Skip to main content

Advertisement

Log in

Resistance to endocrine therapy in breast cancer

  • Original Article
  • Published:
Cancer Chemotherapy and Pharmacology Aims and scope Submit manuscript

Abstract

Endocrine therapy is the treatment of choice for patients with breast cancer expressing estrogen receptor (ER) and/or progesterone receptor. The efficacy of endocrine therapy is well established in the prevention, adjuvant and metastatic settings. However, either de novo or acquired resistance is frequently observed. Much effort has been made to elucidate the mechanisms of action underlying resistance to endocrine therapy in breast cancer, and several possible explanations have been suggested. Our previous studies have indicated that combined treatment with an antiestrogen, fulvestrant, and an inhibitor of the HER2 signaling pathway, trastuzumab, or an inhibitor of the HER1 signaling pathway, gefitinib, leads to an additive antitumor effect in breast cancer cells expressing ER and HER2 or HER1, respectively. It has also been suggested that the HER1 or HER2 signaling pathway is upregulated during the development of antiestrogen-resistant growth in breast cancer cells. These findings suggest that signal transduction inhibitors are effective for the treatment of antiestrogen-resistant breast cancer. A hypoxic microenvironment has been shown to promote malignant progression in cancer cells. Our previous study and others have suggested that hypoxia posttranscriptionally reduces ER expression and decreases sensitivity to hormonal agents in breast cancer cells. Our preliminary study has also shown that a hypoxic cytotoxin, tirapazamine, increases ER expression in breast cancer xenografts. Differential antitumor activity of tirapazamine on tumor cells under normoxic or hypoxic conditions may cause this phenomenon. These findings suggest that hypoxic cytotoxins may retard the development of endocrine resistance induced by hypoxia. Molecular mechanisms responsible for endocrine resistance in breast cancer are reviewed and possible therapeutic strategies against this resistance are discussed.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  1. Anido J, Matar P, Albanell J, Guzman M, Rojo F, Arribas J, Averbuch S, Baselga J (2003) ZD1839, a specific epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, induces the formation of inactive EGFR/HER2 and EGFR/HER3 heterodimers and prevents heregulin signaling in HER2-overexpressing breast cancer cells. Clin Cancer Res 9:1274–1283

    PubMed  CAS  Google Scholar 

  2. Argiris A, Wang CX, Whalen SG, DiGiovanna MP (2004) Synergistic interactions between tamoxifen and trastuzumab (Herceptin). Clin Cancer Res 10:1409–1420

    Article  PubMed  CAS  Google Scholar 

  3. Arpino G, Green SJ, Allred DC, Lew D, Martino S, Osborne CK, Elledge RM (2004) HER-2 amplification, HER-1 expression, and tamoxifen response in estrogen receptor-positive metastatic breast cancer: a southwest oncology group study. Clin Cancer Res 10:5670–5676

    Article  PubMed  CAS  Google Scholar 

  4. Balleine RL, Hunt SM, Clarke CL (1999) Coexpression of alternatively spliced estrogen and progesterone receptor transcripts in human breast cancer. J Clin Endocrinol Metab 84:1370–1377

    Article  PubMed  CAS  Google Scholar 

  5. Boccardo F, Rubagotti A, Amoroso D, Mesiti M, Romeo D, Caroti C, Farris A, Cruciani G, Villa E, Schieppati G, Mustacchi G; Italian Breast Cancer Cooperative Group (2001) Sequential tamoxifen and aminoglutethimide versus tamoxifen alone in the adjuvant treatment of postmenopausal breast cancer patients: results of an Italian cooperative study. J Clin Oncol 19:4209–4215

    PubMed  CAS  Google Scholar 

  6. Bunone G, Briand PA, Miksicek RJ, Picard D (1996) Activation of the unliganded estrogen receptor by EGF involves the MAP kinase pathway and direct phosphorylation. EMBO J 15:2174–2183

    PubMed  CAS  Google Scholar 

  7. Campbell RA, Bhat-Nakshatri P, Patel NM, Constantinidou D, Ali S, Nakshatri H (2001) Phosphatidylinositol 3-kinase/AKT-mediated activation of estrogen receptor alpha: a new model for anti-estrogen resistance. J Biol Chem 276:9817–9824

    Article  PubMed  CAS  Google Scholar 

  8. Chen D, Pace PE, Coombes RC, Ali S (1999) Phosphorylation of human estrogen receptor alpha by protein kinase A regulates dimerization. Mol Cell Biol 19:1002–1015

