A Signature That May Be Predictive of Early Versus Late Recurrence After Radiation Treatment for Breast Cancer That May Inform the Biology of Early, Aggressive Recurrences.

PURPOSE: Unmet clinical needs in breast cancer (BC) management include the identification of patients at high risk of local failure despite adjuvant radiation and an understanding of the biology of these recurrences. We previously reported a radiation response signature and here extend those studies to identify a signature predictive of recurrence timing (before or after 3 years). METHODS AND MATERIALS: Two independent patient cohorts were used. The training cohort included 119 patients with in-breast tumor recurrence (343 total), and the validation testing cohort had 16 patients with recurrences (112 total). All patients received radiation treatment after breast-conserving surgery. Initial feature selection used Spearman rank correlation, and a linear model was trained and locked before testing and validation. Cox regression was used for univariate and multivariable analyses (UVA and MVA, respectively). Biologically related concepts were identified using gene set enrichment analysis. RESULTS: Spearman correlation identified 485 genes whose expression was significantly associated with recurrence time (early vs late). Feature reduction further refined the list to 41 genes retained within the signature. In training, the correlation of score to recurrence time was 0.85 (P value < 1.3 × 10-31) with an area under the curve (AUC) of 0.91. Application of this early versus late signature to an independent BC testing and validation set accurately identified patients with early versus late recurrences (Spearman correlation = 0.75, P value = .001, AUC = 0.92, sensitivity = 0.75, specificity = 1.0, positive predictive value = 1.0, and negative predictive value = 0.8). Unique associations of breast cancer intrinsic subtype to timing of local recurrence were identified. In UVA and MVA the early versus late recurrence signature remained the most significant factor associated with recurrence. Gene set enrichment analysis identified proliferation and epidermal growth factor receptor concepts associated with early recurrences and luminal and ER-signaling pathways associated with late recurrences. Knockdown of genes associated with the early and late recurrences demonstrated novel effects on proliferation and clonogenic survival, respectively. CONCLUSIONS: We report a breast cancer gene signature that may identify patients unlikely to respond to adjuvant radiation and may be used to predict timing of recurrences with implications for potential treatment intensification and duration of follow-up for women with breast cancer treated with radiation.

Androgen receptor as a mediator and biomarker of radioresistance in triple-negative breast cancer.

Increased rates of locoregional recurrence have been observed in triple-negative breast cancer despite chemotherapy and radiation therapy. Thus, approaches that combine therapies for radiosensitization in triple-negative breast cancer are critically needed. We characterized the radiation therapy response of 21 breast cancer cell lines and paired this radiation response data with high-throughput drug screen data to identify androgen receptor as a top target for radiosensitization. Our radiosensitizer screen nominated bicalutamide as the drug most effective in treating radiation therapy-resistant breast cancer cell lines. We subsequently evaluated the expression of androgen receptor in >2100 human breast tumor samples and 51 breast cancer cell lines and found significant heterogeneity in androgen receptor expression with enrichment at the protein and RNA level in triple-negative breast cancer. There was a strong correlation between androgen receptor RNA and protein expression across all breast cancer subtypes (R2 = 0.72, p < 0.01). In patients with triple-negative breast cancer, expression of androgen receptor above the median was associated with increased risk of locoregional recurrence after radiation therapy (hazard ratio for locoregional recurrence 2.9-3.2)) in two independent data sets, but there was no difference in locoregional recurrence in triple-negative breast cancer patients not treated with radiation therapy when stratified by androgen receptor expression. In multivariable analysis, androgen receptor expression was most significantly associated with worse local recurrence-free survival after radiation therapy (hazard ratio of 3.58) suggesting that androgen receptor expression may be a biomarker of radiation response in triple-negative breast cancer. Inhibition of androgen receptor with MDV3100 (enzalutamide) induced radiation sensitivity (enhancement ratios of 1.22-1.60) in androgen receptor-positive triple-negative breast cancer lines, but did not affect androgen receptor-negative triple-negative breast cancer or estrogen-receptor-positive, androgen receptor-negative breast cancer cell lines. androgen receptor inhibition with MDV3100 significantly radiosensitized triple-negative breast cancer xenografts in mouse models and markedly delayed tumor doubling/tripling time and tumor weight. Radiosensitization was at least partially dependent on impaired dsDNA break repair mediated by DNA protein kinase catalytic subunit. Our results implicate androgen receptor as a mediator of radioresistance in breast cancer and identify androgen receptor inhibition as a potentially effective strategy for the treatment of androgen receptor-positive radioresistant tumors.

Benefits and risks of using gelatin solution as a plasma expander for perioperative and critically ill patients: a meta-analysis.

