ABSTRACT
Colorectal cancer is currently the third most common cancer worldwide,and there are still half of the patients undergoing recurrence and metastasis after surgical treatment,so it is necessary for colorectal cancer patients to receive radiation therapy routinely.Due to the side effects brought by radiotherapy,it is of great importance to solve how to minimize the radiation dose in radiation therapy and improve radiation sensitivity.In recent years,people discovered that microRNAs can not only be involved in the origins of colorectal cancer and progress,but also play a increasingly important role in cancer radiosensitivity.MicroRNAs can regulate tumor radiosensitivity by influencing tumor microenvironment and function on target genes.DNA damage response caused by radiation includes the activation of ATM,histone modification and chromatin remodeling,cell cycle arrest,damage repair and apoptosis.microRNAs can regulate tumor radiosensitivity through above processes.This review focuses on the mechanism of microRNAs in affecting DNA damage repair and prospects the future of microRNAs in influencing the sensitivity of cancer radiotherapy in clinical application.
ABSTRACT
Background: Prediction of radiation response before the completion of the radiotherapy schedule is challenging. Information about radiation response could help oncologist to choose the appropriate combination and sequence of therapies in the multidisciplinary management of cancer. Methods: The study involved 26 patients with squamous cell cancers of the head and neck region who received radiotherapy to a dose of 30 Gy in 10 fractions over a 2-week period as part of a split-course technique. Fine-needle aspiration cytology was performed on day 1 and day 5 of the schedule. The silver staining of the nuclear organiser region (AgNOR) and nuclear morphometric study were done on both days. Results: The median age of the patients was 44 years old. The primary tumours were distributed in the nasopharynx (n = 11), larynx and hypopharynx (n = 5), metastatic node (n = 4), and miscellaneous tumours were found in the head and neck sub sites (n = 6). The mean initial AgNOR score was 3.0, range 1.2–7.0. The median of nuclear and nucleolar diameters were 11.07 μm, range 7.70–16.6 μm, and 2.92 μm, range 1.09–11.66 μm, respectively. Patients with a pre-radiotherapy AgNOR score of greater than 2.5 were associated with disease progression and metastasis. However, the increased of nuclear diameter on day 5 compared with baseline predicted a good radiation response in patients (P = 0.016). Conclusion: Intra-radiotherapy nuclear morphometry combined with baseline AgNOR score could be a simple and useful tool for the prediction of radiation response in head and neck cancers.