Topology and adenocarcinoma cell localization dataset on the labyrinthin diapeutic biomarker.

OBJECTIVE: The discovery and characterization of tumor associated antigens is increasingly important to advance the field of immuno-oncology. In this regard, labyrinthin has been implicated as a neoantigen found on the cell surface of adenocarcinomas. Data on the (1) topology, (2) amino acid (a.a.) homology analyses and (3) cell surface localization of labyrinthin by fluorescent activated cell sorter (FACS) are studied in support of labyrinthin as a novel, pan-adenocarcinoma marker. RESULTS: Bioinformatics analyses predict labyrinthin as a type II protein with calcium binding domain(s), N-myristoylation sites, and kinase II phosphorylation sites. Sequence homologies for labyrinthin (255 a.a.) were found vs. the intracellular aspartyl/asparaginyl beta-hydroxylase (ASPH; 758 a.a.) and the ASPH-gene related protein junctate (299 a.a.), which are both type II proteins. Labyrinthin was detected by FACS on only non-permeablized A549 human lung adenocarcinoma cells, but not on normal WI-38 human lung fibroblasts nor primary cultures of normal human glandular-related cells. Microscopic images of immunofluorescent labelled MCA 44-3A6 binding to A549 cells at random cell cycle stages complement the FACS results by further showing that labyrinthin persisted on the cell surfaces along with some cell internalization for greater than 20 min.

Labyrinthin Expression Is Associated with Poor Prognosis in Patients with Non-Small-Cell Lung Cancer.

To determine Labyrinthin (LAB) expression in non-small-cell lung cancer (NSCLC), we immunostained and scored for LAB immunohistochemistry (IHC) expression on sections of tissue microarrays (TMAs) prepared from 256 archival tissue blocks of NSCLC. Propensity-score-weighted Kaplan-Meier curves and weighted Cox models were used to associate LAB expression with overall survival. LAB mRNA expression was assessed in The Cancer Genome Atlas (TCGA) and correlated with clinical phenotype and outcome. Positive LAB IHC expression (>5% of tumor cells) was detected in 208/256 (81.3%) of NSCLC samples, and found in both lung adenocarcinomas (LUAD) and lung squamous cell cancer (LUSC). LAB positivity was associated with poor overall survival (HR = 3.56, 95% CI: 2.3-5.4; p < 0.0001) and high tumor differentiation grade or metastasis compared with negative LAB expression. Univariant and multivariate survival analyses demonstrated LAB expression as an independent prognostic factor for NSCLC patients. LAB RNA expression in TCGA-LUAD was higher in primary and advanced-stage tumors than in normal tissue, and was associated with poorer overall survival. No significant differences or associations were found with LAB RNA expression in TCGA-LUSC. The LAB IHC assay is being used to identify candidate cancer patients for the first-in-human phase I trial evaluating the LAB vaccines (UCDCC#296, NCT051013560).

Labyrinthin: A distinct pan-adenocarcinoma diagnostic and immunotherapeutic tumor specific antigen.

