Residual cholesteatoma revealed by endoscopy after microsurgery.

Residual cholesteatoma revealed by endoscopy after microsurgery. OBJECTIVE: To endoscopically examine common sites of residual cholesteatoma occurrence after microscopic ear surgery. METHODS: Thirty patients (15 men and 15 women; age range: 7-81 years) who underwent treatment for middle ear cholesteatoma (20 patients with pars flaccida :holesteatoma and 10 patients with pars tensa cholesteatoma) were selected. Following the removal of the cholesteatoma matrix via microscopy, residual matrix presence was assessed using an endoscope system. Additional resection was performed if the residual matrix was detected. Sites of residual matrix and their rates of incidence were then investigated. RESULTS: Residual matrix was observed in nine out of the 30 (30%) patients by endoscopy after microscopic surgery. Residual matrix was observed in eight out of the 20 (40%) patients with pars flaccida cholesteatoma and in one out of :he 10 (10%) patients with pars tensa cholesteatoma. Residual matrix was observed in six out of the 14 (43%) patients who underwent canal wall up (CWU) tympanomastoidectomy and in three out of the 13 (23%) patients who underwent -anal wall down (CWD) tympanomastoidectomy. Sites of residual matrix included the tegmen tympani in two patients, he medial scutal surface in three patients, the tympanic sinus in two patients and the anterior epitympanic recess in three patients. The risk of residual matrix was greater in patients with pars flaccida cholesteatoma than in those with pars tensa :holesteatoma. The attic, tympanic sinus and anterior epitympanic recess are common sites of residual cholesteatoma. CONCLUSION: Endoscopy is advantageous for the assessment of residual cholesteatoma in hidden areas.

Correlation of progression-free and post-progression survival with overall survival in phase III trials of first-line chemotherapy for advanced epithelial ovarian cancer.

PURPOSE OF INVESTIGATION: The authors examined the relation between post-progression survival (PPS) and overall survival (OS) in phase III trials of first-line chemotherapy for advanced epithelial ovarian cancer. MATERIALS AND METHODS: The authors partitioned OS into progression-free survival (PFS) and PPS and evaluated the relation between OS and either PFS or PPS. They also examined whether any association might be affected by the year of completion of trial enrollment. RESULTS: The average PPS was longer in recent trials than in older trials (26.9 vs. 20.2 months,p = 0.0002). For all trials, PPS was strongly associated with OS (r = 0.94), whereas PFS was more moderately but still strongly correlated with OS (r = 0.83). The average proportion of median OS accounted for by median PPS significantly increased from 54.1% in older trials to 60.3% in recent trials (p = 0.0001). CONCLUSION: The present findings indicate that, especially for recent trials, PPS is more highly associated than PFS with OS in first-line chemotherapy for advanced epithelial ovarian cancer.

Integrated genomic and functional analyses reveal glyoxalase I as a novel metabolic oncogene in human gastric cancer.

Chromosomal abnormalities are good guideposts when hunting for cancer-related genes. We analyzed copy number alterations of 163 primary gastric cancers using array-based comparative genomic hybridization and simultaneously performed a genome-wide integrated analysis of copy number and gene expression using microarray data for 58 tumors. We showed that chromosome 6p21 amplification frequently occurred secondary to ERBB2 amplification, was associated with poorer prognosis and caused overexpression of half of the genes mapped. A comprehensive small interfering RNA knockdown of 58 genes overexpressed in tumors identified 32 genes that reduced gastric cancer cell growth. Enforced expression of 16 of these genes promoted cell growth in vitro, and six genes showing more than two-fold activity conferred tumor-forming ability in vivo. Among these six candidates, GLO1, encoding a detoxifying enzyme glyoxalase I (GLO1), exhibited the strongest tumor-forming activity. Coexpression of other genes with GLO1 enhanced growth-stimulating activity. A GLO1 inhibitor, S-p-bromobenzyl glutathione cyclopentyl diester, inhibited the growth of two-thirds of 24 gastric cancer cell lines examined. The efficacy was found to be associated with the mRNA expression ratio of GLO1 to GLO2, encoding glyoxalase II (GLO2), another constituent of the glyoxalase system. GLO1 downregulation affected cell growth through inactivating central carbon metabolism and reduced the transcriptional activities of nuclear factor kappa B and activator protein-1. Our study demonstrates that GLO1 is a novel metabolic oncogene of the 6p21 amplicon, which promotes tumor growth and aberrant transcriptional signals via regulating cellular metabolic activities for energy production and could be a potential therapeutic target in gastric cancer.

