Stage-Dependent Expression of Hormonal Receptors, HER2, Ki-67, and PD-L1 in Breast Cancer: Correlation with Molecular Subtypes and Tumor Microenvironment
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Abstract
Tumor stage and molecular phenotype are both powerful predictors of clinical behavior and therapeutic responsiveness of breast cancer. Although the most used IHC biomarkers, including ER, PR, HER2, Ki-67, and PD-L1, are actively applied in practice, the dynamics of their integration and their connection with the tumor microenvironment (TME) have not been fully described within a single cohort. This retrospective cross-sectional study involved 70 consecutive patients with primary invasive breast carcinoma (Al-Zahraa Teaching Hospital, Iraq; January 2023-December 2024), stratified according to AJCC TNM staging (8th edition). ER, PR, HER2, Ki-67, and PD-L1 (clone 22C3; tumor proportion score [TPS]) IHC were performed on FFPE tissue. Surrogate IHC criteria were used to assign molecular subtypes; TME characteristics (TILs, stromal density, CD163) were evaluated on H&E sections. Inter-observer agreement (Cohen’s κ), chi-square/Fisher’s exact tests, and Cramer’s V effect sizes were applied. ER positivity declined from 85.7% (Stage I) to 28.6% (Stage IV) (P=0.008; V=0.41); PR declined similarly (78.6% to 14.3%; P=0.004; V=0.44). HER2, Ki-67 (>20%), and PD-L1 (TPS≥1%) increased with advancing stage (P=0.042, <0.001, and 0.011, respectively). Spearman’s correlations confirmed significant stage trends: Ki-67 (ρ=0.62; 95% CI: 0.45-0.75; P<0.001), PD-L1 (ρ=0.38; 95% CI: 0.16-0.56; P=0.001), ER (ρ=−0.44; P<0.001), and PR (ρ=−0.46; P<0.001). Stages III-IV were characterized by a predominance of aggressive subtypes (HER2-enriched, TNBC). High TILs were correlated with TNBC and PD-L1-positive tumors; dominance of M2 macrophages was significantly correlated with PD-L1 expression (Fisher’s exact P=0.009). Combinatory biomarker profiling and TME characterization identify stage-specific changes that could be used to improve patient stratification and guide therapeutic choices, especially the choice of immunotherapy in metastatic breast cancer. Future multicentric validation using standardized genomic subtyping is justified.
2. Harbeck N, Penault-Llorca F, Cortes J, Gnant M, Limburg P, Piccart M, et al. Breast cancer. Nat Rev Dis Primers 2019;5:66.
3. Early Breast Cancer Trialists’ Collaborative Group (EBCTCG). Relevance of breast cancer hormone receptors and other factors to the efficacy of adjuvant tamoxifen: patient-level meta-analysis of randomised trials. Lancet 2019;394:1447-58.
4. Gianni L, Pienkowski T, Im YH, Romanov V, Tseng LM, Liu MC, et al. Efficacy and safety of neoadjuvant pertuzumab and trastuzumab in women with locally advanced, inflammatory, or early HER2-positive breast cancer (NeoSphere): a randomised multicentre, open-label, phase 2 trial. Lancet Oncol 2012;13:25-32.
5. Aleskandarany MA, Rakha EA, Ahmed MA, Nolan CC, Ellis IO, Green AR, et al. Role of histopathological and molecular biomarkers in predicting response to neoadjuvant chemotherapy in breast cancer. Breast Cancer Res Treat 2016;157:415-24.
6. Schmid P, Adams S, Rugo HS, Schneeweiss A, Barrios CH, Iwata H, et al. Atezolizumab and nab-paclitaxel in advanced triple-negative breast cancer. N Engl J Med 2018;379:2108-21.
7. Cortes J, Cescon DW, Rugo HS, Nowecki Z, Im SA, Yusof MM, et al. Pembrolizumab plus chemotherapy versus placebo plus chemotherapy for previously untreated locally recurrent inoperable or metastatic triple-negative breast cancer (KEYNOTE-355): a randomised, double-blind, phase 3 clinical trial. Ann Oncol 2021;32(8):997-1007.
8. Binnewies M, Roberts EW, Kersten K, Chan V, Fearon DF, Merad M, et al. Understanding the tumor immune microenvironment (TIME) for effective therapy. Nat Med. 2023;29(3):534-46.
9. Salgado R, Denkert C, Demaria S, Sirtaine N, Klauschen F, Pruneri G, et al. The evaluation of tumor-infiltrating lymphocytes (TILs) in breast cancer: recommendations by an International TILs Working Group 2014. Ann Oncol 2015;26:259-71.
