An integrated approach to the prediction of chemotherapeutic response in patients with breast cancer.

BACKGROUND: A major challenge in oncology is the selection of the most effective chemotherapeutic agents for individual patients, while the administration of ineffective chemotherapy increases mortality and decreases quality of life in cancer patients. This emphasizes the need to evaluate every patient's probability of responding to each chemotherapeutic agent and limiting the agents used to those most likely to be effective. METHODS AND RESULTS: Using gene expression data on the NCI-60 and corresponding drug sensitivity, mRNA and microRNA profiles were developed representing sensitivity to individual chemotherapeutic agents. The mRNA signatures were tested in an independent cohort of 133 breast cancer patients treated with the TFAC (paclitaxel, 5-fluorouracil, adriamycin, and cyclophosphamide) chemotherapy regimen. To further dissect the biology of resistance, we applied signatures of oncogenic pathway activation and performed hierarchical clustering. We then used mRNA signatures of chemotherapy sensitivity to identify alternative therapeutics for patients resistant to TFAC. Profiles from mRNA and microRNA expression data represent distinct biologic mechanisms of resistance to common cytotoxic agents. The individual mRNA signatures were validated in an independent dataset of breast tumors (P = 0.002, NPV = 82%). When the accuracy of the signatures was analyzed based on molecular variables, the predictive ability was found to be greater in basal-like than non basal-like patients (P = 0.03 and P = 0.06). Samples from patients with co-activated Myc and E2F represented the cohort with the lowest percentage (8%) of responders. Using mRNA signatures of sensitivity to other cytotoxic agents, we predict that TFAC non-responders are more likely to be sensitive to docetaxel (P = 0.04), representing a viable alternative therapy. CONCLUSIONS: Our results suggest that the optimal strategy for chemotherapy sensitivity prediction integrates molecular variables such as ER and HER2 status with corresponding microRNA and mRNA expression profiles. Importantly, we also present evidence to support the concept that analysis of molecular variables can present a rational strategy to identifying alternative therapeutic opportunities.

Characterization of Image Quality for 3D Scatter Corrected Breast CT Images.

The goal of this study was to characterize the image quality of our dedicated, quasi-monochromatic spectrum, cone beam breast imaging system under scatter corrected and non-scatter corrected conditions for a variety of breast compositions. CT projections were acquired of a breast phantom containing two concentric sets of acrylic spheres that varied in size (1-8mm) based on their polar position. The breast phantom was filled with 3 different concentrations of methanol and water, simulating a range of breast densities (0.79-1.0g/cc); acrylic yarn was sometimes included to simulate connective tissue of a breast. For each phantom condition, 2D scatter was measured for all projection angles. Scatter-corrected and uncorrected projections were then reconstructed with an iterative ordered subsets convex algorithm. Reconstructed image quality was characterized using SNR and contrast analysis, and followed by a human observer detection task for the spheres in the different concentric rings. Results show that scatter correction effectively reduces the cupping artifact and improves image contrast and SNR. Results from the observer study indicate that there was no statistical difference in the number or sizes of lesions observed in the scatter versus non-scatter corrected images for all densities. Nonetheless, applying scatter correction for differing breast conditions improves overall image quality.

Herbal Dietary Supplements: Safety, Efficacy, and Use by Breast Cancer Survivors

Gemstone Team IMAC (Integrative Medicine and Cancer)

Rare hereditary COL4A3/COL4A4 variants may be mistaken for familial focal segmental glomerulosclerosis.

Focal segmental glomerulosclerosis (FSGS) is a histological lesion with many causes, including inherited genetic defects, with significant proteinuria being the predominant clinical finding at presentation. Mutations in COL4A3 and COL4A4 are known to cause Alport syndrome (AS), thin basement membrane nephropathy, and to result in pathognomonic glomerular basement membrane (GBM) findings. Secondary FSGS is known to develop in classic AS at later stages of the disease. Here, we present seven families with rare or novel variants in COL4A3 or COL4A4 (six with single and one with two heterozygous variants) from a cohort of 70 families with a diagnosis of hereditary FSGS. The predominant clinical finding at diagnosis was proteinuria associated with hematuria. In all seven families, there were individuals with nephrotic-range proteinuria with histologic features of FSGS by light microscopy. In one family, electron microscopy showed thin GBM, but four other families had variable findings inconsistent with classical Alport nephritis. There was no recurrence of disease after kidney transplantation. Families with COL4A3 and COL4A4 variants that segregated with disease represent 10% of our cohort. Thus, COL4A3 and COL4A4 variants should be considered in the interpretation of next-generation sequencing data from such patients. Furthermore, this study illustrates the power of molecular genetic diagnostics in the clarification of renal phenotypes.

