The role of CD133 expression in the carcinogenesis and prognosis of patients with lung cancer.

Cancer stem cells (CSCs) are a small population of undifferentiated cancer cells within tumors, which contribute to tumorigenicity and relapse. In the current study, CD133 (also termed prominin‑1), a CSC marker, was investigated to determine its involvement in predicting carcinogenesis and prognosis in patients with non‑small cell lung carcinoma (NSCLC). CD133‑positive lung cancer cells were isolated to analyze self‑renewal, differentiation and tumorigenic abilities in vitro and in vivo. Quantitative polymerase chain reaction was used to detect the expression of CD133 and three other CSC‑associated markers, octamer‑binding transcription factor 4 (OCT4A), Nanog homeobox (NANOG) and multidrug resistance protein 1 (MDR1), in primary NSCLC and adjacent non‑cancer tissues. A series of statistical methods were used to analyze the correlation between mRNA expression levels, clinicopathological features and patient survival. The results showed that CD133‑positive NSCLC cells demonstrated clonogenic, tumorigenic and drug‑resistance properties compared with their CD133‑negative counterparts or parental cells. In addition, compared with the adjacent normal lung tissue, the levels of CSC‑associated biomarkers CD133, OCT4A, NANOG and MDR1 were significantly increased in NSCLC tissue. Elevated expression of CD133 was associated with stage, tumor size and differentiation of NSCLC; however, the cox hazard regression analysis showed no significant association between CD133 expression and overall patient survival. The present study supports the hypothesis that the stem cell population can be enriched in cells expressing the CD133 cell surface marker and that highly expressed CD133 is involved in the occurrence of NSCLC. However, CD133 may not be considered as an independent factor in predicting the prognosis of patients with NSCLC. Further studies are required to investigate the association between CD133 expression and overall patient survival.