Jan Bernd Weise

p16INK4a overexpression predicts translational active human papillomavirus infection in tonsillar cancer.

The causal role of human papillomaviruses (HPV) in squamous cell carcinogenesis of tonsillar cancers (TSCC) depends on the activity of the viral oncoproteins E6 and E7, leading to inactivation of the cellular tumor suppressor p53 and the retinoblastoma gene product pRb. Because of the negative feedback mechanisms, the pRb inactivation causes an increase of the inhibitor of the cyclin‐dependent kinases p16INK4a. In 39 TSCC specimens, genotyping based on the amplification of HPV DNA was carried out using PCR by applying HPV type‐specific oligonucleotides. Subsequently, amplicons were hybridised with fluorescence‐labeled complementary probes using the Southern blot technology. For HPV E6/E7 mRNA expression, Northern hybridization and RT‐PCR were performed, and for p16INK4a detection, immunohistochemistry was performed. With 21/39 (53%) HPV‐positives, the detection rate is within the range that can be expected in TSCC. The E6/E7 oncogene mRNA was detectable in 11 cases, 10 of which showed positive signals after p16INK4a staining. Albeit the small study group was investigated, the correlation of the HPV DNA status with the p16INK4a expression was of statistical significance (p = 0.02). Kaplan‐Meier estimations revealed better survival outcome for patients with HPV‐positive tumors with detectable E6/E7 mRNA and p16INK4a overexpression (p = 0.02, median observation time 29 months). As mRNA expression tests are not routinely available in many clinical diagnostic laboratories, and based on the high correlation of p16INK4a staining with HPV E6/E7 mRNA expression, in conclusion we suggest for a deeper exploration for the use of p16INK4a as a surrogate marker with the potential to impact the standard of care of HPV DNA‐positive head and neck carcinomas.

Selective upregulation and amplification of the lysyl oxidase like‐4 (LOXL4) gene in head and neck squamous cell carcinoma

Members of the lysyl oxidase family (LOX) are copper and lysyl‐tyrosine quinone cofactor‐containing amine oxidases that are important for the assembly and maintenance of components of the extracellular matrix. Our previous results demonstrated that a novel member, LOXL4, is overexpressed in head and neck squamous cell carcinoma (HNSCC) compared to normal squamous epithelium. Results of the current study showed overexpression of the LOXL4 transcript in 74% (46 of 62) of invasive HNSCC tumours and 90% of both primary and metastatic HNSCC cell lines. Significant correlation was found between LOXL4 expression and local lymph node metastases versus primary tumour types (p < 0.01) and higher tumour stages (p < 0.01). Immunocytochemistry demonstrated cellular overexpression of the LOXL4 protein that correlated with the increased mRNA transcription in HNSCC cells. HNSCC cell lines displayed in significant subset of nuclei increased copies of the LOX4 gene locus on chromosome 10q24, demonstrated by fluorescence in situ hybridization (FISH). Extensive metaphase cytogenetic analysis was performed on UTSCC19A cells, identifying an isochromosome i(10)(q10). Taken together, these results highlight LOXL4 expression as a distinctive trait and suggest a functional role for LOXL4 in the molecular pathogenesis of invasive head and neck carcinomas. Copyright

LOXL4 is a selectively expressed candidate diagnostic antigen in head and neck cancer

Selective up-regulation of the mRNA of LOXL4, a member of the LOX matrix amine oxidase family, significantly correlated with lymph node metastases and higher tumour stages in head and neck squamous cell carcinomas (HNSCC). To evaluate the diagnostic and prognostic value of the protein we produced an antibody specific for LOXL4 and assessed the expression in 317 human HNSCC specimens. The LOXL4 protein was detected in 92.7% of primary tumours, in 97.8% of lymph node metastases and in affected oral mucosa with high-grade dysplasia, but was absent in various non-neoplastic tissues of the head and neck. TNM categories and overall survival did not link to grades of immunoreactivity. Studies in cultured primary hypopharyngeal HTB-43 carcinoma cells detected perinuclear and cell surface expression of LOXL4, but no nuclear localisation. Therefore, its interactive SRCR-domains and catalytic activity combined with tumour cell specific expression and cell surface associated location indicate multiple functions in tumour cell adhesion and interactions with the extracellular matrix. Our data suggest that LOXL4 is useful both as tumour marker and target in the treatment of HNSCC.

Bedeutung dendritischer Zellen für die Immuntherapie von Tumorerkrankungen

Die maßgebliche Erkenntnis der letzten 10 Jahre, dass maligne Tumoren Antigene exprimieren, die vom zellulären Immunsystem spezifisch angegriffen werden können, hat zur Entwicklung innovativer Strategien der Immuntherapie von Krebs geführt. Dendritische Zellen nehmen in der Induktion einer Immunantwort eine Schlüsselfunktion ein. Sie sind wirksame antigenpräsentierende Zellen, die endogenes oder aufgenommenes Antigen zu immunogenen MHC-Klasse Ibzw. -II-Peptidkomplexen (MHC: Major-Histokompatibilitäts-Komplex) binden und über Liganden T-Lymphozyten stimulieren. Eine tumorspezifische zytotoxische T-Zell-Antwort ist das primäre Ziel einer erfolgreichen aktiven spezifischen Immuntherapie und wird derzeit in klinischen Studien mit dendritischen Zellen überprüft.