Human Papillomavirus-Induced Chromosomal Instability and Aneuploidy in Squamous Cell Cancers

Chromosomal instability (CIN) and aneuploidy are hallmarks of cancer. CIN is defined as a continuous rate of chromosome missegregation events over the course of multiple cell divisions. CIN causes aneuploidy, a state of abnormal chromosome content differing from a multiple of the haploid. Human papillomavirus (HPV) is a well-known cause of squamous cancers of the oropharynx, cervix, and anus. The HPV E6 and E7 oncogenes have well-known roles in carcinogenesis, but additional genomic events, such as CIN and aneuploidy, are often required for tumor formation. HPV+ squamous cancers have an increased frequency of specific types of CIN, including polar chromosomes. CIN leads to chromosome gains and losses (aneuploidies) specific to HPV+ cancers, which are distinct from HPV- cancers. HPV-specific CIN and aneuploidy may have implications for prognosis and therapeutic response and may provide insight into novel therapeutic vulnerabilities. Here, we review HPV-specific types of CIN and patterns of aneuploidy in squamous cancers, as well as how this impacts patient prognosis and treatment.

A predominant enhancer co-amplified with the SOX2 oncogene is necessary and sufficient for its expression in squamous cancer

Amplification and overexpression of the SOX2 oncogene represent a hallmark of squamous cancers originating from diverse tissue types. Here, we find that squamous cancers selectively amplify a 3' noncoding region together with SOX2, which harbors squamous cancer-specific chromatin accessible regions. We identify a single enhancer e1 that predominantly drives SOX2 expression. Repression of e1 in SOX2-high cells causes collapse of the surrounding enhancers, remarkable reduction in SOX2 expression, and a global transcriptional change reminiscent of SOX2 knockout. The e1 enhancer is driven by a combination of transcription factors including SOX2 itself and the AP-1 complex, which facilitates recruitment of the co-activator BRD4. CRISPR-mediated activation of e1 in SOX2-low cells is sufficient to rebuild the e1-SOX2 loop and activate SOX2 expression. Our study shows that squamous cancers selectively amplify a predominant enhancer to drive SOX2 overexpression, uncovering functional links among enhancer activation, chromatin looping, and lineage-specific copy number amplifications of oncogenes.

Decoupling epithelial-mesenchymal transitions from stromal profiles by integrative expression analysis

Epithelial-to-mesenchymal transition (EMT) is the most commonly cited mechanism for cancer metastasis, but it is difficult to distinguish from profiles of normal stromal cells in the tumour microenvironment. In this study we use published single cell RNA-seq data to directly compare mesenchymal signatures from cancer and stromal cells. Informed by these comparisons, we developed a computational framework to decouple these two sources of mesenchymal expression profiles using bulk RNA-seq datasets. This deconvolution offers the opportunity to characterise EMT across hundreds of tumours and examine its association with metastasis and other clinical features. With this approach, we find three distinct patterns of EMT, associated with squamous, gynaecological and gastrointestinal cancer types. Surprisingly, in most cancer types, EMT patterns are not associated with increased chance of metastasis, suggesting that other steps in the metastatic cascade may represent the main bottleneck. This work provides a comprehensive evaluation of EMT profiles and their functional significance across hundreds of tumours while circumventing the confounding effect of stromal cells.

Activation of DNA damage repair factors in HPV positive oropharyngeal cancers

The mechanisms regulating viral pathogenesis of human papillomavirus (HPV) associated oropharyngeal squamous cell cancers (OPSCC) are not well understood. In the cervix, activation of DNA damage repair pathways is critical for viral replication but little is known about their role in OPSCC. APOBEC factors have been shown to be increased in OPSCC but the significance of this is unclear. We therefore examined activation of DNA damage and APOBEC factors in HPV-induced OPSCC. Our studies show significantly increased levels of pCHK1, FANCD2, BRCA1, RAD51, pSMC1 and γH2AX foci in HPV-positive samples as compared to HPV-negative while the ATM effector kinase, pCHK2, was not increased. Similar differences were observed when the levels of proteins were examined in OPSCC cell lines. In contrast, the levels of APOBEC3B and 3A were found to be similar in both HPV-positive and -negative OPSCC. Our studies suggest members of ATR pathway and FANCD2 may be important in HPV-induced OPSCC.