Structural analysis and detection of optimal cell surface localization of labyrinthin, a pan-adenocarcinoma target, was studied with respect to adenocarcinoma specificity vs. normal and non-adenocarcinoma cells. Patient-derived tissue microarray immunohistochemistry (IHC) was performed on 729 commercially prepared tissue blocks of lung, colon, breast, pancreas, prostate, and ovary cancers combined, plus a National Cancer Institute (NCI) tissue microarray derived from another 236 cases. The results confirmed that anti-labyrinthin mouse monoclonal MCA 44-3A6 antibody recognized adenocarcinomas, but not normal or non-adenocarcinoma cancer cells. The consensus of multiple topology analysis programs on labyrinthin (255 amino acids) estimate a type II cell membrane associated protein with an N-terminus signal peptide. However, because the labyrinthin sequence is enveloped within the 758 amino acids of the intracellular aspartyl/asparaginyl beta-hydroxylase (ASPH), a purported tumor associated antigen, standard IHC methods that permeabilize cells can expose common epitopes. To circumvent antibody cross-reactivity, cell surface labyrinthin was distinguished from intracellular ASPH by FACS analysis of permeabilized vs non-permeabilized cells. All permeabilized normal, adeno-and non-adenocarcinoma cells produced a strong MCA 44-3A6 binding signal, likely reflecting co-recognition of intracellular ASPH proteins along with internalized labyrinthin, but in non-permeabilized cells only adenocarcinoma cells were positive for labyrinthin. Confocal microscopy confirmed the FACS results. Labyrinthin as a functional cell-surface marker was suggested when: 1) WI-38 normal lung fibroblasts transfected with labyrinthin sense cDNA displayed a cancerous phenotype; 2) antisense transfection of A549 human lung adenocarcinoma cells appeared more normal; and 3) MCA44-3A6 suppressed A549 cell proliferation. Collectively, the data indicate that labyrinthin is a unique, promising adenocarcinoma tumor-specific antigen and therapeutic target. The study also raises a controversial issue on the extent, specificity, and usefulness of ASPH as an adenocarcinoma tumor-associated antigen.

Dual Role of microRNAs in Autophagy of Colorectal Cancer.

Autophagy is an evolutionarily conserved pathway that eliminates unwanted proteins out of the cell and increases cell survival. However, dysfunctional autophagy is associated with cancer progression, cellular adaptation, cancer metastasis and makes it an attractive therapeutic target. MicroRNAs (miRNAs) are small single-stranded non-coding RNA molecules that usually bind to 3'UTR of mRNAs. This interaction eventually inhibits protein synthesis by repressing translation and/or by degrading mRNAs. miRNAs play a crucial role in the regulation of autophagy and also behave as both tumor suppressors and promoters in colorectal cancer. This paper defines an overall molecular view of how miRNAs regulate the dual role of autophagy in colorectal cancer. It also highlights how long noncoding RNAs modulate miRNAs expression to regulate autophagy in colorectal cancer. Thus, targeting autophagy by miRNAs seems to be a potential therapeutic strategy for colorectal cancer.

DNA Methylation in Human Breast Cancer Cell Lines Adapted to High Nitric Oxide.

BACKGROUND: Nitric oxide (NO) exposure has been suggested to cause alterations in DNA methylation in breast cancer. We investigated the effect of NO on DNA methylation of promoters in cell lines of breast cancer. MATERIAL AND METHODS: The methylation status of the promoters of breast cancer 1 (BRCA1), deleted in colon cancer (DCC), Ras-association domain family 1A (RASSF1A), O6-methylguanine-DNA methyltransferase (MGMT), and secreted frizzled related protein 1 (SFRP1) were analyzed in the parental and high nitric oxide-adapted cell lines of breast cancer using Illumina MiSequencing. RESULTS: Methylation of RASSF1A promoter in BT-20-HNO (74.7%) was significantly higher than that in BT-20 cells (72%) (p<0.05), whereas in MCF-7-HNO cells, methylation of MGMT promoter was found to have significantly decreased as compared to its parental cell line (45.1% versus 50.1%; p<0.0001). Promoter methylation of SFRP and DCC was elevated in T-47D-HNO relative to its parent cell line (p<0.05). CONCLUSION: Similarly to the double-edged effects of NO on tumorigenesis, its epigenetic effects through DNA methylation are diverse and contradictory in breast cancer.

Labyrinthin, The Tumor Marker Recognized By MCA 44-3A6: A Case For Pan-Tumor Markers As Targets To Treat Cancer.

A paradigm shift is currently underway on the relationship between cancer treatment markers and therapies. Labyrinthin is a prime example of such a marker because it is a pan-cancer target for adenocarcinomas. This movement supports the idea that we must change our thinking from various cancer types (eg, lung, breast, colon) to "cancer arising" in a given tissue or organ. In doing so, this would further support the efforts toward pan-treatments rather than organ-specific treatments.

Colder environments are associated with a greater cancer incidence in the female population of the United States.

