Inhibitor of DNA-binding (Id) – 1 and 3 proteins overexpression has impact on prognosis of lung adenocarcinoma

The inhibitor of DNA–binding (Id) are involved in cell cycle regulation, apoptosis and angiogenesis. Many authors suggest participation of Id genes in development and progression of large number of human cancer, but their role in lung cancer has not been evaluated. Objectives: To evaluate Id 1, 2 and 3 expressions in lung adenocarcinoma and relation to stage and survival. Methods: IDs were quantified in tumoral and non-tumoral tissues from 43 patients who underwent lobectomy for lung adenocarcinoma. Their preoperative clinical stages were T 1-3 N 0-1 M0 and the mean follow-up was 26.7 months. Immunohistochemistry was applied to analyze the intensity of Ids expression in nucleus and cytoplasm (quantitative scores performed in 500 cells). The impact of these markers was tested on follow-up until death from recurrent lung cancer. Results: Distinct profile of Ids expression was observed between tumoral and the matched adjacent nonmalignant tissue. Ids were significantly more expressed in tumoral cells. Patients whose tumor cells expressed lower scores of cytoplasm Id3 tended to present better long-term survival (p=0.05). The Cox model controlled for lymph node stage showed up Id 1 and 3 were associated with survival. A median score for nuclear Id1 in adjacent non-tumoral cells (> 49.7) and for tumoral cytoplasmic Id3 (> 394.9) identified patients with worse prognosis and higher risk of death (2.02 and 1.97, respectively). Conclusion: These findings suggest Ids 1 and 3 may provide additional information about tumor behavior. Further studies are required to determine whether Ids 1 and 3 expressions might be useful prognostic markers in non small cells lung cancer.