Cytomorphological and clinicopathological spectrum of pulmonary marginal zone lymphoma: the utility of immunophenotyping, PCR and FISH studies.

OBJECTIVE: To review cytomorphological criteria and clinicopathological findings in combination with ancillary tests for the specific diagnosis of pulmonary marginal zone lymphoma (MZL) in fine needle aspiration (FNA) specimens. METHODS: Cases of pulmonary MZL diagnosed using cytological specimens from 2005 to 2012 were retrieved and reviewed by three cytopathologists. Results of immunophenotypic analysis, interphase fluorescence in situ hybridization (FISH) and molecular assays were collated, together with clinical information and imaging data. Concurrent surgical biopsies were also retrieved. RESULTS: Fifteen lung FNA specimens were identified. The smears consisted predominantly of small centrocyte-like cells. Marked plasma cell differentiation was evident in 11 cases. All cases with slides available showed tissue fragments with lymphoid tangles (TFLTs). Multinucleated giant cells were present in nine cases, two of which showed granulomas. Immunophenotyping confirmed B-cell clonality in all cases. B-cell clonality was detected by polymerase chain reaction (PCR) in two samples. FISH identified MALT1 translocation in four of 10 cases tested and trisomy 3 in three of four cases. Concurrent surgical biopsies were diagnosed independently as MZL in seven cases. CONCLUSIONS: Cytology smears from lung FNA samples consisting of small lymphoid cells with a relative abundance of plasma cells or plasmacytoid cells and large TFLTs should prompt immunophenotyping and other ancillary studies, even if multinucleated giant cells and poorly formed granulomas are also identified. Specific diagnosis of pulmonary MZL in FNA samples can be rendered on the basis of morphological features coupled with the demonstration of B-cell clonality by immunophenotyping or PCR and cytogenetic abnormalities by FISH.

Normothermic acellular ex vivo liver perfusion reduces liver and bile duct injury of pig livers retrieved after cardiac death.

We compared cold static with acellular normothermic ex vivo liver perfusion (NEVLP) as a novel preservation technique in a pig model of DCD liver injury. DCD livers (60 min warm ischemia) were cold stored for 4 h, or treated with 4 h cold storage plus 8 h NEVLP. First, the livers were reperfused with diluted blood as a model of transplantation. Liver injury was determined by ALT, oxygen extraction, histology, bile content analysis and hepatic artery (HA) angiography. Second, AST levels and bile production were assessed after DCD liver transplantation. Cold stored versus NEVLP grafts had higher ALT levels (350 ± 125 vs. 55 ± 35 U/L; p < 0.0001), decreased oxygen extraction (250 ± 65 mmHg vs. 410 ± 58 mmHg, p < 0.01) and increased hepatocyte necrosis (45% vs. 10%, p = 0.01). Levels of bilirubin, phospholipids and bile salts were fivefold decreased, while LDH was sixfold higher in cold stored versus NEVLP grafts. HA perfusion was decreased (twofold), and bile duct necrosis was increased (100% vs. 5%, p < 0.0001) in cold stored versus NEVLP livers. Following transplantation, mean serum AST level was higher in the cold stored versus NEVLP group (1809 ± 205 U/L vs. 524 ± 187 U/L, p < 0.05), with similar bile production (2.5 ± 1.2 cc/h vs. 2.8 ± 1.4 cc/h; p = 0.2). NEVLP improved HA perfusion and decreased markers of liver duct injury in DCD grafts.

Resection of ectopic mediastinal parathyroid glands with the da Vinci robotic system.

