Background <p>Methionyl-tRNA synthetase 1 (MARS1) is a critical enzyme in translation initiation, responsible for catalyzing the transfer of Met to the initiator tRNA. In this study, we aimed to examine whether MARS1 expression is different between normal follicular cells and papillary thyroid carcinoma (PTC) cells in thyroid tissue and whether it can supplement the limitations of general cell staining methods currently performed for diagnosis of PTC.</p> Methods <p>Initially, 103 patients were included to compare MARS1 expression in PTC and normal follicular cells. Next, 100 patients were selected to compare MARS1 expression using immunohistochemical analysis in patients with (<i>n</i> = 50) and without (<i>n</i> = 50) lateral neck metastasis.</p> Results <p>The average MARS1 expression grade of PTC cells was 2.59 and that of normal follicular cells was 1.28. MARS1 expression in the two groups showed significant differences (<i>p</i> &lt; 0.001). There was a significant difference in the average MARS1 expression grade of PTC cells between the metastasis and non-metastasis groups (<i>p</i> &lt; 0.05). Additionally, a significant difference was observed in the average MARS1 expression grade between the lymph node of the metastasis group and PTC cells of the non-metastasis group (<i>p</i> &lt; 0.05).</p> Conclusions <p>Our analyses suggest that MARS1 could be used as a complementary method to the current fine needle aspiration biopsy tissue staining method. Additionally, MARS1 could be a predictor of the prognosis of PTC.</p>