Abstract
Hormone receptor-positive (HR + )/HER2-negative (HER2 − ) early breast cancers (BCs) are typically considered immunologically cold. However, combining immune checkpoint inhibitors (ICIs) with chemotherapy has shown to improve pathological complete response (pCR) in high-risk patients. Understanding the relationship between immune activation and tumor biology may help identify HR + /HER2 − BC patients most likely to benefit from such combinations. Baseline gene expression data from two neoadjuvant trials (GIADA and LETLOB) including HR + /HER2 − BC patients were analyzed. PAM50 intrinsic subtyping and relevant immune-related gene signatures were calculated. Tumor-infiltrating lymphocytes (TILs) were assessed on baseline samples. Among 109 tumors, PAM50 classified 44% as Luminal-B (LumB), 33% Luminal-A (LumA), 18% Basal-like, and 5% HER2-enriched. TIL levels (available for N = 101) were generally low (median 2; range 0–100), with higher levels in Basal-like BCs (p = 0.008). Basal-like BCs exhibited significantly higher levels of immune-related signatures (CD8 T-cells, Cytotoxic cells, IFN-γ, response to ICI + CT in GeparNuevo) and of PD-1, PD-L1, and PD-L2 genes. No differences were found between LumA and LumB subtypes. TILs and immune signatures showed a significant weak-to-moderate positive correlation with the basal-like signature. HR + /HER2- BCs that display both features of biological aggressiveness and enhanced immunogenicity may represent ideal candidates for the combination of ICI and chemotherapy.
Similar content being viewed by others
Data availability
Data that support the findings of this study are available from the corresponding author upon request, pending on formalization of a Data Transfer Agreement and reinforcing the compliance with the EU privacy law. Further information is available from the corresponding author upon request.
References
Nitz, U. A. et al. Endocrine therapy response and 21-gene expression assay for therapy guidance in HR+/HER2- early breast cancer. J. Clin. Oncol. 40, 2557–2567 (2022).
Loibl, S. et al. Early breast cancer: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up. Ann. Oncol. 35, 159–182 (2024).
Parker, J. S. et al. Supervised risk predictor of breast cancer based on intrinsic subtypes. J. Clin. Oncol. 27, 1160–1167 (2009).
Cejalvo, J. M. et al. Clinical implications of the non-luminal intrinsic subtypes in hormone receptor-positive breast cancer. Cancer Treat. Rev. 67, 63–70 (2018).
Griguolo, G. et al. Gene-expression signatures to inform neoadjuvant treatment decision in HR+/HER2- breast cancer: available evidence and clinical implications. Cancer Treat. Rev. 102, 102323 (2022).
Bottosso, M. et al. Gene expression assays to tailor adjuvant endocrine therapy for HR+/HER2- breast cancer. Clin. Cancer Res. 30, 2884–2894 (2024).
Bertucci, F., Finetti, P., Goncalves, A. & Birnbaum, D. The therapeutic response of ER+/HER2- breast cancers differs according to the molecular Basal or Luminal subtype. NPJ Breast Cancer 6, 8 (2020).
Prat, A. et al. A PAM50-based chemoendocrine score for hormone receptor-positive breast cancer with an intermediate risk of relapse. Clin. Cancer Res. 23, 3035–3044 (2017).
Schmid, P. et al. Event-free survival with pembrolizumab in early triple-negative breast cancer. N. Engl. J. Med 386, 556–567 (2022).
Cardoso, F. et al. Pembrolizumab and chemotherapy in high-risk, early-stage, ER+/HER2− breast cancer: a randomized phase 3 trial. Nat. Med 31, 442–448 (2025).
Loi, S. et al. Neoadjuvant nivolumab and chemotherapy in early estrogen receptor-positive breast cancer: a randomized phase 3 trial. Nat. Med 31, 433–441 (2025).
Dieci, M. V. et al. Neoadjuvant chemotherapy and immunotherapy in luminal B-like breast cancer: results of the phase II GIADA trial. Clin. Cancer Res 28, 308–317 (2022).
Criscitiello, C. et al. Tumor-infiltrating lymphocytes (TILs) in ER+/HER2− breast cancer. Breast Cancer Res. Treat. 183, 347–354 (2020).
Fujimoto, Y. et al. Prognostic significance of tumor-infiltrating lymphocytes may differ depending on Ki67 expression levels in estrogen receptor-positive/HER2-negative operated breast cancers. Breast Cancer 26, 738–747 (2019).
Ayers, M. et al. IFN-γ–related mRNA profile predicts clinical response to PD-1 blockade. J. Clin. Investig. 127, 2930–2940 (2017).
Griguolo, G. et al. Immune microenvironment and intrinsic subtyping in hormone receptor-positive/HER2-negative breast cancer. NPJ Breast Cancer 7. https://doi.org/10.1038/s41523-021-00223-x (2021).
Huppert, L. A. et al. Pathologic complete response (pCR) rates for patients with HR+/HER2− high-risk, early-stage breast cancer (EBC) by clinical and molecular features in the phase II I-SPY2 clinical trial. Ann. Oncol. 36, 172–184 (2025).
Nanda, R. et al. Effect of pembrolizumab plus neoadjuvant chemotherapy on pathologic complete response in women with early-stage breast cancer: an analysis of the ongoing phase 2 adaptively randomized I-SPY2 trial. JAMA Oncol. 6, 676–684 (2020).
Mittempergher, L. et al. The ImPrint immune signature to identify patients with high-risk early breast cancer who may benefit from PD1 checkpoint inhibition in I-SPY2. J. Clin. Oncol. 40, 514–514 (2022).