    PubMed  CAS  Google Scholar 

  9. Chia SK, Wykoff CC, Watson PH, Han C, Leek RD, Pastorek J, Gatter KC, Ratcliffe P, Harris AL (2001) Prognostic significance of a novel hypoxia-regulated marker, carbonic anhydrase IX, in invasive breast carcinoma. J Clin Oncol 19:3660–3668

    PubMed  CAS  Google Scholar 

  10. Cohen MH, Williams GA, Sridhara R, Chen G, McGuinn WD Jr, Morse D, Abraham S, Rahman A, Liang C, Lostritto R, Baird A, Pazdur R (2004) United States food and drug administration drug approval summary: Gefitinib (ZD1839; Iressa) tablets. Clin Cancer Res 10:1212–1218

    Article  PubMed  CAS  Google Scholar 

  11. Coombes RC, Hall E, Gibson LJ, Paridaens R, Jassem J, Delozier T, Jones SE, Alvarez I, Bertelli G, Ortmann O, Coates AS, Bajetta E, Dodwell D, Coleman RE, Fallowfield LJ, Mickiewicz E, Andersen J, Lonning PE, Cocconi G, Stewart A, Stuart N, Snowdon CF, Carpentieri M, Massimini G, Bliss JM; Intergroup Exemestane Study (2004) A randomized trial of exemestane after two to three years of tamoxifen therapy in postmenopausal women with primary breast cancer. N Engl J Med 350:1081–1092

    Google Scholar 

  12. Cooper C, Liu GY, Niu YL, Santos S, Murphy LC, Watson PH (2004) Intermittent hypoxia induces proteasome-dependent down-regulation of estrogen receptor alpha in human breast carcinoma. Clin Cancer Res 10:8720–8727

    Article  PubMed  CAS  Google Scholar 

  13. Daffada AA, Johnston SR, Smith IE, Detre S, King N, Dowsett M (1995) Exon 5 deletion variant estrogen receptor messenger RNA expression in relation to tamoxifen resistance and progesterone receptor/pS2 status in human breast cancer. Cancer Res 55:288–293

    PubMed  CAS  Google Scholar 

  14. deGraffenried LA, Friedrichs WE, Russell DH, Donzis EJ, Middleton AK, Silva JM, Roth RA, Hidalgo M (2004) Inhibition of mTOR activity restores tamoxifen response in breast cancer cells with aberrant Akt activity. Clin Cancer Res 10:8059–8067

    Article  PubMed  Google Scholar 

  15. Esslimani-Sahla M, Simony-Lafontaine J, Kramar A, Lavaill R, Mollevi C, Warner M, Gustafsson JA, Rochefort H (2004) Estrogen receptor beta (ER beta) level but not its ER beta cx variant helps to predict tamoxifen resistance in breast cancer. Clin Cancer Res 10:5769–5776

    Article  PubMed  CAS  Google Scholar 

  16. Faridi J, Wang L, Endemann G, Roth RA (2003) Expression of constitutively active Akt-3 in MCF-7 breast cancer cells reverses the estrogen and tamoxifen responsivity of these cells in vivo. Clin Cancer Res 9:2933–2939

    PubMed  CAS  Google Scholar 

  17. Fleming FJ, Myers E, Kelly G, Crotty TB, McDermott EW, O’Higgins NJ, Hill AD, Young LS (2004) Expression of SRC-1, AIB1, and PEA3 in HER2 mediated endocrine resistant breast cancer; a predictive role for SRC-1. J Clin Pathol 57:1069–1074

    Article  PubMed  CAS  Google Scholar 

  18. Forward DP, Cheung KL, Jackson L, Robertson JF (2004) Clinical and endocrine data for goserelin plus anastrozole as second-line endocrine therapy for premenopausal advanced breast cancer. Br J Cancer 90:590–594

    Article  PubMed  CAS  Google Scholar 

  19. Franke TF, Hornik CP, Segev L, Shostak GA, Sugimoto C (2003) PI3K/Akt and apoptosis: size matters. Oncogene 22:8983–8998

    Article  PubMed  CAS  Google Scholar 

  20. Gandara DR, Lara PN Jr, Goldberg Z, Le QT, Mack PC, Lau DH, Gumerlock PH (2002) Tirapazamine: prototype for a novel class of therapeutic agents targeting tumor hypoxia. Semin Oncol 29 (1 Suppl 4):102–109

