Objective: To investigate the expression and its significance of DNA topoisomerase I (Topo I) in small cell lung cancer (SCLC).
Methods: Topo I expression was detected by immunohistochemical S-P technique on 50 cases of SCLC and 12 cases of normal lung tissues.
Results: The total positive rate of Topo I in normal lung tissue was 25.0% (3/12) and 78.0% (39/50) in SCLC. The expression of Topo I does not correlate with age, gender, smoking, tumor size and tumor site (P > 0.05), but significantly correlated with lymph node metastasis and clinical stage (P <0.05).
Conclusion: High Topo I expression is a rationale indication of Topo I inhibitor treatment of malignancies. It should be possible to predict anti-tumor drug sensitivity by assessment of Topo I expression and help to improve the therapeutic efficacy for cancer patients.