University of Wisconsin–Madison

Hormone Receptor Molecular Imaging and Biology Lab

Led by Amy Fowler, MD, PhD, the Hormone Receptor Molecular Imaging and Biology Lab’s research focuses on advancing the use of molecular imaging to better understand the biology of breast cancer including its response to targeted drug therapies and early identification of drug resistance. Predictive and pharmacodynamic molecular imaging biomarkers may help physicians choose the best treatment tailored to each patient based on their specific tumor signaling characteristics and ultimately improve survival. Specifically, the lab is interested in quantitative imaging of steroid hormone receptors (estrogen and progesterone receptor) and their associated signaling pathways since the majority of breast cancer deaths occur in patients with metastatic estrogen receptor alpha (ER) positive disease.

The lab’s experimental approaches span the translational continuum from preclinical (cell-based assays and tumor xenograft models) to clinical studies. Currently the lab focuses on using 18F-labeled radiopharmaceuticals and multimodality imaging with positron emission tomography (PET) and computed tomography (CT) or magnetic resonance imaging (MRI). Additionally, optical imaging (fluorescence and bioluminescence) is an important tool used for the preclinical work.

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Biomarkers to Detect Endocrine Therapy Resistance

Brief Summary: This pilot observational study is being done to identify possible biomarkers of response to endocrine therapy in patients with ER/PR+ metastatic lobular breast cancer (LBC) starting new endocrine therapy. 18F-fluorofuranylnorprogesterone Positron Emission Tomography/Computed Tomography (FFNP-PET/CT) and liquid biopsies will be performed at baseline and after 4 weeks of treatment. Baseline levels and dynamic on-treatment changes in estrogen signaling as measured by FFNP-PET/CT and circulating tumor cell (CTC) liquid biopsy will be correlated with clinical response to endocrine therapy and progression-free survival in the above cohort of patients.

Progesterone Receptor Imaging

Phase II Study of 18F-FFNP Breast PET/MRI in the Assessment of Early Response of Breast Cancer to Presurgical Endocrine Therapy

Brief Summary: This clinical trial will investigate an estrogen-regulated parameter as an early measure of endocrine therapy response: progesterone receptor (PR) protein with a progestin-based radioligand, 18F-fluorofuranylnorprogesterone (18F-FFNP). The overall purpose of this research is to test the efficacy of 18F-FFNP PET/MRI for predicting response to presurgical endocrine therapy and to determine the quantitative reliability of 18F-FFNP breast PET/MRI in patients with newly diagnosed PR+ primary breast cancer.

Estrogen Receptor Imaging

Tamoxifen Dose Optimization for Metastatic Breast Cancer Patients with ESR1 Mutations

Brief Summary: Despite broad advancements in endocrine therapy for ERα+ breast cancer, resistance ultimately develops. A common driver of resistance are known ESR1 mutations that lead to constitutively active receptor signaling and transcriptional regulation that is always “turned on” despite the absence of estrogen. Patients with ESR1 mutations are expected to have decreased binding affinity for tamoxifen and thus may be underdosed on standard therapy. [18F]-fluoroestradiol Positron Emission Tomography/Computed tomography (FES-PET/CT) imaging is a novel functional imaging technique that can non-invasively measure ERα expression and inhibition in metastatic ERα+ breast cancer. The proposed a pilot study uses FES-PET/CT imaging to measure ERα blockade to determine the optimal dose of tamoxifen in patients with ESR1 mutations.

Prostate Specific Membrane Antigen Imaging

Evaluation of Prostate Specific Membrane Antigen (PSMA) in HER2-negative, Androgen Receptor (AR)-positive Metastatic Breast Cancer with 18F-DCFPyL PSMA-based PET/CT

Brief Summary: The purpose of this research is to determine the expression of prostate specific membrane antigen (PSMA) in human epidermal growth factor receptor 2 (HER2)-negative, androgen receptor (AR)-positive metastatic breast cancer, and to determine its role in resistance to the anti-androgen, bicalutamide. The investigators hypothesize that PSMA expression will correlate with resistance to anti-androgen therapies, as has been documented in prostate cancer, and this can be used to select patients most likely to benefit from these therapies in future clinical trials. 15 people with HER2-negative, AR-positive metastatic breast cancer will be enrolled and be on study for about 3 days.

18F-Fluoroestradiol (FES) PET as a Predictive Measure for Endocrine Therapy in Patients with Newly Diagnosed Metastatic Breast Cancer

Brief Summary: This phase II trial studies F-18 16 alpha-fluoroestradiol (FES) positron emission tomography (PET)/computed tomography (CT) in predicting response to endocrine therapy in patients with newly diagnosed breast cancer that has spread to other parts of the body. FES is a radioactive form of the hormone estrogen and may “light up” where cancer is in the body. Diagnostic procedures using FES, such as FES PET/CT, may help measure the FES and help doctors predict how well the cancer will respond to treatment.

