Features of the cell cycle in patients with colorectal cancer

Purpose of the study. The objective of this study was to evaluate cell cycle indices in tumor cells and conditionally intact intestinal tissue (resection line) in male and female patients with colorectal cancer (CRC). Patients and methods. Cell cycle phases were analyzed in 36 male and 36 female patients with CRC involving the rectum, and with right-sided or left-sided tumor localization. The mean age was 66 years. The degree of tumor differentiation in all cases corresponded to G2. None of the patients had received neoadjuvant treatment before surgery. In 10 % of tumor homogenates and resection line samples, cell cycle phases were determined using an ADAMII LS fluorescent cell analyzer (Korea). For cell cycle analysis, propidium iodide (PI), specially prepared for the ADAMII LS, was used. This reagent mixture contained PI and RNaseA, and cells were stained directly without an additional fixation step. The instrument’s high sensitivity enabled precise discrimination of cells in the G0/G1 phase (resting cells [G0] and early G1), S phase, and G2/M phase. Statistical analysis was performed using Statistica 10.0 software. Results. The proportions of viable and dead cells in the samples were generally comparable. In men, viable cells ranged from 56.6 % to 73.6 %, and dead cells from 26.4 % to 43.4 %. In women, viable cells ranged from 60.8 % to 77.3 %, and dead cells from 22.7 % to 39.2 %. In men, tumor samples from left-sided CRC contained predominantly S and G2 phase cells, whereas in right-sided CRC and rectal tumors, the majority of cells were in the G1 phase. In women with left-sided CRC, tumor samples showed the highest proportion of cells in the G1 phase, while samples from right-sided CRC and rectal tumors contained predominantly S phase cells. Conclusion. The identified cell cycle characteristics and tumor cell death patterns in CRC patients, depending on sex and tumor localization, reflect the proliferative status of the tissue. These findings may provide a basis for personalized recommendations on the use of antitumor agents targeting cells in specific cell cycle phases.