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Study Design: Retrospective cohort study.

Objective: Spinal metastases are common in patients with breast cancer, and accurate estimation of postoperative survival is crucial for selecting appropriate candidates for metastasis surgery. This study investigated the association between breast cancer subtype, according to the St. Gallen classification, and survival after surgery for spinal metastases with the aim of improving prognostic assessment and supporting informed patient counselling.

Methods:: This study included 110 patients with breast cancer who underwent surgery for spinal metastases identified from the Swedish Spine Register and the Swedish National Quality Register of Breast Cancer. Patients were categorized in terms of the breast cancer subtype according to the St. Gallen classification. Postoperative survival was analysed using Kaplan-Meier estimates and a Cox proportional hazards model.

Results: The overall median survival following spinal surgery was 25 months (95% CI 19-31), while the median postoperative survival by subtype was 39 months (95% CI 28-50) for luminal A patients, 20 months (95% CI 9-31) for luminal B patients, and 48 months (95% CI 20-76) for luminal B/HER2+ patients. The median survival was not reached for the nonluminal HER2+ group, whereas patients with triple-negative breast cancer had a median survival of only 5 months (95% CI 4-6). The St. Gallen subtype was significantly associated with postoperative survival according to univariable (P<0.001) and multivariable analyses (P = 0.011).

Conclusions: Breast cancer subtype according to the St. Gallen classification was significantly associated with survival after surgery for spinal metastases. These findings indicate that the St. Gallen classification may serve as a valuable prognostic tool in the metastatic spine setting. Incorporation of molecular subtype information may improve estimation of postoperative survival and support informed patient counselling, expectation management, and individualized surgical decision-making in patients with breast cancer spinal metastases.

Introduction: Fibrillar collagens accumulate in the breast cancer stroma and appear as poorly defined spiculated masses in mammography imaging. The prognostic value of tissue type I collagen remains elusive in treatment-naïve and chemotherapy-treated breast cancer patients. Here, type I collagen mRNA and protein expression were analysed in 2 large independent breast cancer cohorts. Levels were related to clinicopathological parameters, prognostic biomarkers, and outcome.

Method: COL1A1 mRNA expression was analysed in 2509 patients with breast cancer obtained from the cBioPortal database. Type I collagen protein expression was studied by immunohistochemistry in 1395 women diagnosed with early invasive breast cancer.

Results: Low COL1A1 mRNA and protein levels correlated with poor prognosis features, such as hormone receptor negativity, high histological grade, triple-negative subtype, node positivity, and tumour size. In unadjusted analysis, high stromal type I collagen protein expression was associated with improved overall survival (OS) (HR = 0.78, 95% CI = 0.61-0.99, p = .043) and trended towards improved breast cancer–specific survival (BCSS) (HR = 0.65, 95% CI = 0.42-1.01, P = 0.053), although these findings were lost after adjustment for other clinical variables. In unadjusted analysis, high expression of type I collagen was associated with better OS (HR = 0.70, 95% CI = 0.55-0.90, P = .006) and BCSS (HR = 0.55, 95% CI = 0.34-0.88, P = .014) among patients not receiving chemotherapy. Strikingly, the opposite was observed among patients receiving chemotherapy. There, high expression of type I collagen was instead associated with worse OS (HR = 1.83, 95% CI = 0.65-5.14, P = .25) and BCSS (HR = 1.72, 95% CI = 0.54-5.50, P = .357).

Conclusion: Low stromal type I collagen mRNA and protein expression are associated with unfavourable tumour characteristics in breast cancer. Stromal type I collagen might predict chemotherapy response.

Background: Breast cancer is the most common cancer in women. Cancer cells can persist in a prolonged dormant state for years without any clinical evidence of disease creating an urgent need to better understand the molecular mechanisms leading to relapse. This study aimed to identify extracellular matrix (ECM) components associated with hypoxia-induced breast cancer dormancy. The effects of selected ECM proteins on breast cancer cell proliferation were analyzed, along with their correlation with established prognostic markers in human breast cancer tissue.

Materials and methods: Screening of extracellular matrix proteins was performed in hypoxia-induced dormant MCF-7 breast cancer cells. Proliferation of MCF-7 cells in vitro was subsequently determined in the presence of recombinant ColVII. Adipose tissue-derived mesenchymal stem cells (AdMSCs) subpopulation overexpressing ColVII were indirectly isolated by ColVII receptor integrin-α6 specific antibodies. AdMSCs- MCF-7 3D spheroid cultures were generated to model solid tumour conditions. In addition, the association between ColVII and various prognostic markers was evaluated in clinical samples of human breast cancer tissue.

Results: Dormant MCF-7 cells showed an elevated expression of ColVII while MCF-7 cells cultured on ColVII exhibited reduced proliferation in vitro. In AdMSCs-MCF-7 3D spheroids, a reduced proliferation of MCF-7 cells was observed in Int-α6+/ ColVIIhigh compared with Int-α6-/ ColVIIlow AdMSCs spheroids. In human tissue, high ColVII expression correlated to several positive prognostic markers. Staining for Cytokeratin-5 revealed that ColVIIhigh-expressing cells were predominantly myoepithelial cells.

Conclusion: ColVII is associated with reduced proliferation of breast cancer cells in vitro. ColVII is strongly expressed in myoepithelial cells and in breast cancer tissue the high ColVII expression correlates with several well-known positive prognostic markers, highlighting its potential as a prognostic marker in breast cancer.