Interim FDG-PET/CT for predicting response of HER2-positive breast cancer to neoadjuvant therapy (DIRECT Trial)

Brief Summary: This phase II trial tests how well an imaging procedure called fludeoxyglucose F-18 (FDG) positron emission tomography/computed tomography (PET/CT) works in predicting response to standard of care chemotherapy prior to surgery in patients with HER2-positive stage IIa-IIIc breast cancer. FDG is a radioactive tracer that is given in a vein before PET/CT imaging and helps to identify areas of active cancer. PET and CT are imaging techniques that make detailed, computerized pictures of areas inside the body. The use of FDG-PET/CT may help doctors better decide if a patient needs more or less treatment before surgery in order to get the best response. This study evaluates whether FDG-PET/CT is useful in predicting a patient’s response to standard of care chemotherapy.

FFNP PET/MR Imaging of Progesterone Receptor Expression in Invasive Breast Cancer

Brief Summary: The goal of this research is to test the accuracy of PET/MRI imaging with 18F-fluorofuranylnorprogesterone (FFNP) for measuring progesterone receptor (PR) expression in patients with invasive breast cancer. The hypothesis is that FFNP SUVmax from PET/MRI will correlate well against the semi-quantitative PR immunohistochemistry score.

A Randomized, Double-blind, Placebo-Controlled Study of 4-hydroxytamoxifen Topical Gel in Women with Mammographically Dense Breast

Brief Summary: This randomized phase II trial studies how well afimoxifene works in reducing the risk of breast cancer in women with mammographically dense breast. Estrogen can cause the growth of breast cancer cells. Hormone therapy using afimoxifene may fight breast cancer by blocking the use of estrogen by the tumor cells.

Onapristone and Fulvestrant for ER+ HER2- Metastatic Breast Cancer After Endocrine Therapy and CDK4/​6 Inhibitors (The SMILE Study)

Brief Summary: A phase II single-arm trial of onapristone in combination with fulvestrant for women and men with ER-positive, PgR-positive or negative and HER2-negative locally advanced or metastatic breast cancer after progression on aromatase and CDK4/6 inhibitors. The study will enroll up to 39 participants.

PET/MR Imaging of Estrogen Receptor Expression in Non-invasive Breast Cancer

Brief Summary: This prospective, one-arm study would enroll participants with biopsy-proven DCIS scheduled for diagnostic breast MRI for preoperative staging/extent of disease evaluation as part of standard of care. Eligible participants would be consented for participation in the research study which included a directed breast PET/MRI with 18F-FES. 18F-FES uptake of the known malignancy was measured on the PET/MRI examination using standardized uptake values (SUV) and tumor-to-normal tissue ratios.

Cover Article

The article below was featured on the cover of the April 2020 issue of Hormones and Cancer.

Fowler AM; Salem K; DeGrave M; Ong IM; Rassman S; Powers GL; Kumar M; Michel CJ; Mahajan AM. Progesterone receptor gene variants in metastatic estrogen receptor positive breast cancer. Hormones and Cancer. 2020 Jan; 11(2):63-75.

Brief Summary: Tumor mutations in the gene encoding estrogen receptor alpha (ESR1) have been identified in metastatic breast cancer patients with endocrine therapy resistance. However, relatively little is known about the occurrence of mutations in the progesterone receptor (PGR) gene in this population. The study objective was to determine the frequency and prognostic significance of tumor PGR mutations for patients with estrogen receptor (ER)-positive metastatic breast cancer. Thirty-five women with metastatic or locally recurrent ER+ breast cancer were included in this IRB-approved, retrospective study. Targeted next-generation sequencing of the PGR gene was performed on isolated tumor DNA. Associations between mutation status and clinicopathologic factors were analyzed as well as overall survival (OS) from time of metastatic diagnosis. The effect of the PGR variant Y890C (c.2669A>G) identified in this cohort on PR transactivation function was tested using ER−PR− (MDA-MB-231), ER+PR+ (T47D), and ER+PR− (T47D PR KO) breast cancer cell lines.

