The expression of ALDH1 in cervical carcinoma

BACKGROUND: ALDH1 has been shown to play a role in the early differentiation of stem cells in some human malignancies. Whether cancer stem cells occur in ALDH1-associated cervical cancer is not known. MATERIAL/METHODS: We tested the hypothesis that cervical carcinomas contain subpopulations of cells that express ALDH1. The following sources of cervical carcinoma tissues were examined for the presence of stem cell marker ALDH1 by immunohistochemistry. Flow cytometric isolation of cancer cells was based on enzymatic activity of ALDH (Aldefluor assay). The mRNA and protein levels of ALDH1 were investigated by qRT-PCR and Western blot, respectively. We also detected the expression of CD133 identified as a stem cell marker for several cancers. RESULTS: 23/89 samples of invasive squamous carcinoma and 4/20 samples of adenocarcinomas exhibited immunoreactivity to stem cell marker aldehyde dehydrogenase 1 (ALDH1). Expression of ALDH1 was found in 24.77% of the samples. Flow cytometric analysis, qRT-PCR and Western blot also confirmed the presence of small subpopulations of ALDH1-positive cells. In contrast, we found cervical carcinoma had low CD133 population. CONCLUSIONS: Cervical carcinoma contains a small subpopulation of cells that may relate to a cancer stem cell-like phenotype, ALDH1.