Transcription profiling by array of breast cancer distant metastasis based on outcome over time and identification of pathway activities of late relapse

Previous reports have described the use of microarrays to assess the molecular classification of human breast cancers and defined new subgroups based on gene expression that are relevant to patient management through their ability to predict metastatic relapse and survival relapse. However, different mechanisms may be associated with the development of early and late distant metastases. With the hypothesis that tumors may lead to early or distant metastases based on their intrinsic biological initial features. We aimed at defining molecular profiles for several subgroups of patients based on their outcome over time. Breast primary tumors were selected from retrospective series of patients with frozen material available. These series include patients of all ages, LN- and LN+; Estrogen or Progesteron-receptor positive, Her2-negative, no adjuvant treatment, with a follow-up of more than 10 years (y) for the control group or distant metastatic relapse as first event (DM) for the study group. Patients tumors were classified in 3 groups: no relapse at 10y (M0), DM before 5 y (M0-5), DM between 5 and 15 y (M5-15).Gene expression analysis of breast tumor samples was performed using custom-made Agilent 4x44K high-density microarrays and hybridized against the Mammaprint reference pool (MRP). MRP=MammaReference Pool (The reference sample consisted of pooled and amplified RNA of 105 primary breast tumors, see Glas AM, BMC Genomics, 2006). The design of this study consists to 20 hybridizations in dual color with Agilent Human Genome 4x44K (design 014850) of breast tumors with a MRP reference with an addition as controls of 2 dye swaps and two self-self of the MRP and HMG (Human normal mammary Gland , Clontech).