Karl Hoermann

Phase I trial with the CD44v6-targeting immunoconjugate bivatuzumab mertansine in head and neck squamous cell carcinoma

CD44v6 is a tumor associated antigen abundantly expressed in head and neck squamous cell carcinomas (HNSCC) and in normal squamous epithelium. The immunoconjugate bivatuzumab mertansine (BIWI 1) consists of a highly potent antimicrotubule agent coupled to a monoclonal antibody against CD44v6. The maximum tolerated dose (MTD), safety and efficacy of BIWI 1 administered IV in patients with HNSCC has not been determined. In a clinical phase I trial, adult patients with recurrent or metastatic HNSCC were treated intravenously with BIWI 1. Starting with 25mg/m(2), the dose was escalated in steps of 25mg/m(2) until dose limiting toxicity was observed. Six women and 25 men were included. The MTD was 300 mg/m(2). Twelve patients were treated with at least the MTD. The principal toxic effects were maculopapular rashes, focal blister formation and skin exfoliation. Three patients had partial responses at doses of 200, 275 and 325 mg/m(2). The concept that bivatuzumab can direct mertansine activity to CD44v6 expressing tumors was confirmed. Although CD44v6 was abundantly expressed in all tumors, the response to BIWI 1 was variable. Binding to CD44v6 on skin keratinocytes mediated serious skin toxicity with a fatal outcome in a parallel trial, which led to the termination of the development program of bivatuzumab mertansine and the present study.

Rhinophyma: diagnosis and treatment options for a disfiguring tumor of the nose.

Rhinophyma is a benign dermatologic disease of the nose affecting primarily Caucasian men in their fifth to seventh decades of life. It is characterized by a slowly progressive enlargement with irregular thickening of the nasal skin and nodular deformation. It is assumed to be the end stage of chronic acne rosacea. Main reasons that urge the patients to seek help are plastic cosmetic and functional impairments such as nasal obstruction. Surgical removal of the hyperplastic tumor mass is the treatment of choice for rhinophyma. In a retrospective review, the authors describe the pros and cons of the main treatment modalities that have been described in literature and present their own clinical experience.

Current oncologic concepts and emerging techniques for imaging of head and neck squamous cell cancer

The incidence of head and neck squamous cell carcinoma (HNSCC) is increasing and currently they account for 5% of all malignancies worldwide. Inspite of ongoing developments in diagnostic imaging and new therapeutic options, HNSCC still represents a multidisciplinary challenge. One of the most important prognostic factors in HNSCC is the presence of lymph node metastases. Patients with confirmed nodal involvement have a considerable reduction of their 5-year overall survival rate. In the era of individually optimised surgery, chemotherapy and intensity modulated radiotherapy, the main role of pre- and posttherapeutic imaging remains cancer detection at an early stage and accurate follow-up. The combined effort of early diagnosis and close patient monitoring after surgery and/or radio-chemotherapy influences disease progression and outcome predicition in patients with HNSCC. This review article focuses on currrent oncologic concepts and emerging tools in imaging of head and neck squamous cell cancer. Besides the diagnostic spectrum of the individual imaging modalities, their limitations are also discussed. One main part of this article is dedicated to PET-CT which combines functional and morphological imaging. Furthermore latest developments in MRI are presented with regard to lymph node staging and response prediction. Last but not least, a clinical contribution in this review explains, which information the head and neck surgeon requires from the multimodality imaging and its impact on operation planning.

Mutation analysis of "Endoglin" and "Activin receptor-like kinase" genes in German patients with hereditary hemorrhagic telangiectasia and the value of rapid genotyping using an allele-specific PCR-technique

BackgroundHereditary hemorrhagic telangiectasia (HHT), also known as Rendu-Osler-Weber syndrome, is an autosomal dominant disorder which is clinically characterised by recurrent epistaxis, mucocutaneous telangiectasia and visceral arteriovenous malformations. Genetic linkage studies identified two genes primarily related to HHT: endoglin (ENG) on chromosome 9q33-34 and activin receptor-like kinase1 (ACVRL1) on chromosome 12q13. We have screened a total of 41 unselected German patients with the suspected diagnosis of HHT. Mutation analysis for the ENG and ACVRL1 genes in all patients was performed by PCR amplification. Sequences were then compared to the HHT database http://www.hhtmutation.org sequences of the ENG mRNA (accession no. BC014271.2) and the ACVRL1 mRNA (accession no. NM000020.1).ResultsWe identified 15 different mutations in 18 cases by direct sequencing. Among these mutations, one novel ENG mutation could be detected which has not yet been described in the literature before. The genotype-phenotype correlation was consistent with a higher frequency of pulmonary arteriovenous malformations in patients with ENG mutations than in patients with ACVRL1 mutations in our collective.ConclusionFor rapid genotyping of mutations and SNPs (single nucleotide polymorphisms) in ENG and ACVRL1, allele-specific PCR methods with sequence-specific primers (PCR-SSP) were established and their value analysed.

