High Fatty Acid-Binding Protein 4 Expression Associated with Favorable Clinical Characteristics and Prognosis in Papillary Thyroid Carcinoma

Fatty acid-binding protein 4 (FABP4), a fatty acid transporter that coordinates lipid metabolism, is reported to exert a tumorigenic role in certain cancers. We investigated the effects of FABP4 in the carcinogenesis of thyroid cancer. Bioinformatics data about FABP4 in thyroid cancer were collected from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA). Sixteen paired papillary thyroid cancer (PTC) tissues from Taipei Medical University (TMU) were gathered, and commercial thyroid cancer complementary (c)DNA and tissue arrays were purchased to measure FABP4 messenger (m)RNA and protein levels. By analyzing data from the GEO and TCGA, we showed that FABP4 mRNA was reduced in PTC and follicular thyroid carcinoma (FTC). In addition, a lower FABP4 mRNA level in PTC was associated with poor clinical parameters and outcomes in the TCGA database. Moreover, FABP4 transcripts and proteins were downregulated in PTC and FTC, and its mRNA expression was associated with PTC staging in clinical specimens. In the TCGA database and TMU cohort, FABP4 mRNA levels were associated with thyroglobulin (r = 0.511 and r = 0.656, respectively), thyroid peroxidase (r = 0.612 and r = 0.909, respectively), and sodium iodide symporter (r = 0.485 and r = 0.637, respectively) transcripts. In conclusion, FABP4 mRNA and protein levels were reduced in PTC and FTC, and may be used as a potential indicator for thyroid cancer evolution in clinical settings. Further, well-designed research to dissect the molecular mechanism of FABP4 in modulating thyroid carcinogenesis is needed.