    Article  PubMed  CAS  Google Scholar 

  21. Gee JM, Robertson JF, Ellis IO, Nicholson RI (2001) Phosphorylation of ERK1/2 mitogen-activated protein kinase is associated with poor response to anti-hormonal therapy and decreased patient survival in clinical breast cancer. Int J Cancer 95:247–254

    Article  PubMed  CAS  Google Scholar 

  22. Gee JM, Harper ME, Hutcheson IR, Madden TA, Barrow D, Knowlden JM, McClelland RA, Jordan N, Wakeling AE, Nicholson RI (2003) The antiepidermal growth factor receptor agent gefitinib (ZD1839/Iressa) improves antihormone response and prevents development of resistance in breast cancer in vitro. Endocrinology 144:5105–5117

    Article  PubMed  CAS  Google Scholar 

  23. Girault I, Lerebours F, Amarir S, Tozlu S, Tubiana-Hulin M, Lidereau R, Bieche I (2003) Expression analysis of estrogen receptor alpha coregulators in breast carcinoma: evidence that NCOR1 expression is predictive of the response to tamoxifen. Clin Cancer Res 9:1259–1266

    PubMed  CAS  Google Scholar 

  24. Hockel M, Vaupel P (2001) Tumor hypoxia: definitions and current clinical, biologic, and molecular aspects. J Natl Cancer Inst 93:266–276

    Article  PubMed  CAS  Google Scholar 

  25. Hopp TA, Weiss HL, Parra IS, Cui Y, Osborne CK, Fuqua SA (2004) Low levels of estrogen receptor beta protein predict resistance to tamoxifen therapy in breast cancer. Clin Cancer Res 10:7490–7499

    Article  PubMed  CAS  Google Scholar 

  26. Houston SJ, Plunkett TA, Barnes DM, Smith P, Rubens RD, Miles DW (1999) Overexpression of c-erbB2 is an independent marker of resistance to endocrine therapy in advanced breast cancer. Br J Cancer 79:1220–1226

    Article  PubMed  CAS  Google Scholar 

  27. Jakesz R, Hausmaninger H, Kubista E, Gnant M, Menzel C, Bauernhofer T, Seifert M, Haider K, Mlineritsch B, Steindorfer P, Kwasny W, Fridrik M, Steger G, Wette V, Samonigg H; Austrian Breast and Colorectal Cancer Study Group Trial 5 (2002) Randomized adjuvant trial of tamoxifen and goserelin versus cyclophosphamide, methotrexate, and fluorouracil: evidence for the superiority of treatment with endocrine blockade in premenopausal patients with hormone-responsive breast cancer—Austrian Breast and Colorectal Cancer Study Group Trial 5. J Clin Oncol 20:4621–4627

    Google Scholar 

  28. Jhabvala-Romero F, Evans A, Guo S, Denton M, Clinton GM (2003) Herstatin inhibits heregulin-mediated breast cancer cell growth and overcomes tamoxifen resistance in breast cancer cells that overexpress HER-2. Oncogene 22:8178–8186

    Article  PubMed  CAS  Google Scholar 

  29. Joel PB, Smith J, Sturgill TW, Fisher TL, Blenis J, Lannigan DA (1998) pp90rsk1 regulates estrogen receptor-mediated transcription through phosphorylation of Ser-167. Mol Cell Biol 18:1978–1984

    PubMed  CAS  Google Scholar 

  30. Johnston SR, Saccani-Jotti G, Smith IE, Salter J, Newby J, Coppen M, Ebbs SR, Dowsett M (1995) Changes in estrogen receptor, progesterone receptor, and pS2 expression in tamoxifen-resistant human breast cancer. Cancer Res 55:3331–3338

    PubMed  CAS  Google Scholar 

  31. Kato S, Endoh H, Masuhiro Y, Kitamoto T, Uchiyama S, Sasaki H, Masushige S, Gotoh Y, Nishida E, Kawashima H (1995) Activation of the estrogen receptor through phosphorylation by mitogen-activated protein kinase. Science 270:1491–1494

    Article  PubMed  CAS  Google Scholar 

  32. Klijn JG, Beex LV, Mauriac L, van Zijl JA, Veyret C, Wildiers J, Jassem J, Piccart M, Burghouts J, Becquart D, Seynaeve C, Mignolet F, Duchateau L (2000) Combined treatment with buserelin and tamoxifen in premenopausal metastatic breast cancer: a randomized study. J Natl Cancer Inst 92:903–911

