Correlation of Radiation Response of Cervical Cancer Stem Cells with Their Initial Number before Treatment and Molecular Genetic Features of Papillomavirus Infection.

The proportion of CD44+CD24low cancer stem cells (CSC) was determined in cervical scrapings of 41 patients with squamous cell carcinoma of the uterine cervix before treatment and after irradiation in a total focal dose of 10 Gy. The relationship of quantitative changes in the CSC population with such parameters of papillomavirus infection as genotype, viral load, and physical status of HPV DNA (the absence or presence of HPV DNA integration into the cell genome and the degree of integration) was studied. Single- and multi-factor analysis revealed 2 independent indicators affecting the radiation response of CSC: initial number of these cells before treatment and physical status of HPV DNA. The increase in the CSC proportion after radiation exposure was observed 4.5-fold more often in patients with an initially low proportion of CSC (<3%) than that in other patients (p=0.001). The CSC proportion increased by on average 3% after irradiation in patients with complete integration of HPV 16/18 DNA and decreased by 3.8 % in patients with partial integration or no integration (p=0.03).

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.

The Presence of Human Papillomavirus DNA Integration is Associated with Poor Clinical Results in Patients with Third-Stage Cervical Cancer.

The presence of virus DNA integration into the cell genome was studied for 47 primary HPV16-positive patients with morphologically verified stage III cervical cancer. By using ROC analysis, the patients were divided into two groups: with and without HPV DNA integration into the host cell genome. The differences between the groups by the histological type, degree of tumor differentiation, and primary response to therapy were statistically insignificant. Virus DNA integration more than 7-fold reduced 5-year relapse-free survival and 1.7-fold reduced overall survival rate in comparison with patients without HPV DNA integration (p=0.0002 and p=0.05, respectively). The relative risk of adverse outcome of the disease in patients with the presence of HPV16 DNA integration increases by 4 times over a period of less than 3 years (р=0.0006) at high AUC level. The probability of earlier progression of the disease in patients with of HPV DNA integration calculated according to the Cox proportional hazards model was 85.5% (hazard ratio 5.96; p=0.002). Thus, the results suggest that the presence of HPV16 DNA integration into the cell genome is an independent factor in predicting clinical outcome of advanced cervical cancer and can serve as an effective criterion for the individual choice of treatment tactics for the patients.

[Frequency of Lymphocytes with Mutations at the Locus of T-Cell Receptor in Residents of Radiation Polluted Bryansk Region 28 Years after the Chernobyl Nuclear Power Plant Accident].

The aim of this study is to assess the level of somatic mutagenesis according to the frequency of lymphocytes bearing mutations at the locus of T-cell receptor (TCR) in the residents of the Bryansk region contaminated with radionuclides as a result of the Chernobyl accident. The study was :conducted in 2014 in two regional centers - Klintsy and Novozybkov (average¹³7Cs pollution density of 322 and 708 kBq/m²,.respectively). The average frequency of the TCR-mutant cells in the total group of examined residents of the Bryansk region (n = 237) was not significantly different from that in the group of agematched control persons living in un- contaminated areas (n = 146): 3.8 x 10⁻4 vs 3.5 x 10⁻4, respectively (p = 0.84). However, after separation of examinees into 3 groups depending on age at the start of irradiation (at.the moment of the Chernobyl acci- dent) it was found that the average frequency of the TCR-mutant cells in the persons exposed in utero was 1.6 higher than that in the control group (p = 0.04). Proportion of persons with an increased frequency of the mutant cells (more than the age norm of this indicator) among prenatally exposed population reached 23.8%; which was about.4 times higher than in the control group (p = 0.04). Proportion of persons with an increased frequency of the TCR-mutant cells in group "0-17 years at the start of irradiation", was about 2 times higher than in controls, but this difference was not statistically significant (8.0% vs 4.3%, respectively, p = 0.33). In the third group "18 or more years old at the start of irradiation" we could not register the difference in the average frequency of theTCR mutant cells or the proportion of persons with an increased frequency of these cells in comparison with the age-matched control group. In general, comparison with earlier data shows that age-related regularities of somatic mutagenesis established 15-18 years after the Chernobyl accident persist at a later date (after 28 years in this study).

The Content of ROS in Blood Lymphocytes of Healthy Individuals, Individuals Irradiated as a Result of Chernobyl Disaster and Patients with Prostate Cancer.

The ROS concentration and proliferation activity (Ki67 expression.marker) have been studied in the periphery blood lymphocytes of Moscow and Obninsk citizens, donors, Chernobyl disaster liquidators, inhabitants of the region contaminated after Chernobyl disaster (Klincy) and individuals with prostate cancer. It was shown that ROS concentration in lymphocytes of the liquidators and residents of the polluted region was lowered. But in lymphocytes of patients with tumors the ROS content was higher in comparison with the control. The cell content with Ki67 expression in lymphocytes of the individuals resided in the polluted region and tumor patients was lowered.