Differential expression of two activating transcription factor 5 isoforms in papillary thyroid carcinoma

Abstract

Background: Activating transcription factor 5 (ATF5) is a member of the activating transcription/cAMP response element-binding protein family of basic leucine zipper proteins that plays an important role in cell survival, differentiation, proliferation, and apoptosis. The ATF5 gene generates two transcripts: ATF5 isoform 1 and ATF5 isoform 2. A number of studies indicate that ATF5 could be an attractive target for therapeutic intervention in several tumor types; however, so far, the role of ATF5 has not been investigated in papillary thyroid carcinoma (PTC). Methods: Quantitative real-time reverse transcription polymerase chain reaction and immunohistochemical staining were used to study ATF5 mRNA and protein expression in PTC. Results: We report here that ATF5 is expressed more in PTC tissue than in normal thyroid tissue. Furthermore, this is the first study that describes the presence of both ATF5 isoforms in PTC. Conclusion: These findings could provide potential applications in PTC cancer treatment.