title: RSF1 and not cyclin D1 gene amplification may predict lack of benefit from adjuvant tamoxifen in high-risk pre-menopausal women in the MA.12 randomized clinical trial.
abstract: Most women with estrogen receptor expressing breast cancers receiving anti-estrogens such as tamoxifen may not need or benefit from them. Besides the estrogen receptor, there are no predictive biomarkers to help select breast cancer patients for tamoxifen treatment. CCND1 (cyclin D1) gene amplification is a putative candidate tamoxifen predictive biomarker. The RSF1 (remodeling and spacing factor 1) gene is frequently co-amplified with CCND1 on chromosome 11q. We validated the predictive value of these biomarkers in the MA.12 randomized study of adjuvant tamoxifen vs. placebo in high-risk premenopausal early breast cancer. Premenopausal women with node-positive/high-risk node-negative early breast cancer received standard adjuvant chemotherapy and then were randomized to tamoxifen (20 mg/day) or placebo for 5 yrs. Overall survival (OS) and relapse-free survival (RFS) were evaluated. Fluorescent in-situ hybridization was performed on a tissue microarray of 495 breast tumors (74% of patients) to measure CCND1 and RSF1 copy number. A multivariate Cox model to obtain hazard ratios (HR) adjusting for clinico-pathologic factors was used to assess the effect of these biomarkers on Os and RFS. 672 women were followed for a median of 8.4 years. We were able to measure the DNA copy number of CCND1 in 442 patients and RSF1 in 413 patients. CCND1 gene amplification was observed in 8.7% and RSF1 in 6.8% of these patients, preferentially in estrogen receptor-positive breast cancers. No statistically significant interaction with treatment was observed for either CCND1 or RSF1 amplification, although patients with high RSF1 copy number did not show benefit from adjuvant tamoxifen (HR = 1.11, interaction p = 0.09). Unlike CCND1 amplification, RSF1 amplification may predict for outcome in high-risk premenopausal breast cancer patients treated with adjuvant tamoxifen.
authors.affiliation: Department of Oncology and Surgery, Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada.
authors.forename: Dana
authors.initials: D
authors.lastname: Keilty
authors.affiliation: Department of Oncology and Surgery, Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada.
authors.forename: Marguerite
authors.initials: M
authors.lastname: Buchanan
authors.affiliation: Department of Pathology, Jewish General Hospital, Montreal, Quebec, Canada.
authors.forename: Katerina
authors.initials: K
authors.lastname: Ntapolias
authors.affiliation: Department of Pathology, Jewish General Hospital, Montreal, Quebec, Canada.
authors.forename: Olga
authors.initials: O
authors.lastname: Aleynikova
authors.affiliation: NCIC Clinical Trials Group, Cancer Research Institute, Queen's University, Ontario, Canada.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Tu
authors.affiliation: NCIC Clinical Trials Group, Cancer Research Institute, Queen's University, Ontario, Canada.
authors.forename: Xiao
authors.initials: X
authors.lastname: Li
authors.affiliation: NCIC Clinical Trials Group, Cancer Research Institute, Queen's University, Ontario, Canada.
authors.forename: Lois
authors.initials: L
authors.lastname: Shepherd
authors.affiliation: Department of Medical Oncology, Tom Baker Cancer Centre, Calgary, Alberta, Canada.
authors.forename: Vivien
authors.initials: V
authors.lastname: Bramwell
authors.affiliation: Department of Oncology and Surgery, Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Basik
mesh_terms: D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics*; D019938:Cyclin D1 / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D009687:Nuclear Proteins / Q000235:genetics*; D017697:Premenopause; D013629:Tamoxifen / Q000627:therapeutic use*; D015534:Trans-Activators / Q000235:genetics*; D016896:Treatment Outcome
chemical_list: D018931:Antineoplastic Agents, Hormonal; C530104:CCND1 protein, human; D009687:Nuclear Proteins; C452851:RSF1 protein, human; D015534:Trans-Activators; D013629:Tamoxifen; D019938:Cyclin D1