The association of topoisomerase 2α expression with prognosis in surgically resected non-small cell lung cancer (NSCLC) patients.

BACKGROUND: Topoisomerase 2α (Topo 2α) is a nuclear enzyme that alters the topology of DNA. It's essential for normal chromosome segregation during cellular division. We aimed to investigate the association of Topo 2α expression with clinical, pathological parameters and prognosis in surgically resected non-small cell lung cancer (NSCLC) patients.
METHODS: The study is comprised of 100 surgically resected NSCLC (squamous cell carcinoma in 50 patients, adenocarcinoma in 50 patients). The paraffin embedded tumor sections were retrieved for expression of Topo 2α. Nuclear and cytoplasmic expression of Topo 2α was determined by immunohistochemistry. Clinical, pathological data and survival of patients were determined from the hospital files. Median follow-up time was 35 (range, 4-120) months.
RESULTS: Nuclear and cytoplasmic expression of Topo 2α was positive in 41 (41%) and 66 (66%) patients, respectively. There was no significant association between nuclear or cytoplasmic expression of Topo 2α and age, gender, smoking history. While nuclear expression was significantly increased in squamous cell carcinoma (P=0.008), OR (95% CI): 3.01 (1.31-6.92), cytoplasmic expression wasn't different. Both nuclear and cytoplasmic expression didn't show any association with tumor diameter, pathological stage, tumor differentiation and relapse. There was no significant association between nuclear or cytoplasmic expression of Topo 2α and survival. Tumor diameter (P=0.031) and metastasis to N2 lymph nodes (P=0.005) were independent prognostic factors.
CONCLUSIONS: There was no association between Topo 2α expression and prognosis in surgically resected NSCLC patients. Nuclear expression of Topo 2α was significantly higher in patients with squamous cell carcinoma.