Retinoic acid has antiproliferative and redifferentiation effects in thyroid carcinoma therapy. It has been previously shown in pretreated follicular thyroid carcinoma FTC-133 and FTC-238 cell lines to reduce cell proliferation and tumour cell growth of xenotransplants. However, the molecular mechanisms of retinoic acid are not yet well understood. This study by Trojanowicz et al. used comparative 2D difference gel electrophoresis analysis and mass spectrometry to investigate the molecular mechanisms of retinoic acid in follicular thyroid carcinoma cell lines. The study found that in FTC-133 and FTC-238 cell lines retinoic acid downregulated an α-enolase (ENO1) 48 kDa phosphoprotein, correlating with a reduction of cell invasiveness. The ENO1 phosphoprotein represents a novel target and effector for retinoic acid. The study identified retinoic acid-induced reduction of the key glycolytic enzyme and downregulation of the MYC oncoprotein as additional targets and parameters in anti-tumour therapy. Trojanowicz, B., Winkler, A., Hammje, K., Chen, Z., Sekulla, C., Glanz, D., Schmutzler, C., Mentrup, B., Hombach-Klonisch, S., Klonisch, T., Finke, R., Köhrle, J., Dralle, H., Hoang-Vu, C. Journal of Molecular Endocrinology 2009, 42: 249-260. DOI: 10.1677/JME-08-0118