Postnatally-transmitted HIV-1 Envelope variants have similar neutralization-sensitivity and function to that of nontransmitted breast milk variants.

BACKGROUND: Breastfeeding is a leading cause of infant HIV-1 infection in the developing world, yet only a minority of infants exposed to HIV-1 via breastfeeding become infected. As a genetic bottleneck severely restricts the number of postnatally-transmitted variants, genetic or phenotypic properties of the virus Envelope (Env) could be important for the establishment of infant infection. We examined the efficiency of virologic functions required for initiation of infection in the gastrointestinal tract and the neutralization sensitivity of HIV-1 Env variants isolated from milk of three postnatally-transmitting mothers (n = 13 viruses), five clinically-matched nontransmitting mothers (n = 16 viruses), and seven postnatally-infected infants (n = 7 postnatally-transmitted/founder (T/F) viruses). RESULTS: There was no difference in the efficiency of epithelial cell interactions between Env virus variants from the breast milk of transmitting and nontransmitting mothers. Moreover, there was similar efficiency of DC-mediated trans-infection, CCR5-usage, target cell fusion, and infectivity between HIV-1 Env-pseudoviruses from nontransmitting mothers and postnatal T/F viruses. Milk Env-pseudoviruses were generally sensitive to neutralization by autologous maternal plasma and resistant to breast milk neutralization. Infant T/F Env-pseudoviruses were equally sensitive to neutralization by broadly-neutralizing monoclonal and polyclonal antibodies as compared to nontransmitted breast milk Env variants. CONCLUSION: Postnatally-T/F Env variants do not appear to possess a superior ability to interact with and cross a mucosal barrier or an exceptional resistance to neutralization that define their capability to initiate infection across the infant gastrointestinal tract in the setting of preexisting maternal antibodies.

Recombinant Adeno-Associated Virus-Mediated Gene Therapy for Treatment of Familial Hypercholesterolemia in Rabbits

Familial hypercholesterolemia (FH) is a genetic disorder characterized by abnormally high concentrations of low-density lipoprotein-cholesterol (LDLcholesterol) in the blood that can contribute to heart disease. FH can result from a defect in the gene for the LDL receptor (LDL-R). FH patients lacking functional LDL-R may benefit from viral-mediated transfer of a functional copy of the open reading frame (ORF) of the LDL-R. Since a recombinant adeno-associated virus (rAAV) is not immunogenic and can be mass-produced, it shows promise for gene therapy applications. AAV6 and AAV8 have been shown to specifically transduce hepatocytes in several species, which normally remove the majority of LDL-cholesterol from the blood via LDL-R-mediated endocytosis. Because of the potential of rAAV to treat FH by delivery of a correct LDL-R ORF to hepatocytes, the liver specificity of these two AAV serotypes was evaluated. Additionally, rabbits were chosen as the animal model for this study because a specific strain of rabbits, Watanabe heritable hyperlipidemic (WHHL), adequately mimics the pathology of FH in humans. Exposure of rabbit liver to rAAV with the marker LacZ and subsequent inspection of liver tissue showed that AAV8 transduced rabbit liver more efficiently than AAV6. To assess the feasibility of producing a rAAV capable of transferring the LDL-R ORF to rabbit hepatocytes in vivo, rAAV8-LDL-R was mass-produced by a baculovirus system in suspension grown insect cells.

Investigation and Development of a Fully 3D Tilt Capable Hybrid SPECT - CT System for Dedicated Breast Imaging

X-ray mammography has been the gold standard for breast imaging for decades, despite the significant limitations posed by the two dimensional (2D) image acquisitions. Difficulty in diagnosing lesions close to the chest wall and axilla, high amount of structural overlap and patient discomfort due to compression are only some of these limitations. To overcome these drawbacks, three dimensional (3D) breast imaging modalities have been developed including dual modality single photon emission computed tomography (SPECT) and computed tomography (CT) systems. This thesis focuses on the development and integration of the next generation of such a device for dedicated breast imaging. The goals of this dissertation work are to: [1] understand and characterize any effects of fully 3-D trajectories on reconstructed image scatter correction, absorbed dose and Hounsifeld Unit accuracy, and [2] design, develop and implement the fully flexible, third generation hybrid SPECT-CT system capable of traversing complex 3D orbits about a pendant breast volume, without interference from the other. Such a system would overcome artifacts resulting from incompletely sampled divergent cone beam imaging schemes and allow imaging closer to the chest wall, which other systems currently under research and development elsewhere cannot achieve.

