New Data to be Presented at the 2025 SABCS Demonstrates Potential Expanded Utility of the Breast Cancer Index Test, the Leading Biomarker in Personalizing Endocrine Therapy Duration

Findings from 11 investigational studies include new data in premenopausal women and comparative analyses of BCI Testing to the 21-gene assay

Hologic, Inc. (Nasdaq: HOLX) and its subsidiary, Biotheranostics, Inc., today announced that 11 studies featuring the Breast Cancer Index ^® (BCI™) Test will be presented at the 2025 San Antonio Breast Cancer Symposium ^® (SABCS). Findings from these studies support the company's ongoing commitment to help inform personalized treatment recommendations for patients with early-stage, hormone receptor-positive (HR+) breast cancer. Building on the test's established position as the only guideline-recognized and most extensively validated test to predict which patients are likely to benefit from extended endocrine therapy, ^1-7 these new insights explore potential expanded utility in premenopausal women and comparison to the 21-gene assay for extended endocrine therapy treatment decisions.

"These data reinforce Hologic's continued commitment to oncology innovation and advancing precision diagnostics in breast cancer care," said Jennifer Schneiders, Ph.D., President of Diagnostic Solutions at Hologic. "This impressive volume of evidence provides deeper insight into premenopausal patient populations, supports more nuanced endocrine therapy decision-making and highlights the consistency of the BCI Test's performance across diverse patient subgroups and sample types."

Among the new findings to be presented, one study, " Identifying Premenopausal Patients with Early-Stage Hormone Receptor-Positive Node-Negative Breast Cancer at Minimal Risk of Distant Recurrence by Breast Cancer Index [#PS3-07-27]," explores the BCI Test's potential ability to identify a group of premenopausal patients with early-stage, HR+ breast cancer who are at minimal risk of experiencing metastatic recurrence. Results from this translational analysis of the two largest landmark ovarian function suppression (OFS) trials, Suppression of Ovarian Function Trial (SOFT) and Tamoxifen and Exemestane Trial (TEXT), support the potential utility of BCI Testing in identifying premenopausal women who may forgo the addition of OFS therapy to primary adjuvant endocrine therapy. ⁸ ^*

"As we observe an increasing number of women being diagnosed with breast cancer at a younger age, it is imperative to balance the need for effective recurrence prevention with the preservation of patient quality of life," said primary study author Dr. Ruth O'Regan, MD. "The ability to accurately identify premenopausal women who can safely avoid more aggressive treatment regimens would represent a significant advancement in the field of personalized medicine, allowing us to tailor therapies to individual patient needs while minimizing unnecessary side effects."

A full list of studies to be presented at the 2025 SABCS conference includes:

• Poster Session 2: December 10, 2025, 5:00pm – 6:30pm CST
  • Endocrine Sensitivity and Predicted Benefit of Extended Endocrine Therapy Based on Breast Cancer Index (BCI) in BRCA1, BRCA2 and CHEK2 Pathogenic Variant Carriers with ER+/HER2– Breast Cancer [#PS2-08-25]: Examines how BCI Testing may help identify differences in hormone-therapy benefit among women with inherited BRCA1, BRCA2 or CHEK2 gene variants. ⁹ *

• Poster Session 3: December 11, 2025, 12:30pm – 2pm CST
  • Breast Cancer Index Re-stratifies 21-Gene Assay Risk Groups for Risk of Recurrence and Extended Endocrine Therapy Benefit: Final Analysis of the BCI Registry Study [#PS3-07-24]: Demonstrates that BCI Testing provides added insight for doctors already using other genomic tests to guide treatment planning and emphasizes the need to use the right test for each clinical decision. ¹⁰ *
  • Identifying Premenopausal Patients with Early-Stage Hormone Receptor-Positive Node-Negative Breast Cancer at Minimal Risk of Distant Recurrence by Breast Cancer Index [#PS3-07-27]: Highlights the BCI Test's ability to identify premenopausal patients with early-stage, HR+ breast cancer who are at minimal risk of experiencing metastatic recurrence. ⁸ ^*
  • Prognostic Performance of Breast Cancer Index in Patients with Early-Stage HR+ HER2+ Breast Cancer Treated with Adjuvant Trastuzumab: NCCTG N9831 (Alliance) [#PS3-07-28]: Supports the BCI Test's ability to assess recurrence risk in patients with HER2+ disease. ¹¹ *
  • Comparative Analysis of Breast Cancer Index Testing in Hispanic and Non-Hispanic Populations [#PS3-08-07]: Evaluates ethnicity-based differences in BCI Results and treatment patterns. ¹² *
  • Comparison of Breast Cancer Index Scores from Core-Needle Biopsies Versus Surgical Excisions in Early-Stage Breast Cancer [#PS3-08-26]: Demonstrates that BCI Testing delivers consistent results from both biopsies and surgical tissue samples. ¹³ *