Cancer incidence and/or mortality among individuals varies with diet, socio-culture, ethnicity, race, gender, and age. Similarly, environmental temperature modulates many biological functions. To study the effect of environment temperature on cancer incidence, the US population was selected. Because, county-wise cancer incidence rate data of various anatomical site-specific cancers and different races/ethnicities for both males and females are available. Moreover, the differences amongst the aforementioned factors among individuals are much less, as compared to the world population. Statistical analysis showed a negative correlation between the average annual temperature and cancer incidence rate at all anatomical sites and individually for 13 types (out of 16 types) of anatomical site-specific cancer incidence rates (e.g. uterine, bladder, thyroid, breast, esophagus, ovary, melanoma, non-Hodgkin lymphoma, leukemia, brain, pancreas, etc.) for females. Further analysis found a similar inverse trend in all races/ethnicities of the female population but not in all male races/ethnicities or anatomical site-specific cancers. Moreover, the majority of the counties having the top-most cancer incidence rate in females are located above the latitude 36.5°N. These findings indicate that living in a cold county in the United States might have a higher risk of cancer irrespective of cancer type (except cervical and liver) and races/ethnicities for females but not in all such cases for the male population.

Expression of cross-tolerance to a wide range of conditions in a human lung cancer cell line after adaptation to nitric oxide.

Previously, we have shown that A549, a human lung adenocarcinoma, can be adapted to nitric oxide (NO●). NO● is a nitrogen-based free radical that is synthesized by a family of enzymes known as nitric oxide synthases. NO● has been shown to be overexpressed in patient populations of different cancers. In addition, it has been observed that patients who express high levels of nitric oxide synthases tend to have poorer clinical outcomes than those with low levels of expression. The original cell line A549 (parent) and the adapted A549-HNO (high nitric oxide) cell line serve as a useful model system to investigate the role of NO● in tumor progression and prognosis. We have previously shown that the A549-HNO-adapted cells grow aggressively when compared to A549-parent cells. Furthermore, we have shown that the A549-HNO-adapted cells exhibit a higher percentage of cell viability when exposed to ultraviolet and X-ray radiation than the A549-parent cells. Cancer patients who develop resistance to one treatment often become resistant to other previously unencountered forms of treatment. This phenomenon is known as cross-tolerance. To determine whether NO● is a potential cross-tolerance causing agent, we have expanded our research by conducting parallel studies to a variety of other agents and conditions beyond radiation and ultraviolet exposure. We exposed both cell lines to varying levels of chemotherapeutic drugs (taxol and doxorubicin), temperature, pH, calcium chloride, cadmium chloride, copper chloride, sodium chloride, ferrous chloride, and sodium-R-lipoic acid. Our results show that the A549-HNO cells exhibit greater viability than the A549-parent cells when exposed to each of the various conditions. Therefore, NO● is one potential driving force that can make tumor cells exhibit cross-tolerance.

Is cholesterol a mediator of cold-induced cancer?

Many factors such as smoking, obesity, and high fat have been either directly or indirectly linked to cancer deaths and/or incidences. Similarly, abnormal serum cholesterol levels have been assigned as a risk factor for cancer, but some studies show a discrepant result. To resolve this discrepancy, we have analyzed cholesterol data of 166 countries. Univariate analysis showed a positive correlation between serum average total cholesterol (ATC) and overall cancer mortality rate (CMR) [tau = 0.277, z = 5.19, p < 0.0001]. It was also observed that a similar positive correlation was found between ATC and different anatomical site-specific CMRs in lung, bladder, ovarian, breast, and pancreatic cancers. Our recent published data documented an existence of a negative correlation between average annual temperature (AAT) and overall CMR, as well as CMR of the abovementioned anatomical site-specific cancers. Statistical analysis further shows a negative correlation between AAT and ATC, similar to that of AAT and CMR. The resulting patterns of univariate analysis between AAT and CMR are almost identical with AAT and ATC, when this analysis was performed every 2 °C of AAT increment for all countries. Moreover, geographical location of the top 50 countries having the highest CMR is almost similar to the top 50 countries having the highest ATC. Similarly, the least 50 countries having the lowest CMR are located in the same geographical region, similar to the least 50 countries having the lowest ATC. These data along with other literature reports suggest that cholesterol could be a mediator of cold-induced cancer mortality.

