Pathology skills lab: use of macroscopic tumor models in pathology teaching.

BACKGROUND: The shortage of pathologists in Germany, coupled with an aging workforce, requires innovative approaches to attract medical students to the field. Medical education must address different learning styles to ensure that all students are successful. METHODS: The pilot project "Practical Pathology" aims to enhance students' understanding of pathology by providing hands-on experience in macroscopic gross analysis through the use of tumor dummies built from scratch. RESULTS: An evaluation survey, completed by 63 participating students provided positive feedback on the course methodology, its relevance to understanding the pathology workflow, and its improvement over traditional teaching methods. The majority of students recognized the importance of hands-on training in medical education. Students with previous work experience rated the impact of the course on knowledge acquisition even more positively. CONCLUSION: The course improved students' understanding of pathological processes and potential sources of clinical-pathological misunderstanding. An increase in motivation for a potential career in the field of pathology was observed in a minority of students, although this exceeded the percentage of pathologists in the total medical workforce.

[Receptor tyrosine kinase- fusions in paediatric spindle cell tumors]. / Rezeptor-Tyrosinkinase-Fusionen in spindelzelligen Tumoren des Kindesalters.

Pediatric spindle cell tumors are rare and often difficult to diagnose due to a similar morphology and a non-specific immunohistochemical profile. Genetic characterization of these lesions has been constantly improving, which has led to the identification of new subgroups that were partly included in the WHO classification. Receptor tyrosine kinase fusions play a special role in these tumors and their verification has diagnostic relevance and can be an option for target-oriented therapies. In the case of pediatric spindle cell tumors, genetic fusions form especially with NTRK1­3, ALK, RET, and ROS1. Overall, pediatric tumors with receptor tyrosine kinase fusions are predominantly low-grade tumors, which are often subdivided into the group of intermediate-malign tumors.

Nectin-4 is widely expressed in head and neck squamous cell carcinoma.

PURPOSE: Nectin-4 has been successfully established as a target molecule in locally advanced and metastatic bladder cancer. An antibody-drug conjugate (enfortumab-vedotin) directed against nectin-4 has shown marked tumor remission rates in this tumor type, which is known for high expression rates of nectin-4. As head and neck cancer and urothelial carcinomas share morphological and molecular similarities, we aimed to evaluate Nectin-4 expression in head and neck squamous cell carcinoma (HNSCC). MATERIAL AND METHODS: A previously described and clinically characterized cohort of HNSCC (n = 159) was analyzed by immunohistochemistry for Nectin-4 expression. The expression data was correlated to clinico-pathological parameters including patient outcome. RESULTS: Nectin-4 was found in 86.2% of HNSCC, with medium/high expression seen in 32.7% of cases. Non smokers and p16 positive HNSCC showed a higher expression of Nectin-4 (p < 0.005). There was no correlation of Nectin-4 with grading or tumor stage. Nectin-4 positive tumors showed a significant better survival (log rank p = 0.006). CONCLUSIONS: Similar to urothelial carcinoma, Nectin-4 is found in the majority of HNSCC, which clearly warrants further studies to clarify if HNSCC also respond to targeted therapy with enfortumab-vedotin. Moreover, expression of Nectin-4 is associated with HPV infection and may serve as a prognostic marker in HNSCC.

CD103+ Tissue Resident T-Lymphocytes Accumulate in Lung Metastases and Are Correlated with Poor Prognosis in ccRCC.

Clear cell renal cell carcinoma (ccRCC) is a highly immunogenic tumor with variable responses to immune checkpoint therapy. The significance of the immune cell infiltrate in distant metastases, their association with the immune infiltrate in the primary tumors and their impact on prognosis are poorly described. We hypothesized that specific subtypes of immune cells may be involved in the control of metastases and may have an impact on the prognosis of ccRCC. We analyzed the immune microenvironment in ccRCC primary tumors with distant metastases, paired distant metastases and non-metastasized ccRCC (n = 25 each group) by immunohistochemistry. Confirmatory analyses for CD8+ and CD103+ cells were performed in a large ccRCC cohort (n = 241) using a TCGA-KIRC data set (ITGAE/CD103). High immune cell infiltration in primary ccRCC tumors was significantly correlated with the development of distant tumor metastasis (p < 0.05). A high density of CD103+ cells in ccRCC was more frequent in poorly differentiated tumors (p < 0.001). ccRCCs showed high levels of ITGAE/CD103 compared with adjacent non-neoplastic tissue. A higher density of CD103+ cells and a higher ITGAE/CD103 expression were significantly correlated with poor overall survival in ccRCC (log rank p < 0.05). Our results show a major prognostic value of the immune pattern, in particular CD103+ cell infiltration in ccRCC, and highlight the importance of the tumor immune microenvironment.

Pan-Cancer Analysis of the Mediator Complex Transcriptome Identifies CDK19 and CDK8 as Therapeutic Targets in Advanced Prostate Cancer.

