A recent meta-analysis of 32 IHC markers that may be useful in the distinction of thymomas from thymic carcinomas, and that included 38 articles reporting on 636 thymic carcinomas and 1861 thymomas, showed significant differences in expression between these two entities for beta-5t, Bcl-2, calretinin, CD1a, CD5, CD117, CEA, CK19, GLUT1, IGF-1R, mesothelin, MOC31, MUC1, p21, and TdT [24]. This evidence concerns the gene CD5 and thymoma.