BACKGROUND: Mediastinal ectopic parathyroid adenoma is a frequent cause of persistent or recurrent hyperparathyroidism, traditionally treated by open surgery. Thoracoscopic access is associated with reduced morbidity in mediastinal surgery. The aim of this study was to evaluate the feasibility and effectiveness of robot-assisted dissection for mediastinal ectopic parathyroid glands. METHODS: Two patients with recurrent secondary hyperparathyroidism and three with complicated primary hyperparathyroidism were operated on between July 2004 and August 2008 for ectopic mediastinal parathyroid glands. Fusion of single-photon emission computed tomography and computed tomography led to an exact identification of the culprit glands. Surgery was performed thoracoscopically with the da Vinci robotic system using a three-trocar approach. RESULTS: All procedures were completed successfully with the robotic system. No perioperative morbidity or mortality was noted. Median operating time was 58 (range 42-125) min. Intraoperative parathyroid hormone reduction indicated complete resection. Median hospital stay was 3 (range 2-4) days. CONCLUSION: Robot-assisted dissection is a promising approach for resection of ectopic parathyroid glands in remote narrow anatomical locations such as the mediastinum.

[Role of endovascular therapy for redo surgery in patients after aortoiliac aneurysm exclusion]. / Stellenwert der endovaskulären Therapie bei Reeingriffen nach Ausschaltung aortoiliakaler Aneurysmata.

INTRODUCTION: Redo surgery or reintervention following conventional or endovascular aortoiliac reconstruction often requires exclusion of new aneurysms. In the present study the potentials of endovascular management of such lesions are investigated. METHODS: All patients with endovascular reoperation for of newly developed aortoiliac aneurysms were identified from a prospectively run data-base. The indications and results of endovascular therapy were analysed retrospectively. In detail, data were analysed for the type of original operation, interval until and kind of reoperation, and results concerning survival, technical success and complications. RESULTS: From 12 / 2003 through 3 / 2007 195 patients with aortoiliac aneurysms were operated. Endovascular repair was performed in 15 cases of previously excluded aneurysms. Mean age of these 15 patients (12 men) was 73 (64-85) years. Ten patients had a primary conventional (group A) and 5 patients had a primary endovascular (group B) aneurysm repair. The mean time interval between the first and second operation was 8.9 (1-26) years. The secondary endovascular therapy in group A was successful in all cases. In group B endoleaks type I a (n = 1), I a / b (n = 1), II (n = 2) and III (n = 1) were treated. One type II endoleak could only be treated successfully by conversion to open repair, the other one was successfully treated by reintervention. All but one patient are alive and -remained free of pathological findings during a median follow-up of 13 (2-39) months. DISCUSSION: Because of the clearly elevated operation risk of redo surgery after conventional or endovascular aneurysm repair, endovascular aneurysm exclusion represents the method of first choice. The reasonable selection and combination of procedures allows for an optimal adaptation of therapy to the individual case.

[Minimally invasive thymus surgery]. / Minimal-invasive Chirurgie des Thymus.

There are absolute and relative indications for complete removal of the thymus gland. In the complex therapy of autoimmune-related myasthenia gravis, thymectomy plays a central role and is performed with relative indication. In case of thymoma with or without myasthenia, thymectomy is absolutely indicated. Thymus resection is further necessary for cases of hyperparathyroidism with ectopic intrathymic parathyroids or with certain forms of multiple endocrine neoplasia. The transcervical operation technique traditionally reflected the well-founded desire for minimal invasiveness for thymectomy. Due to the requirement of radicality however, most of these operations were performed using sternotomy. With the evolution of therapeutic thoracoscopy in thoracic surgery, several pure or extended minimally invasive operation techniques for thymectomy have been developed. At present uni- or bilateral, subxiphoid, and modified transcervical single or combination thoracoscopic techniques are in use. Recently a very precise new level of thoracoscopic operation technique was developed using robotic-assisted surgery. There are special advantages of this technique for thymectomy. An overview of the development and experiences with minimally invasive thymectomy is presented, including data from the largest series published so far.

Outcomes by treatment modality in elderly patients with localized gastric and esophageal cancer.