    Article  PubMed  CAS  Google Scholar 

  33. Kronblad A, Helczynska K, Nielsen NH, Pahlman E, Emdin S, Pahlman S, Landberg G (2003) Regional cyclin D1 overexpression or hypoxia correlate inversely with heterogeneous oestrogen receptor-alpha expression in human breast cancer. In Vivo 17:311–318

    PubMed  CAS  Google Scholar 

  34. Kunisue H, Kurebayashi J, Otsuki T, Tang CK, Kurosumi M, Yamamoto S, Tanaka K, Doihara H, Shimizu N, Sonoo H (2000) Anti-HER2 antibody enhances the growth inhibitory effect of anti-oestrogen on breast cancer cells expressing both oestrogen receptors and HER2. Br J Cancer 82:46–51

    Article  PubMed  CAS  Google Scholar 

  35. Kurebayashi J, Otsuki T, Moriya T, Sonoo H (2001) Hypoxia reduces hormone responsiveness of human breast cancer cells. Jpn J Cancer Res 92:1093–1101

    PubMed  CAS  Google Scholar 

  36. Kurebayashi J, Yamamoto Y, Okubo S, Sonoo H, Nagasawa H, Uto Y, Hori H, Moriya T (2003) Experimental study for overcoming endocrine resistance in breast cancer: implication of hypoxic cytotoxins (in Japanese). Basic Invest Breast Carcinoma 12:35–38

    CAS  Google Scholar 

  37. Kurebayashi J, Nishimura R, Tanaka K, Kohno N, Kurosumi M, Moriya T, Ogawa Y, Taguchi T (2004) Significance of serum tumor markers in monitoring advanced breast cancer patients treated with systemic therapy: a prospective study. Breast Cancer 11:389–395

    PubMed  Google Scholar 

  38. Kurebayashi J, Okubo S, Yamamoto Y, Sonoo H (2004) Inhibition of HER1 signaling pathway enhances antitumor effect of endocrine therapy in breast cancer. Breast Cancer 11:38–41

    PubMed  Google Scholar 

  39. Kurokawa H, Lenferink AE, Simpson JF, Pisacane PI, Sliwkowski MX, Forbes JT, Arteaga CL (2000) Inhibition of HER2/neu (erbB-2) and mitogen-activated protein kinases enhances tamoxifen action against HER2-overexpressing, tamoxifen-resistant breast cancer cells. Cancer Res 60:5887–5894

    PubMed  CAS  Google Scholar 

  40. Lapidus RG, Nass SJ, Butash KA, Parl FF, Weitzman SA, Graff JG, Herman JG, Davidson NE (1998) Mapping of ER gene CpG island methylation-specific polymerase chain reaction. Cancer Res 58:2515–2519

    PubMed  CAS  Google Scholar 

  41. Lavinsky RM, Jepsen K, Heinzel T, Torchia J, Mullen TM, Schiff R, Del-Rio AL, Ricote M, Ngo S, Gemsch J, Hilsenbeck SG, Osborne CK, Glass CK, Rosenfeld MG, Rose DW (1998) Diverse signaling pathways modulate nuclear receptor recruitment of N-CoR and SMRT complexes. Proc Natl Acad Sci USA 95:2920–2925

    Article  PubMed  CAS  Google Scholar 

  42. Maruyama K, Endoh H, Sasaki-Iwaoka H, Kanou H, Shimaya E, Hashimoto S, Kato S, Kawashima H (1998) A novel isoform of rat estrogen receptor beta with 18 amino acid insertion in the ligand binding domain as a putative dominant negative regulator of estrogen action. Biochem Biophys Res Commun 246:142–147

    Article  PubMed  CAS  Google Scholar 

  43. Michalides R, Griekspoor A, Balkenende A, Verwoerd D, Janssen L, Jalink K, Floore A, Velds A, van’t Veer L, Neefjes J (2004) Tamoxifen resistance by a conformational arrest of the estrogen receptor alpha after PKA activation in breast cancer. Cancer Cell 5:597–605

    Article  PubMed  CAS  Google Scholar 

  44. Michaud LB, Jones KL, Buzdar AU (2001) Combination endocrine therapy in the management of breast cancer. Oncologist 6:538–546

    Article  PubMed  CAS  Google Scholar 

  45. Myers E, Fleming FJ, Crotty TB, Kelly G, McDermott EW, O’higgins NJ, Hill AD, Young LS (2004) Inverse relationship between ER-beta and SRC-1 predicts outcome in endocrine-resistant breast cancer. Br J Cancer 91:1687–1693

