.G. Kang, C.S. Kim, S.H. Ihm, M.G. Choi, S.J. Lee, Enigma Plays Roles in Survival of Thyroid Carcinoma Cells through PI3K/AKT Signaling and Survivin, Anticancer research 38(6) (2018) 3515-3525. [3] A.A. Firek, M.C. Perez, A. Gonda, L. Lei, I. Munir, A.A. Simental, F.E. Carr, B.J. Becerra, M. De Leon, S. Khan, Pathologic significance of a novel oncoprotein in thyroid cancer progression, Head & neck 39(12) (2017) 2459-2469.