Background: We aimed to assess current treatment patterns and outcomes in elderly patients with localized gastric and esophageal (ge) cancers. Methods: This retrospective analysis considered patients 75 years of age or older with ge cancers treated during 2012-2014. Patient demographics and tumour characteristics were collected. Overall survival (os) and disease-free survival were assessed by univariable and multivariable Cox proportional hazards regression, adjusting for demographics. Logistic regression analyses were used to examine factors affecting treatment choices. Results: The 110 patients in the study cohort had a median age of 81 years (range: 75-99 years). Primary disease sites were esophageal (55%) and gastric (45%). Treatment received included radiation therapy alone (29%), surgery alone (26%), surgery plus perioperative therapy (14%), chemoradiation alone (10%), and supportive care alone (14%). In multivariable analyses, surgery (hazard ratio: 0.48; 95% confidence interval: 0.26 to 0.90; p = 0.02) was the only independent predictor for improved os. Patients with a good Eastern Cooperative Oncology Group performance status (p = 0.008), gastric disease site (p = 0.02), and adenocarcinoma histology (p = 0.01) were more likely to undergo surgery. Conclusions: At our institution, few patients 75 years of age and older received multimodality therapy for localized ge cancers. Outcomes were better for patients who underwent surgery than for those who did not. To ensure optimal treatment selection, comprehensive geriatric assessment should be considered for patients 75 years of age and older with localized ge cancers.

[Oral administration of intravenous contrast media: a tasty alternative to conventional oral contrast media in computed tomography]. / Intravenöse Kontrastmittel oral appliziert: Eine wohlschmeckende Alternative zum herkömmlichen oralen Kontrastmittel in der Computertomografie.

PURPOSE: Many patients dislike oral contrast media due to their bad taste. The aim of the present study was to identify a solution that tastes better while providing the same opacification in order to offer oncological patients an alternative to the routinely used bad tasting oral contrast media. MATERIALS AND METHODS: In a single blinded, prospective clinical study, the orally administered intravenous contrast media iohexol (Omnipaque), iopromide (Ultravist), and iotrolan (Isovist) as well as the oral contrast media sodium amidotrizoate (Gastrografin) and ioxithalamate (Telebrix) were each compared to the oral contrast medium lysine amidotrizoate as the reference standard at a constant dilution. The density values of all contrast media with the same dilutions were first measured in a phantom study. The patient study included 160 patients who had undergone a prior abdominal CT scan with lysine amidotrizoate within 6 months. The patients rated their subjective taste impression on a scale of 0 (very bad) to 10 (excellent). In addition, adverse events and opacification were recorded and prices were compared. RESULTS: The phantom study revealed identical density values. Patients assigned much higher taste impression scores of 8 and 7 to iohexol and iotrolan, respectively, as compared to a score of 3 for the conventional lysine amidotrizoate (p< 0.05). Iopromide and sodium amidotrizoate did not differ significantly from lysine amidotrizoate. The opacification of all contrast media and experienced adverse events did not differ significantly. Iotrolan (ca. 120 euro/100 ml), Iohexol and Iopromide (ca. 70 euro/100 ml) are more expensive than the conventional oral contrast media (ca. 10 - 20 euro/100 ml). CONCLUSION: Orally administered solutions of non-ionic contrast media improve patient comfort due to the better taste and provide the same opacification in comparison to conventional oral contrast media. At present, their use should be limited to individual cases due to the higher costs.

Description of a novel fusion transcript between HMGI-C, a gene encoding for a member of the high mobility group proteins, and the mitochondrial aldehyde dehydrogenase gene.

Aberrations involving the chromosomal region 12q24 are a nonrandom cytogenetic abnormality in frequent benign tumors mainly of mesenchymal origin, e.g., uterine leiomyomas, pleomorphic adenomas of the salivary gland, lipomas, or hamartomas of the lung. Mostly, these 12q24 abnormalities occur as a result of inversions also affecting chromosomal region 12q14-15. In addition to the frequent tumors mentioned above, these abnormalities have also been found in rare mesenchymal tumors, e.g., hemangiopericytomas. Although recently the molecular basis of the aberrations of chromosomal region 12q14-15, i.e., a rearrangement of the HMGI-C gene has been identified, the molecular roots of the 12q24 changes still remain to be elucidated. Herein we report on 3' rapid amplification of cDNA ends PCR results on cDNA from a primary uterine leiomyoma. As an ectopic sequence fused to exon 3 of the HMGI-C gene, we have identified a cDNA sequence that revealed 100% homology to exon 13 of the human mitochondrial aldehyde dehydrogenase gene (ALDH 2). Because ALDH 2 maps to 12q24.1, this fusion transcript is a good candidate underlying the chromosomal rearrangements involving 12q24.

