Lothar Tietze

Comparison of high resolution melting analysis, pyrosequencing, next generation sequencing and immunohistochemistry to conventional Sanger sequencing for the detection of p.V600E and non-p.V600E BRAF mutations

BackgroundThe approval of vemurafenib in the US 2011 and in Europe 2012 improved the therapy of not resectable or metastatic melanoma. Patients carrying a substitution of valine to glutamic acid at codon 600 (p.V600E) or a substitution of valine to leucine (p.V600K) in BRAF show complete or partial response. Therefore, the precise identification of the underlying somatic mutations is essential. Herein, we evaluate the sensitivity, specificity and feasibility of six different methods for the detection of BRAF mutations.MethodsSamples harboring p.V600E mutations as well as rare mutations in BRAF exon 15 were compared to wildtype samples. DNA was extracted from formalin-fixed paraffin-embedded tissues by manual micro-dissection and automated extraction. BRAF mutational analysis was carried out by high resolution melting (HRM) analysis, pyrosequencing, allele specific PCR, next generation sequencing (NGS) and immunohistochemistry (IHC). All mutations were independently reassessed by Sanger sequencing. Due to the limited tumor tissue available different numbers of samples were analyzed with each method (82, 72, 60, 72, 49 and 82 respectively).ResultsThere was no difference in sensitivity between the HRM analysis and Sanger sequencing (98%). All mutations down to 6.6% allele frequency could be detected with 100% specificity. In contrast, pyrosequencing detected 100% of the mutations down to 5% allele frequency but exhibited only 90% specificity. The allele specific PCR failed to detect 16.3% of the mutations eligible for therapy with vemurafenib. NGS could analyze 100% of the cases with 100% specificity but exhibited 97.5% sensitivity. IHC showed once cross-reactivity with p.V600R but was a good amendment to HRM.ConclusionTherefore, at present, a combination of HRM and IHC is recommended to increase sensitivity and specificity for routine diagnostic to fulfill the European requirements concerning vemurafenib therapy of melanoma patients.

Benign metastasizing leiomyoma: A cytogenetically balanced but clonal disease

Benign metastasizing leiomyoma (BML) is a rare condition, characterized by the occurrence of multiple smooth-muscle nodules, most often located in the lung after previous hysterectomy because of histologically benign appearing leiomyoma. Although the condition resembles a metastatic process, case studies provided evidence that it may be the result of an intravenous leiomyomatosis or an independent and multifocal smooth-muscle proliferation. Comparative genomic hybridization and X-chromosome inactivation analysis were used in a case of BML to determine whether pulmonary and uterine tumors are related one to another. A balanced karyotype, previously reported in leiomyomas and an identical X-chromosome inactivation pattern found in all tumorlets, is most consistent with a monoclonal origin of both uterine and pulmonary tumors and the interpretation that pulmonary lesions are metastatic.

Differences in genetic alterations between primary lobular and ductal breast cancers detected by comparative genomic hybridization

Infiltrating ductal (DC) and lobular carcinoma (LC) of the breast represent the most frequently observed varieties of invasive breast cancer, characterized by differences in their histological and clinical properties. Although comparative genomic hybridization (CGH) of invasive breast carcinomas has revealed a complex and consistent pattern of DNA copy number changes, the data with regard to type specific aberrations are limited. A comprehensive study was therefore performed on 19 LCs and 29 DCs to ascertain type‐specific differences of unbalanced DNA copy number changes by CGH. Statistical analysis revealed significantly higher frequencies for underrepresentation of chromosomes 16q (p<0.01), 22 (p<0.05), and 17q (p<0.05), and a lower frequency for overrepresentation of chromosome 8q (p<0.01) in LC. Similar frequencies of non‐random chromosomal changes in LC and DC were obtained for gain of 1q (74%/59%) and loss of 19p (53%/52%), parts of 1p (42%/41%) and 11q (21%/24%). Less frequently, gains mainly involving parts of chromosomes 20q, 20p, 3q, and 5p and partial losses of chromosomes 17p and 13 were observed in both groups of tumours. Minimal regions of overlapping amplifications were mapped to 17q23 exclusively in DC (17%) and 11q13–q14 in both DC and LC (21% and 11%, respectively). High occurrences of DNA copy number decreases were detected at the distal part of chromosomes 1p, 19 and 22, but further analysis is required to confirm these imbalances. It is suggested that the observed differences are involved in the development of type‐specific properties of DC and LC. Copyright

Influence of heat shock protein 70 and metallothionein induction by Zinc-Bis-(DL-Hydrogenaspartate) on the release of inflammatory mediators in a porcine model of recurrent endotoxemia

