Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Radiation Oncology cung cấp cho các bạn kiến thức về ngành y đề tài: Tumor response to radiotherapy is dependent on genotype-associated mechanisms in vitro and in vivo. | Williams et al. Radiation Oncology 2010 5 71 http content 5 1 71 RADIATION ONCOLOGY RESEARCH Open Access Tumor response to radiotherapy is dependent on genotype-associated mechanisms in vitro and in vivo 1 2 2 1 3 1 Jerry R Williams Yonggang Zhang Haoming Zhou Daila S Gridley Cameron J Koch John F Dicello James M Slater1 John B Little4 Abstract Background We have previously shown that in vitro radiosensitivity of human tumor cells segregate non-randomly into a limited number of groups. Each group associates with a specific genotype. However we have also shown that abrogation of a single gene p21 in a human tumor cell unexpectedly sensitized xenograft tumors comprised of these cells to radiotherapy while not affecting in vitro cellular radiosensitivity. Therefore in vitro assays alone cannot predict tumor response to radiotherapy. In the current work we measure in vitro radiosensitivity and in vivo response of their xenograft tumors in a series of human tumor lines that represent the range of radiosensitivity observed in human tumor cells. We also measure response of their xenograft tumors to different radiotherapy protocols. We reduce these data into a simple analytical structure that defines the relationship between tumor response and total dose based on two coefficients that are specific to tumor cell genotype fraction size and total dose. Methods We assayed in vitro survival patterns in eight tumor cell lines that vary in cellular radiosensitivity and genotype. We also measured response of their xenograft tumors to four radiotherapy protocols 8 X 2 Gy 2 X 5Gy 1 X Gy and 1 X 15 Gy. We analyze these data to derive coefficients that describe both in vitro and in vivo responses. Results Response of xenografts comprised of human tumor cells to different radiotherapy protocols can be reduced to only two coefficients that represent 1 total cells killed as measured in vitro 2 additional response in vivo not predicted by cell killing. These .
