Expression of proteins related to autotaxin–lysophosphatidate signaling in thyroid tumors

BACKGROUND: We aimed to investigate the expression of proteins related with autotaxin (ATX)–lysophosphatidate (LPA) signaling and the clinical implications in primary and metastatic thyroid tumors. METHODS: We constructed tissue microarrays with 545 primary thyroid tumors [338 papillary thyroid carcinoma (PTC), 111 follicular carcinoma (FC), 69 medullary carcinoma (MC), 23 poorly differentiated carcinoma (PDC), and four anaplastic carcinoma (AC)]. Immunohistochemical stains for proteins related to ATX–LPA signaling (e.g., ATX, LPA1, LPA2, and LPA3) were performed. RESULTS: The expression of ATX was highest in MC, while the LPA1 expression was higher in PDC and AC, and the expression of LPA2 and LPA3 was highest in PTC (p < 0.001). Additionally, the expression of ATX, LPA1, and LPA2 was higher in conventional-type PTC than in follicular-variant PTC (p < 0.05). PTC with BRAF V600E mutation showed higher expression of ATX, LPA1, LPA2, and LPA3 than PTC without BRAF V600E mutation (p < 0.001). In univariate analysis, ATX positivity (p = 0.005) and LPA1 positivity (p = 0.014) were correlated with shorter overall survival in PTC. CONCLUSION: Proteins related to the ATX–LPA axis showed different levels of expression in primary thyroid tumors according to subtype.