Mechanism of Carcinogenesis

Not only radiation but also various chemical substances and ultraviolet rays, etc. damage DNA. However, cells have a mechanism to repair damaged DNA and DNA damage is mostly repaired. Even if repair was not successful, the human body has a function to eliminate cells wherein DNA damage has not been completely repaired (p.88 of Vol. 1, “Damage and Repair of DNA”).

Nevertheless, cells with incompletely repaired DNA survive as mutated cells in very rare cases. Genetic aberrations may be accumulated in cells that happen to survive and these cells may develop into cancer cells. However, this process requires a long period of time. Among atomic bomb survivors, leukemia increased in around two years, but the incidence decreased thereafter. On the other hand, cases of solid cancer started to increase after an incubation period of around 10 years.
(Related to p.90 of Vol. 1, “Lapse of Time after Exposure and Effects”)

• Included in this reference material on March 31, 2013
• Updated on March 31, 2019