Sinn, B. V. et al. Immune-related gene expression predicts response to neoadjuvant chemotherapy but not additional benefit from PD-L1 inhibition in women with early triple-negative breast cancer. Clin. Cancer Res. 27, 2584–2591 (2021).
Ayers, M. et al. Relationship between immune gene signatures and clinical response to PD-1 blockade with pembrolizumab (MK-3475) in patients with advanced solid tumors. J. Immunother. Cancer 3, P80 (2015).
Hendry, S. et al. Assessing tumor-infiltrating lymphocytes in solid tumors: a practical review for pathologists and proposal for a standardized method from the international immunooncology biomarkers working group: part 1: assessing the host immune response, TILs in invasive breast carcinoma and ductal carcinoma in situ, metastatic tumor deposits and areas for further research. Adv. Anat. Pathol. 24, 235–251 (2017).
Salgado, R. et al. The evaluation of tumor-infiltrating lymphocytes (TILs) in breast cancer: recommendations by an International TILs Working Group 2014. Ann. Oncol. 26, 259–271 (2015).
Guarneri, V. et al. Double-blind, placebo-controlled, multicenter, randomized, phase IIB neoadjuvant study of letrozole-lapatinib in postmenopausal hormone receptor–positive, human epidermal growth factor receptor 2–negative, operable breast cancer. J. Clin. Oncol. 32, 1050–1057 (2014).
Guarneri, V. et al. Double-blind, placebo-controlled, multicenter, randomized, phase IIB neoadjuvant study of letrozole-lapatinib in postmenopausal hormone receptor-positive, human epidermal growth factor receptor 2-negative, operable breast cancer. J. Clin. Oncol. 32, 1050–1057 (2014).
The R foundation. R: The R project for statistical computing. Available at https://www.r-project. org n.d.
Acknowledgements
This work was supported by University of Padova, Department of Surgery, Oncology and Gastroenterology DOR 2023-2024 (to V.G., M.V.D., G.G., F.M.; grant number not applicable), Ricerca Corrente funding from the Italian Ministry of Health (grant number not applicable). Fondazione AIRC under 5 per mille 2019 (ID. 22759 program—group leader VG) and under IG 27152 to M.V.D.
Author information
Authors and Affiliations
Contributions
Study design: G.G., M.V.D. and V.G.; Acquisition of clinical data: G.G., M.B., F.M., D.G.G., A.M., S.S., G.M.V., T.G., R.C., F.P., K.G., M.V.D., and V.G.; Translational Analyses, data analysis and interpretation: G.G., M.B., L.P., R.C., S.B., E.T., A.T., F.S., A.P., and M.V.D.; Manuscript drafting: M.B. and G.G.; Manuscript revision and final approval of manuscript: all authors.
Corresponding author
Ethics declarations
Competing interests
G.G. reports fees for advisory role from Gilead, Seagen, Menarini, personal fees as an invited speaker from Eli Lilly, Novartis, MSD. M.B. reports travel support from Eli Lilly. F.M. reports personal fees from Roche, Novartis, Pfizer, Seagen, Menarini, MSD, Gilead, Astrazeneca. A.M. report consulting or advisory role from Eli Lilly, Eisai Europe, Daiichi Sankyo/Astra Zeneca, Novartis, research funding from Eli Lilly and Roche, travel/accommodations from Pfizer. S.S. reports the following: Novartis (speaker honoraria, advisory board, travel and expense Reimbursement for congress), Daiichi-Sankyo (speaker honoraria, tutorship, advisory board, travel and expense reimbursement for congress), Roche (travel and expense reimbursement for congress), Seagen, MSD and AstraZeneka (speaker honoraria and advisory board), Gentili and Mundipharma (speaker honoraria). T.G. reports personal fees from Novartis and Eli Lilly. F.P. reports, outside the submitted work, the following: consultancy/advisory board for Daichii Sankyo, Novartis, Pfizer, Roche; honoraria as a speaker from Novartis, Lilly, MSD, Pfizer. A.P. reports advisory and consulting fees from AstraZeneca, Roche, Pfizer, Novartis, Daiichi Sankyo, Ona Therapeutics, and Peptomyc, lecture fees from AstraZeneca, Roche, Novartis, and Daiichi Sankyo, institutional financial interests from AstraZeneca, Novartis, Roche, and Daiichi Sankyo; stockholder and employee of Reveal Genomics; patents filed PCT/EP2016/080056, PCT/EP2022/086493, PCT/EP2023/060810, EP23382703, and EP23383369. M.V.D. reports personal fees for consultancy/advisory role from: Eli Lilly, Pfizer, Novartis, Seagen, Gilead, MSD, Exact Sciences, AstraZeneca, Roche, Daiichi Sankyo, Roche. V.G. reports personal fees for advisory board participation for AstraZeneca, Daiichi Sankyo, Eli Lilly, Gilead, MSD, Novartis, Pfizer, Pierre Fabre, Roche, Menarini Stemline, Exact Sciences, personal fees as an invited speaker for AstraZeneca, Daiichi Sankyo, Eli Lilly, Exact Sciences, Gilead, GSK, Novartis, Roche, Zentiva, Menarini Stemline, personal fees for expert testimony for Eli Lilly, patents for HER2DX (Institution). All remaining authors have declared no conflicts of interest.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary information
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
About this article
Cite this article
Griguolo, G., Bottosso, M., Paré, L. et al. Basal-like HR + /HER2- breast cancers show higher tumor-infiltrating lymphocytes and immune signatures with potential therapeutic implications. npj Breast Cancer (2025). https://doi.org/10.1038/s41523-025-00886-w
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41523-025-00886-w