Organised haematoma of the maxillary sinus: pathophysiological differences suggesting a new aetiological hypothesis.

BACKGROUND AND OBJECTIVES: Organised haematomas of the maxillary sinus are rare, non-neoplastic, haemorrhagic lesions which can extend into the nasal cavity and/or the other paranasal sinuses. This study aimed to investigate the pathology of maxillary sinus organised haematoma, and also proposes a new aetiological hypothesis based on the observed pathology. METHODS: Biopsies, computed tomography, magnetic resonance imaging and post-surgical histopathological examination of resected specimens were carried out. CONCLUSION: Distinct pathological differences were observed between the basal and peripheral portions of organised haematomas. We propose that an organised haematoma originates from the exudation of blood components between vascular endothelial cells. As a result, the basal portion consists of aggregated, dilated vessels around the natural ostium of the maxillary sinus. In addition, pseudovessels, without endothelial cells, arise from endocapillary vessels within the haematoma. Exudation of additional blood components from the pseudovessels advances the growth of the organised haematoma.

TU-E-BRB-01: Similar-Case-Based Optimization of Beam Arrangements in Stereotactic Body Radiation Therapy.

PURPOSE: The quality of a treatment plan for stereotactic body radiotherapy (SBRT) depends on an experience of each treatment planner. Therefore, the treatment plans are subjectively determined by comparison of several treatment plans developed by time consuming iterative manners, while considering the benefit to a tumor and the risk to the surrounding normal tissues. The aim of our study was to develop an automated optimization method for beam arrangements based on similar cases in a database including plans designed by senior experienced treatment planners. METHODS: Our proposed method consists of three steps. First, similar cases were automatically selected based on image features from the treatment planning point of view. We defined four types of image features relevant to planning target volume (PTV) location, PTV shape, lung size, and spinal cord positional features. Second, the beam angles of the similar case were registered to the objective case with respect to lung regions using a linear registration technique. Third, the beam direction of the objective case was locally optimized based on the cost function considering radiation absorption in normal tissues and organs at risk. The proposed method was evaluated with 10 test cases and a treatment planning database including 81 cases by using eight planning evaluation indices such as D95, lung V20, and maximum spinal cord dose. RESULTS: The proposed method may provide usable beam directions, which have no statistically significant differences with the original beam directions (P > 0.05) in terms of the seven planning evaluation indices. Moreover, the mean value of D95 for 10 test cases was improved with a statistically significant difference by using the proposed method, compared with the original beam directions (P = 0.03). CONCLUSIONS: The proposed method could be used as a computer-assisted treatment planning tool for determination of beam directions in SBRT.

WE-G-BRCD-04: Development of Automated Determination Method of Robust Beam Directions against Patient Setup Errors Based on Spatial Distribution of Electron Density in Particle Therapy.

PURPOSE: The three-dimensional (3D) dose distribution covering a tumor region tends to be more breakable if the beam's eye view (BEV) of the 3D electron density (ED) map in a beam direction changes more abruptly with large fluctuations. Our aim of this study was to develop an automated determination method of robust beam directions against the patient setup error based on the ED-based BEV in the beam direction in the particle therapy. METHODS: The basic idea of our proposed method was to find the robust beam directions, whose the ED-based BEV has the spatial fluctuations with low special frequency and small amplitude. For evaluation of the spatial fluctuation in the ED-based BEV in a beam direction, we obtained power spectra of the ED-based BEVs in all directions, i.e., 0 to 355 degree, with an interval of 5 degree. It was assumed that as the average spatial frequency and amplitude of the fluctuation in the ED-based BEV in a beam direction is lower and smaller, respectively, the absolute value of a gradient of the power spectrum becomes larger. Therefore the gradient of the power spectrum was calculated for determination of the robust beam direction. The ED-based BEV was produced by projecting a 3D electron density map derived from the computed tomography (CT) image from a beam source to the distal end of a planning target volume (PTV). Four cases of head and neck cancer patients were selected for evaluation of the proposed method. RESULTS: As a preliminary result, radiation oncologists agreed with most beam directions, which seem to be robust against patient setup errors, suggested by the proposed method. CONCLUSIONS: Our proposed method could be feasible to suggest the robust beam directions against patient setup errors in hadron particle therapy.

