@misc{oai:repo.qst.go.jp:00071511,
 author = {谷, 修祐 and 尚, 奕 and 柿沼, 志津子 and 森岡, 孝満 and 小久保, 年章 and 島田, 義也 and 谷 修祐 and 尚 奕 and 柿沼 志津子 and 森岡 孝満 and 小久保 年章 and 島田 義也},
 month = {Sep},
 note = {Calorie restriction (CR) is repeatedly reported to extend mean and maximum life span in a variety of species.  It also suppresses the tumor development, which occurs not only spontaneously but also is induced by chemicals and radiation.  The molecular and cellular mechanisms of cancer prevention in CR have been studied intensively.  In this study, we evaluated mathematically the effect of CR on cancer risk using Armitage-Doll model.
  The data we utilized are those conducted in our laboratory (Shang et al. 2014); male B6C3F1 mice were irradiated with 3.8 Gy of X rays or non-irradiated at neonate (one week after birth), treated with CR (65 kcal/week/mouse, about 30% calorie reduction compared to 95 kcal/week/mouse) from 7 weeks of age and observed through lifespan.  Armitage-Doll model has been utilized to estimate the parameters of multi-stage carcinogenesis of each organ.  Based on the slope and intercept in double logarithmic graph of the model, it is possible to estimate the number of stages up until full malignancy and the product of the probabilities of the transformation from (r-1) th cell to r th cell.
  In spontaneous hepatocarcinogenesis, the number of stages was 3.9 in non-CR group and 7.2 in CR group, indicating that higher calorie load (95 kcal/week/mouse) has an ability to facilitate 3.3 stages of hepatocarcinogenesis.  The number of stages was 2.8 in non-CR group and 5.1 in CR group in radiation-induced hepatocarcinogenesis.  The number of stages of spontaneous lung adenocarcinoma in CR group also increased compared to that in non-CR group (7.4 in CR group and 4.3 in non-CR group).  On the other hand, in radiation-induced Harderian tumorigenesis, the number of stage remained unchanged (3.5 in non-CR group and 3.7 in CR group).  But, the intercept of Harderian tumor graph in CR group was about 1/10 of that in non-CR group, indicating that higher calorie load accelerated the speed to accumulate mutations within a cell although it did not change the stages for carcinogenesis.  It is suggested not only that CR changes the number of stages for carcinogenesis but also that the (r-1) th cells transform to r th cells easier in high calorie condition.  Therefore, the mechanism of cancer prevention in CR is different in an organ specific manner., Conference on Radiation & Health},
 title = {Analysis of the role of calorie restriction in prevention of spontaneous and radiation-induced carcinogenesis using mathematical multistage carcinogenesis model},
 year = {2014}
}