Stem cells play a role in many mucosal disorders characterized by abnormal proliferation and differentiation of keratinocytes, such as oral lichen planus (OLP), oral hyperkeratosis dysplasia and carcinoma. The present investigation was carried out to detect expression of β1 integrin in OLP patients (smokers and non smokers) versus healthy controls. The present investigation was carried out to detect expression of β1 integrin in OLP patients versus healthy controls. The present results revealed that, Therefore, the stem cell phenotype in OLP (non smokers and smokers ), maybe altered in response to pathological signaling. Classification of these changes is essential to understand the role of adult stem cells in the pathogenesis of oral diseases characterized by abnormal keratinocyte proliferation and differentiation