Antiangiogenic therapy is a promising approach for the treatment of breast cancer. In practice, however, only a subset of patients who receive antiangiogenic drugs demonstrate a significant response. A key challenge, therefore, is to discover biomarkers that are predictive of response to antiangiogenic therapy. To address this issue, we have designed a window-of-opportunity study in which bevacizumab is administered as a short-term first-line treatment to primary breast cancer patients. Central to our approach is the use of a detailed pharmacodynamic assessment, consisting of pre- and post-bevacizumab multi-parametric magnetic resonance imaging scans and core biopsies for exon array gene expression analysis. Here, we illustrate three intrinsic patterns of response to bevacizumab and discuss the molecular mechanisms that may underpin each. Our results illustrate how the combination of dynamic imaging data and gene expression profiles can guide the development of biomarkers for predicting response to antiangiogenic therapy.

<b><i>Introduction:</i></b> Tobacco contains several genotoxic agents including N-nitrosamine which has the potential to cause significant nuclear damage. Nuclear blebbing is a form of protrusion on the nuclear membrane and could potentially be caused by tobacco-induced genotoxicity and is closely associated with malignancy. Thus, the present study aimed to assess if tobacco-associated oral potentially malignant disorders including oral submucous fibrosis (OSF) and oral leukoplakia have a higher nuclear blebbing frequency than patients with normal oral mucosa with no history of tobacco use. <b><i>Methods:</i></b> The sample consisted of patients with OSF (<i>n</i> = 30) and oral leukoplakia (<i>n</i> = 10) and normal oral mucosa (<i>n</i> = 10). Exfoliated cells collected from the study groups were smeared on a clean microscopic slide and stained by May-Grunwald-Giemsa stain. A baseline frequency of nuclear blebbing was evaluated using a bright-field microscope with a ×100 objective. The number of nuclear blebbing per 1,000 epithelial cells was recorded and expressed in percentage. ANOVA, the Mann-Whitney U test, and Spearman’s correlation were used to analyze the data. <b><i>Results:</i></b> The mean rank of distribution of nuclear blebbing showed significant difference between all 3 groups, with the highest frequency noted in leukoplakia, followed by oral submucous and normal oral mucosa. Within OSF, the frequency of nuclear blebbing significantly increased from early stage to advanced stage. In OSF, a statistically significant positive linear correlation was noted between duration (in years), frequency (per day) of tobacco use, clinical grading, and nuclear blebbing. <b><i>Discussion/Conclusions:</i></b> The frequency of nuclear blebbing was significantly higher in oral potentially malignant disorders than normal mucosa. Nuclear blebbing also exhibited a strong dose- and time-dependent correlation with tobacco usage and clinical staging in OSF. The nuclear blebbing frequency could be a noninvasive, economic tool to assess malignant risk in tobacco-induced oral potentially malignant disorders.