The dependence of x-ray scatter radiation on object shape, size, material composition and the CT acquisition trajectory, was investigated with a well-established beam stop array (BSA) scatter correction method. While the 2D scatter to primary ratio (SPR) was the main metric used to characterize total system scatter, a new metric called ‘normalized scatter contribution’ was developed to compare the results of scatter correction on 3D reconstructed volumes. Scatter estimation studies were undertaken with a sinusoidal saddle (±15° polar tilt) orbit and a traditional circular (AZOR) orbit. Clinical studies to acquire data for scatter correction were used to evaluate the 2D SPR on a small set of patients scanned with the AZOR orbit. Clinical SPR results showed clear dependence of scatter on breast composition and glandular tissue distribution, otherwise consistent with the overall phantom-based size and density measurements. Additionally, SPR dependence was also observed on the acquisition trajectory where 2D scatter increased with an increase in the polar tilt angle of the system.

The dose delivered by any imaging system is of primary importance from the patient’s point of view, and therefore trajectory related differences in the dose distribution in a target volume were evaluated. Monte Carlo simulations as well as physical measurements using radiochromic film were undertaken using saddle and AZOR orbits. Results illustrated that both orbits deliver comparable dose to the target volume, and only slightly differ in distribution within the volume. Simulations and measurements showed similar results, and all measured dose values were within the standard screening mammography-specific, 6 mGy dose limit, which is used as a benchmark for dose comparisons.

Hounsfield Units (HU) are used clinically in differentiating tissue types in a reconstructed CT image, and therefore the HU accuracy of a system is very important, especially when using non-traditional trajectories. Uniform phantoms filled with various uniform density fluids were used to investigate differences in HU accuracy between saddle and AZOR orbits. Results illustrate the considerably better performance of the saddle orbit, especially close to the chest and nipple region of what would clinically be a pedant breast volume. The AZOR orbit causes shading artifacts near the nipple, due to insufficient sampling, rendering a major portion of the scanned phantom unusable, whereas the saddle orbit performs exceptionally well and provides a tighter distribution of HU values in reconstructed volumes.

Finally, the third generation, fully-suspended SPECT-CT system was designed in and developed in our lab. A novel mechanical method using a linear motor was developed for tilting the CT system. A new x-ray source and a custom made 40 x 30 cm2 detector were integrated on to this system. The SPECT system was nested, in the center of the gantry, orthogonal to the CT source-detector pair. The SPECT system tilts on a goniometer, and the newly developed CT tilting mechanism allows ±15° maximum polar tilting of the CT system. The entire gantry is mounted on a rotation stage, allowing complex arbitrary trajectories for each system, without interference from the other, while having a common field of view. This hybrid system shows potential to be used clinically as a diagnostic tool for dedicated breast imaging.

Incidence of febrile neutropenia and neutropenic infections in elderly patients receiving anthracycline-based chemotherapy for breast cancer without primary prophylaxis with colony-stimulating factors

There is concern about the potential increase of hematological toxicity in elderly patients treated with chemotherapy. Recently, primary prophylaxis with colony-stimulating factors (CSFs) was proposed for elderly patients receiving moderately toxic chemotherapy. However, evidence for the benefits of this primary prophylaxis for elderly breast cancer patients is currently lacking. We retrospectively analyzed the incidence of febrile neutropenia (FN) and neutropenic infections in elderly breast cancer patients receiving anthracycline-based chemotherapy without primary prophylaxis with colony-stimulating factors. In addition, we assessed the direct costs of hospitalization for these complications. Febrile neutropenia or neutropenic infection occurred in 13% of the 46 patients. Further studies are needed to adequately evaluate the risk of neutropenic complications (NC) in elderly patients receiving standard-dose chemotherapy for breast cancer and the potential benefits of primary prophylaxis with colony-stimulating factors. © 2004 Elsevier Ireland Ltd. All rights reserved.

The bigger the better? or what we know and what we still need to learn about anthracycline dose per course, dose density and cumulative dose in the treatment of breast cancer.