SU-E-J-117: Computer-Assisted Verification of Accumulated Dose Distribution during the Treatment Time Based on Estimation of Four-Dimensional Dose Distribution Using an Electronic Portal Imaging Device.

PURPOSE: The accumulated dose distributions during the course of radiation treatment are substantially important for verifying whether treatment dose distributions are produced according to planned dose distributions. The purpose of this study was to develop a computer-assisted verification method of accumulated dose distribution during the irradiation of a tumor based on estimation of four-dimensional (4D) dose distribution using an electronic portal imaging device (EPID). METHODS: The 4D 'treatment' computed tomography (CT) images during the irradiation were estimated based on affine transformations including respiratory motions, which were derived by registration between a planning portal dose image and treatment portal dose dynamic image. Planning portal dose images were calculated from planning CT images and an algorithm for calculation of dose spatial distribution. Treatment portal dose images were estimated from EPID dynamic images obtained during a treatment time. The planning portal dose images were registered to the treatment portal dose images to obtain the affine transformation, which could include respiratory motion in a patient body. The CT images at a treatment time were determined by deforming the planning CT images using the affine transformation matrix. 4D dose distributions during a treatment delivery were obtained by applying a dose calculation algorithm to the 4D treatment CT images. Finally, accumulated dose distributions during the course of radiation treatment were verified with planned dose distributions. RESULTS: We applied the proposed method to EPID dynamic images of 2 lung cancer patients, and evaluated the difference in accumulated dose distribution between the plan and treatment using a gamma evaluation (3mm/3%). The average pass rate for 2 cases was 78.2%. CONCLUSIONS: The proposed method can be used for adaptively modifying the plan based on the dose discrepancy between the plan and treatment. This work was partially supported by Grant-in-Aid for Scientific Research (C) (22611011) and Okawa Foundation for Information and Telecommunications.

SU-E-J-26: Automated Estimation Method of Patient Setup Errors Using Simulated Portal Images for Prostate Cancer Radiotherapy.

PURPOSE: We developed a novel automated estimation method for patient setup errors based on simulated and real portal images for prostate cancer radiotherapy. METHODS: The estimation of patient setup errors in this study was based on a template matching technique with a cross-correlation coefficient and Sobel filter between the real portal image and localized pelvic template of reference image, which were DRR (digitally reconstructed radiography) images and simulated portal images. The simulated portal image was derived by projecting a CT image according to an inverse exponential power law of x-ray attenuation for a water-equivalent path length of each voxel of the CT image on each ray from a source to each pixel on the EPID (electric portal imaging device). A localized pelvic template of each patient in AP (anterior-posterior) or lateral view was automatically extracted from the DRR or simulated portal images by cropping a rectangular region, which was determined by using the mean pelvic template and four anatomical feature points. We applied the proposed method to three prostate cancer cases, and evaluated it using the residual error between the patient setup error obtained by proposed method and the gold standard setup error determined by two radiation oncologists. RESULTS: The average residual errors of the patient setup error for the DRR and simulated portal images were 0.79 and 1.26 mm in the left-right (LR) direction, 3.17 and 2.05 mm in the superior-inferior (SI) direction, 1.69 and 5.82 mm in the anterior-posterior (AP) direction, 3.84 and 6.94 mm in Euclidean distance (ED), respectively. If we used the simulated portal image for LR and SI directions and the DRR image for AP direction, the Euclidean distance was 3.22 mm. CONCLUSIONS: The proposed method has a potential to correctly estimate patient setup errors for prostate cancer radiotherapy.