A Molecular View of Pathological Microcalcification in Breast Cancer.

Breast microcalcification is a potential diagnostic indicator for non-palpable breast cancers. Microcalcification type I (calcium oxalate) is restricted to benign tissue, whereas type II (calcium hydroxyapatite) occurs both in benign as well as in malignant lesions. Microcalcification is a pathological complication of the mammary gland. Over the past few decades, much attention has been paid to exploit this property, which forms the basis for advances in diagnostic procedures and imaging techniques. The mechanism of its formation is still poorly understood. Hence, in this paper, we have attempted to address the molecular mechanism of microcalcification in breast cancer. The central theme of this communication is "how a subpopulation of heterogeneous breast tumor cells attains an osteoblast-like phenotype, and what activities drive the process of pathophysiological microcalcification, especially at the invasive or infiltrating front of breast tumors". The role of bone morphogenetic proteins (BMPs) and tumor associated macrophages (TAMs) along with epithelial to mesenchymal transition (EMT) in manipulating this pathological process has been highlighted. Therefore, this review offers a novel insight into the mechanism underlying the development of microcalcification in breast carcinomas.

Glutamine at focus: versatile roles in cancer.

During the past decade, a heightened understanding of metabolic pathways in cancer has significantly increased. It is recognized that many tumor cells are genetically programmed and have involved an abnormal metabolic state. Interestingly, this increased metabolic autonomy generates dependence on various nutrients such as glucose and glutamine. Both of these components participate in various facets of metabolic activity that allow for energy production, synthesis of biomass, antioxidant defense, and the regulation of cell signaling. Here, we outline the emerging data on glutamine metabolism and address the molecular mechanisms underlying glutamine-induced cell survival. We also discuss novel therapeutic strategies to exploit glutamine addiction of certain cancer cell lines.

A549 cells adapted to high nitric oxide show reduced surface CEACAM expression and altered adhesion and migration properties.

The migration and adhesion properties of tumors affect their metastatic rate. In the present study, we investigated carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 1, 5, and 6 expression in high nitric oxide (HNO)-adapted lung cancer cells compared to parent cells. We observed high transcript levels of CEACAM 1 (4S, 4L), CEACAM 5, and CEACAM 6 in HNO cells compared to parent cells. However, the surface expression was low in HNO cells. Interestingly, the intracellular protein levels were high for these three CEACAMs. We confirmed these results with immunohistochemical experiments. Further, the adhesion and migration assays showed reduced clumping in HNO-adapted A549 (A549-HNO) cells and faster migration rates, respectively. These results document the altered adhesion and migration properties of cells adapted to HNO. Further, our studies also indicate a dynamic regulation of CEACAM protein expression and surface transport in HNO cells.

Part I-mechanism of adaptation: high nitric oxide adapted A549 cells show enhanced DNA damage response and activation of antiapoptotic pathways.