Clinical Trial

International guidelines for management of metastatic breast cancer: Can metastatic breast cancer be cured?

A distinctive subset of metastatic breast cancer (MBC) is oligometastatic disease, which is characterized by single or few detectable metastatic lesions. The existing treatment guidelines for patients with localized MBC include surgery, radiotherapy, and regional chemotherapy. The European School of Oncology-Metastatic Breast Cancer Task Force addressed the management of these patients in its first consensus recommendations published in 2007. The Task Force endorsed the possibility of a more aggressive and multidisciplinary approach for patients with oligometastatic disease, stressing also the need for clinical trials in this patient population. At the sixth European Breast Cancer Conference, held in Berlin in March 2008, the second public session on MBC guidelines addressed the controversial issue of whether MBC can be cured. In this commentary, we summarize the discussion and related recommendations regarding the available therapeutic options that are possibly associated with cure in these patients. In particular, data on local (surgery and radiotherapy) and chemotherapy options are discussed. Large retrospective series show an association between surgical removal of the primary tumor or of lung metastases and improved long-term outcome in patients with oligometastatic disease. In the absence of data from prospective randomized studies, removal of the primary tumor or isolated metastatic lesions may be an attractive therapeutic strategy in this subset of patients, offering rapid disease control and potential for survival benefit. Some improvement in outcome may also be achieved with optimization of systemic therapies, possibly in combination with optimal local treatment. © 2010. Published by Oxford University Press.

Androgens and breast cancer

info:eu-repo/semantics/published

Negative hormonal control by the androgen DHT and antiestrogen EM-139 on cell cycle kinetics and proliferation in human breast cancer ZR-75-1 cells

info:eu-repo/semantics/submittedForPublication

Androgens and breast cancer

We have recently demonstrated that physiological levels of androgens exert direct and potent inhibitory effects on the growth of human breast cancer ZR-75-1 cells in vivo in nude mice as well as in vitro under both basal and estrogen-stimulated conditions. The inhibitory effect of androgens has also been confirmed on the growth of dimethylbenz(a)anthracene (DMBA)-induced mammary carcinoma in the rat. Such observations are in close agreement with the clinical data showing that androgens and the androgenic compound medroxyprogesterone acetate (MPA) have beneficial effects in breast cancer in women comparable to other endocrine therapies, including tamoxifen. Although the inhibitory action of androgens on cell proliferation in estrogen-induced ZR-75-1 cells results, in part, from their suppressive effect on expression of the estrogen receptor, the androgens also exert a direct inhibitory effect independent of estrogens. Androgens cause a global slowing effect on the duration of the cell cycle. These observations support clinical data showing that androgenic compounds induce an objective remission after failure of antiestrogen therapy as well as those indicating that the antiproliferative action of androgens is additive to that of antiestrogens. We have also recently demonstrated in ZR-75-1 human breast cancer cells the antagonism between androgens and estrogens on the expression of GCDFP-15 and GCDFP-24 which are two major proteins secreted in human gross cystic disease fluid. The effects of androgens and estrogens as well as those of progestins and glucocorticoids on GCDFP-15 and GCDFP-24 mRNA levels and secretion are opposite to those induced by the same steroids on cell growth in ZR-75-1 cells.

Effect of lesion morphology on microwave signature in 2-D ultra-wideband breast imaging

This paper studies the possibility of distinguishing between benign and malignant masses by exploiting the morphology-dependent temporal and spectral characteristics of their microwave backscatter response in ultra-wideband breast cancer detection. The spiculated border profiles of 2-D breast masses are generated by modifying the baseline elliptical rings based upon the irregularity of their peripheries. Furthermore, the single- and multilayer lesion models are used to characterize a distinct mass region followed by a sharp transition to background, and a blurred mass border exhibiting a gradual transition to background, respectively. Subsequently, the complex natural resonances (CNRs) of the backscatter microwave signature can be derived from the late-time target response and reveal diagnostically useful information. The fractional sequence CLEAN algorithm is proposed to estimate the lesions' delay intervals and identify the late-time responses. Finally, it is shown through numerical examples that the locations of dominant CNRs are dependent on the lesion morphologies, where 2-D computational breast phantoms with single and multiple lesions are investigated. The analysis is of potential use for discrimination between benign and malignant lesions, where the former usually possesses a better-defined, more compact shape as opposed to the latter.