DIAPH2 alterations increase cellular motility and may contribute to the metastatic potential of laryngeal squamous cell carcinoma.

Low 5-year survival rate in laryngeal squamous cell carcinoma (LSCC) is to large extent attributable to high rate of recurrences and metastases. Despite the importance of the latter process, its complex genetic background remains not fully understood. Recently, we identified two metastasis-related candidate genes, DIAPH2 and DIAPH3 to be frequently targeted by hemizygous/homozygous deletions, respectively, in LSCC cell lines. They physiologically regulate such processes as cell movement and adhesion, hence we found it as a rationale, to study if tumor LSCC specimens harbor mutations of these genes and whether the mutations are associated with metastasizing tumors. As a proof of concept, we sequenced both genes in five LSCC cell lines derived from lymph node metastases assuming there the highest probability of finding alterations. Indeed, we identified one hemizygous deletion (c.3116_3240del125) in DIAPH2 targeting the FH2 domain. Moreover, we analyzed 95 LSCC tumors (53 N0 and 42 N+) using the Illumina platform and identified three heterozygous single nucleotide variants in DIAPH2 targeting conserved domains exclusively in N+ tumors. By combining these results with cBioPortal data we showed significant enrichment of DIAPH2 mutations (P = 0.036) in N+ tumors. To demonstrate the consequences of DIAPH2 inactivation, CRISPR/Cas9 editing was used to obtain a heterozygous DIAPH2+/- mutant HEK-293T cell line. Importantly, the edited line shows a shift from 'proliferation' to 'migration' phenotype typically observed in metastasizing cells. In conclusion, we report that DIAPH2 alterations are present primarily in metastasizing specimens of LSCC and suggest that they may contribute to the metastatic potential of the tumor.

Recurrent CDK1 overexpression in laryngeal squamous cell carcinoma.

In this study, we analyzed the expression profile of four genes (CCNA2, CCNB1, CCNB2, and CDK1) in laryngeal squamous cell carcinoma (LSCC) cell lines and tumor samples. With the application of microarray platform, we have shown the overexpression of these genes in all analyzed LSCC samples in comparison to non-cancer controls from head and neck region. We have selected CDK1 for further analysis, due to its leading role in cell cycle regulation. It is a member of the Ser/Thr protein kinase family of proven oncogenic properties. The results obtained for CDK1 were further confirmed with the application of reverse transcription quantitative polymerase chain reaction (RT-qPCR) technique, Western blot, and immunohistochemistry (IHC). The observed upregulation of CDK1 in laryngeal squamous cell carcinoma has encouraged us to analyze for genetic mechanisms that can be responsible this phenomenon. Therefore, with the application of array-CGH, sequencing analysis and two methods for epigenetic regulation analysis (DNA methylation and miRNA expression), we tried to identify such potential mechanisms. Our attempts to identify the molecular mechanisms responsible for observed changes failed as we did not observe significant alterations neither in the DNA sequence nor in the gene copy number that could underline CDK1 upregulation. Similarly, the pyrosequencing and miRNA expression analyses did not reveal any differences in methylation level and miRNA expression, respectively; thus, these mechanisms probably do not contribute to elevation of CDK1 expression in LSCC. However, our results suggest that alteration of CDK1 expression on both mRNA and protein level probably appears on the very early step of carcinogenesis.

HPV-driven oncogenesis-much more than the E6 and E7 oncoproteins.

High-risk human papillomaviruses are well-established drivers of several cancer types including cervical, head and neck, penile as well as anal cancers. While the E6 and E7 viral oncoproteins have proven to be critical for malignant transformation, evidence is also beginning to emerge suggesting that both host pathways and additional viral genes may also be pivotal for malignant transformation. Here, we focus on the role of host APOBEC genes, which have an important role in molecular editing including in the response to the viral DNA and their role in HPV-driven carcinogenesis. Further, we also discuss data developed suggesting the existence of HPV-derived miRNAs in HPV + tumors and their potential role in regulating the host transcriptome. Collectively, while recent advances in these two areas have added complexity to the working model of papillomavirus-induced oncogenesis, these discoveries have also shed a light onto new areas of research that will be required to fully understand the process.

Chromosomal gains and losses indicate oncogene and tumor suppressor gene candidates in salivary gland tumors.

The incidence of salivary gland tumor in Poland is growing in the last two decades. Simultaneously a progress in understanding the genetic mechanisms of formation of this tumor was achieved by detecting several genes like PLAG1 involved in its pathogenesis. In this study we perform a whole genome, CGH analysis with the aim to identify recurrent, chromosomal copy number changes possibly indicating novel tumor suppressor gene or oncogene loci. 29 salivary tumor samples: Cystadenolymphoma-warthin (15) and adenoma polymorphum (14) located in the parotid (27) and submandibular gland (2) were collected and CGH was performed. The established copy number profiles were compared in order to asses the smallest common region of gains and losses. The delineated regions were further analyzed with the UCSC Genome Browser on Human Mar. 2006 Assembly to asses their gene content. Altogether, salivary gland tumors presented a different aberration pattern than these reported for head and neck squamous cell carcinoma (HNSCC) but no significant differences were observed between Warthin and adenoma polymorphum tumors. Moreover, several potential tumor suppressor genes and oncogenes were identified in the smallest, common altered regions. We show a frequent deletion of the harakiri gene (12q24.2) in 12/29 tumors and TP53 gene (17p13.1) in 11/29 tumors as potential tumor suppressors in salivary gland cancers. Besides, we detected a frequent amplification of the 13q22.1-22.2 region in 13/29 cases harboring the KLF5 and KLF12 genes. KLF5 regulates the expression of survivin, an oncogene widely expressed in the majority of human cancers. The observed alterations may indicate important genetic events in the formation of salivary gland tumors. Especially the amplification in 13q may be a mechanism contributing to the expression of survivin and tumor progression.