Human HMGA2 promoter is coregulated by a polymorphic dinucleotide (TC)-repeat.

HMGA proteins are thought to be causally involved in the progression of different diseases, including benign and malignant tumors, obesity, arteriosclerosis, and restenosis. As HMGA proteins are architectural transcription factors, their binding to DNA leads to changes in DNA-conformation modulating the environment for the assembly and function of transcriptional complexes, thus influencing the expression of a huge variety of genes. Despite the emerging role of HMGA proteins for important diseases, only limited information is available about mechanisms regulating the expression of the HMGA2 gene. In this report, 2240 bp of the 5' flanking region of the HMGA2 gene were functionally analyzed by luciferase assay experiments. Besides the identification of novel positive and negative regulatory elements, it was shown that transcription is initiated from two independent promoter regions within cell lines HeLa, MCF7, and L14TSV40. Furthermore, a functional polymorphic dinucleotide repeat (TCTCT(TC)(n)) 500 bp upstream of the ATG translational start codon was found to regulate strongly the human HMGA2 promoter with an activation pattern that correlates to its TC-repeat length.

Aspects of computer-aided detection (CAD) and volumetry of pulmonary nodules using multislice CT.

With the superb spatial resolution of modern multislice CT scanners and their ability to complete a thoracic scan within one breath-hold, software algorithms for computer-aided detection (CAD) of pulmonary nodules are now reaching high sensitivity levels at moderate false positive rates. A number of pilot studies have shown that CAD modules can successfully find overlooked pulmonary nodules and serve as a powerful tool for diagnostic quality assurance. Equally important are tools for fast and accurate three-dimensional volume measurement of detected nodules. These allow monitoring of nodule growth between follow-up examinations for differential diagnosis and response to oncological therapy. Owing to decreasing partial volume effect, nodule volumetry is more accurate with high resolution CT data. Several studies have shown the feasibility and robustness of automated matching of corresponding nodule pairs between follow-up examinations. Fast and automated growth rate monitoring with only few reader interactions also adds to diagnostic quality assurance.

[Surgery for congestive heart failure--the role of computed tomography in the pre- and postoperative diagnostic evaluation]. / Chirurgie der Herzinsuffizienz -- Stellenwert der Computertomographie in der prä- und postoperativen Diagnostik.

The treatment of advanced, drug resistant congestive heart failure gains in importance in the field of cardiac surgery. Cardiac imaging for preoperative assessment and follow-up focuses on the determination of ventricular volumes and function as well as on the detection of postoperative complications. Computed tomography (CT) is highly accurate irrespective of the individual patient's anatomic situation, has a low examiner dependence and short examination time, does not require an arterial vascular access and can be performed in patients with metal implants. CT is the modality of choice in the follow-up of heart transplants to detect extracardiac and cardiac complications including coronary calcifications as an early sign of transplant vasculopathy. In addition, CT visualizes the elements of mechanical assist devices and can identify their possible local cardiac and mediastinal complications. CT can detect fibrolipomatous involution of the mobilized muscle flap in dynamic cardiomyoplasty and can depict fibrous reactions along the epicardial mesh implant in passive cardiac containment. Further indications include assessment of typical local postoperative complications, such as intrathoracic infection and mediastinal bleeding, intracardiac thrombus formation or pericardial effusion. CT is routinely used for evaluating bypass patency but is limited in assessing associated valve defects since it does not visualize flow.

Telomeric repeat fragment lengths are not correlated to histological grading in 85 breast cancers.

The mean telomeric repeat fragment (TRF) lengths of 85 breast cancer samples were determined. The TRF length varied between 7260 bp and 14570 bp (average 11370 bp) reflecting a unimodal distribution. There was no significant correlation between TRF length and the histological grade of the tumor. Neither were there differences in telomeric length between different histological types of tumors, in particular lobular and ductal types, nor correlations between TRF length and age of patient, tumor volume, lymph node status, or steroid receptor status. These results contradict the hypothesis that the telomere repeat fragment sizes represent limiting or promoting factors for the growth of breast cancer.