Purpose: The Mediator complex is a multiprotein assembly, which serves as a hub for diverse signaling pathways to regulate gene expression. Because gene expression is frequently altered in cancer, a systematic understanding of the Mediator complex in malignancies could foster the development of novel targeted therapeutic approaches.Experimental Design: We performed a systematic deconvolution of the Mediator subunit expression profiles across 23 cancer entities (n = 8,568) using data from The Cancer Genome Atlas (TCGA). Prostate cancer-specific findings were validated in two publicly available gene expression cohorts and a large cohort of primary and advanced prostate cancer (n = 622) stained by immunohistochemistry. The role of CDK19 and CDK8 was evaluated by siRNA-mediated gene knockdown and inhibitor treatment in prostate cancer cell lines with functional assays and gene expression analysis by RNAseq.Results: Cluster analysis of TCGA expression data segregated tumor entities, indicating tumor-type-specific Mediator complex compositions. Only prostate cancer was marked by high expression of CDK19 In primary prostate cancer, CDK19 was associated with increased aggressiveness and shorter disease-free survival. During cancer progression, highest levels of CDK19 and of its paralog CDK8 were present in metastases. In vitro, inhibition of CDK19 and CDK8 by knockdown or treatment with a selective CDK8/CDK19 inhibitor significantly decreased migration and invasion.Conclusions: Our analysis revealed distinct transcriptional expression profiles of the Mediator complex across cancer entities indicating differential modes of transcriptional regulation. Moreover, it identified CDK19 and CDK8 to be specifically overexpressed during prostate cancer progression, highlighting their potential as novel therapeutic targets in advanced prostate cancer. Clin Cancer Res; 23(7); 1829-40. ©2016 AACR.

Targeting DDR2 in head and neck squamous cell carcinoma with dasatinib.

Squamous cell carcinoma of the head and neck (HNSCC) is the tenth most common tumor entity in men worldwide. Nevertheless therapeutic options are mostly limited to surgery and radio-chemotherapy resulting in 5-year survival rates of around 50%. Therefore new therapeutic options are urgently needed. During the last years, targeting of receptor tyrosine kinases has emerged as a promising strategy that can complement standard therapeutical approaches. Here, we aimed at investigating if the receptor tyrosine kinase DDR2 is a targetable structure in HNSCC. DDR2 expression was assessed on a large HNSCC cohort (554 patients) including primary tumors, lymph node metastases and recurrences and normal mucosa as control. Subsequently, DDR2 was stably overexpressed in two different cell lines (FaDu and HSC-3) using lentiviral technology. Different tumorigenic properties such as proliferation, migration, invasion, adhesion and anchorage independent growth were assessed with and without dasatinib treatment using in-vitro cell models and in-vivo zebrafish xenografts. DDR2 was overexpressed in all tumor tissues when compared to normal mucosa. DDR2 overexpression led to increased migration, invasion, adhesion and anchorage independent growth whereas proliferation remained unaltered. Upon dasatinib treatment migration, invasion and adhesion could be inhibited in-vitro and in-vivo whereas proliferation was unchanged. Our data suggest treatment with dasatinib as a promising new therapeutic option for patients suffering from DDR2 overexpressing HNSCC. Since dasatinib is already FDA-approved we propose to test this drug in clinical trials so that patients could directly benefit from this new treatment option.

MERTK as a novel therapeutic target in head and neck cancer.

Although head and neck cancer (HNSCC) is the sixth most common tumor entity worldwide therapy options remain limited leading to 5-year survival rates of only 50 %. MERTK is a promising therapeutic target in several tumor entities, however, its role in HNSCC has not been described yet. The aim of our study was to investigate the biological significance of MERTK and to evaluate its potential as a novel therapeutic target in this dismal tumor entity. In two large HNSCC cohorts (n=537 and n=520) we found that MERTK is overexpressed in one third of patients. In-vitro, MERTK overexpression led to increased proliferation, migration and invasion whereas MERTK inhibition with the small molecule inhibitor UNC1062 or MERTK knockdown reduced cell motility via the small GTPase RhoA.Taken together, we are the first to show that MERTK is frequently overexpressed in HNSCC and plays an important role in tumor cell motility. It might therefore be a potential target for selected patients suffering from this dismal tumor entity.

Laser microdissection separation of pure spermatozoa from epithelial cells for short tandem repeat analysis.

Short tandem repeat (STR) analysis is a valuable tool in identifying the source of biological stains, particularly from the investigation of sexual assault crimes. Difficulties in analysis arise primarily in the interpretation of mixed genotypes when cell separation of the sexual assailant's sperm from the victim's cells is incomplete. The forensic community continues to seek improvements in cell separation methods from mixtures for DNA typing. The feasibility of applying laser microdissection (LMD) technology to precisely separate sexual assault cell mixtures by visual inspection coupled with laser dissection was assessed through three experiments. First, various histological stains were evaluated for use with LMD and DNA analysis. Second, different DNA isolation methods were evaluated on LMD-collected cells. Finally, STR analysis was performed on LMD-separated sperm cells from mixtures of semen and female buccal epithelial cells. The results indicated (a) hematoxylin/eosin staining performed best in its ability to differentiate sperm and epithelial cells while exhibiting the least negative effect on further downstream analysis; (b) both QIAamp and Lyse-N-Go methods were useful for recovery of DNA from LMD-collected sperm cells; and (c) LMD separation provided clear STR profiles of the male donor with the absence of any additional alleles from the female donor. This report describes an efficient, low-manipulation LMD method for the efficient separation of spermatozoa from two-donor sperm/epithelial cell mixtures.