Matrix metalloproteinases (MMPs) are a group of 24 zinc containing enzymes in man. These enzymes were originally described as cleaving extracellular matrix (ECM) substrates with a predominant role in ECM homeostasis, but it is now clear that they have much wider functionality. An imbalance between MMP activity and that of their inhibitors (tissue inhibitors of metalloproteinases, TIMPs) is considered to play a critical role in the synthesis or degradation of the extracellular matrix of the airway architecture which results in fixed airflow obstruction in both asthma and chronic obstructive pulmonary disease (COPD). Using quantitative real time polymerase chain reaction (RT-PCR) the investigators have identified a difference between the level of steady state mRNA for MMP-9, MMP-14 and MMP-2 in 2 patients with asthma compared to 4 healthy controls using our method. However the investigators require further refinement of the process in order to optimise RNA quality and to evaluate the effect of montelukast across the entire family of MMPs and their inhibitors (TIMPs).