# Gene Editing with CRISPR/Cas Methodology and Thyroid Cancer: Where Are We?
## 5 Perspectives  
The consolidation of the CRISPR/Cas9 methodology, a versatile tool for gene editing and gene modulation (Cas9 mutants), has paved the way for the rapid expansion in the understanding of the molecular mechanism of cell signaling in thyroid cancer as summarized in Table 3. Most of the studies presented in this review utilize CRISPR/Cas9 methodology to blunt the expression of a target gene. However, further applications, such as gene correction using CRISPR/Cas9 +donor DNA (HDR) and gene-expression modulation (dCas9-KRAB or dCas9-VPR, for example), compose an array of applications that have the potential to be implemented in future cancer treatments. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Section** & **Targeted Gene** & \begin{tabular}{c} **Cell** \\ **Line/Animal** \\ **Model** \\ \end{tabular} & \begin{tabular}{c} **Thyroid** \\ **Cancer** \\ **Histotype** \\ \end{tabular} & **Type of Cas** & **Main Observations** & **Reference** \\ \hline \multirow{6}{*}{_Twist3_} & \begin{tabular}{c} Zebrafish \\ Tg-BRAF-TOM \\ \end{tabular} & PTC & Cas9 & \begin{tabular}{c} Partial restoration of \\ thyroid follicular \\ structure in zebrafish. \\ \end{tabular} & [41] \\ \cline{2-6}  & \multirow{2}{*}{_EGFR_} & \multirow{2}{*}{SW579} & \multirow{2}{*}{ATC} & \multirow{2}{*}{Cas9} & \begin{tabular}{c} Cell cycle arrest and \\ reduction of colony \\ formation in ATC cell \\ line. \\ \end{tabular} & [42] \\ \cline{2-6}  & \multirow{2}{*}{_NF2_} & \multirow{2}{*}{KTC1} & PTC & Cas9 & \begin{tabular}{c} Depletion of NF2 did \\ not change PTC cell \\ growth; \\ Overexpression \\ reduced cell growth. \\ \end{tabular} & [45] \\ \cline{2-6}  & \multirow{2}{*}{_NF1_} & \begin{tabular}{c} Murine \\ HrasG12V/p53 flox/flox \\ cell line \\ \end{tabular} & PDTC & Cas9 & \begin{tabular}{c} Induction of \\ resistence to \\ Tipifarnib. \\ \end{tabular} & [46] \\ \cline{2-6}  & \multirow{2}{*}{_EIF1 AX_} & \begin{tabular}{c} CAL62, TTA1 \\ and C643 \\ \end{tabular} & ATC & Cas9 & \begin{tabular}{c} EIF1 AX A113-splice \\ duration increased \\ colony formation; \\ while A113-splice \\ correction reduced \\ colony formation. \\ \end{tabular} & [47] \\ \cline{2-6}  & \multirow{2}{*}{_PDGFRA_} & \multirow{2}{*}{SW579} & \multirow{2}{*}{ATC} & \multirow{2}{*}{Cas9} & \begin{tabular}{c} Restored epithelial \\ gene expression and \\ reduced cell invasion \\ in vitro; impaired \\ lung metastasis \\ in vivo. \\ \end{tabular} & [51] \\ \cline{2-6}  & \multirow{2}{*}{_HN1_} & \multirow{2}{*}{_HN1_} & \multirow{2}{*}{\begin{tabular}{c} 8505C and \\ CAL62 \\ \end{tabular} } & \multirow{2}{*}{ATC} & \multirow{2}{*}{Cas9} & \
\begin{tabular}{c} Reduced cell \\ invasion and \\ migration in vitro; \\ Inhibited tumor \\ growth in vivo. \\ \end{tabular} & [52] \\ \cline{2-6}  & \multirow{2}{*}{_MFN2_} & \multirow{2}{*}{Cal62} & \multirow{2}{*}{ATC} & \multirow{2}{*}{Cas9} &
\begin{tabular}{c} Promotes epithelial- \\ mesenchymal \\ transition and \\ invasion of ATC cells. \\ \end{tabular} & [53] \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Applications of CRISPR/Cas9 gene editing in thyroid cancer. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Section**} & \multirow{2}{*}{**Targeted Gene**} & \multicolumn{2}{c}{**Cell**} & \multicolumn{2}{c}{**Thyroid**} & \multirow{2}{*}{**Type of Cas**} & \multirow{2}{*}{**Main Observations**} & \multirow{2}{*}{**Reference**} \\  & & **Line/Animal** & **Cancer** & & & \\  & & **Model** & **Histotype** & & & \\ \hline \multirow{5}{*}{_BAG5_} & \multirow{5}{*}{IHH4} & \multirow{5}{*}{PTC} & \multirow{5}{*}{Cas9} & Reduced cell invasion and immigration by downregulation of FN1 via miR-144-3p. & \multirow{5}{*}{[54]} \\  & & & & & \\  & & & & & \\ \cline{1-1}  & \multirow{5}{*}{_LIMD2_} & \multirow{5}{*}{BCPAP/TPC1} & \multirow{5}{*}{PTC} & \multirow{5}{*}{Cas9} & Reduced cell invasion and EMT markers while improved cell polarity.