10. Loi S, Michiels S, Salgado R, Vandermeer S, Darb-Esfahani S, Langenberg MH, et al. Tumor infiltrating lymphocytes (TILs) in early breast cancer (EBC): results of the pooled analysis of the BIG-NABCG collaboration. Ann Oncol 2014;25:1536-43.
11. Denkert C, Loibl S, Noske A, Roller M, Muller BM, Komor M, et al. Tumor-associated lymphocytes as an independent predictor of response to neoadjuvant chemotherapy in breast cancer. J Clin Oncol 2010;28:105-13.
12. Medrek C, Ponten F, Jirstrom K, Leandersson K. The presence of tumor associated macrophages in tumor stroma as a prognostic marker for breast cancer patients. BMC Cancer 2012;12:306.
13. Loi S, Schmid P, Cortes J, Sonnenblick A, McArthur H, Lam M, et al. The evolving landscape of biomarkers for checkpoint inhibitor immunotherapy in breast cancer. Ann Oncol 2023;34:22-35.
14. Turner D, Ro J, Kim SB, Bartsch R, Yardley DA, Yap YS, et al. PD-L1 combined positive score as a predictive biomarker in metastatic triple-negative breast cancer: a systematic review and meta-analysis. Breast Cancer Res Treat 2022;193:321-33.
15. Hammond ME, Hayes DF, Dowsett M, Allred DC, Hagerty KL, Badve S, et al. American Society of Clinical Oncology/College of American Pathologists guideline recommendations for immunohistochemical testing of estrogen and progesterone receptors in breast cancer. J Clin Oncol 2010;28:2784-95.
16. Wolff AC, Hammond MEH, Allison KH, Harvey BE, Mangu PB, Bartlett JMS, et al. Human epidermal growth factor receptor 2 testing in breast cancer: American Society of Clinical Oncology/College of American Pathologists clinical practice guideline focused update. J Clin Oncol 2018;36:2105-22.
17. Goldhirsch A, Winer EP, Coates AS, Gelber RD, Piccart-Gebhart M, Thürlimann B, et al. Personalizing the treatment of women with early breast cancer: highlights of the St Gallen International Expert Consensus on the Primary Therapy of Early Breast Cancer 2013. Ann Oncol 2013;24:2206-23.
18. Perou CM, Sorlie T, Eisen MB, van de Rijn M, Jeffrey SS, Rees CA, et al. Molecular portraits of human breast tumours. Nature 2000;406:747-52.
19. Lehmann BD, Bauer JA, Chen X, Sanders ME, Chakravarthy AB, Shyr Y, et al. Identification of human triple-negative breast cancer subtypes and preclinical models for selection of targeted therapies. J Clin Invest 2011;121:2750-67.
20. Chen X, Zhang B, Tao L, Fan Y. Prognostic significance of PD-L1 expression in breast cancer: a systematic review and meta-analysis. Breast Cancer Res Treat 2020;180:295-305.
21. Loi S, Drubay D, Adams S, Pruneri G, Francis PA, Lacroix-Triki M, et al. Tumor-infiltrating lymphocytes and prognosis: a pooled individual patient analysis of early-stage triple-negative breast cancers. J Clin Oncol 2019;37:559-69.
22. Mittendorf EA, Zhang H, Barrios CH, Saji S, Jung KH, Hegg R, et al. Neoadjuvant atezolizumab in combination with sequential nab-paclitaxel and anthracycline-based chemotherapy versus placebo and chemotherapy in patients with early-stage triple-negative breast cancer (IMpassion031): a randomised, double-blind, phase 3 trial. Lancet 2020;396:1090-100.
23. Niu X, Zhang T, Qi C, Li X. Tumor-associated macrophages: a review of targeting vascular endothelial growth factor-A (VEGF-A) as an anti-angiogenic therapeutic strategy. Front Pharmacol 2017;8:108.
24. Adams S, Schmid P, Rugo HS, Winer EP, Loirat D, Awada A, et al. Health-related quality of life with pembrolizumab in advanced triple-negative breast cancer: results from the phase III KEYNOTE-355 trial. Ann Oncol 2020;31:640-7.
25. Rugo HS, Loi S, Adams S, Schmid P, Schneeweiss A, Barrios CH, et al. PD-L1 immunohistochemistry assay comparison in atezolizumab plus nab-paclitaxel-treated advanced triple-negative breast cancer. J Natl Cancer Inst. 2021;113:1733-43.
| Files | ||
| Issue | Vol 64 No 8 (2026) | |
| Section | Original Articles | |
| Keywords | ||
| Breast cancer Estrogen receptor Human epidermal growth factor receptor 2 (HER2) Ki-67 Programmed death-ligand 1 (PD-L1) Tumor microenvironment Tumor-infiltrating lymphocytes Molecular subtypes Immunohistochemistry AJCC staging | ||
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