This meta-analysis aimed to evaluate the benefits and risks of gelatin solutions compared to other intravenous fluids for patients in perioperative and critical care settings. Of the 66 studies identified from MEDLINE and EMBASE databases, 30 randomised controlled trials involving 2709 patients met the inclusion criteria and were subject to meta-analysis. The risk of mortality (odds ratio 1.03, 95% confidence interval 0.80 to 1.32) and amount of blood loss (weighted-mean-difference 7.56 ml, 95% confidence interval 18.75 to 33.87) were not significantly different between patients who were treated with gelatin solutions and other types of intravenous fluids. When compared to starches, gelatin solutions were associated with a lower risk of acute renal failure (odds ratio 0.43, 95% confidence interval 0.20 to 0.92; P=0.03). When gelatin solutions were compared to isotonic albumin, patients who were treated with gelatin solutions required a small, but significantly greater amount of blood transfusion (weighted-mean-difference 180 ml, 95% confidence interval 8.1 to 353.6; P=0.04). These findings suggest that using gelatin solutions is associated with a lower risk of acute renal failure compared to older starches. Using gelatin as a plasma expander appears to have no significant advantages over crystalloids or isotonic albumin on mortality and may have a slightly higher risk of requiring allogeneic blood transfusion in perioperative and critically ill patients. An adequately powered randomised controlled trial with economic analysis is needed before gelatin solution can be recommended as a routine plasma expander for patients undergoing major surgery or who are critically ill.

Joining distributed pattern processing and homeostatic plasticity in recurrent on-center off-surround shunting networks: noise, saturation, short-term memory, synaptic scaling, and BDNF.

The activities of neurons vary within small intervals that are bounded both above and below, yet the inputs to these neurons may vary many-fold. How do networks of neurons process distributed input patterns effectively under these conditions? If a large number of input sources intermittently converge on a cell through time, then a serious design problem arises: if cell activities are sensitive to large inputs, then why do not small inputs get lost in internal system noise? If cell activities are sensitive to small inputs, then why do they not all saturate at their maximum values in response to large inputs and thereby become incapable of processing analog differences in inputs across an entire network? Grossberg (1973) solved this noise-saturation dilemma using neurons that obey the membrane, or shunting, equations of neurophysiology interacting in recurrent and non-recurrent on-center off-surround networks, and showed how different signal functions can influence the activity patterns that the network stores in short-term memory. These results demonstrated that maintaining a balance between excitation and inhibition in a neural network is essential to process distributed patterns of inputs and signals without experiencing the catastrophies of noise or saturation. However, shunting on-center off-surround networks only guarantee that cell activities remain sensitive to the relative sizes of inputs and recurrent signals, but not that they will use the full dynamic range that each cell can support. Additional homeostatic plasticity mechanisms are needed to anchor the activities of networks to exploit their full dynamic range. This article shows how mechanisms of synaptic scaling can be incorporated within recurrent on-center off-surround networks in such a way that their pattern processing capabilities, including the ability to make winner-take-all decisions, is preserved. This model generalizes the synaptic scaling model of van Rossum, Bi, & Turrigiano (2000) for a single cell to a pattern-processing network of shunting cells that is capable of short-term memory storage, including a representation of how BDNF may homeostatically scale the strengths of excitatory and inhibitory synapses in opposite directions.

Effectiveness of common shelter-in-place techniques in reducing ammonia exposure following accidental release.

Shelter-in-place strategies such as remaining indoors; breathing through a damp cloth; sealing cracks in windows and doors using towels, duct tape, or plastic sheeting; and running a shower are often recommended by emergency response officials to protect against accidental or intentional release of hazardous airborne chemicals and biologicals. Similar recommendations have been made to and used by community members exposed to anhydrous ammonia after catastrophic release of ammonia gas due to a derailment or other accidents. Such incidents have resulted in fatalities and serious injury to exposed individuals; however, other individuals within the same area have escaped injury and, in many cases, sustained no injuries as a result of sheltering-in-place. Although there are some studies that have evaluated the effectiveness of remaining in the home or breathing through a damp cloth to reduce exposure to various agents, there have been no studies that directly address the efficacy of running the shower in reducing exposure to ammonia gas. The present study was designed to simulate sheltering-in-place inside a typical bathroom with the shower running. The effectiveness of breathing through a damp cloth was also evaluated using a CPR mannequin placed inside a chamber built to represent a typical household bathroom. Ammonia gas at 300 or 1000 ppm was added to the chamber until the concentration peaked and stabilized, then the shower was turned on and the ammonia gas concentration was continuously monitored. In the mannequin studies, using a damp cloth reduced exposure to ammonia gas by 2- to 18-fold. Turning on the shower was even more effective at reducing ammonia levels. After 27 min, the ammonia concentration in the chamber was reduced to 2% of the initial concentration, even though gas was being continuously added to the chamber. These results indicate that use of shelter-in-place strategies substantially reduces ammonia exposure and that by combining shelter-in-place strategies, inhalation of ammonia gas can be reduced 100-fold even during prolonged exposure periods.