Increased plasma levels of serine proteinase inhibitors in lung cancer patients.

BACKGROUND: Tumor growth and invasiveness occur through infiltration of tumor cells into the host cells and by angiogenesis, which is modulated by proteinases and antiproteinases released from tumor cells that carry out tissue remodelling. A number of studies have revealed variations in the plasma levels of serine proteases and their inhibitors among tumor types. PATIENTS AND METHODS: By immunological methods we analysed the levels of serine protease inhibitors AAT, ACT and SLPI in newly diagnosed lung cancer patients (n=14) compared to non-smoker and smoker, age- and gender-matched control groups (n=16), and also in an expanded group of lung cancer patients with local tumors (n=14) and with metastasis (n=18).
RESULTS: Our data show that plasma levels of AAT, ACT and SLPI were elevated in lung cancer patients by 1.43-fold, p<0.01, 2.57-fold, p<0.01 and 1.6-fold, p<0.001, respectively when compared to controls. In addition, we found that levels of AAT and ACT were higher by 1.47-fold, p<0.001 and 2.27-fold, p<0.001, respectively in lung cancer cases with metastasis compared to localized tumor.
CONCLUSION: These inhibitor levels may provide measures of cancer progression in individual patients and possibly offer useful information for an understanding of the mechanisms of metastasis.