Also of interest, albeit from a therapeutic perspective, van den Bogaard et al. (2013) recently reported that activation of the AHR by coal tar in a submerged culture of human keratinocytes and human organotypic skin from patients with atopic dermatitis enhanced epidermal differentiation and thickening of the SC in the skin equivalents; in biopsies from patients treated with coal tar, the expression of filaggrin and other markers of differentiation were increased. This evidence concerns the gene FLG and atopic eczema.