Quantitative Changes in the Population of Cancer Stem Cells after Radiation Exposure in a Dose of 10 Gy as a Prognostic Marker of Immediate Results of the Treatment of Squamous Cell Cervical Cancer

Prognostic significance of the proportion of cancer stem cells in cervical scrapings from 38 patients with uterine cervical cancer before treatment and after irradiation in a total dose of 10 Gy was assessed for immediate results of radio- and combined chemoradiotherapy evaluated by the degree of tumor regression in 3-6 months after the treatment. Cancer stem cells were detected as cells with CD44+CD24low immunophenotype by flow cytometry. The proportion of cancer stem cells in patients with the complete tumor regression decreased by on average 2.2±1.1% after irradiation, while in patients with partial regression this indicator increased by on average 3.3±2.3% (p=0.03). Multiple regression analysis revealed two independent indicators affecting tumor regression: the stage of the disease (which is quite expected) and change in the proportion of cancer stem cells after the first irradiation sessions (R=0.60, p<0.002 for the model in the whole). The proportion of cancer stem cells before the treatment did not have prognostic significance.