Oral epithelial stem cells that express Lrig1 are slow-cycling but are stress responsive [166], thus it is possible that IL-17, in the states of chronic inflammation in the oral cavity and precancerous lesions, such as lichen planus where IL-17 expression in the lesion correlates with disease severity [34], stimulates these cells for tissue repair and possibly induces tumorigenesis. Here, IL17A is linked to lichen planus.