Five additional studies featuring data on the clinical utility of the BCI Test will be presented by external investigators at 2025 SABCS, including:

• Poster Session 3: December 11, 2025, 12:30pm – 2pm CST
  • Guidelines for Breast Cancer Index Test before and after Epic software enhancement [#PS3-03-18] ¹⁴
  • Higher Breast Tumor Grades Could More Likely Benefit from Extended Adjuvant Endocrine Therapy [#PS3-09-10] ¹⁵
  • Correlation Between Breast Cancer Index (BCI) and RSClin Late in Assessing 5-10 Year Recurrence Risk in Early-Stage Hormone Receptor-Positive Breast Cancer [#PS3-09-19] ¹⁶
  • Retrospective study on breast cancer index testing in a community hospital and analyzing its impact on physician-decision making for extended endocrine therapy in early breast cancer [#PS3-10-23] ¹⁷

• Poster Session 4: December 11, 2025, 5:00pm – 6:30pm CST
  • Spatial transcriptomics of TNBCs show an association between HOXB13 expression and formation of a plasmablast-rich neighborhood [#PS4-07-08] ¹⁸

"The research to be presented at 2025 SABCS continues to offer insight into expanded clinical applications of the BCI Test," said Schneiders. "With more than a decade of clinical use by over 9,000 providers, and its proven ability to influence extended endocrine therapy decisions, it's encouraging to see additional real-world and independent data reinforcing the BCI Test's impact. These findings underscore our ongoing commitment to help clinicians deliver more personalized, confident care for patients."

About the Breast Cancer Index Test

The Breast Cancer Index Test is a molecular, gene expression-based test uniquely positioned to provide information to help physicians individualize treatment decisions for patients with early-stage, HR+ breast cancer. This breakthrough test helps oncology care teams and patients navigate the difficult trade-offs between taking steps to prevent recurrence of their disease and facing significant side effects and safety challenges related to unnecessary treatment.

The Breast Cancer Index Test has guideline designation from the American Joint Committee on Cancer for cancer staging based on molecular profile. The ASCO ^® Clinical Practice Guideline and the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines ^® ) acknowledge the Breast Cancer Index Test as a biomarker to help inform extended endocrine treatment decisions. ^6,7 It is the only test recognized by guidelines to predict which early-stage, HR+ breast cancer patients are likely to benefit from extended endocrine therapy. ^6,7

The Breast Cancer Index Test is intended for routine clinical use, and physician treatment decisions based on results are the responsibility of the physician. It is a sole-source laboratory-developed test (LDT) performed by Biotheranostics, Inc., a CLIA-certified and CAP-accredited diagnostic laboratory. It has not been cleared or approved by the U.S. Food and Drug Administration. For more information, visit www.breastcancerindex.com .

About Hologic, Inc.

Hologic, Inc. is a global leader in women's health dedicated to developing innovative medical technologies that effectively detect, diagnose and treat health conditions and raise the standard of care around the world. To learn more, visit www.hologic.com and connect with us on LinkedIn , Facebook , X , Instagram and YouTube .

Forward-Looking Statements

This news release may contain forward-looking information that involves risks and uncertainties, including statements about the use of Hologic's and its subsidiaries' products. There can be no assurance these products will achieve the benefits described herein or that such benefits will be replicated in any particular manner with respect to an individual patient, as the actual effect of the use of the products can only be determined on a case-by-case basis. In addition, there can be no assurance that these products will be commercially successful or achieve any expected level of sales. Hologic expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any such statements presented herein to reflect any change in expectations or any change in events, conditions or circumstances on which any such data or statements are based.

^Note: Incorporation of refined risk estimates in the results reported by the Breast Cancer Index test are pending appropriate regulatory approvals. For the Breast Cancer Index Intended Uses and Limitations, please visit breastcancerindex.com .

*Biotheranostics, Inc. researchers are named authors in this study.

Hologic, Breast Cancer Index, BCI and associated logos are trademarks and/or registered trademarks of Hologic, Inc. and/or its subsidiaries in the United States and/or other countries. All other trademarks are the property of their respective owners.

