Protein phosphatase 2A (PP2A) inhibitor CIP2A indicates resistance to radiotherapy in rectal cancer.

Preoperative (chemo)radiotherapy, (C)RT, is an essential part of the treatment of rectal cancer patients, but tumor response to this therapy among patients is variable. Thus far, there are no clinical biomarkers that could be used to predict response to (C)RT or to stratify patients into different preoperative treatment groups according to their prognosis. Overexpression of cancerous inhibitor of protein phosphatase 2A (CIP2A) has been demonstrated in several cancers and is frequently associated with reduced survival.

Compass model-based quality assurance for stereotactic VMAT treatment plans.

Purpose: To use Compass as a model-based quality assurance (QA) tool for stereotactic body radiation therapy (SBRT) and stereotactic radiation therapy (SRT) volumetric modulated arc therapy (VMAT) treatment plans calculated with Eclipse treatment planning system (TPS).

Materials And Methods: Twenty clinical stereotactic VMAT SBRT and SRT treatment plans were blindly selected for evaluation. Those plans included four different treatment sites: prostate, brain, lung and body.

Dose monitoring in pediatric and young adult head and cervical spine CT studies at two emergency duty departments.

Purpose: As the number of pediatric computed tomography (CT) imaging is increasing, there is a need for real-time radiation dose monitoring and evaluation of the imaging protocols. The aim of this study was to present the imaging data, patient doses, and observations of pediatric and young adult trauma-and routine head CT and cervical spine CT collected by a dose monitoring software.

Methods: Patient age, study date, imaging parameters, and patient dose as volume CT dose index (CTDI) and dose length product (DLP) were collected from two emergency departments' CT scanners for 2-year period.

Excess of Radiation Burden for Young Testicular Cancer Patients using Automatic Exposure Control and Contrast Agent on Whole-body Computed Tomography Imaging.

Background: The aim of the study was to assess patient dose from whole-body computed tomography (CT) in association with patient size, automatic exposure control (AEC) and intravenous (IV) contrast agent.

Patients And Methods: Sixty-five testicular cancer patients (mean age 28 years) underwent altogether 279 whole-body CT scans from April 2000 to April 2011. The mean number of repeated examinations was 4.

LOW-DOSE CT PROTOCOL OPTIMIZATION FOR THE ASSESSMENT OF ACUTE APPENDICITIS: THE OPTICAP PHANTOM STUDY.

Unlabelled: The aim was to evaluate effects of voltage, noise input (NI) and iterative reconstruction (IR) on radiation dose and image quality in order to establish a contrast enhanced low-dose protocol for assessment of acute appendicitis. An anthropomorphic abdominal phantom mimicking contrast enhanced abdomen was scanned with 80, 100 and 120 kV, standard and strong IR and 11 NIs (66 protocols). A total of 14 test tubes of increasing iodine dilutions and one tube with an appendicolith were evaluated within the phantom.

Comparison of Effective Dose and Image Quality for Newborn Imaging on Seven Commonly Used CT Scanners.

This study compares the image quality and the patient doses on seven different computed tomography (CT) scanners for newborn chest imaging. The dose was measured by using an anthropomorphic newborn phantom and thermoluminescence dosemeters (TLDs). The effective dose was estimated separately based on a dose-length-product display, TLD measurements and the ImPACT CT dose calculation software.

HSV-1 Infection Modulates the Radioresponse of a HPV16-positive Head and Neck Cancer Cell Line.

Background: The combined effects of Human papillomavirus (HPV) and Herpes simplex type 1 (HSV-1) infections and their effects on cancer cell radioresistance are unexplored.

Materials And Methods: An HPV16-positive hypopharyngeal carcinoma cell line (UD-SCC-2) was infected with wt-HSV-1 at low multiplicity of infection (MOI) and irradiated with 2 Gy at 24 h postinfection. Viability assays and quantitative reverse-transcriptase PCR for HPV16 E6, E7, nuclear factor kappa B1, B-cell CLL/lymphoma 2 (BCL2), and caspases 3, 8 and 9 at 24, and 72 h, as well as immunocytochemistry for BCL2, caspase 3, cyclin E, mouse double minute 2 homolog (MDM2), HSV-1 and Ki-67 were performed at 144 h postirradiation.

Comparison of physical quality assurance between Scanora 3D and 3D Accuitomo 80 dental CT scanners.

Background: The use of cone beam computed tomography (CBCT) in dentistry has proven to be useful in the diagnosis and treatment planning of several oral and maxillofacial diseases. The quality of the resulting image is dictated by many factors related to the patient, unit, and operator.