Tetraphocomelia and bilateral cleft lip in a historical case of Roberts syndrome [Virchow, 1898].

We discuss an unlabelled specimen of tetraphocomelia and bilaterally cleft lip from the former Virchow Museum of our Medical School. Identity of the subject with a case of what was later termed "Roberts syndrome" published by Rudolf Virchow in 1898 is demonstrated. Rediscovery of this important historical case is gratifying, since almost 95% of the specimens of Virchow's collection were lost during World War II. We have restudied Virchow's case. Recent CT scan images of the fetus are presented. We review data from the literature and present new clinical details. The fate of the original clinical data after passing through three reviews is documented briefly. We also reconstruct Virchow's view on phocomelia and its consequences for later research.

Computed tomography-guided transtracheal needle aspiration of paratracheal lymphadenopathy in endoscopically normal patients.

RATIONALE AND OBJECTIVES: The authors investigated the diagnostic value of computed tomography-guided bronchoscopic transtracheal needle biopsy of paratracheal lymphadenopathy without any endoscopical signs of stenosis or protrusion. METHODS: Twenty consecutive patients with an age of 22 to 76 years underwent fiberoptic bronchoscopy with transtracheal needle biopsy under computed tomography guidance of paratracheal lymphadenopathies (diameter between 10 to 19 mm). Computed tomography fluoroscopy as a special low-dose computed tomography technique was used in the region of interest. The results of needle aspirates (cytologic examination) were verified by surgical interventions (n = 4), mediastinoscopy (n = 9), percutaneous needle biopsy (n = 1), or clinical/radiologic follow-up (n = 10). RESULTS: All patients were without endoscopic signs of lymphadenopathy or tumor. Sufficient material of lymphatic tissue for cytologic assessment was obtained in 23 out of 24 patients (96%). In 5 of 10 patients with malignant diseases and 13 of 14 patients with benign enlarged lymph nodes, the lymph nodes were demonstrated exactly by transtracheal needle biopsy. There were no bleeding complications. CONCLUSIONS: Computed tomography-guided bronchoscopic needle biopsy of paratracheal lymphadenopathy is a low-risk procedure. If malignant cells can be demonstrated with these technique, other more invasive procedures (surgery, mediastinoscopy) can be avoided. The numerous false-negative results (5 of 10) suggest, that the cytologic evidence of benign cells is without any diagnostic value in cases of paratracheal lymphadenopathy.

Dy-EOB-DTPA: tolerance and pharmacokinetics in healthy volunteers and preliminary liver imaging in patients.