Articles

Kamaraju S; Fowler AM; Tarima S; Chaudhary LN; Burkard M; Giever T; Cheng YC; Parkes A; Lange C; Pipp-Dahm M; Hegeman R; Siddiqui N; Stella A; Rajguru S; Twaroski K; Zurbriggen L; Jorns J; Rui H; Keigley QJ; Perlman SB; Salem K; Bradshaw TJ; Sahmoud T; Wisinski K. A Phase II Trial of OnapriStone and FuLvestrant for Patients with ER+ and HER2- Metastatic Breast Cancer. Clinical Breast Cancer. 2024.

Brief Summary: The SMILE study is a multi-institutional phase II clinical trial to determine the efficacy and safety of an antiprogestin, onapristone, in combination with fulvestrant as second-line therapy for patients with ER+, PgR+/-, HER2- metastatic breast cancer. This study was terminated early and herein, we report patient characteristics, and outcomes.

Salem K; Reese RM; Alarid ET; Fowler AMProgesterone receptor mediated regulation of cellular glucose and 18F-fluorodeoxyglucose uptake in breast cancer. Journal of the Endocrine Society. 2023; 7(2):bvac186.

Brief Summary: Positron emission tomography imaging with 2-deoxy-2-[18F]-fluoro-D-glucose (FDG) is used clinically for initial staging, restaging, and assessing therapy response in breast cancer. Tumor FDG uptake in steroid hormone receptor–positive breast cancer and physiologic FDG uptake in normal breast tissue can be affected by hormonal factors such as menstrual cycle phase, menopausal status, and hormone replacement therapy. The purpose of this study was to determine the role of the progesterone receptor (PR) in regulating glucose and FDG uptake in breast cancer cells.

Note: This manuscript was chosen for the Endocrine Society Thematic Issue on Women’s Health 2023 guided by Altmetric Attention Scores and Feature Article designations.

Parent EE; Fowler AMNuclear receptor imaging in vivo – clinical and research advances. Journal of the Endocrine Society. 2022 Dec; 7(3):bvac197.

Brief Summary: Nuclear receptors are transcription factors that function in normal physiology and play important roles in diseases such as cancer, inflammation, and diabetes. Noninvasive imaging of nuclear receptors can be achieved using radiolabeled ligands and positron emission tomography (PET). This quantitative imaging approach can be viewed as an in vivo equivalent of the classic radioligand binding assay. A main clinical application of nuclear receptor imaging in oncology is to identify metastatic sites expressing nuclear receptors that are targets for approved drug therapies and are capable of binding ligands to improve treatment decision-making. Research applications of nuclear receptor imaging include novel synthetic ligand and drug development by quantifying target drug engagement with the receptor for optimal therapeutic drug dosing and for fundamental research into nuclear receptor function in cells and animal models. This mini-review provides an overview of PET imaging of nuclear receptors with a focus on radioligands for estrogen receptor, progesterone receptor, and androgen receptor and their use in breast and prostate cancer.

Fowler AM; Strigel RM. Clinical advances in PET/MRI for breast cancer. The Lancet Oncology. 2022; 23(1)e32-e43.

Brief Summary: Imaging is paramount for early detection of breast cancer, clinical staging, informing management decisions, and directing therapy. Positron emission tomography/magnetic resonance imaging (PET/MRI) is a quantitative hybrid imaging technology that combines metabolic, functional PET data with anatomic detail and functional perfusion information from MRI. The clinical applications for which PET/MRI may be beneficial for breast cancer is an active area of research. This Review discusses the rationale for using PET/MRI for patients with breast cancer and summarizes the clinical evidence across the spectrum of diagnosis, staging, prognosis, tumor phenotyping, and treatment response assessment. Continued development and approval of targeted radiopharmaceuticals, together with radiomics and automated analysis tools, will further expand the opportunity for PET/MRI to provide added value for breast cancer imaging and patient care.

Fowler AM; Kumar M; Henze Bancroft L; Salem K; Johnson JM; Karow J; Perlman SB; Bradshaw TJ; Hurley SA; McMillan AB; Strigel RM; Measuring glucose uptake in primary invasive breast cancer using simultaneous time-of-flight breast PET/MRI:  a method comparison study with prone PET/CT. Radiology Imaging Cancer. 2021; 3(1):e200091.

Brief Summary: To compare the measurement of glucose uptake in primary invasive breast cancer using simultaneous, time-of-flight breast PET/MRI with prone time-of-flight PET/CT.

Note: This manuscript was highlighted by a commentary article:

Mankoff DA; Surti S. PET/MRI for Primary Breast Cancer: A Match Made Better by PET Quantification? Radiology Imaging Cancer. 2021;3(1):e200150.

Kumar M; Salem K; Michel CJ; Jeffery JJ; Yan Y; Fowler AM. 18F-Fluoroestradiol positron emission tomography imaging of activating estrogen receptor alpha mutations in breast cancer. The Journal of Nuclear Medicine. 2019; 60:1247-1252.

