Genetic variations in genes involved in regulation of MMPs and TIMPs levels, such as interleukin(IL)-10, IL-13, epithelial growth factor (EGF) and tumor necrosis factor-α (TNF-α) [27,28]may clearly influence the imbalance of MMPs and TIMPs in COPD. The gene discussed is EGF; the disease is chronic obstructive pulmonary disease.