title: Effects of a pure antiestrogen on apoptosis and proliferation within human breast ductal carcinoma in situ.
abstract: Adjuvant antiestrogen (AE) therapy has been proposed for all women with ductal carcinoma in situ (DCIS). However, many cases of DCIS are of the high-grade, estrogen receptor (ER)-negative subtype that are unlikely to respond to AE treatment. Hormonal agents work by increasing apoptosis and/or decreasing cell proliferation; therefore, we studied the effect of a pure AE on levels of apoptosis and proliferation in human DCIS xenografts using an in vivo model. Women (n = 23) with mammographic microcalcification suggestive of DCIS were identified at the time of surgery (day 0), a sample of representative tissue was obtained, divided into multiple 2x2x1-mm xenografts, and implanted s.c. into female BALB/c nu/nu mice (eight xenografts/mouse). Day 0 grafts underwent immunohistochemical assessment of ER status. Fourteen days after implantation, four xenografts were retrieved and mice were randomly divided into one of three treatment groups: (a) insertion of a slow release 2-mg 17beta-estradiol pellet; (b) weekly 5-mg injections of the pure AE Faslodex (Zeneca Pharmaceuticals); and (c) injections of a control vehicle oil alone. After 2 weeks of treatment, the remaining four xenografts were retrieved from each mouse. Retrieved xenografts containing DCIS were assessed for morphological evidence of apoptotic cell death [apoptotic index (AI)] and cell proliferation (by immunohistochemical detection of the Ki67 proliferation antigen LI). Both AI and LI were higher in the day 0 specimens of 16 ER- DCIS lesions compared with 7 ER+ DCIS lesions (mean values, 1.47% versus 0.32% and 20.6% versus 3.1%; both P<0.0001). AI and LI values within ER- DCIS did not differ between xenografts exposed to 17beta-estradiol or AE treatment compared with the controls or pretreatment values (mean AI and LI in estradiol-treated, antiestrogen-treated, and control groups 1.04% versus 0.98% versus 1.29% and 17.2% versus 20.5% versus 17.7% respectively). In contrast, treatment of mice bearing ER+ DCIS xenografts with 17beta-estradiol raised both the AI (1.03% versus 0.40%, P = 0.03) and LI (11.0% versus 5.1%, P = 0.007) compared with controls. AE therapy of ER+ DCIS xenografts did not affect proliferation but resulted in higher apoptosis than in controls (0.9% versus 0.4% respectively, P = 0.04). AE therapy should be reserved for patients with estrogen receptor positive DCIS.
authors.affiliation: University Department of Surgery, University Hospital of South Manchester, Manchester, United Kingdom.
authors.forename: A
authors.initials: A
authors.lastname: Gandhi
authors.forename: P A
authors.initials: PA
authors.lastname: Holland
authors.forename: W F
authors.initials: WF
authors.lastname: Knox
authors.forename: C S
authors.initials: CS
authors.lastname: Potten
authors.forename: N J
authors.initials: NJ
authors.lastname: Bundred
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001943:Breast Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D002278:Carcinoma in Situ / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D002455:Cell Division / Q000187:drug effects; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology; D020847:Estrogen Receptor Modulators / Q000494:pharmacology*; D005260:Female; D000077267:Fulvestrant; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008875:Middle Aged; D009368:Neoplasm Transplantation; D011960:Receptors, Estrogen / Q000502:physiology; D014183:Transplantation, Heterologous
chemical_list: D000970:Antineoplastic Agents; D020847:Estrogen Receptor Modulators; D011960:Receptors, Estrogen; D000077267:Fulvestrant; D004958:Estradiol