Comparison between radiation-induced cell cycle delay in lymphocytes and radiotherapy response in head and neck cancer

Abstract

Summary A study was made evaluating the use of radiation-induced cell cycle delay in lymphocytes to predict tumour response to radiotherapy. Peripheral blood lymphocytes were isolated from whole blood from 49 patients with head and neck cancer before treatment with radiotherapy and from 25 healthy donors. The clinical response to radiotherapy was assessed at 0-2 months after treatment. The level of radiation-induced cell cycle delay was measured using flow cytometry after mitogen stimulation of lymphocytes. The analysis of ten normal donors gave no significant difference in variability between the intra-assay and the intra-donor samples. However, the cell cycle data for lymphocytes from these healthy donors showed significant inter-individual differences in G2 phase accumulation. Patients showing no response to radiotherapy had a high level of S-phase cells compared with partial (P < 0.001) and complete responders (P = 0.016). An inverse relationship was found when analysing the fraction of cells in G2 (P= 0.009 and 0.034 respectively). In general, healthy donors had similar cell cycle kinetics compared with the non-responders. In conclusion, the result indicates that radiation-induced cell cycle delay in lymphocytes is inversely correlated with tumour response to radiotherapy in head and neck cancer patients. However, the value of the present test for predicting individual tumour response is limited, because of assay variability and overlap between groups.

MicroRNA-449a Enhances Radiosensitivity in CL1-0 Lung Adenocarcinoma Cells

“…In contrast, decreasing S population was observed in radiosensitive CL1-5 (Fig. 1D), which is consistent with previous reports in squamous cancer cells and lymphocytes [48], [49]. Furthermore, the decreasing G0/G1 population was observed in CL1-0 over-expressed with miR-449a, which was probably caused by the G2/M arrest (Fig.…”

Avaliação semanal dos efeitos da radioterapia externa convencional pela contagem dos leucócitos e plaquetas de pacientes portadores de câncer nas áreas de cabeça e pescoço, tórax e pelve

“…Differently, Yang et al (6) , in a study with 117 patients with cancer of head and neck, chest and pelvis submitted to conventional external beam radiation therapy, has observed that the major decrease in the peripheral blood cells count occurred in the first week of treatment. Studies in the literature have reported that the decrease in the peripheral blood cells counts starts in the first weeks of conventional external beam radiation therapy (11,15,16) .…”

Let-7b overexpression leads to increased radiosensitivity of uveal melanoma cells

“…Cells are most radiosensitive in the M and G2 phases and are most radioresistant in the S phase. Interestingly, the radioresistant cell line had a higher population of cells in the S phase than in the radiosensitive cell line [37], and patients who showed no response to radiotherapy had higher levels of S-phase lymphocytes than partial or complete responders [38].…”