The research group led by Shizuko Kakinuma, director of the National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, experienced pregnancy and childbirth even after being exposed to high-dose radiation in early childhood through joint research with Tokyo Metropolitan University. Animal studies have shown that this reduces the risk of breast cancer.
It is a well-known medical fact that pregnancy and childbirth experience reduce the risk of breast cancer in women.Conversely, high doses of radiation exposure are also known to increase the risk of breast cancer.However, the relationship between breast cancer risk after radiation exposure and pregnancy / childbirth experience was not well understood.
Therefore, the research group investigated the relationship in experiments using rats.Among rats exposed to high doses of radiation before puberty, those who did not experience pregnancy / childbirth had an increased risk of breast cancer, but those who experienced pregnancy / childbirth had a breast cancer risk of pregnancy without irradiation. -It was as low as a rat that did not experience childbirth.
In prepubertal irradiated rats, the amount of progesterone (a signal that increases mammary gland cells and breast cancer cells) decreased due to pregnancy and childbirth experience.Therefore, it is speculated that this hormone is involved in reducing the risk of breast cancer.
This result is expected to be a clue to develop drugs that reduce the risk of breast cancer after exposure by simulating changes in the body that occur after pregnancy and childbirth experience.