References

1. Zhang Y, et al. Breast Cancer Index identifies early-stage estrogen receptor–positive breast cancer patients at risk for early- and late-distant recurrence. Clin Cancer Res. 2013;19(15):4196-4205. doi:10.1158/1078-0432.CCR-13-0804.
2. Sgroi DC, et al. Prediction of late disease recurrence and extended adjuvant letrozole benefit by the HOXB13/IL17BR biomarker. JNCI J Natl Cancer Inst . 2013;105(14):1036-1042. doi:10.1093/jnci/djt146.
3. Bartlett JMS, et al. Breast Cancer Index and prediction of benefit from extended endocrine therapy in breast cancer patients treated in the Adjuvant Tamoxifen–To Offer More? (aTTom) trial. Ann Oncol. 2019;30(11):1776-1783. doi:10.1093/annonc/mdz289.
4. Noordhoek I, et al. Breast Cancer Index predicts extended endocrine benefit to individualize selection of patients with HR‐positive early-stage breast cancer for 10 years of endocrine therapy. Clin Cancer Res. 2021;27(1):311-319. doi:10.1158/1078-0432.CCR-20-2737.
5. Mamounas EP, et al. Breast Cancer Index (BCI) and prediction of benefit from extended aromatase inhibitor therapy in HR+ breast cancer: NRG Oncology/NSABP B-42. J Clin Oncol . 2021;39(15_suppl):501. doi:10.1200/JCO.2021.39.15_suppl.501
6. Referenced with permission from the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines ^® ) for Breast Cancer V.5.2025. © National Comprehensive Cancer Network, Inc. 2025. All rights reserved. Accessed November 6, 2025. To view the most recent and complete version of the guideline, go online to NCCN.org. NCCN makes no warranties of any kind whatsoever regarding their content, use or application and disclaims any responsibility for their application or use in any way.
7. Andre F, et al. J Clin Oncol. 2022;40(16):1816-1837. Referenced with permission from the American Society of Clinical Oncology (ASCO): Clinical Practice Guideline Endorsements for Adjuvant Endocrine and Chemotherapy in Early-Stage Breast Cancer. © American Society of Clinical Oncology, 2025. All rights reserved. To view the most recent and complete version of the guideline, go online to https://ascopubs.org/guidelines [ascopubs.org]. ASCO Clinical Practice Guideline makes no warranties of any kind whatsoever regarding their content, use of application and disclaims any responsibility for their application or use in any way.
8. O'Regan R, et al. Identifying premenopausal patients with early-stage hormone receptor–positive node-negative breast cancer at minimal risk of distant recurrence by Breast Cancer Index. Presented at: San Antonio Breast Cancer Symposium (SABCS); December 11, 2025; San Antonio, TX.
9. Yadav S, et al. Endocrine sensitivity and predicted benefit of extended endocrine therapy based on Breast Cancer Index (BCI) in BRCA1, BRCA2, and CHEK2 pathogenic variant carriers with ER+/HER2– breast cancer. Presented at: San Antonio Breast Cancer Symposium (SABCS); December 10, 2025; San Antonio, TX.
10. Chuy V, et al. Breast Cancer Index re-stratifies 21-gene assay risk groups for risk of recurrence and extended endocrine therapy benefit: Final analysis of the BCI Registry Study. Presented at: San Antonio Breast Cancer Symposium (SABCS); December 11, 2025; San Antonio, TX.
11. Chumsri S, et al. Prognostic performance of Breast Cancer Index in patients with early-stage HR+ HER2+ breast cancer treated with adjuvant trastuzumab: NCCTG N9831 (Alliance). Presented at: San Antonio Breast Cancer Symposium (SABCS); December 11, 2025; San Antonio, TX.
12. Sandoval-Leon AC, et al. Comparative analysis of Breast Cancer Index testing in Hispanic and non-Hispanic populations. Presented at: San Antonio Breast Cancer Symposium (SABCS); December 11, 2025; San Antonio, TX.
13. Kapoor NS, et al. Comparison of Breast Cancer Index scores from core-needle biopsies versus surgical excisions in early-stage breast cancer. Presented at: San Antonio Breast Cancer Symposium (SABCS); December 11, 2025; San Antonio, TX.
14. Tran CC, et al. Guidelines for Breast Cancer Index test before and after Epic software enhancement. Presented at: San Antonio Breast Cancer Symposium (SABCS); December 11, 2025; San Antonio, TX.
15. Ogunsesan Y, et al. Higher breast tumor grades could more likely benefit from extended adjuvant endocrine therapy . Presented at: San Antonio Breast Cancer Symposium (SABCS); December 11, 2025; San Antonio, TX.
16. Rupani KV, et al. Correlation between Breast Cancer Index (BCI) and RSClin late in assessing 5–10-year recurrence risk in early-stage hormone receptor–positive breast cancer. Presented at: San Antonio Breast Cancer Symposium (SABCS); December 11, 2025; San Antonio, TX.
17. Essarani M, et al. Retrospective study on Breast Cancer Index testing in a community hospital and analysis of its impact on physician decision-making for extended endocrine therapy in early breast cancer. Presented at: San Antonio Breast Cancer Symposium (SABCS); December 11, 2025; San Antonio, TX.
18. Flood B, et al. Spatial transcriptomics of TNBCs show an association between HOXB13 expression and formation of a plasmablast-rich neighborhood . Presented at: San Antonio Breast Cancer Symposium (SABCS); December 11, 2025; San Antonio, TX.

SOURCE: Hologic, Inc.

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