SU-E-I-115: Wavelet Analysis of Ultrasound Image for the Diagnosis of Sjögren's Syndrome.

PURPOSE: Sjögren's syndrome (SS) is an auto-immune disease presenting with dry eyes and mouth (keratoconjunctivitis sicca and xerostomia). Ultrasonography is used for the initial and non-invasive investigation of the parotid gland in the disease. The purpose of this study is to develop an image processing for diagnosis of SS by applying wavelet analysis to ultrasound image. METHODS: Ultrasound B-mode images of the parotid gland were captured and analyzed by a personal computer. A square region of interest (ROI) was set on the image and two-dimensional discrete wavelet transform was performed within the ROI. As a Result, the image was decomposed into an approximate image and three detailed images in vertical, horizontal and diagonal directions in different scales. A feature quantity for image classification was defined by calculating from the wavelet coefficients of detailed images within selected scales. The ultrasound images of 80 patients who had been referred to Nagasaki University Hospital because of suspicion of SS were analyzed. A total of 37 patients fulfilled the criteria for SS, whereas the remaining 43 patients did not. The severity of SS was graded into four degrees by sialography. The images with each feature quantity were classified by statistical cluster analysis. RESULTS: In this method, the images can be divided into two groups which mainly contained SS and non-SS. The sensitivity and specificity in the detection of SS was 78% and 95%, respectively. It was also found that the defined feature quantity tended to change with the severity of SS. CONCLUSIONS: In ultrasonography, the image analysis based on wavelet transform was useful for the diagnosis of Sjögren's syndrome.

Expression profile of early lung adenocarcinoma: identification of MRP3 as a molecular marker for early progression.

Early lung adenocarcinoma is well-recognized as a small-sized non-invasive adenocarcinoma or localized non-mucinous bronchioloalveolar carcinoma (LNMBAC); however, the molecular events associated with these early lesions are not clear. To determine the genes involved in tumorigenesis at the early stage of lung adenocarcinoma, we compared the mRNA expression profiles of LNMBAC and normal lungs with an oligonucleotide array. Immunohistochemical analyses were performed to confirm the expression of detected genes. We identified 183 differentially expressed genes, of which 15 were up-regulated and 168 down-regulated. Among them, most up-regulated genes, such as AQP3 and Claudin-4, were expressed in both adenocarcinoma cells and type II alveolar pneumocytes, corresponding to the histological similarity between these cell types. However, multidrug resistant protein 3 (MRP3) was only expressed on tumour cell membranes and not in type II alveolar pneumocytes, as confirmed by immunohistochemistry. Moreover, the number of MRP3-positive cells significantly increased from AAH (the precursor lesion of lung adenocarcinoma) to LNMBAC. We conclude that MRP3 could be a novel molecular marker for LNMBAC, whose expression increases during the early progression of tumourigenesis.

GASDERMIN, suppressed frequently in gastric cancer, is a target of LMO1 in TGF-beta-dependent apoptotic signalling.

Defining apoptosis-regulatory cascades of the epithelium is important for understanding carcinogenesis, since cancer cells are considered to arise as a result of the collapse of the cascades. We previously reported that a novel gene GASDERMIN (GSDM) is expressed in the stomach but suppressed in gastric cancer cell lines. Furthermore, in this study, we demonstrated that GSDM is expressed in the mucus-secreting pit cells of the gastric epithelium and frequently silenced in primary gastric cancers. We found that GSDM has a highly apoptotic activity and its expression is regulated by a transcription factor LIM domain only 1 (LMO1) through a sequence to which Runt-related transcription factor 3 (RUNX3) binds, in a GSDM promoter region. We observed coexpression of GSDM with LMO1, RUNX3 and type II transforming growth factor-beta receptor (TGF-betaRII) in the pit cells, and found that TGF-beta upregulates the LMO1- and GSDM-expression in the gastric epithelial cell line and induces apoptosis, which was confirmed by the finding that the apoptosis induction is inhibited by suppression of each LMO1-, RUNX3- and GSDM expression, respectively. The present data suggest that TGF-beta, LMO1, possibly RUNX3, and GSDM form a regulatory pathway for directing the pit cells to apoptosis.

