p53 functions in the heart to promote myocardial injury after multiple types of stress. However, how p53 regulates radiation-induced myocardial injury, which develops after radiation therapy, is not well understood. Here, we utilize the Cre-loxP system to demonstrate that p53 functioned in endothelial cells to protect mice from myocardial injury after whole-heart irradiation. Mice with an endothelial cell-specific deletion of p53 succumbed to heart failure after whole-heart irradiation due to myocardial necrosis, systolic dysfunction and cardiac hypertrophy. Moreover, the onset of cardiac dysfunction was preceded by alterations in myocardial vascular permeability and density, which resulted in cardiac ischemia and myocardial hypoxia. Mechanistic studies using primary cardiac endothelial cells irradiated in vitro indicated that p53 signaling caused mitotic arrest and protected cardiac endothelial cells against radiation-induced mitotic catastrophe. Furthermore, mice lacking the cyclin-dependent kinase inhibitor p21, which is a transcriptional target of p53, were also sensitized to myocardial injury after wholeheart irradiation. Together, our results demonstrate that the p53/p21 axis functions to prevent radiation-induced myocardial injury in mice.
BackgroundUtilizing the linear quadratic model and the radiosensitivity index (RSI), we have derived an expression for the genomically adjusted radiation dose (GARD) to model radiation dose effect. We hypothesize GARD is associated with local recurrence and can be used to optimize individual triple negative breast cancer (TNBC) radiation dose.MethodsTN patients from two independent datasets were assessed. The first cohort consisted of 58 patients treated at 5 European centers with breast conservation surgery followed by adjuvant radiotherapy (RT). The second dataset consisted of 55 patients treated with adjuvant radiation therapy.FindingsIn cohort 1, multivariable analysis revealed that as a dichotomous variable (HR: 2.5 95% CI 1–7.1; p = .05), GARD was associated with local control. This was confirmed in the second independent dataset where GARD was the only significant factor associated with local control (HR: 4.4 95% CI 1.1–29.5; p = .04). We utilized GARD to calculate an individualized radiation dose for each TN patient in cohort 2 by determining the physical dose required to achieve the GARD target value (GARD ≥ 21). While 7% of patients were optimized with a dose of 30 Gy, 91% of patients would be optimized with 70 Gy.InterpretationGARD is associated with local control following whole breast or post-mastectomy radiotherapy (RT) in TN patients. By modeling RT dose effect with GARD, we demonstrate that no single dose is optimal for all patients and propose the first dose range to optimize RT at an individual patient level in TNBC.
Background: To evaluate the effect of diabetes mellitus (DM) on clinical outcomes in patients managed surgically for non‐small cell lung cancer (NSCLC).
Methods: Patients who underwent surgery for pathological I‐IIIA NSCLC at Duke University from 1995–2005 were analyzed. Postoperative mortality was defined as any death occurring within 30 days of resection or during the initial hospitalization after surgery. Disease recurrence at the surgical margin, ipsilateral hilum, and/or mediastinum was considered a local/regional recurrence (LRR). Survival and LRR rates were estimated using the Kaplan‐Meier method and compared using a log rank test. A multivariate regression analysis assessed the association between candidate factors, including DM, and disease recurrence and survival.
Results: Of 957 patients, DM was present in 122 (13%). DM was associated with an increased risk of postoperative mortality (7.4% vs. 3.2%, P= 0.04). However, the proportion of patients undergoing sublobar resections, mediastinal lymph node dissection, and receiving adjuvant chemotherapy, was no different among patients with or without DM. Five‐year LRR rates were 27% in patients with DM, versus 21% in patients without DM (P= 0.23). Survival at five years was 43% for patients with DM, and 47% for patients without DM (P= 0.10). On multivariate analysis, DM was not independently associated with a higher risk of LRR (hazard ratio [HR] 1.33, P= 0.34), distant recurrence (HR 0.86, P= 0.58), or overall survival (HR 1.08, P= 0.63).
Conclusions: Although a higher risk of postoperative mortality was noted in patients with DM, a detriment in local or distant disease control or overall survival was not observed.
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