Materials And Methods: In this work, two dental CBCT units, namely Scanora 3D and 3D Accuitomo 80, were assessed and compared in terms of quantitative effective dose delivered to specific locations in a dosimetry phantom.

CIP2A is an Oct4 target gene involved in head and neck squamous cell cancer oncogenicity and radioresistance.

Radiotherapy is a mainstay for treatment of many human cancer types, including head and neck squamous cell carcinoma (HNSCC). Thereby, it is clinically very relevant to understand the mechanisms determining radioresistance. Here, we identify CIP2A as an Oct4 target gene and provide evidence that they co-operate in radioresistance.

The combined effects of irradiation and herpes simplex virus type 1 infection on an immortal gingival cell line.

Background: Oral mucosa is frequently exposed to Herpes simplex virus type 1 (HSV-1) infection and irradiation due to dental radiography. During radiotherapy for oral cancer, the surrounding clinically normal tissues are also irradiated. This prompted us to study the effects of HSV-1 infection and irradiation on viability and apoptosis of oral epithelial cells.

Isocentric integration of intensity-modulated radiotherapy with electron fields improves field junction dose uniformity in postmastectomy radiotherapy.

Background: In postmastectomy radiotherapy (PMRT), the dose coverage of the planning target volume (PTV) with additional margins, including the chest wall, supraclavicular, interpectoral, internal mammary and axillar level I-III lymph nodes, is often compromised. Electron fields may improve the medial dose coverage while maintaining organ at risk (OAR) doses at an acceptable level, but at the cost of hot and cold spots at the electron and photon field junction. To improve PMRT dose coverage and uniformity, an isocentric technique combining tangential intensity-modulated (IM)RT fields with one medial electron field was implemented.

A dosimetric phantom study of dose accuracy and build-up effects using IMRT and RapidArc in stereotactic irradiation of lung tumours.

Background And Purpose: Stereotactic lung radiotherapy (SLRT) has emerged as a curative treatment for medically inoperable patients with early-stage non-small cell lung cancer (NSCLC) and the use of intensity-modulated radiotherapy (IMRT) and volumetric modulated arc treatments (VMAT) have been proposed as the best practical approaches for the delivery of SLRT. However, a large number of narrow field shapes are needed in the dose delivery of intensity-modulated techniques and the probability of underdosing the tumour periphery increases as the effective field size is decreased. The purpose of this study was to evaluate small lung tumour doses irradiated by intensity-modulated techniques to understand the risk for dose calculation errors in precision radiotherapy such as SLRT.

Identification and regulation of a stage-specific stem cell niche enriched by Nanog-positive spermatogonial stem cells in the mouse testis.

The ability of spermatogonial stem cells to acquire embryonic stem cell (ESC) properties in vitro has recently been of great interest. However, studies focused on the in vivo regulation of testicular stem cells have been hampered because the exact anatomical location of these cells is unknown. Moreover, no specialized stem cell niche substructure has been identified in the mammalian testis thus far.

Increased beam attenuation and surface dose by different couch inserts of treatment tables used in megavoltage radiotherapy.

The use of solid carbon fiber table materials in radiotherapy has become more common with the implementation of image-guided radiotherapy (IGRT), since the solid materials give less imaging artifacts than the so-called tennis racket couchtops. The downside of the solid carbon fiber couch inserts is that they increase the beam attenuation, resulting in increased surface doses and inaccuracies in determine the dose in the patient. The purpose of this study was to evaluate the interaction of 6 and 15 MV photons with eight different couch inserts.

A method to improve target dose homogeneity of craniospinal irradiation using dynamic split field IMRT.

Purpose: Craniospinal irradiation (CSI) is technically very challenging and field edge matching is needed because of the mechanical limitations of standard linear accelerators. We assessed the feasibility of intensity-modulated radiotherapy (IMRT) in CSI to overcome the standard feathering and dose inhomogeneities associated with the standard feathering technique in the junction areas.

Materials And Methods: The use of IMRT in CSI was studied with five patients CT scanned in the supine position.

The EGFR inhibitor gefitinib suppresses recruitment of pericytes and bone marrow-derived perivascular cells into tumor vessels.

Drugs that target EGFR have established anti-tumor effect and are used in the clinic. Here we addressed whether inhibition of EGFR tyrosine kinase activity by gefitinib in tumor microenvironment affected tumor angiogenesis or vasculogenesis. A syngeneic tumor model of mice with grafted GFP-labeled bone marrow cells was used to analyze the effects of gefitinib on different cellular components of tumor vasculature.