Memory trace of motor learning shifts transsynaptically from cerebellar cortex to nuclei for consolidation.

Adaptation of ocular reflexes is a prototype of motor learning. While the cerebellum is acknowledged as the critical site for motor learning, the functional differences between the cerebellar cortex and nuclei in motor memory formation are not precisely known. Two different views are proposed: one that the memory is formed within the cerebellar flocculus, and the other that the memory is formed within vestibular nuclei. Here we developed a new paradigm of long-term adaptation of mouse horizontal optokinetic response eye movements and examined the location of its memory trace. We also tested the role of flocculus and inferior olive in long-term adaptation by chronic lesion experiments. Reversible bilateral flocculus shutdown with local application of 0.5 microl-5% lidocaine extinguished the memory trace of day-long adaptation, while it very little affected the memory trace of week-long adaptation. The responsiveness of vestibular nuclei after week-long adaptation was examined by measuring the extracellular field responses to the electrical stimulation of vestibular nerve under trichloroacetaldehyde anesthesia. The amplitudes and slopes of evoked monosynaptic field response (N1) of week-long adapted mice were enhanced around the medial vestibular nucleus compared with those of control mice. Chronic flocculus or inferior olive lesions abolished both day and week-long adaptations. These results suggest that the functional memory trace of short-term adaptation is formed initially within the cerebellar cortex, and later transferred to vestibular nuclei to be consolidated to a long-term memory. Both day and week-long adaptations were markedly depressed when neural nitric oxide was pharmacologically blocked locally and when neuronal nitric oxide synthase was ablated by gene knockout, suggesting that cerebellar long-term depression underlies both acquisition and consolidation of motor memory.

Changes in the awareness of oral health among new students newly enrolled at the University of Tokyo over the past 15 years.

OBJECTIVE: The aim of this study was to examine changes in awareness of oral health among Japanese university students. METHODS: Between 1990 and 2004, a total of 51,650 students newly enrolled at the University of Tokyo responded to an annual written questionnaire on oral health. RESULTS: (i) Approximately 60% of the students brushed their teeth twice a day. Female students brushed more frequently than male students. (ii) The percentage of students who brushed for 2-3 min per time decreased, while the percentage who brushed four or more minutes increased. (iii) The number of students who had learned how to brush properly increased. This trend was particularly clear-cut among male students, although the proportion of female students who had learned to brush properly remained higher than that of male students. (iv) The percentage of female students who sought treatment for malocclusion was higher than that of male students. The percentage of students who underwent orthodontic treatment increased from 11.6 to 19.7%. The percentage of female students who received orthodontic treatment was approximately twofold that of male students. (v) The percentage of students who had temporomandibular disorders was 0.7% in males and 1.5% in females. (vi) More than 40% of the students had periodontal diseases, with a higher prevalence among male students than female students. (vii) Approximately 20% of the students wanted to consult our service centre. CONCLUSIONS: The awareness of oral health among new undergraduates at the University of Tokyo has improved over the past 15 years.

Curvature analysis of the mandibular condyle.

OBJECTIVE: To determine whether curvature analysis on high resolution CT images can be used as a tool for evaluation of mandibular condyle morphology. METHODS: Curvature analysis was performed on reconstructed oblique coronal CT images of 634 normal condyles from 317 patients (144 men and 173 women; age range 4-89 years) with inner or middle ear disease. The condyles were scanned with 1 mm collimation using helical CT. The CT images were analysed manually on a personal computer. RESULTS: The condyle CT images could be categorized into five curvature profile patterns: (1) bi-peak; (2) no peak; (3) tri-peak; (4) bi-peak with an intervening bottom above the base line (bi-peak with a col); and (5) bi-peak with an intervening negative phase. A separate evaluation using computer graphic condyle models indicated that these curvature patterns corresponded to flat (bi-peak), round (no peak), convex (bi-peak with a col), concave (bi-peak with a negative phase) and angled (tri-peak) contours of the condyle's superior surface. The curvature profiles were identical between bilateral condyles in 40% (126/317) of the patients. Gender-related differences in the incidence of the curvature profiles were also found, the bi-peak with a col profile being more frequently observed in women and the bi-peak with a negative phase profile being observed more frequently in men. CONCLUSION: Curvature analysis on CT images depicts condyle morphology effectively and may be an adjunctive tool for condyle morphometry.