RATIONALE AND OBJECTIVES: To investigate the tolerance and pharmacokinetics of the new liver-specific x-ray contrast agent Dy-EOB-DTPA [(4S)-4-(4-ethoxybenzyl)-3,6,9-tris(carboxylatomethyl)-3,6,9-triazaundecanedioic acid, dysprosium (Dy) complex, disodium salt] in healthy volunteers and to obtain preliminary imaging data by abdominal spiral computed tomography (CT) in tumor patients with liver metastases. METHODS: A total of 40 healthy male volunteers received 10-minute intravenous infusions of 0.05, 0.1, 0.25, 0.375, or 0.5 mmol/kg Dy-EOB-DTPA (n = 6 per dose group) or placebo (n = 10). Blood, urine, and feces were sampled for Dy measurements by inductively coupled plasma atomic emission spectrometry (ICP-AES) and for the detection of possible metabolites by high-performance liquid chromatography analysis with ICP-AES detection. Safety parameters were determined before, during, and after the study. Two patients with suspected liver metastases first received 120 mL of iopromide (300 mg iodine/mL; approximately 0.6 mmol/kg) and, 24 or 72 hours later, Dy-EOB-DTPA at a dose of 0.25 mmol/kg. Computed tomography images were obtained 50 seconds after iopromide administration and before and 90 minutes after Dy-EOB-DTPA administration. RESULTS: Dysprosium-EOB-DTPA was well tolerated. At the higher doses (0.375 and 0.5 mmol/kg), there was a slight increase in side effect intensity. In general, nausea, headache, and paresthesia mainly were reported as mild to moderate adverse events. Laboratory parameters did not exceed the normal range. Electrocardiographic, vital sign, or hemodynamic parameters were not affected by contrast agent administration. The terminal half-life of elimination of Dy-EOB-DTPA was approximately 1.5 hours, total clearance was 2 to 3 mL x min(-1) x kg(-1), and the renal clearance was approximately 1.5 mL x min(-1) x kg(-1). There was a significant dose dependence for the following parameters: maximal concentration in blood, terminal half-life, mean residence time, total clearance, urinary excretion, and fecal excretion. The volume of distribution in the steady state and renal clearance were not dependent on dose. In the blood and urine, no metabolites of Dy-EOB-DTPA could be detected. In the tumor patients, CT scanning after Dy-EOB-DTPA injection increased the number of detected metastases from 27 (plain scan) to 40 (iopromide) and then to 41 (Dy-EOB-DTPA) in patient No. 1 and from 1 (plain scan and iopromide) to 3 (Dy-EOB-DTPA) in patient No. 2. CONCLUSIONS: Dysprosium-EOB-DTPA was shown to be a well-tolerated liver-specific contrast agent. Its pharmacokinetic profile is characterized by a terminal half-life of approximately 1.5 hours. There are indications of saturation of liver uptake at the highest dose level of 0.5 mmol/kg. In comparison with plain scans and scans performed after iodinated contrast agent administration, Dy-EOB-DTPA seems to increase the number of detectable liver lesions.

High mobility group protein HMGA1 expression in breast cancer reveals a positive correlation with tumour grade.

Members of the HMGA protein (high mobility group protein A) family act as master switches of the chromatin structure by bending DNA and thus modulating the formation of transcription factor complexes of a number of target genes. Accordingly, HMGA proteins have been shown to be associated with the development and/or progression of a variety of benign and malignant tumours. Nevertheless, the HMGA1 expression studies published so far have not included primary breast cancer samples. In this study we have investigated the HMGA1 expression patterns in a series of 170 breast cancer samples by immunohistochemistry. We have found a strong variation in HMGA1 expression between the tumours. Based on an immunoreactive score (IRS) 14.1% of the tumour samples were scored to IRS 8-12 (strong positivity for HMGA1), 24.7% were scored to IRS 4-6 (moderate positivity), 25.3% were scored to IRS 1-3 (weak positivity), and 35.9% showed no positivity at all. Immunoreaction could be detected in all histological types of breast cancers analysed with the exception of invasive papillary and cribriform carcinoma. Statistical analysis revealed a strong correlation between tumour grade and HMGA1 expression (rs=0.3516, p<0.0001). Thus, the HMGA1 expression level can be considered a potential prognostic marker for breast cancer.

Large deletion of part of the HMGIC locus accompanying a t(3;12)(q27 approximately q28;q14 approximately q15) in a lipoma.

The high mobility group protein gene HMGIC has been found to be rearranged in a variety of human benign solid tumors. Often, these rearrangements lead to fusion genes of which that between HMGIC and LPP underlying t(3;12)(q27 approximately q28;q14 approximately q15) is by far the most common. Herein, we analysed a lipoma with a t(3;12)(q27 approximately q28;q14 approximately q15). RT-PCR revealed the presence of a HMGIC-LPP fusion transcript composed of exons 1-3 of HMGIC and exons 9-11 of LPP, but the absence of the reverse LPP-HMGIC fusion transcript. Fluorescence in situ hybridization experiments using different probes derived from the HMGIC gene and its 3' vicinity showed the absence of FISH signals on the derivative chromosome 3. Thus, in the present tumor the t(3;12)(q27 approximately q28;q14 approximately q15) was accompanied by a large genomic deletion. Roughly, it can be estimated that at least 170 kb of chromosome 12 material were deleted. To the best of our knowledge, this is the first report showing that the "simple" t(3;12)(q27 approximately q28;q14 approximately q15) results in a large deletion of DNA.