Functional effects of SDF-1α on a CD44+ CXCR4+ squamous cell carcinoma cell line as a model for interactions in the cancer stem cell niche

Stromal cell-derived factor-1α (SDF-1α), also known as CXCL12, has variable effects on a plurality of cells. It is known to have selective effects on cell migration, morphology, survival and cell homing. As such the SDF-1-CXCR4 axis is postulated to be a crucial key pathway in the interaction between (cancer) stem cells and their surrounding supportive cells, the so-called (cancer) stem cell niche. We evaluated the expression of CD44 as a cancer stem cell (CSC) marker and the expression of CXCR4 in the head and neck squamous cell carcinoma (HNSCC) cell line UM-SCC 11A. In addition, we monitored proliferation, formation of podia and migration of UM-SCC 11A cells under the influence of SDF-1α. Whereas SDF-1α induced the formation of podia of CD44(+) CXCR4(+) UM-SCC 11A cells in a dose-dependent manner and the maximum number of cells exhibiting the formation of podia was observed under the influence of 10 ng/ml SDF-1α (P=5.3x10(-6)), the highest number of migrating cells was noted using a concentration of 100 ng/ml (P=0.027). Proliferation and survival were not affected by SDF-1α. We showed that UM-SCC 11A cells could be a target for SDF-1α by CXCR4 expression and these cells also showed characteristics of HNSCC CSCs via CD44 expression. We demonstrated that SDF-1α is a chemoattractant for UM-SCC 11A cells, and a maximum directed migration was achieved under the influence of 100 ng/ml SDF-1α. Changes in cell morphology by presenting filopodia or a prominent uropod were noted following treatment of 10 ng/ml SDF-1α. The SDF-CXCR4 axis may play a crucial role in the interaction between CSCs and their supportive cells in the CSC niche. Understanding these interactions may help to gain further insight into the pathophysiology of the progression and recurrence of malignant diseases and thus help to develop novel strategies for therapy.

SDF-1-CXCR4 axis: Cell trafficking in the cancer stem cell niche of head and neck squamous cell carcinoma

Stromal cell-derived factor-1α (SDF-1α), also known as CXCL12, has variable effects on a plurality of cells. CXCR4 has been identified as its corresponding receptor. The SDF-1-CXCR4 axis is postulated to be a crucial key pathway in the interaction between (cancer) stem cells and their surrounding supportive cells in the cancer stem cell niche. We evaluated the expression of CD44 as a cancer stem cell marker and of CXCR4 in human HNSCC tissue samples. Afterwards, we monitored the concentration of SDF-1 in peripheral blood samples of HNSCC patients and healthy donors. We showed that CD44 and CXCR4 are expressed in human HNSCC tissues. Markedly, CD44 showed a high expression in HNSCC cells bordering cancer stromal cells. CXCR4 was mainly expressed in HNSCC tumor nests, but not in the surrounding stromal cells. No significant difference was noted between the SDF-1 concentration in the peripheral blood of HNSCC patients compared to healthy donors. We showed that CD44, as a stem cell marker in HNSCC, is located mainly at the borderline of HNSCC tumor nests with the surrounding cells. In addition, we demonstrated that CXCR4 as the corresponding receptor to SDF-1 is highly expressed in HNSCC tumor nests, but not in the tumor stroma. We collected evidence that SDF-1-CXCR4 interaction may be a crucial pathway in cell trafficking in the cancer stem cell niche of HNSCC, while SDF-1 was not detected in the peripheral blood of HNSCC patients. The SDF-1-CXCR4 axis may play an important role in the cancer stem cell theory of HNSCC. As SDF-1α also exhibits a multitude of functional effects on HNSCC cells, such as migration and polarization, it may be possible that the SDF-1-CXCR4 axis is also involved in the pathophysiology of the progression, recurrence and metastasis of malignant disease. Understanding these interactions may help to gain further insight into these mechanisms and as such help to discover new strategies of therapy.

Possibilities and problems of using the holmium laser in ENT

Infrared lasers are the most favored systems for laser micro surgery. The reason is due to the short penetration depth of these emission wavelengths in water. The application of pulsed lasers with sufficient short pulse widths prevents the diffusion of heat from the irradiated volume to the surrounding tissue. Therefore, using pulsed lasers rather than cw-lasers reduces the damage zone significantly. In contrast to the radiation of the CO2-laser and the Er:YAG laser, there are quartz fibers available for the Ho:YAG laser. These fibers are biocompatible and offer a high spectral transmission and a high laser damage threshold. In paranasal sinus and middle ear surgery both the fiberoptic transmission and the possibility of bone ablation are preconditions for an optimal laser use. Because the beam profile of the laser radiation is determined by the fiber, the question arises for the quality of the obtained incisions and for optimal working conditions.