Inhibition of the Numb/Notch signaling pathway increases radiation sensitivity in human nasopharyngeal carcinoma cells

Radiation therapy is the primary treatment for primary nasopharyngeal carcinoma (NPC). The aim of this study is to identify the effect of the Numb/Notch signaling pathway on radiation sensitivity in human NPC cells. NPC tissues and normal nasopharyngeal tissues were collected. To evaluate the regulatory effects of the Numb/Notch signaling pathway, NPC cells were subjected to radiotherapy and various doses of the Numb/Notch signaling pathway inhibitor gamma secretase inhibitor (GSI). Next, the expression of Notch and Numb proteins was determined in NPC tissues and normal nasopharyngeal tissues, and the correlation of Notch and Numb protein expression with the clinicopathological features of NPC tissues was analyzed. Then, the effect of radiotherapy on NPC cell survival rate, survival fraction, apoptosis rate, proliferation, migration, and invasion as well as Numb/Notch signaling pathway-related molecules was detected. The results demonstrated that the Numb/Notch signaling pathway was activated in NPC tissues. Following treatment with radiotherapy and GSI, the Numb/Notch signaling pathway was inhibited. In addition, the NPC cell survival rate, survival fraction, cell proliferation, migration, and invasion were decreased, whereas the colony number and apoptosis rate were increased. Following radiotherapy and GSI treatment, Numb expression was increased, whereas Notch1, Hes1, Jagged1, and c-Myc expression was decreased. However, the greatest difference was noted upon treatment with radiotherapy +15 μM GSI. The results reported in this study suggest that a high dose of the inhibitor of the Numb/Notch signaling pathway GSI increased the radiation sensitivity in human NPC cells.

The Antiproliferative and Apoptotic Effects of Capsaicin on an Oral Squamous Cancer Cell Line of Asian Origin, ORL-48

Background and Objectives: The antitumor activities of capsaicin on various types of cancer cell lines have been reported but the effect of capsaicin on oral cancer, which is prevalent among Asians, are very limited. Thus, this study aimed to investigate the effects of capsaicin on ORL-48, an oral cancer cell line of Asian origin. Materials and Methods: Morphological changes of the ORL-48 cells treated with capsaicin were analyzed using fluorescence microscopy. The apoptotic-inducing activity of capsaicin was further confirmed by Annexin V-Fluorescein isothiocyanate / Propidium iodide (V-FITC/PI) staining using flow cytometry. In order to establish the pathway of apoptosis triggered by the compound on ORL-48 cells, caspase activity was determined and the mitochondrial pathway was verified by mitochondrial membrane potential (MMP) assay. Cell cycle analysis was also performed to identify the cell cycle phase of ORL-48 cells being inhibited by the capsaicin compound. Results: Fluorescence microscopy exhibited the presence of apoptotic features in capsaicin-treated ORL-48 cells. Apoptosis of capsaicin-treated ORL-48 cells revealed disruption of the mitochondrial-membrane potential, activation of caspase-3, -7 and -9 through an intrinsic apoptotic pathway and subsequently, apoptotic DNA fragmentation. The cell cycle arrest occurred in the G1-phase, confirming antiproliferative effect of capsaicin in a time-dependent manner. Conclusion: This study demonstrated that capsaicin is cytotoxic against ORL-48 cells and induces apoptosis in ORL-48 cells possibly through mitochondria mediated intrinsic pathway resulting in cell cycle arrest.

Plerixafor for the Treatment of WHIM Syndrome

WHIM syndrome (warts, hypogammaglobulinemia, infections, and myelokathexis), a primary immunodeficiency disorder involving panleukopenia, is caused by autosomal dominant gain-of-function mutations in CXC chemokine receptor 4 (CXCR4). Myelokathexis is neutropenia caused by neutrophil retention in bone marrow. Patients with WHIM syndrome are often treated with granulocyte colony-stimulating factor (G-CSF), which can increase neutrophil counts but does not affect cytopenias other than neutropenia. In this investigator-initiated, open-label study, three severely affected patients with WHIM syndrome who could not receive G-CSF were treated with low-dose plerixafor, a CXCR4 antagonist, for 19 to 52 months. Myelofibrosis, panleukopenia, anemia, and thrombocytopenia were ameliorated, the wart burden and frequency of infection declined, human papillomavirus-associated oropharyngeal squamous-cell carcinoma stabilized, and quality of life improved markedly. Adverse events were mainly infections attributable to the underlying immunodeficiency. One patient died from complications of elective reconstructive surgery. (Funded by the National Institutes of Health.).

Multicenter Phase II Study of Panitumumab in Platinum Pretreated, Advanced Head and Neck Squamous Cell Cancer

Lessons Learned.

Panitumumab shows activity in terms of disease control rate and preventing disease progression but not for tumor shrinkage in head and neck squamous cell cancer for second‐line treatment. Epidermal growth factor receptor (EGFR) copy number gain, a property of tumor cells that theoretically could identify patients more likely to experience disease response, was common among patients having disease control.

Our trial, given the lower toxicity with an every‐2‐week schedule, provides guidance for future trials, for example, in combinations of immune therapies and anti‐EGFR‐antibodies.

Background.

The objective of this study was to investigate the efficacy and safety of panitumumab (anti‐epidermal growth factor receptor [EGFR] antibody) given as a single agent in platinum‐pretreated head and neck squamous cell cancer (HNSCC).