Brief Summary: The purpose of this study was to determine the effect of estrogen receptor-α gene (ESR1) mutations at the tyrosine (Y) 537 amino acid residue within the ligand binding domain on 18F-fluoroestradiol (18F-FES) binding and in vivo tumor uptake compared with wild-type (WT)-estrogen receptor α (ER).

Salem K; Kumar M; Yan Y; Jeffery JJ; Kloepping KC; Michel CJ; Powers GL; Mahajan AM; Fowler AM. Sensitivity and isoform specificity of 18F-fluorofuranylnorprogesterone for measuring progesterone receptor protein response to estradiol challenge in breast cancer. The Journal of Nuclear Medicine. 2019; 60(2):220-226.

Brief Summary: The purpose of this study was to evaluate the ability of 21-18F-fluoro-16α,17α-[(R)-(1′-α-furylmethylidene)dioxy]-19-norpregn-4-ene-3,20-dione (18F-FFNP) to measure alterations in progesterone receptor (PR) protein level and isoform expression in response to 17β-estradiol (E2) challenge.

Note: This manuscript was selected as the Featured Basic Science Article for this issue and was highlighted by an invited perspective:

Paquette M, Turcotte E. Measuring estrogen receptor functionality using progesterone receptor PET imaging: rising to the (estradiol) challenge! The Journal of Nuclear Medicine. 2019; 60(2):218–219.

Personnel

The Hormone Receptor Molecular Imaging and Biology Lab consists of scientists, post-docs, graduate students, and undergraduates working in a collaborative, multidisciplinary environment focused on translational breast cancer imaging research. There are occasionally medical students, residents, and fellows involved with the lab’s clinical research projects.

Lab Member’s Expertise

The lab welcomes individuals with experience in, or wishing to gain experience in:

  • The design and performance of cancer biology/molecular imaging experiments using in vitro and in vivo models of breast cancer
  • Design and implementation of clinical trials of molecular imaging agents for breast cancer
  • Writing/editing manuscripts and grants

Open positions will be posted here when available.

Principal Investigator

Amy Fowler

Amy Fowler, MD, PhD

Publications at NCBI My Bibliography

Education

Undergraduate: South Dakota State University (Brookings, SD)
Graduate School: University of Wisconsin–Madison, Cellular and Molecular Biology Program
Medical School: University of Wisconsin School of Medicine and Public Health
Internship: Gundersen Lutheran Medical Center (La Crosse, WI)
Residency: Mallinckrodt Institute of Radiology, Washington University (St. Louis, MO)
Fellowship: Mallinckrodt Institute of Radiology, Washington University (St. Louis, MO)

Current Lab Members

Mary Pat Berry, BA, MA

Breast Cancer Research Advocate

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Blue-Leaf Cordes, MD, PhD

Scientist III

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Mary Ozers, PhD

Scientist III

Kelley Salem, PhD

Scientist I

Natasha Solodin, BS

Scientist I

Previous Lab Members

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Tianrui Liu, BA

Research Intern

Undergraduate: University of
Wisconsin–Madison

Manoj Kumar, MS, PhD

Research Assistant (Graduate Student)
UW Institute of Clinical and Translational Research Clinical Investigation Program

Undergraduate: Uttar Pradesh Technical University, India
Graduate School: University of Wisconsin–Madison, Master of Science in Biotechnology Program

Ciara Michel

Undergraduate Student

Undergraduate: University of Wisconsin–Madison, Microbiology
Graduate School: Emory University, Master of Public Health
Medical School: University of Wisconsin School of Medicine and Public Health

Kyle Kloepping, PhD

Research Associate (Post-Doc)

Undergraduate: University of Wisconsin–Platteville (Platteville, WI)
Graduate School: University of Iowa, Free Radical and Radiation Biology Program

Ginny Powers, PhD

Assistant Scientist

Undergraduate: St. Norbert College (De Pere, WI)
Graduate School: University of Wisconsin–Madison, Molecular and Cellular Pharmacology Program
Postdoctoral: University of Wisconsin–Madison, Pharmaceutical Sciences

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Michael DeGrave, BS

2015 Shapiro Summer Research Scholar
University of Wisconsin School of Medicine and Public Health

Undergraduate: University of Wisconsin–Madison

Contact Information

Amy Fowler, MD, PhD
Principal Investigator and Associate Professor
Department of Radiology
University of Wisconsin School of Medicine and Public Health
600 Highland Avenue
Madison, WI  53792-3252
Contact: AFowler@uwhealth.org