Stimulation of human tumor xenograft growth by local estrogen biosynthesis in stromal cells

Jun Ichi Koh, Tetsuro Kubota, Hironobu Sasano, Mitsumasa Hashimoto, Yoichiro Hosoda, Masaki Kitajima

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Background. Both biochemical and histochemical studies have demonstrated the expression of aromatase activity in stromal cells surrounding breast cancers, suggesting that local estrogen biosynthesis promotes the growth of these cancers. However, the role of local aromatase activity in stimulating hormone-dependent breast cancer is still controversial. Materials and methods. A hormone-dependent human breast carcinoma xenograft, Br-10 and human fibroblast cells obtained from a patient with benign breast disease were used in the experients. When subcutanously inoculated Br-10 started exponential growth in female nude mice, 106 fibroblast cells were injected around the tumor with or without intramuscular administration of 50 mg/kg testosterone. Results. The growth of Br-10 treated with fibroblasts and testosterone was significantly enhanced in comparison with the control (p < 0.05). This stimulation by fibroblasts and testosterone was also observed in ovariectomized nude mice. Immunohistochemical staining for aromatase was observed in tumor sections containing Br-10 from mice treated with fibroblasts and testosterone, particularly around the carcinomatous glands. Conclusion. We conclude that estrogen produced locally by aromatase in fibroblasts can regulate the growth of hormone-dependent breast carcinoma cells.

Original languageEnglish
Pages (from-to)2375-2380
Number of pages6
JournalAnticancer research
Issue number4 A
Publication statusPublished - 1998 Jul


  • Aromatase
  • Breast cancer
  • Fibroblast
  • Nude mouse

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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