Nonrandom DNA copy number changes related to lymph node metastases in squamous cell carcinoma of the lung.

Lung cancer is one of the most common malignancies and cancer-related death worldwide. Lymph node metastasis is the main cause of treatment failure. Although many studies were performed to evaluate genetic events associated with development and progression of lung cancer, molecular mechanism still remains poorly defined. In the present study, using comparative genomic hybridization (CGH) technique, we described the pattern of DNA copy number changes in a cohort of 42 primary squamous cell carcinomas (SCC) of the lung. A direct comparison of nonmetastatic (TxN0M0) and metastatic (TxN1-2M0) tumors was performed to define chromosomal imbalances related to lymph node metastases. Some genetic alterations were observed more frequently in metastatic than in non-metastatic tumors, including losses at 11q, 16p, 16q, 19p and gains at 4q, 7q, 12p, 13q, 18p. The gain at 7q with the smallest common altered region 7q31.2-q32, was found to be directly associated with lymph node involvement (p=0.0407). We suggest that the established chromosomal region harbors two putative tumor suppressor genes WNT2 and c-Met. An overexpresion of these genes seems to be involved in inducing the invasive growth and metastatic potential of SCC of the lung.

Inactivation of the putative ubiquitin-E3 ligase PDLIM2 in classical Hodgkin and anaplastic large cell lymphoma.

Apart from its unique histopathological appearance with rare tumor cells embedded in an inflammatory background of bystander cells, classical Hodgkin lymphoma (cHL) is characterized by an unusual activation of a broad range of signaling pathways involved in cellular activation. This includes constitutive high-level activity of nuclear factor-κB (NF-κB), Janus kinase/signal transducer and activator of transcription (JAK/STAT), activator protein-1 (AP-1) and interferon regulatory factor (IRF) transcription factors (TFs) that are physiologically only transiently activated. Here, we demonstrate that inactivation of the putative ubiquitin E3-ligase PDLIM2 contributes to this TF activation. PDLIM2 expression is lost at the mRNA and protein levels in the majority of cHL cell lines and Hodgkin and Reed-Sternberg (HRS) cells of nearly all cHL primary samples. This loss is associated with PDLIM2 genomic alterations, promoter methylation and altered splicing. Reconstitution of PDLIM2 in HRS cell lines inhibits proliferation, blocks NF-κB transcriptional activity and contributes to cHL-specific gene expression. In non-Hodgkin B-cell lines, small interfering RNA-mediated PDLIM2 knockdown results in superactivation of TFs NF-κB and AP-1 following phorbol 12-myristate 13-acetate (PMA) stimulation. Furthermore, expression of PDLIM2 is lost in anaplastic large cell lymphoma (ALCL) that shares key biological aspects with cHL. We conclude that inactivation of PDLIM2 is a recurrent finding in cHL and ALCL, promotes activation of inflammatory signaling pathways and thereby contributes to their pathogenesis.

Moving towards personalised therapy in head and neck squamous cell carcinoma through analysis of next generation sequencing data.

Personalised medicine tumour boards, which leverage genomic data to improve clinical management, are becoming standard for the treatment of many cancers. This paper is designed as a primer to assist clinicians treating head and neck squamous cell carcinoma (HNSCC) patients with an understanding of the discovery and functional impact of recurrent genetic lesions that are likely to influence the management of this disease in the near future. This manuscript integrates genetic data from publicly available array comparative genome hybridization (aCGH) and next-generation sequencing genetics databases to identify the most common molecular alterations in HNSCC. The importance of these genetic discoveries is reviewed and how they may be incorporated into clinical care decisions is discussed. Considerations for the role of genetic stratification in the clinical management of head and neck cancer are maturing rapidly and can be improved by integrating data sets. This article is meant to summarise the discoveries made using multiple genomic platforms so that the head and neck cancer care provider can apply these discoveries to improve clinical care.

Second primary tumors (SPT) of head and neck: distinguishing of "true" SPT from micrometastasis by LOH analysis of selected chromosome regions.

The reason of treatment failures in head and neck tumors is often connected with the appearance of second primary tumors (SPT). Three mechanisms of SPT development of clonal or non clonal secondary tumors were described: 1. via micrometastases (clonal); 2. from a common carcinogenic field - Second Field Tumors (SFT - partially clonal); 3. via independent events (from different carcinogenic fields - "true" SPT - not clonal). Assessing the clonality of diagnosed tumors carries important clinical implications including chemoprevention, radiotherapy and general patient management. In this study a set of 12 microsatellite markers was used to find similarities and/or differences in allelic imbalance patterns between 22 pairs of tumors (the first tumor designate as index and SPT). The aim of the study was to identify a potential clonal origin and progression within given pairs of tumors. The results indicate that within the tumors diagnosed by clinical examination as SPT at least two mechanisms mentioned above should be taken into account as 6/23 (26%) were clonally unrelated ("true" SPT) and 3/23 (13%) carried clonal genetic changes (formation by micrometastasis or SFT). In 14/23 (61%) cases the results were insufficient or ambiguous to determine the clonality status. The final results indicate the complexity of carcinogenesis in these tumors and thus stress that clinical diagnosis of second primary tumors should be considered carefully.