Journal of Carcinogenesis & Mutagenesis

Ryoichi Asaka

Publications

• Research Article
  Elevated Serum Levels of Estradiol Induce Endometrial Hyperplasia Rather than Carcinoma in a Mouse Model Using a Carcinogen
  Author(s): Ryoichi Asaka, Tsutomu Miyamoto, Yasushi Yamada, Hirofumi Ando, David Hamisi Mvunta, Hisanori Kobara, Hiroyasu Kashima and Tanri ShiozawaRyoichi Asaka, Tsutomu Miyamoto, Yasushi Yamada, Hirofumi Ando, David Hamisi Mvunta, Hisanori Kobara, Hiroyasu Kashima and Tanri Shiozawa
  
  Objective: Although estrogen has been regarded as a risk factor for endometrial carcinoma, its concentrationdependent carcinogenetic effects remain unclear, because most endometrial carcinomas occur in post-menopausal women, whose serum estrogen levels are relatively low. We previously reported that high levels of estradiol (E2) may suppress endometrial carcinogenesis by up-regulating DNA mismatch repair (MMR) in vitro. The present study was undertaken to further examine the carcinogenetic role of estrogen at various concentrations in vivo. Methods: N-methyl-N-nitrosourea (MNU) was injected into the uterine cavity of 29 mice, and E2 was administered by pellets or orally. Uteri were removed for histological examinations 24 weeks later, and serum E2 levels were measured. The immunohistochemical expression of MMR proteins in uterine epithelia was .. View More»
  DOI: 10.4172/2157-2518.1000308

  Abstract PDF