Concurrent cetuximab, cisplatin, and radiation for squamous cell carcinoma of the head and neck in vitro.

Background And Purpose: For locoregionally advanced HNSCC, chemoradiotherapy with cisplatin or another platinum compound is considered as one of the standard treatment regimes. Cisplatin has improved the loco-regional control, but also increased especially the acute side effects. Cetuximab blocks ligand binding and receptor activation by binding to the extracellular domain of the EGFR.

Concomitant chemoirradiation with vinorelbine and gefitinib induces additive effect in head and neck squamous cell carcinoma cell lines in vitro.

Background And Purpose: The study was performed to measure the radiosensitizing effect of vinorelbine together with gefitinib in head and neck squamous cell carcinoma (HNSCC) cell lines in vitro.

Materials And Methods: Three recently established HNSCC cell lines, originating from larynx and oral cavity tumors, were tested in this study. Vinorelbine concentration of 0.

Concurrent use of vinorelbine and gefitinib induces supra-additive effect in head and neck squamous cell carcinoma cell lines.

Purpose: Squamous cell carcinoma of the head and neck (HNSCC) remains a clinical challenge because of the high rate of locoregional disease recurrence. Standard treatment includes surgery, radiation, chemoradiation or a combination of these approaches. New therapies are needed to achieve improved survival, quality of life and organ function in these patients.

Signaling via ErbB2 and ErbB3 associates with resistance and epidermal growth factor receptor (EGFR) amplification with sensitivity to EGFR inhibitor gefitinib in head and neck squamous cell carcinoma cells.

Purpose: The epidermal growth factor receptor (EGFR) inhibitor gefitinib (Iressa) has shown antitumor activity in clinical trials against cancers, such as non-small cell lung cancer and head and neck squamous cell carcinoma (HNSCC). Research on non-small cell lung cancer has elucidated factors that may predict response to gefitinib. Less is known about molecular markers that may predict response to gefitinib in HNSCC patients.

Head and neck carcinoma cell lines are sensitive to vinflunine in vitro.

Background: New treatment models are needed for the management of advanced stage head and neck carcinomas (HNSCC). Vinflunine is a novel vinca alkaloid which has shown remarkable improvement in efficiency and reduced side-effects in both in vitro and in vivo studies. Better locoregional control and prevention of distant metastasis in advanced HNSCC would be welcome and, with this new efficient compound, these might be expected.

Preoperative hyperfractionated accelerated radiotherapy and radical surgery in advanced head and neck cancer: a prospective phase II study.

Background And Purpose: To evaluate whether preoperative hyperfractionated accelerated radiotherapy (RT) combined with major radical surgery is feasible and successful in the treatment of advanced primary head and neck cancer.

Patients And Methods: Ninety four patients with histologically confirmed head and neck squamous cell cancer (HNSCC) in the oral cavity (41/96; 43%), supraglottis (14/96; 15%), glottis (5/96; 5%), oropharynx (16/96; 17%), nasal cavity/paranasal sinuses (8/96; 8%), nasopharynx (3/96; 3%), hypopharynx (7/96; 7%) and two (2%) with unknown primary tumour and large cervical lymph nodes entered into the study. 21/96 patients (22%) had stage II, 17/96 (18%) stage III and 58/96 patients (60%) stage IV disease.

Head and neck squamous cell carcinoma cell lines are highly sensitive to the new taxanes, BMS-184476, BMS-188797, in vitro.

Background: The development of synthetic taxanes targets at increasing solubility of the drug, improved clinical efficacy and reduced side-effects. We evaluated the sensitivity of head and neck squamous cell carcinoma cell lines to BMS-184476 and BMS-188797 in vitro.

Materials And Methods: The effects of paclitaxel and the synthetic taxanes were tested on six recently established cell lines (3 oral cavity SCC, 3 laryngeal SCC) using the 96-well plate clonogenic assay.

Concomitant vinorelbine and radiation in head and neck squamous cell carcinoma in vitro.

Concomitant chemoradiotherapy has been used for locally advanced head and neck squamous cell carcinoma (HNSCC) particularily with cisplatin, 5-FU, methotrexate, bleomycin and taxanes. Vinorelbine is a semisynthetic vinca alcaloid, which causes a block in the G2/M phase of the cell cycle. HNSCC cell lines have previously been reported to be sensitive to vinorelbine in nanomolar concentrations.