Significant correlation between the breakpoints of rare clonal aberrations in benign solid tumors and the assignment of HMGIY retropseudogenes.

Recently, we described a mechanism by which a retropseudogene, during evolution, becomes an exon of a pre-existing active gene. Similar mechanisms may account for the activation of processed genes by chromosomal rearrangements in neoplasms. Because genes of the high-mobility group protein family HMGI(Y) are known to be involved in the development of a variety of benign solid tumors, it was the aim of the present study to analyze breakpoints of clonal chromosome abnormalities in that group of benign tumors for a possible correlation with retropseudogenes of the HMGIY gene. Whereas the HMGIYL1 retrospeudogene has recently been mapped to Xp22.1, we assigned a further retropseudogene by FISH to 4q13, and database research allowed us to assign a third retropseudogene to 12q24.1. Sequence analyses of these retropseudogenes revealed high-identity indices to the HMGIY gene and no frame-shift divergences. Breakpoint information was obtained from cytogenetic aberrations in uterine leiomyomas, lipomas, pleomorphic adenomas, and pulmonary chondroid hamartomas because, in all of these tumor entities, cytogenetic subgroups involving genes of the HMGI(Y) family exist. Chromosomal bands harboring HMGIY retropseudogenes were affected with a significantly higher frequency than expected under the assumption of purely randomly occurring breakages. These results support our hypothesis that HMGIY-related retropseudogenes can be affected by chromosomal rearrangements in benign human tumors.

A novel high mobility group protein gene is a candidate for Xp22 abnormalities in uterine leiomyomas and other benign tumors.

Because genes of the high mobility group protein family HMGI(Y) are known to take part in the development of a variety of benign solid tumors, the aim of the present study was to search for further members of that family in the human genome. Analysis for HMGI(Y)-related sequences by the polymerase chain reaction (PCR) with the use of cDNA-specific primers offered evidence for HMGIY-like sequences, whereas HMGIC-related sequences were apparently absent. By chromosomal assignment of somatic cell hybrids PCR, HMGIY cDNA-related sequences were detected on seven chromosomes. Positive clones were obtained by screening of a P1-derived artificial chromosome library and mapped by fluorescence in situ hybridization. One of these clones assigned to Xp22.1 was chosen for further analysis because Xp22 is a target region for clonal aberrations in benign solid tumors. Sequence analysis of a DNA fragment of this clone, designated as HMGIYL1, revealed a 94.4% homology to the coding region of HMGIY. Within the HMGIYL1 sequence, no nucleotide sequence divergences leading to a frame shift or a new termination codon compared to HMGIY were found, and a TATA-box-like motif 5' of it was detected. By reverse transcriptase PCR experiments with the use of HeLa cells and human fetal tissue, HMGIYL1 expression was not detectable. Nevertheless, if not active by itself, it is possible that HMGIYL1 may become activated by chromosomal rearrangements of Xp22 observed in benign solid tumors.

Two human breast cancer cell lines showing decreasing telomeric repeat length during early in vitro passaging.

Specific DNA repeats serve as a molecular protection shield at the telomeric ends of mammalian chromosomes. The absence of telomerase activity leads to a gradual decrease of telomeric repeat length in normal somatic cells. In contrast, immortalized cells from malignant tumors are usually thought to re-express telomerase to overcome a self-limited growth. Following this hypothesis, re-expression of telomerase is due to a rare mutational event. Herein we describe our results of telomeric length determination in two newly established breast cancer cell lines. During in vitro establishment from pleural effusions, both cell lines showed a marked decrease of the upper border range of telomeric repeat length distribution. The lower border remained within a constant range characteristic for each cell line. In no case was decrease of repeat length accompanied by an increased incidence of telomeric associations or fusions. The results show that a constant telomeric repeat length does not constitute a characteristic feature of immortalized cells. Furthermore, the kinetics of repeat length decrease and the constant range of the lower border reveal that the onset of telomerase activity is not necessarily due to a rare, i.e., mutational, event.