The Clinical and Pathological Significance of RCAS1 Expression as a Prognostic Biomarker in Non-small Cell Lung Cancer

摘要

Background: Lung cancer remains a major health problem due to its incidence and mortality. Receptor-binding cancer antigen expressed on SiSo cells (RCAS1) is a protein that can be expressed in cancer cells and is involved in tumor cell escape from immune system surveillance. Aim: The aim of this study was to evaluate the clinical significance of immunohistochemical staining for RCAS1 in non-small cell lung cancer (NSCLC). Materials and Methods: Tissue microarrays of tumor specimens from 112 consecutive patients with newly diagnosed primary NSCLC were constructed. RCAS1 and Ki-67 immunohistochemistry were studied through computerized image analysis. Associations between RCAS1 and Ki-67 expression and clinico-pathological variables and survival were analyzed. Results: RCAS1 expression was higher in grade III tumors (p=0.009), regardless of the histological type, and in adenocarcinomas with lymphovascular invasion (p=0.014). A positive correlation between RCAS1 and Ki-67 levels was observed (p=0.002). Moreover, there was an inverse correlation of overall survival with RCAS1 (hazard ratio=0.99, p<0.001) and Ki-67 (hazard ratio=1.05, p=0.003) levels. Particularly, patients with higher expression of RCAS1 or Ki-67 had a significantly shorter survival than those with lower expression. Conclusion: RCAS1 could be a useful immunohistochemical biomarker, indicating not only tumor aggressiveness but also a poorer prognosis for patients with NSCLC.