Potential involvement of the AML1-MTG8 fusion protein in the granulocytic maturation characteristic of the t(8;21) acute myelogenous leukemia revealed by microarray analysis.

The AML1 (RUNX1)-MTG8 (ETO) fusion transcription factor generated by the t(8;21) translocation is believed to deregulate the expression of genes that are crucial for normal differentiation and proliferation of hematopoietic progenitors, resulting in acute myelogenous leukemia. To elucidate the role of AML1-MTG8 in leukemogenesis, we used oligonucleotide microarrays to detect alterations in gene expression caused by ectopic expression of AML1-MTG8 in a murine myeloid progenitor cell line, L-G. Microarray analysis of approximately 6500 genes identified 32 candidate genes under the downstream control of AML1-MTG8. Among the 32 genes, 23 were not known to be regulated by AML1-MTG8. These included many granule protein genes and several cell surface antigen genes. Interestingly, AML1-MTG8 enhanced the expression of several genes that are usually induced during granulocytic differentiation, particularly those encoding azurophil granule proteins, including cathepsin G, myeloperoxidase and lysozyme. This indicates that AML1-MTG8 induces partial differentiation of myeloid progenitor cells into promyelocytes in the absence of the usual differentiation signals, while it inhibits terminal differentiation into mature granulocytes. Thus, AML1-MTG8 itself may play a crucial role in defining a unique cytologic type with abnormal maturation, characteristic of t(8;21) acute myelogenous leukemia.

Structure of human holocarboxylase synthetase gene and mutation spectrum of holocarboxylase synthetase deficiency.

Holocarboxylase synthetase (HLCS) is an enzyme that catalyzes the incorporation of biotin into apo-carboxylases, and its deficiency causes biotin-responsive multiple carboxylase deficiency. The reported sequences of cDNA for human HLCS from liver, lymphocyte, and KG-1 myeloid cell lines differ at their 5' regions. To elucidate variations of the human HLCS mRNA and longer 5' cDNA ends, we performed screening of the human liver cDNA library and rapid amplification of the cDNA ends (RACE). Our results suggest the existence of three types of HLCS mRNA that start at different exons. The first type starts at exon 1, and the second type starts at exon 3, and both are found in various human tissues. The third type, corresponding to the cDNA from the KG-1 cell, starts at exon 2 of the HLCS gene. Various splicing patterns from exons 3-6 were also observed. None of the variations of cDNA found created a new initiation codon. Mutation screening from exons 6-14, therefore, was sufficient to detect amino acid changes in HLCS in patients. Our direct sequencing strategy for screening mutations in the HLCS gene revealed mutations in five Japanese patients and seven non-Japanese patients. Our analyses involving 12 Japanese and 13 non-Japanese patients and studies by others indicate that (1) there is no panethnically prevalent mutation; (2) the Arg508Trp, Gly581Ser, and Val550Met mutations are found in both Japanese and non-Japanese populations; (3) the IVS10+5G-->A mutation is predominant and probably a founder mutation in European patients; (4) the 655-656insA, Leu237Pro, and 780delG mutations are unique in Japanese patients; (5) the spectrum of the mutations in the HLCS gene may vary substantially among different ethnic groups.

Activation of AML1-mediated transcription by MOZ and inhibition by the MOZ-CBP fusion protein.