Our previous studies demonstrate that A549, a human lung adenocarcinoma line, could be adapted to the free radical nitric oxide (NO([Symbol: see text])). NO([Symbol: see text]) has been shown to be overexpressed in human tumors. The original cell line, A549 (parent), and the newly adapted A549-HNO (which has a more aggressive phenotype) serves as a useful model system to study the role of NO([Symbol: see text]) in tumor biology. It is well known that DNA damage response (DDR) is altered in cancer cells and NO([Symbol: see text]) is known to cause DNA damage. Modulations in molecular mechanisms involved in DNA damage response in A549-HNO cells can provide better insights into the enhanced growth behavior of these cells. Thus, here, we carried out a series of time course experiments by treating A549 and A549-HNO cells with NO([Symbol: see text]) donor and examining levels of proteins involved in the DDR pathway. We observed induced expression of key components of DDR pathway in A549-HNO cells. The HNO cells showed sustained expression of key proteins involved in both nonhomologous end joining (NHEJ) and homologous recombination pathways, whereas parent cells only expressed low levels of NHEJ pathway proteins. Further with prolonged NO([Symbol: see text]) exposure, ATR, Chk1, and p53 were activated and upregulated in HNO cells. Activation of p53 results in inhibition of apoptosis through induced Mcl1 expression. It also leads to cell cycle modulation. Interestingly, several reports show that cancer stem cells have enhanced expression of proteins involved in DNA damage response and also activated an antiapoptotic response. Our results here suggest that our HNO adapted A549 cells have increased activation of DNA damage response pathway proteins which can lead to better DNA repair function. Enhanced DDR leads to activation of antiapoptosis response and modulation in the cell cycle which may lead to better survival of these cells under harsh conditions. Thus, our present investigation further supports the hypothesis that HNO exposure leads to survival of these cells.

Part II-mechanism of adaptation: A549 cells adapt to high concentration of nitric oxide through bypass of cell cycle checkpoints.

Previous work has shown enhanced survival capacity in high nitric oxide (HNO)-adapted tumor cells. In Part I of this series of manuscripts, we have shown that A549-HNO cells demonstrate an improved growth profile under UV and X-ray radiation treatment. These cells exhibit increased expression of proteins involved in DNA damage recognition and repair pathway, both the non-homologous end joining pathway and homologous recombination. These include Ku80, DNA-PK, XLF ligase and MRN complex proteins. Further, the A549-HNO cells show high levels of ATM, ATR, Chk1 and Chk2, and phospho-p53. Activation of these molecules may lead to cell cycle arrest and apoptosis due to DNA damage. This is observed in parent A549 cells in response to NO donor treatment; however, the A549-HNO cells proliferate and inhibit apoptosis. Cell cycle analysis showed slowed progression through S phase which will allow time for DNA repair. Thus, to better understand the increased growth rate in A549-HNO when compared to the parent cell line A549, we studied molecular mechanisms involved in cell cycle regulation in A549-HNO cells. During the initial time period of NO donor treatment, we observe high levels of cyclin/Cdk complexes involved in regulating various stages of the cell cycle. This would lead to bypass of G1-S and G2-M checkpoints. The HNO cells also show much higher expression of Cdc25A. Cdc25A activates Cdk molecules involved in different phases of the cell cycle. In addition, there is enhanced phosphorylation of the Rb protein in HNO cells. This leads to inactivation of Rb/E2F checkpoint regulating G1-S transition. This may lead to faster progression in S phase. Thus, all of these perturbations in HNO cells lead to accelerated cell cycle progression and a higher growth rate. We also assessed expression of cell cycle inhibitors in HNO cells. Interestingly, the HNO cells show a significant decline in p21CIP1 at initial time points, but with prolonged exposure, the levels were much higher than those of the parent cells. This suggests an initial bypass of cell cycle checkpoints as p21CIP1 can inhibit the activity of all cyclin/Cdk complexes. p21CIP1 is also known to inhibit p53-induced apoptosis. This could be important during later phases of the cell cycle to allow time for repair of damaged DNA and thus better survival of HNO cells.

Photodynamic therapy: occupational hazards and preventative recommendations for clinical administration by healthcare providers.

OBJECTIVE: Photodynamic therapy (PDT) as a medical treatment for cancers is an increasing practice in clinical settings, as new photosensitizing chemicals and light source technologies are developed and applied. PDT involves dosing patients with photosensitizing drugs, and then exposing them to light using a directed energy device in order to manifest a therapeutic effect. Healthcare professionals providing PDT should be aware of potential occupational health and safety hazards posed by these treatment devices and photosensitizing agents administered to patients. MATERIALS AND METHODS: Here we outline and identify pertinent health and safety considerations to be taken by healthcare staff during PDT procedures. RESULTS: Physical hazards (for example, non-ionizing radiation generated by the light-emitting device, with potential for skin and eye exposure) and chemical hazards (including the photosensitizing agents administered to patients that have the potential for exposure via skin, subcutaneous, ingestion, or inhalation routes) must be considered for safe use of PDT by the healthcare professional. CONCLUSIONS: Engineering, administrative, and personal protective equipment controls are recommendations for the safe use and handling of PDT agents and light-emitting technologies.

