Cervical cancer is the fourth most common
cancer affecting women worldwide. Among many factors, the presence of cancer stem cells, a subpopulation of cells inside the
tumor, has been associated with a worse prognosis. Considering the importance of gene expression studies to understand the biology of
cervical cancer stem cells (CCSC), this work identifies stable reference genes for
cervical cancer cell lines SiHa, HeLa, and ME180 as well as their respective
cancer stem-like cells. A literature review was performed to identify validated reference genes currently used to normalize RT-qPCR data in
cervical cancer cell lines. Then, cell lines were cultured in regular monolayer or in a condition that favors
tumor sphere formation. RT-qPCR was performed using five reference genes: ACTB, B2M, GAPDH, HPRT1, and
TBP. Stability was assessed to validate the selected genes as suitable reference genes. The evaluation validated B2M, GAPDH, HPRT1, and
TBP in these experimental conditions. Among them, GAPDH and
TBP presented the lowest variability according to the analysis by Normfinder, Bestkeeper, and ΔCq methods, being therefore the most adequate genes to normalize the combination of all samples. These results suggest that B2M, GAPDH, HPRT1, and
TBP are suitable reference genes to normalize RT-qPCR data of established
cervical cancer cell lines SiHa, HeLa, and ME180 as well as their derived
cancer stem-like cells. Indeed, GAPDH and
TBP seem to be the most convenient choices for studying gene expression in these cells in monolayers or spheres.