Methods.

Patients with advanced HNSCC previously treated with platinum‐containing therapy were included. Panitumumab was administered intravenously every 2 weeks at a dose of 6 mg/kg. Primary endpoint was overall response rate (ORR) according to Response Evaluation Criteria In Solid Tumors (RECIST) version 1.1; secondary endpoints were progression‐free survival (PFS) and safety. A Simon's two‐step design was chosen; 4 partial remissions (PR) in the first 32 patients were required for continuing to step two. An exploratory biomarker analysis was performed.

Results.

Thirty‐three patients were enrolled. Two patients obtained a PR for an ORR of 6%, and 15 (45%) showed stable disease (SD) for at least 2 months, resulting in a 51% disease control rate. Median PFS was 2.6 months (95% confidence interval [CI]: 1.7–3.7), while median OS was 9.7 months (95% CI: 6.3–17.2). The most frequent adverse drug reactions were cutaneous rash (64%) and hypomagnesemia (55%). Overall, 30% of patients experienced grade 3/4 adverse events. No infusion‐related reactions occurred. EGFR copy number gain (CNG) was more frequent in patients who benefitted from panitumumab. Two uncommon KRAS mutations (G48E, T50I) and 3 canonical PIK3CA mutations (all E545K) were detected. High‐risk HPV16 was found in 10 patients and EGFR CNG in 13 treated patients. EGFR CNG seems to be more frequent in individuals with at least SD compared with patients with progressive disease (59% vs. 30%). PFS for patients with EGFR CNG was 4.6 months (95% CI: 1.0–9.2 months) and 1.9 months (95% CI: 1.0–3.2 months) for patients without CNG (p = .02).

Conclusion.

Panitumumab monotherapy in pretreated HNSCC patients was well tolerated but moderately active. We observed a considerable disease control rate. Future strategies with this agent comprise right patient selection through the identification of reliable biomarkers and gene signatures predicting response and, considering good tolerability and convenience, combination strategies with novel agents and immune therapeutic agents.

A Common Interleukin-6 Promoter Polymorphism in Patients With Vulvar Cancer

OBJECTIVE

Besides its important role in immune response and inflammatory processes the cytokine interleukin-6 (IL-6) is crucially involved in carcinogenesis. A common polymorphism within the gene encoding IL-6 (IL6) is known to alter IL-6 protein expression and has been associated with patients' prognosis in various malignancies. No data are available with respect to vulvar cancer. Therefore, we determined the prognostic potential of the common -174(G-->C) single nucleotide polymorphism in the promoter region of IL6 in a series of patients with this disease.

METHODS

The IL6 promoter polymorphism was investigated in 81 Caucasian patients with surgically treated squamous cell vulvar cancer using pyrosequencing. Results were correlated with clinical data.

RESULTS

No association was ascertained between the IL6 promoter polymorphism and the investigated clinicopathologic parameters, ie, tumor stage, lymph node involvement, tumor grade, and patient's age at diagnosis. In an univariate analysis, lymph node involvement and patients' age at diagnosis were associated with patient prognosis. In a multivariate analysis, including tumor stage and lymph node involvement as established prognostic factors and the IL6 promoter polymorphism, lymph node involvement, and the presence of at least one mutant allele, but not tumor stage, were associated with increased disease-free and overall survival.

CONCLUSION

Our data suggest that the IL6 -174(G-->C) promoter polymorphism might serve as an additional prognostic parameter in patients with vulvar cancer.

Gene Variability Between Perineural-positive and Perineural-negative Squamous Cell Skin Cancers

AIM

To identify differentially expressed genes (DEGs) between perineural invasion-positive (PP) and -negative (PN) cutaneous squamous cell cancers (CSCC).

MATERIALS/METHODS

Forty CSCC samples with and without perineural invasion were processed for RNA isolation and hybridization to Affymetrix-U219 DNA microarrays. Raw gene expression data were normalized by Robust Multi-array Averaging (RMA) and log2 transformed. Gene expression-based classification models were created and accuracies evaluated using leave-one-out cross-validation.

RESULTS

At a stringent limma p-value (p<0.001), 24 genes were differentially expressed between PP and PN samples. The cross-validated performance of the eight classification models exhibited a mean accuracy of 85-95%. Diagonal linear discriminant was most accurate at 95%, followed by Bayesian compound covariate at 94%. The poorest accuracy (85%) was observed for 1-Nearest neighbor and Support vector machines.

CONCLUSION

Gene expression may distinguish between PP and PN CSCC. Understanding these gene patterns may potentiate more timely diagnosis of perineural invasion and guide comprehensive therapies.

