Differential Expression of Cancer Stem Cell Markers ALDH1 and CD133 in Various Lung Cancer Subtypes.

Cancer stem cells (CSCs) are hypothesized to be the main culprit of lung cancer progression. Clinicopathological significance of stem cell markers CD133 and ALDH1 in a large group of lung cancer patients was evaluated. ALDH1 and CD133 had higher expression levels in the NSCLC compared to the SCLC. Over-expression of both ALDH1 and CD133 markers was exclusively found in SCC and ADC. Low level of ALDH1 expression was strongly correlated with poor differentiation in ADC cases. Thus, ALDH1(high)/CD133(high) phenotype can be considered as a CSC marker in some lung cancer subtypes.