No abstract

No abstract

Background: Anti-angiogenic therapy holds much promise for the treatment of breast cancer. In practice however, only a subset of patients who receive these drugs demonstrate a significant response to therapy. A key challenge therefore is to elucidate markers that are predictive of response to anti-angiogenic agents such as bevacizumab, and which would enable the selection of patients who would get the most benefit from these expensive therapies. Materials and Methods: We used high temporal resolution dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to assess tumor vascularity in 20 patients with primary breast cancer. Patients were imaged both before and two weeks after single dose Bevacizumab therapy (15mg/kg). Pharmacokinetic modelling techniques were used to quantify the volume transfer constant Ktrans, the rate constant kep, and the fractional volume of the extra-vascular extracellular space ve. Specifically, we used Tofts model with a population-based arterial input function (modified Fritz-Hansen) to model the contrast agent concentration time courses on a voxel-wise basis. Non-enhancing voxels were detected automatically with the use of a Bayesian noise model, and the corresponding pharmacokinetic parameter values for these voxels were set to zero. The median pharmacokinetic parameter values over the tumor volumes of interest were then computed both pre-and post Bevacizumab. Results: We found marked variation across patients in the baseline level and percentage change in median Ktrans, kep and ve following Bevacizumab. In particular, median Ktrans at baseline ranged form 0.12 to 0.88. Changes in median Ktrans varied from −97% to +19% across all patients, with an average change of −49%. Notably, we found a highly significant negative correlation (r = −0.92, P = 1e-08) between the absolute change in median Ktrans and the median Ktrans at baseline. In particular, tumors with a high median Ktrans at baseline demonstrated the greatest change in Ktrans following Bevacizumab therapy, whereas tumors with low median Ktrans at baseline demonstrated relatively little change in Ktrans. Discussion: Although Ktrans is a complex function of vessel permeability, surface area, and tumor blood flow, it has previously been demonstrated to be a reliable biomarker of response to anti-angiogenic therapy in a number of different cancers. Our results illustrate that therapy-induced changes in Ktrans can be predicted from the value of Ktrans at baseline, and hence DCE-MRI scans may enable the selection of primary breast cancer patients who show the greatest response to single-dose Bevacizumab therapy. Whether this will translate into longer term benefit and improvements in outcome for patients remains to be shown. The relationship between baseline and pre-/post-therapy change in Ktrans with the corresponding changes in gene expression is currently under study in a larger number of patients. Figure available in online version. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-02-07.

Background: Bevacizumab is an approved drug for advanced breast cancer alongside chemotherapy. To date there is no biomarker proven to be effective in patient stratification. To address this, a window of opportunity study was designed where bevacizumab is administered as a short-term first line treatment with a detailed pharmacodynamic assessment to identify the patients who are most likely to benefit from this therapy. This assessment consisted of Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) and gene expression analysis. Method: This is an on going two-centre, Phase II, non-randomised study. 43 locally advanced breast cancer patients aged &gt;18 years, with performance status 0-1 who have adequate bone marrow, renal and liver functions have been enrolled. A single infusion of bevacizumab (15mg/kg) was given prior to commencement of neoadjuvant chemotherapy. DCE-MRI and core biopsies for exon gene array analysis were performed both at baseline and 2 weeks after bevacizumab. Pharmacokinetic modelling of DCE-MRI was used to quantify the volume transfer constant Ktrans, the rate constant kep, and the fractional volume of the extra-vascular extracellular space ve. The median pharmacokinetic parameter values over the tumour volumes of interest were then computed both pre-and post-bevacizumab. Results: Our initial gene expression analysis from 21 patients showed a high variability in the response. This was true for both single gene analysis and pathway signatures. In particular the expression fold changes of hypoxia and proliferation signatures after bevacizumab ranged from a minimum of 0.6 fold decrease to a maximum of 4.3 fold increase. Interestingly, fold changes in both these signatures were significantly positively correlated (Spearman rho=0.81, P&lt;0.001). Changes in the proliferation signature were significantly inversely correlated with changes in mean and median ve (rho=-0.57, P&lt;0.01 in both cases). Changes in the hypoxia signature were significantly inversely correlated with changes in mean and median kep (rho=-0.48, p=0.03 and rho=-0.58, p=0.007 respectively). Significantly over-represented pathways amongst genes up-regulated after bevacizumab were T-cell activation, inflammation, PDGF and apoptosis signalling. Discussion: Our initial results provide several potentially important avenues for further research, which may be useful in the identification of new therapeutic approaches. For example, the unexpected correlation of induction of hypoxia and proliferation in the same tumours has important implications for combination therapy. Furthermore, patients whose tumours showed the largest reduction in kep, a measure of vascular leakiness, also showed the greatest increase in hypoxia. In addition, patients who experienced the largest reduction in ve showed the highest fold change in proliferation. Although these results are preliminary and will need to be confirmed at study completion, they illustrate how the integrated analysis of DCE-MRI pharmacokinetic parameters and the corresponding gene expression profiles may enable an improved understanding of the mechanisms governing response and resistance to bevacizumab. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-09-28.

No abstract