for people ages 18 years and up (full criteria)
at San Francisco, California and other locations
study started
completion around
Principal Investigator
by Rita Mukhtar, MDLaura Esserman, MD
Headshot of Rita Mukhtar
Rita Mukhtar
Headshot of Laura Esserman
Laura Esserman



The FLEX Registry will be implemented to operate as a large-scale, population based, prospective registry. All patients with stage I to III breast cancer who receive MammaPrint® and BluePrint testing on a primary breast tumor are eligible for entry into the FLEX Registry, which is intended to enable additional study arms at low incremental effort and cost. FLEX Registry will utilize an adaptive design, where additional targeted substudies and arms can be added after the initial study is opened.

Official Title

MammaPrint, BluePrint, and Full-genome Data Linked With Clinical Data to Evaluate New Gene EXpression Profiles: An Adaptable Registry (FLEX)


The FLEX Registry will include all patients with stage I-III breast cancer who have received MammaPrint and BluePrint testing in any clinical setting. Study arm appendices will specify treatment arm, inclusion criteria, and number of patients needed. Approximately 30,000 patients from 125+ US based institutions will be enrolled.

Treatment is at the discretion of the physician adhering to NCCN approved regimens of a recognized alternative.

Clinical data will be collected and entered online at the time points listed: patient enrollment, time of treatment, 1 year post-treatment, and 3, 5, and 10 years post diagnosis.


  • Create a large scale, population-based registry of full genome expression data and clinical data to investigate new gene associations with prognostic and/or predictive value
  • Utilize shared registry infrastructure to examine smaller groups of interest
  • Generate hypotheses for targeted subset analyses and trials based on full genome data

FLEX is an observational (phase IV) study.


Breast Cancer, stage I, stage II, stage III, Breast Neoplasms, MammaPrint, BluePrint, and Full-Genome Testing, MammaPrint and BluePrint testing


You can join if…

Open to people ages 18 years and up

  • Stage I, II, or III patients who receive MammaPrint, with or without BluePrint testing (male or female)
  • Informed consent form signed on the same day or before enrollment
  • New primary lesion

You CAN'T join if...

  • Tumor sample shipped to Agendia with ≤ 30% tumor cells or that fails QA or QC criteria
  • Metastatic disease
  • Recurrent disease
  • Stage 0 disease


  • UCSF Breast Care Center accepting new patients
    San Francisco California 94158 United States
  • Adventist Health - Bakersfield accepting new patients
    Bakersfield California 93301 United States

Lead Scientists at UCSF

  • Rita Mukhtar, MD
    Dr. Rita Mukhtar specializes in breast surgery and general surgery for urgent conditions. For her patients with breast cancer, she offers expertise in total skin-sparing mastectomies, breast conservation, wire localization surgery (used to show the location of tissue requiring biopsy) and sentinel lymph node biopsy (used to see if cancer has spread).
  • Laura Esserman, MD
    Dr. Laura Esserman, M.D., M.B.A is a surgeon and breast cancer oncology specialist practicing at the UCSF Breast Care Center where she has also held the position of Director since 1996. She co-leads the Breast Oncology Program, the largest of the UCSF Helen Diller Comprehensive Cancer Center's multidisciplinary programs.


accepting new patients
Start Date
Completion Date
Study Type
Observational [Patient Registry]
Expecting 30000 study participants
Last Updated