The AML1-CBF beta transcription factor complex is the most frequent target of specific chromosome translocations in human leukemia. The MOZ gene, which encodes a histone acetyltransferase (HAT), is also involved in some leukemia-associated translocations. We report here that MOZ is part of the AML1 complex and strongly stimulates AML1-mediated transcription. The stimulation of AML1-mediated transcription is independent of the inherent HAT activity of MOZ. Rather, a potent transactivation domain within MOZ appears to be essential for stimulation of AML1-mediated transcription. MOZ, as well as CBP and MOZ-CBP, can acetylate AML1 in vitro. The amount of AML1-MOZ complex increases during the differentiation of M1 myeloid cells into monocytes/macrophages, suggesting that the AML1-MOZ complex might play a role in cell differentiation. On the other hand, the MOZ-CBP fusion protein, which is created by the t(8;16) translocation associated with acute monocytic leukemia, inhibits AML1-mediated transcription and differentiation of M1 cells. These results suggest that MOZ-CBP might induce leukemia by antagonizing the function of the AML1 complex.

Involvement of the NUP98 gene in a chromosomal translocation t(11;20)(p15;q11.2) in a patient with acute monocytic leukemia (FAB-M5b).

We report here a case of acute monocytic leukemia (M5b subtype according to the French-American-British [FAB] classification) with chromosomal translocation t(11;20)(p15;q11.2). Fluorescence in situ hybridization analysis with a probe for the NUP98 gene, which is located at chromosome band 11p15, showed that the probe hybridized to both derivative chromosomes 11 and 20 as well as to the remaining normal chromosome 11, indicating that the NUP98 gene was split and involved in this translocation. This is the first report of t(11;20)(p15;q11.2) involving the NUP98 gene in overt leukemia.

Identification of cIAP1 as a candidate target gene within an amplicon at 11q22 in esophageal squamous cell carcinomas.

Amplification of chromosomal DNA is thought to be one of the mechanisms that activate cancer-related genes in tumors. In a recent study, we identified high copy-number amplification at 11q21-q23 in cell lines derived from esophageal squamous cell carcinomas (ESCs) using comparative genomic hybridization. Because 11q21-q23 amplification has been reported in tumors of various other types as well, gene(s) associated with tumor progression may lie within this chromosomal region. To identify the most likely target(s) for amplification at 11q21-q23, we determined the extent of the amplicon by fluorescence in situ hybridization and then analyzed ESC cell lines for expression levels of 11 known genes and one uncharacterized transcript present within the 1.8-Mb commonly amplified region. Only cIAP1, a member of the IAP (antiapoptotic) gene family, was consistently overexpressed in cell lines that showed amplification. Additionally, the cIAP1 protein was overexpressed in the primary tumors from which those cell lines had been established. The ESC cell lines with cIAP1 amplification were resistant to apoptosis induced by chemotherapeutic reagents. An increase in cIAP1 copy number was also detected in 4 of 42 (9.5%) primary ESC tumors that were not related to the cell lines examined. Because inhibition of apoptosis seems to be an important feature of carcinogenesis, cIAP1 is likely to be a target for 11q21-23 amplification and may be involved in the progression of ESC, as well as other malignancies.

Homozygous deletion in a neuroblastoma cell line defined by a high-density STS map spanning human chromosome band 1p36.

Recent molecular studies have shown a relatively high rate of loss of heterozygosity (LOH) in neuroblastoma (NB) as well as other types of tumors in human chromosome band 1p36. To identify candidate tumor suppressor genes in NB, we searched for homozygous deletions in NB cell lines with PCR according to a high-density sequence tagged site (STS)-content map spanning 1p35-36. Among 25 NB cell lines examined, only one cell line, NB-1, showed no signal with 27 STSs in a 480 kb region in 1p36.2. The sequence analysis has revealed that the defective region included seven known genes (E4, KIF1B, SCYA5, PGD, Cortistatin, DFF45, and PEX14), nine expressed sequence tags (ESTs), and two microsatellite markers. These genes are related to apoptosis, an ubiquitin-proteasome pathway, a neuronal microtubule-associated motor molecule, and components of a common translocation machinery. The region between the DFF45 and KIF1B genes was defined as homozygous deletion by Southern blotting. The search in LOH regions with high-density STSs may be useful for the isolation and identification of tumor suppressor genes in other tumors as well as NBs.