PGR and erythema multiforme: On the other hand, when using both 3-marker and 4-marker panels with typical EM-type (ER+/Vim+/CEA- or PR+/ER+/Vim+/CEA-) immunoprofiles in definitively diagnosing primary EMA, the 3-marker panel had only a slightly higher accuracy rate compared with the 4-marker panel (68.6% vs. 65.7%).