Application of immunohistochemical staining to detect antigen destruction as a measure of tissue damage.

Electrocautery and directed energy devices (DEDs) such as lasers, which are used in surgery, result in tissue damage that cannot be readily detected by traditional histological methods, such as hematoxylin and eosin staining. Alternative staining methods, including 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) to stain live tissue, have been reported. Despite providing superior detection of damaged tissue relative to the hematoxylin and eosin (H&E) method, the MTT method possesses a number of drawbacks, most notably that it must be carried out on live tissue samples. Herein, we report the development of a novel staining method, "antigen destruction immunohistochemistry" (ADI), which can be carried out on paraffin-embedded tissue. The ADI method takes advantage of epitope loss to define the area of tissue damage and provides many of the benefits of live tissue MTT staining without the drawbacks inherent to that method. In addition, the authors provide data to support the use of antibodies directed at a number of gene products for use in animal tissue for which there are no species-specific antibodies commercially available, as well as an example of a species-specific direct antibody. Data are provided that support the use of this method in many tissue models, as well as evidence that ADI is comparable to the live tissue MTT method.

Long-term adaptation of the human lung tumor cell line A549 to increasing concentrations of hydrogen peroxide.

Previously, we demonstrated that A549, a human lung cancer cell line, could be adapted to the free radical nitric oxide (NO●). NO● is known to be over expressed in human tumors. The original cell line, A549 (parent), and the newly adapted A549-HNO (which has a more aggressive phenotype) serve as a useful model system to study the biology of NO●. To see if tumor cells can similarly be adapted to any free radical with the same outcome, herein we successfully adapted A549 cells to high levels of hydrogen peroxide (HHP). A549-HHP, the resulting cell line, was more resistant and grew better then the parent cell line, and showed the following characteristics: (1) resistance to hydrogen peroxide, (2) resistance to NO●, (3) growth with and without hydrogen peroxide, and (4) resistance to doxorubicin. Gene chip analysis was used to determine the global gene expression changes between A549-parent and A549-HHP and revealed significant changes in the expression of over 1,700 genes. This gene profile was markedly different from that obtained from the A549-HNO cell line. The mitochondrial DNA content of the A549-HHP line determined by quantitative PCR favored a change for a more anaerobic metabolic profile. Our findings suggest that any free radical can induce resistance to other free radicals; this is especially important given that radiation therapy and many chemotherapeutic agents exert their effect via free radicals. Utilizing this model system to better understand the role of free radicals in tumor biology will help to develop new therapeutic approaches to treat lung cancer.

Verification of dose distribution for volumetric modulated arc therapy total marrow irradiation in a humanlike phantom.

PURPOSE: Volumetric modulated arc therapy (VMAT) treatment planning studies have been reported to provide good target coverage and organs at risk (OARs) sparing in total marrow irradiation (TMI). A comprehensive dosimetric study simulating the clinical situation as close as possible is a norm in radiotherapy before a technique can be used to treat a patient. Without such a study, it would be difficult to make a reliable and safe clinical transition especially with a technique as complicated as VMAT-TMI. To this end, the dosimetric feasibility of VMAT-TMI technique in terms of treatment planning, delivery efficiency, and the most importantly three dimensional dose distribution accuracy was investigated in this study. The VMAT-TMI dose distribution inside a humanlike Rando phantom was measured and compared to the dose calculated using RapidArc especially in the field junctions and the inhomogeneous tissues including the lungs, which is the dose-limiting organ in TMI. METHODS: Three subplans with a total of nine arcs were used to treat the planning target volume (PTV), which was determined as all the bones plus the 3 mm margin. Thermoluminescent detectors (TLDs) were placed at 39 positions throughout the phantom. The measured TLD doses were compared to the calculated plan doses. Planar dose for each arc was verified using mapcheck. RESULTS: TLD readings demonstrated accurate dose delivery, with a median dose difference of 0.5% (range: -4.3% and 6.6%) from the calculated dose in the junctions and in the inhomogeneous medium including the lungs. CONCLUSIONS: The results from this study suggest that RapidArc VMAT technique is dosimetrically accurate, safe, and efficient in delivering TMI within clinically acceptable time frame.