The manipulation of stress gene expression by heavy metals provides protection against the lethal effects of endotoxemia in murine models of septic shock. Recent in vitro studies with alveolar macrophages or monocytes show that induction of the stress response in these cells is followed by a decreased liberation of major cytokines [tumor necrosis factor-alpha (TNF alpha) and interleukin-1 (IL-1)] after endotoxin challenge. These findings suggest that the increased resistance to endotoxin in vivo after stress protein induction could be explained by an altered pattern of inflammatory mediator release. Therefore, we measured the time course of thromboxane-B2 (TxB2), 6-keto-PGF1 alpha, platelet activating factor (PAF), TNF alpha, interleukin-1 beta (IL-1 beta), and interleukin-6 (IL-6) formation with and without induction of the stress response in an established porcine model of recurrent endotoxemia (Klosterhalfen et al., Biochem Pharmacol 43: 2103-2109, 1992). Induction of the stress response was done by a pretreatment with Zn2+ (25 mg/kg zinc-bis-(DL-hydrogenasparate = 5 mg/kg Zn2+). Pretreatment with Zn2+ prior to lipopolysaccharide (LPS) infusion induced an increased heat shock protein 70 and metallothionein expression in the lungs, liver, and kidneys and increased plasma levels of TNF alpha, IL-1 beta, IL-6, and TxB2 as opposed to untreated controls. After LPS infusion, however, pretreated animals showed significantly decreased peak plasma levels of all mediators as opposed to the untreated group. The time course of mediator release was identical with the decreasing and increasing three peak profiles described previously. Hemodynamic data presented significantly decreased peak pulmonary artery pressures and significantly altered hypodynamic/hyperdynamic cardiac output levels in the pretreated group. In conclusion, the data show that the induction of stress proteins by Zn2+ could be a practicable strategy to prevent sepsis.

The Influence Of Heat Shock Protein 70 Induction On Hemodynamic Variables In A Porcine Model Of Recurrent Endotoxemia

The manipulation of stress gene expression by heavy metals provides protection against the lethal effects of endotoxemia in murine models of septic shock. These findings suggest that the increased resistance to endotoxin in vivo after stress protein induction could be explained by an attenuation of hemodynamic alterations and an altered pattern of inflammatory mediator release. Therefore, we measured main hemodynamic variables such as systemic and pulmonary artery pressure, cardiac output, heart rate, central venous pressure, and pulmonary artery wedge pressure, as well as the time-course of thromboxane-B2, 6-keto-PGF1α, and interleukin 6 formation with and without induction of the stress response in an established porcine model of recurrent endotoxemia (Circ Shock 35:237–244, 1991). Induction of the stress response was carried out by a pretreatment with Zn2+ (25 mg/kg zinc-bis-(DL-hydrogenaspartate) = 5 mg/kg Zn2+). Pretreatment with Zn2+ prior to lipopolysaccharide (LPS) infusion induced an increased heat shock protein 70 (HSP70) expression in the lungs, liver, and kidneys and significantly increased plasma levels of interleukin 6, 6-keto-PGF1α, and thromboxane-B2, compared with untreated controls. After LPS infusion, however, pretreated animals showed significantly decreased peak plasma levels of all mediators compared with the untreated group. Hemodynamic data presented significantly decreased peak pulmonary artery pressure and pulmonary vascular resistance index values, significantly increased systemic artery pressure and systemic vascular resistance index values, and significantly altered hypodynamic/hyperdynamic cardiac output levels in the pretreated group. In conclusion, the data show that the induction of HSP70 by Zn2+ attenuates the liberation of inflammatory mediators, as well as the course of hemodynamic variables due to LPS.

Expression of Heat Shock Proteins 72/73 in Human Peritoneal Mesothelial Cells in vivo and in vitro

Leukocyte accumulation during peritonitis leads to an injurious microenvironment which is involved in the host defense reaction but is also thought to cause peritoneal damage. We tested the hypothesis that mesothelial cells (MC) respond to the injurious microenvironment during peritonitis by an increased expression of heat shock proteins (HSP 72/73), a basic way by which cells are protected against injury. Comparison of resting MC and activated MC during peritonitis in vivo by means of immunohistochemistry revealed an increased expression of HSP 72/73. As assessed by Western immunoblotting, incubation of MC in vitro with tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) caused a time-dependent induction of HSP 72/73 expression, which was maximal 6 h after stimulation. We suggest that the increased HSP 72/ 73 expression of MC during peritonitis is in part induced by TNF-α and IL-1β and may exert a cell-protective function, lessening MC damage during peritonitis.

Simultaneous appearance of an adenomyoma and pancreatic heterotopia of the stomach

Abstract Adenomyomas of the stomach are rare tumours characterised by duct/gland-like structures embedded within a smooth muscle stroma. Although the histogenesis of adenomyomas remains unclear, the histological appearance has justified the assumption that these are abortive forms of pancreatic heterotopia. We report an unusual case with simultaneous and independent appearance of both adenomyoma and pancreatic heterotopia of the stomach including immunohistochemical characterisation, supporting the concept of a common histiogenetic origin of both lesions.

Consensus polymerase chain reaction and enzyme-linked immunosorbent assay for human papillomavirus detection and typing in cervical specimens.

Human papillomavirus (HPV) infection is common in cervical intraepithelial neoplasia (CIN). This study investigates HPV detection and typing assay based on polymerase chain reaction amplification of L1 open reading frame with general primers GP5/GP6, followed by enzyme-linked immunosorbent assay detection with type-specific DNA probes. To determine the sensitivity of this assay, formalin-fixed CaSki cells were used as reference cell lines. Fifty copies of viral DNA diluted in DNA from 100,000 noninfected cells could be detected. This assay was also investigated for HPV detection and typing of 67 cervical specimens diagnosed with with CIN III or carcinoma in situ (CIS) and their adjacent squamous epithelium. The CIN III lesions were infected in approximately 80% of the samples, 81% in the neighboring CIN II, and 68% in CIN I. The HPV infection was even detectable in 54% of nondysplastic epithelium located near a CIN III lesion.