Purpose: In view of the increasing number of patients diagnosed with lung cancer every year worldwide, there is an urgent need for an effective screening marker to improve its early detection.
Methods: We quantified the level of immunoreactive proteins for the tissue inhibitors of metalloproteinase (TIMP)-1 and TIMP-2 in the sera of 54 patients with non-small cell lung cancer (NSCLC) and 25 healthy control subjects, by using enzyme-linked immunosorbent assays with specific monoclonal antibodies.
Results: The TIMP-1 level was significantly higher, and the TIMP-2 level was significantly lower in the patients with NSCLC than in the controls. Furthermore, both TIMP-1 and TIMP-2 were significantly higher in patients with squamous cell carcinoma than in those with adenocarcinoma. The TIMP-1 level in patients with stage III/IV disease was significantly higher than that in those with stage I/II disease. The TIMP-1/TIMP-2 ratio was significantly higher in the patients with NSCLC, and the receiver-operating characteristic curves analysis revealed that the TIMP-1/2 ratio, but not TIMP-1 or -2 alone, was a better screening marker for NSCLC than carcinoembryonic antigen (P < 0.0001). Patients with a high TIMP-1 value had significantly shorter disease-free survival (P = 0.0479), but those with a high TIMP-1/2 ratio did not.
Conclusion: The TIMP-1/2 ratio may be a good screening marker of NSCLC; however, it was less effective than TIMP-1 as a prognostic factor.