Western blot confirmation of the H+/K+-ATPase proton pump in the human larynx and submandibular gland.

OBJECTIVE: The authors have previously demonstrated the H(+)/K(+)-ATPase (proton pump) in human larynx and lung glands via immunohistochemistry (IHC). The present hypothesis is that the proton pump is expressed in other seromucinous glands of the digestive tract that can be confirmed by IHC and Western blot analysis. STUDY DESIGN: Prospective controlled tissue analysis study. SETTING: Academic medical institution. METHODS: Ten anonymous fresh-frozen donor specimens were obtained, comprising 3 submandibular glands, 4 larynges, and 3 normal stomach specimens for control. Submandibular gland sections were immunostained with 2 monoclonal antibodies selectively reactive with α or ß subunits of the H(+)/K(+)-ATPase. Western blot analysis was performed on all specimens. RESULTS: Consistent IHC staining was observed in the submandibular gland specimens for both α and ß subunits. Western blot analysis revealed very strong expression for the stomach at 100 kDa, corresponding to the α protein, and weak but notable banding for all larynx and submandibular gland specimens. Similar findings were noted for the 60- to 80-kDa glycosylated ß subunit protein, as well as the 52-kDa ß subunit precursor for all specimens. CONCLUSION: The H(+)/K(+)-ATPase (proton) pump is present in the human larynx and submandibular gland although in much lower concentrations than in the stomach. Proton pump involvement in human aerodigestive seromucinous glands may have a role in protecting mucosa from acid environments (local or systemic), explain heightened laryngeal sensitivity in those patients with laryngopharyngeal reflux, and be a site of action for proton pump inhibitor pharmacotherapy.

Total marrow irradiation with RapidArc volumetric arc therapy.

PURPOSE: To develop a volumetric arc therapy (VMAT)-total marrow irradiation (TMI) technique for patients with hematologic malignancies. METHODS AND MATERIALS: VMAT planning was performed for 6 patients using RapidArc technology. The planning target volume consisted of all the bones in the body from the head to the mid-femur, excluding the extremities, except for the humerus, plus a 3.0-mm margin. The organs at risk included the lungs, heart, liver, kidneys, bowels, brain, eyes, and oral cavity. The VMAT-TMI technique consisted of three plans: the head and neck, the chest, and the pelvis, each with three 330° arcs. The plans were prescribed to ensure, at a minimum, 95% planning target volume dose coverage with the prescription dose (percentage of volume receiving dose of ≥12 Gy was 95%). The treatments were delivered and verified using MapCheck and ion chamber measurements. RESULTS: The VMAT-TMI technique reported in the present study provided comparable dose distributions with respect to the fixed gantry linear accelerator intensity-modulated TMI. RapidArc planning was less subjective and easier, and, most importantly, the delivery was more efficient. RapidArc reduced the treatment delivery time to approximately 18 min from 45 min with the fixed gantry linear accelerator intensity-modulated TMI. When the prescription dose coverage was reduced to 85% from 95% and the mandible and maxillary structures were not included in the planning target volume as reported in a tomotherapy study, a considerable organ at risk dose reduction of 4.2-51% was observed. The average median dose for the lungs and lenses was reduced to 5.6 Gy from 7.2 Gy and 2.4 Gy from 4.5 Gy, respectively. CONCLUSION: The RapidArc VMAT technique improved the treatment planning, dose conformality, and, most importantly, treatment delivery efficiency. The results from our study suggest that the RapidArc VMAT technology can be expected to facilitate the clinical transition of TMI.