    PubMed  CAS  Google Scholar 

  46. Newby JC, Johnston SR, Smith IE, Dowsett M (1997) Expression of epidermal growth factor receptor and c-erbB2 during the development of tamoxifen resistance in human breast cancer. Clin Cancer Res 3:1643–1651

    PubMed  CAS  Google Scholar 

  47. Nicholson RI, McClelland RA, Gee JM, Manning DL, Cannon P, Robertson JF, Ellis IO, Blamey RW (1994) Epidermal growth factor receptor expression in breast cancer: association with response to endocrine therapy. Breast Cancer Res Treat 29:117–125

    Article  PubMed  CAS  Google Scholar 

  48. Okubo S, Kurebayashi J, Otsuki T, Yamamoto Y, Tanaka K, Sonoo H (2004) Additive antitumour effect of the epidermal growth factor receptor tyrosine kinase inhibitor gefitinib (Iressa, ZD1839) and the antioestrogen fulvestrant (Faslodex, ICI 182,780) in breast cancer cells. Br J Cancer 90:236–244

    Article  PubMed  CAS  Google Scholar 

  49. Osborne CK, Schiff R, Fuqua SA, Shou J (2001) Estrogen receptor: current understanding of its activation and modulation. Clin Cancer Res 7(12 Suppl):4338s–4342s

    PubMed  CAS  Google Scholar 

  50. Osborne CK, Bardou V, Hopp TA, Chamness GC, Hilsenbeck SG, Fuqua SA, Wong J, Allred DC, Clark GM, Schiff R (2003) Role of the estrogen receptor coactivator AIB1 (SRC-3) and HER-2/neu in tamoxifen resistance in breast cancer. J Natl Cancer Inst 95:353–361

    Article  PubMed  CAS  Google Scholar 

  51. Palmieri C, Lam EW, Mansi J, MacDonald C, Shousha S, Madden P, Omoto Y, Sunters A, Warner M, Gustafsson JA, Coombes RC (2004) The expression of ER beta cx in human breast cancer and the relationship to endocrine therapy and survival. Clin Cancer Res 10:2421–2428

    Article  PubMed  CAS  Google Scholar 

  52. Robertson JFR, Gutteridge E, Cheung KL, Oweres R, Koehler M, Hamilton L (2002) A phase II study of ZD1839 (Iressa) in tamoxifen resistant ER positive and endocrine insensitive (ER negative) breast cancer. Breast Cancer Res Treat 76:S96

    Google Scholar 

  53. Roodi N, Bailey LR, Kao WY, Verrier CS, Yee CJ, Dupont WD, Parl FF (1995) Estrogen receptor gene analysis in estrogen receptor-positive and receptor-negative primary breast cancer. J Natl Cancer Inst 87:446–451

    Article  PubMed  CAS  Google Scholar 

  54. Schiff R, Massarweh SA, Shou J, Bharwani L, Mohsin SK, Osborne CK (2004) Cross-talk between estrogen receptor and growth factor pathways as a molecular target for overcoming endocrine resistance. Clin Cancer Res 10 (1 Pt 2):331S–336S

    Article  PubMed  CAS  Google Scholar 

  55. Shibata H, Spencer TE, Onate SA, Jenster G, Tsai SY, Tsai MJ, O’Malley BW (1997) Role of co-activators and co-repressors in the mechanism of steroid/thyroid receptor action. Recent Prog Horm Res 52:141–164

    PubMed  CAS  Google Scholar 

  56. Shoman N, Klassen S, McFadden A, Bickis MG, Torlakovic E, Chibbar R (2005) Reduced PTEN expression predicts relapse in patients with breast carcinoma treated by tamoxifen. Mod Pathol 18:250–259

    Article  PubMed  CAS  Google Scholar 

  57. Shou J, Massarweh S, Osborne CK, Wakeling AE, Ali S, Weiss H, Schiff R (2004) Mechanisms of tamoxifen resistance: increased estrogen receptor-HER2/neu cross-talk in ER/HER2-positive breast cancer. J Natl Cancer Inst 96:926–935

    Article  PubMed  CAS  Google Scholar 

  58. Slamon DJ, Leyland-Jones B, Shak S, Fuchs H, Paton V, Bajamonde A, Fleming T, Eiermann W, Wolter J, Pegram M, Baselga J, Norton L (2001) Use of chemotherapy plus a monoclonal antibody against HER2 for metastatic breast cancer that overexpresses HER2. N Engl J Med 344:783–792

