Elevated levels of circulating matrix metalloproteinase-9 in non-small cell lung cancer patients

Elevated levels of matrix metalloproteinase have been implicated as playing important role in tumour progression in several types of cancers. Our aim was to determine whether these enzyme might be a useful tumour marker for lung cancer and also to evaluate the correlation of circulating levels of matrix metalloproteinase-9 (MMP-9) with tumour histology, staging, nodal status, metastasis and prognosis. Blood samples were collected from 35 nonsmall cell lung cancer patients who were diagnosed histologically, and 14 healthy controls. The MMP-9 levels were significantly higher in the cancer group (p< 0.001). However no significant correlation between several clinical features (such as histology of the tumour, staging, tumour status, or nodal status) and plasma MMP-9 levels have been observed. Though it does not show statistical significance, more patients with metastasis seemed to have higher MMP-9 levels. At the end of six month 11 patients were out of follow-up. Among the remaining 24 patients eight patients had lower MMP-9 levels, seven were survivors at the end of six months. Sixteen patients had MMP-9 levels above the threshold. Only 10 have survived to six months. In conclusion MMP-9 can serve as a marker for metastasis and can be valuable in the follow-up of lung cancer patients.