Purpose: The majority of deaths from breast cancer occur following the development of metastatic disease, a process inhibited by β-blockers in preclinical studies. This phase II randomized controlled trial evaluated the effect of preoperative β-blockade with propranolol on biomarkers of metastatic potential and the immune cell profile within the primary tumor of patients with breast cancer. Patients and Methods: In this triple-blind placebo-controlled clinical trial, 60 patients were randomly assigned to receive an escalating dose of oral propranolol (n = 30; 80–160 mg daily) or placebo (n = 30) for 7 days prior to surgery. The primary endpoint investigated the effect of propranolol on prometastatic and proinflammatory gene expression within the primary tumor. Results: Propranolol downregulated primary tumor expression of mesenchymal genes (P = 0.002) without affecting epithelial gene expression (P = 0.21). Bioinformatic analyses implicated downregulation of Snail/Slug (P = 0.03), NF-κB/Rel (P < 0.01), and AP-1 (P < 0.01) transcription factors in structuring the observed transcriptome alterations, and identified changes in intratumoral neutrophil, natural killer cell, and dendritic cell recruitment (all P < 0.01). Patients with clinical evidence of drug response (lowered heart rate and blood pressure) demonstrated elevated tumor infiltration of CD68+ macrophages and CD8+ T cells. Conclusions: One week of β-blockade with propranolol reduced intratumoral mesenchymal polarization and promoted immune cell infiltration in early-stage surgically-resectable breast cancer. These results show that β-blockade reduces biomarkers associated with metastatic potential, and support the need for larger phase III clinical trials powered to detect the impact of β-blockade on cancer recurrence and survival. See related commentary by Blaes et al., p. 1781

Introduction: Mammographic density (MD), after adjustment for a women’s age and body mass index, is a strong and independent risk factor for breast cancer (BC). Although the BC risk attributable to increased MD is significant in healthy women, the biological basis of high mammographic density (HMD) causation and how it raises BC risk remain elusive. We assessed the histological and immunohistochemical differences between matched HMD and low mammographic density (LMD) breast tissues from healthy women to define which cell features may mediate the increased MD and MD-associated BC risk. Methods: Tissues were obtained between 2008 and 2013 from 41 women undergoing prophylactic mastectomy because of their high BC risk profile. Tissue slices resected from the mastectomy specimens were X-rayed, then HMD and LMD regions were dissected based on radiological appearance. The histological composition, aromatase immunoreactivity, hormone receptor status and proliferation status were assessed, as were collagen amount and orientation, epithelial subsets and immune cell status. Results: HMD tissue had a significantly greater proportion of stroma, collagen and epithelium, as well as less fat, than LMD tissue did. Second harmonic generation imaging demonstrated more organised stromal collagen in HMD tissues than in LMD tissues. There was significantly more aromatase immunoreactivity in both the stromal and glandular regions of HMD tissues than in those regions of LMD tissues, although no significant differences in levels of oestrogen receptor, progesterone receptor or Ki-67 expression were detected. The number of macrophages within the epithelium or stroma did not change; however, HMD stroma exhibited less CD206⁺ alternatively activated macrophages. Epithelial cell maturation was not altered in HMD samples, and no evidence of epithelial–mesenchymal transition was seen; however, there was a significant increase in vimentin⁺/CD45⁺ immune cells within the epithelial layer in HMD tissues. Conclusions: We confirmed increased proportions of stroma and epithelium, increased aromatase activity and no changes in hormone receptor or Ki-67 marker status in HMD tissue. The HMD region showed increased collagen deposition and organisation as well as decreased alternatively activated macrophages in the stroma. The HMD epithelium may be a site for local inflammation, as we observed a significant increase in CD45⁺/vimentin⁺ immune cells in this area.

The rutile TiO₂(110) (1×1) surface is considered the prototypical ‘well-defined’ system in the surface science of metal oxides. Its popularity results partly from two experimental advantages: (i) bulk-reduced single crystals do not exhibit charging, and (ii) stoichiometric surfaces, as judged by electron spectroscopies, can be prepared reproducibly by sputtering and annealing in oxygen. We present results that show that this commonly applied preparation procedure may result in a surface structure that is by far more complex than generally anticipated. Flat, (1×1)-terminated surfaces are obtained by sputtering and annealing in ultrahigh vacuum. When re-annealed in oxygen at moderate temperatures (470–660 K), irregular networks of partially connected, pseudohexagonal rosettes (6.5×6 Åwide), one-unit cell wide strands, and small (≈tens of Å) (1×1) islands appear. This new surface phase is formed through reaction of oxygen gas with interstitial Ti from the reduced bulk. Because it consists of an incomplete, kinetically limited (1×1) layer, this phenomenon has been termed ‘restructuring’. We report a combined experimental and theoretical study that systematically explores this restructuring process. The influence of several parameters (annealing time, temperature, pressure, sample history, gas) on the surface morphology is investigated using STM. The surface coverage of the added phase as well as the kinetics of the restructuring process are quantified by LEIS and SSIMS measurements in combination with annealing in ¹⁸O-enriched gas. Atomic models of the essential structural elements are presented and are shown to be stable with first-principles density functional calculations. The effect of oxygen-induced restructuring on surface chemistry and its importance for TiO₂ and other bulk-reduced oxide materials is briefly discussed.