    Article  PubMed  CAS  Google Scholar 

  59. Smith CL, Nawaz Z, O’Malley BW (1997) Coactivator and corepressor regulation of the agonist/antagonist activity of the mixed antiestrogen, 4-hydroxytamoxifen. Mol Endocrinol 11:657–666

    Article  PubMed  CAS  Google Scholar 

  60. Sonoo H, Kurebayashi J, Iino Y, Inaji H, Watanabe T, Toi M, Kobayashi S, Sato B, Yoshimoto M (1999) Current status and controversial issues concerning endocrine therapy for patients with recurrent breast cancer in Japan. Breast Cancer 6:344–350

    Article  PubMed  Google Scholar 

  61. Speirs V, Malone C, Walton DS, Kerin MJ, Atkin SL (1999) Increased expression of estrogen receptor beta mRNA in tamoxifen-resistant breast cancer patients. Cancer Res 59:5421–5424

    PubMed  CAS  Google Scholar 

  62. Speirs V, Parkes AT, Kerin MJ, Walton DS, Carleton PJ, Fox JN, Atkin SL (1999) Coexpression of estrogen receptor alpha and beta: poor prognostic factors in human breast cancer? Cancer Res 59:525–528

    PubMed  CAS  Google Scholar 

  63. Stoner M, Saville B, Wormke M, Dean D, Burghardt R, Safe S (2002) Hypoxia induces proteasome-dependent degradation of estrogen receptor alpha in ZR-75 breast cancer cells. Mol Endocrinol 16:2231–2242

    Article  PubMed  CAS  Google Scholar 

  64. Sun M, Paciga JE, Feldman RI, Yuan Z, Coppola D, Lu YY, Shelley SA, Nicosia SV, Cheng JQ (2001) Phosphatidylinositol-3-OH Kinase (PI3K)/AKT2, activated in breast cancer, regulates and is induced by estrogen receptor alpha (ERalpha) via interaction between ERalpha and PI3K. Cancer Res 61:5985–5991

    PubMed  CAS  Google Scholar 

  65. Takimoto GS, Graham JD, Jackson TA, Tung L, Powell RL, Horwitz LD, Horwitz KB (1999) Tamoxifen resistant breast cancer: coregulators determine the direction of transcription by antagonist-occupied steroid receptors. J Steroid Biochem Mol Biol 69:45–50

    Article  PubMed  CAS  Google Scholar 

  66. Weis KE, Ekena K, Thomas JA, Lazennec G, Katzenellenbogen BS (1996) Constitutively active human estrogen receptors containing amino acid substitutions for tyrosine 537 in the receptor protein. Mol Endocrinol 10:1388–1398

    Article  PubMed  CAS  Google Scholar 

  67. White R, Sjoberg M, Kalkhoven E, Parker MG (1997) Ligand-independent activation of the oestrogen receptor by mutation of a conserved tyrosine. EMBO J 16:1427–1435

    Article  PubMed  CAS  Google Scholar 

  68. Winer EP, Burstein HJ (2001) New combinations with Herceptin in metastatic breast cancer. Oncology 61:50–57

    Article  PubMed  CAS  Google Scholar 

  69. Yoshida T, Eguchi H, Nakachi K, Tanimoto K, Higashi Y, Suemasu K, Iino Y, Morishita Y, Hayashi S (2000) Distinct mechanisms of loss of estrogen receptor alpha gene expression in human breast cancer: methylation of the gene and alteration of trans-acting factors. Carcinogenesis 21:2193–2201

    Article  PubMed  CAS  Google Scholar 

  70. Youssef E, Tekyi-Mensah S, Hart K, Bolton S, Forman J (2003) Intermittent androgen deprivation for patients with recurrent/metastatic prostate cancer. Am J Clin Oncol 26:e119–e123

    Article  PubMed  Google Scholar 

Download references

Acknowledgments

This work was supported by Research Project Grants (15-501 and 16-501S) from Kawasaki Medical School and by a grant (14571166) from the Ministry of Education, Science, Sports and Culture of Japan.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Junichi Kurebayashi.

Additional information

This work was presented at the 20th Bristol-Myers Squibb Nagoya International Cancer Treatment Symposium, “New Concepts of Treatment Strategies for Hormone-Related Cancer”, 11–12 March 2005, Nagoya, Japan.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Kurebayashi, J. Resistance to endocrine therapy in breast cancer. Cancer Chemother Pharmacol 56 (Suppl 1), 39–46 (2005). https://doi.org/10.1007/s00280-005-0099-z

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00280-005-0099-z

Keywords

Navigation