Alteration of MMP-2 and -14 expression by imatinib in HPV-positive and -negative squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is an aggressive epithelial malignancy. It is known to be the most common neoplasm appearing in the upper aerodigestive tract. The poor 5‑year survival rate has remained unchanged in the last decades even though improved techniques in surgery, radiation and chemotherapy have been established. In contrast to the overall decreasing incidence of head and neck cancer in the US, the incidence of HPV-associated oropharyngeal cancer is increasing, indicating the importance of viral etiology. Furthermore, growth and invasion of HNSCC are strongly influenced by the extracellular matrix (ECM). Matrix metalloproteinases (MMP) have been shown to play key roles in the remodeling of the ECM. Imatinib (STI 571) was originally designed to inhibit the BCR-ABL tyrosine kinase in chronic myeloid leukaemia. But it also has an inhibitory impact, e.g., on the protein-tyrosine-kinase (PTK) receptor c-kit and on its PTK activity in HNSCC. In this study, we incubated the HNSCC cell lines HNSCC 11A and 14C and the p16-positive SCC line CERV196 with increasing concentrations of imatinib or carboplatin. After an incubation time of up to 10 days, we evaluated MMP-2 and -14 expression by ELISA techniques and immunohistochemistry. MMP-2 and -14 expression was demonstrated in all incubated tumor cell lines. Especially incubation with imatinib resulted in a significant decrease in MMP expression in incubated cell lines. Our results indicate that the expression of MMP-2 and -14 is suppressed in the presence of imatinib. Thus, imatinib may exert in part its inhibitory effect on malignant cell growth via the blockage of the signal transduction of PTK receptors. Further studies are warranted, especially keeping in mind the moderate toxicity of imatinib.

Endotracheal tubes for laser surgery: temperature rise and clinical experiences

An infrared camera was used to measure the temperature rise which takes place in endotracheal tubes under laser irradiation. It was seen that a metallic tube was heated up within a second to temperatures of 200 degrees to 300 degrees Celsius which was very destructive to the PVC conduits inside of the tube. A compound tube, on the other hand, reached temperatures of only 38 degrees Celsius at its inner surface. The thermal induced destruction of the conduits inside of the metallic tube is seen as the reason for complications like airway blocking. Furthermore preliminary results of a randomized clinical study are presented, showing that the metallic tube needed higher pressure levels than the compound tube.

Imatinib-associated matrix metalloproteinase suppression in p16-positive squamous cell carcinoma compared to HPV-negative HNSCC cells in vitro

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common type of cancer worldwide. The growth and invasion of HNSCC are strongly influenced by the extracellular matrix (ECM), which is modified by matrix metalloproteinases (MMPs). The MMP family is still relevant to cancer research, as it promotes malignant transformation, cell proliferation and modulation of angiogenesis even in the early stages of cancer. The proteolytic processing of bioactive molecules by MMP-14 (MT1-MMP) causes severe abnormalities in connective tissue, defective angiogenesis and premature death. MMP-2 (gelatinase A) and MMP-14 also play a role in degradation of basement membrane and cell carcinoma invasion. Imatinib blocks the PTK receptor c-kit and forestalls its PTK activity. The aim of the present study was to investigate the expression pattern of MMP-14 and MMP-2 in human papilloma virus (HPV)-negative and p16-positive SCC and to evaluate the chemosensitivity of the tumour cells to the chemotherapeutic agents, imatinib and 5-fluorouracil (5-FU). We incubated the SCC cell lines with imatinib (18 and 30 µmol/ml) and 5-FU (1 and 5 µmol/ml) and detected MMP-14 and MMP-2 by immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) after 48, 72, 120, 192 and 240 h. We detected expression of MMP-2 and MMP-14 in all incubated tumour cell lines. With imatinib in particular, we found a reliable trend towards decreased MMP-2 and MMP-14 expression levels in p16-positive and p16-negative SCC tumour cell lines in addition to an induced apoptotic effect. We found statistically significant imatinib-induced suppression of MMP-2- and MMP-14, dependent on the incubation time and the cell line. We detected a significant suppression of MMP-2 and MMP-14 especially in p16-negative HNSCC14C cells after prolonged treatment time with imatinib. Dose escalation of imatinib and 5-FU had no statistically significant effect on the expression of MMP-2 or MMP-14. The p16-positive SCC cells exhibited higher expression of total protein. We detected a significant suppression of MMP-2 and MMP-14 in all the incubated SCC cell lines, partially after treatment with imatinib. We found higher suppression of MMP-2 in the CERV196 cells after incubation with imatinib. We detected a reliable trend towards increased chemosensitivity of p16-positive tumour cells in vitro after treatment with imatinib. Extended studies and clinical trials are needed to further investigate these findings in HPV-associated HNSCC.