To further validate findings from our transcriptional analysis, we performed immunohistochemical analysis focusing on selected apoptotic and cell cycle regulatory proteins (FOSL1, GDF15, JUNB and CDKN1A) (Fig. 3) in lesional psoriasis skin (control) and 24 h after 311 nm or 290 nm irradiation. The gene discussed is JUNB; the disease is psoriasis.