Epithelium Expressing the E7 Oncoprotein of HPV16 Attracts Immune-Modulatory Dendritic Cells to the Skin and Suppresses Their Antigen-Processing Capacity

Antigen presenting cells (APCs) in skin can promote either antigen-specific effector functions or antigen tolerance, and thus determine clearance or persistence of cutaneous viral infections. Human papillomavirus (HPV) infections can persist in squamous epithelium in immunocompetent individuals, and some persisting HPV infections, particularly with HPV16, promote malignant epithelial transformation. Here, we investigate whether local expression of the HPV16 protein most associated with malignant transformation, HPV16-E7, affects the phenotype and function of APC subsets in the skin. We demonstrate an expanded population of Langerhans cells in HPV16-E7 transgenic skin with distinct cell surface markers which express immune-modulatory enzymes and cytokines not expressed by cells from non transgenic skin. Furthermore, HPV16-E7 transgene expression in keratinocytes attracts new APC subsets to the epidermis. In vivo migration and transport of antigen to the draining lymph node by these APCs is markedly enhanced in HPV16-E7 expressing skin, whereas antigen-processing, as measured by proteolytic cleavage of DQ-OVA and activation of T cells in vivo by APCs, is significantly impaired. These data suggest that local expression of HPV16-E7 in keratinocytes can contribute to persisting infection with this oncogenic virus, by altering the phenotype and function of local APCs.

Anaplastic Lymphoma Kinase Rearrangement in Digestive Tract Cancer: Implication for Targeted Therapy in Chinese Population

BACKGROUND

Anaplastic lymphoma kinase (ALK) rearrangements define a subgroup of lung cancer which is eligible to targeted kinase inhibition. The aim of this study is to observe the incidence rate of ALK fusion in a large cohort of Chinese digestive tract cancer patients.

PATIENTS AND METHODS

Tissue microarray (TMA) was constructed from 808 digestive tract cancer cases, including 169 esophageal squamous cell carcinoma, 182 gastric cancer and 457 colorectal cancer (CRC) cases. We tested all cases for ALK expression via a fully automated immunohistochemistry (IHC) assay. The IHC-positive cases were subjected to fluorescence in situ hybridization (FISH), real-time polymerase chain reaction (qRT-PCR), target gene enrichment and sequencing for confirmation of ALK gene rearrangement and discovery of novel fusion partner.

RESULTS

Among the tested cases, 2 (0.44%) CRC cases showed positive both by IHC and FISH. By qRT-PCR, EML4-ALK fusion was found in one IHC-positive CRC case. In another IHC-positive CRC case, target gene enrichment and sequencing revealed ALK was fused to a novel partner, spectrin beta non-erythrocytic 1 (SPTBN1). One gastric cancer case showed partially positive IHC result, but no fusion was found by FISH and gene sequencing.

CONCLUSIONS

The incidence rate of ALK gene fusion in Chinese CRC patients was 0.44%,but not detectable in gastric and esophageal cancers. The novel SPTBN1 -ALK fusion, together with other ALK fusion genes, may become a potential target for anti-ALK therapy.

[Prediction of Post-operative Lymph Node Metastasis with a Molecular Biological Test in Head and Neck Cancer]

We assessed herein the post-operative lymph node metastasis in head and neck cancer, using the One-step nucleotide amplification (OSNA) method targeting matrix metalloproteinase 7 (MMP-7). Compared with the pathological test, the molecular biological test revealed more lymph node metastasis, resulting in poor prognosis. Six cases, of which the number of lymph node metastasis was the same between pathological and molecular biological test, survived. On the other hand, three of four cases, in which number of lymph node metastasis in the molecular biological test were larger than the pathological test, died from metastasis. We concluded that the pathological test underestimated metastasis, and OSNA with MMP-7 was useful for the prediction of post-operative lymph node metastasis.

EGFR mutation testing of lung cancer patients - Experiences from Vestfold Hospital Trust

BACKGROUND

Patients with advanced stage lung cancer and somatic mutations in the epithelial growth factor receptor (EGFR) gene are currently treated with tyrosine-kinase inhibitors. The Norwegian Lung Cancer Group (NLCG) recommended EGFR testing of all patients with non-small cell lung carcinoma (NSCLC) from June 2010. From March 2013, testing of squamous cell carcinomas was terminated. We have analysed how these recommendation were followed at a medium-sized Norwegian hospital and we present data on mutation frequency, retesting and possible explanations for missing test results.

MATERIAL AND METHODS

All pathology reports for patients diagnosed with NSCLC at Vestfold Hospital Trust were examined for the period June 2010 to December 2013. Mutation analyses were done at the Department of Pathology, Oslo University Hospital.

RESULTS

Material was sent for EGFR analysis for 256 of the 304 eligible patients diagnosed in the period. Material from 48 patients was never sent for EGFR testing, of which five samples consisted of too few tumour cells. For the rest, no obvious reason for omitting EGFR mutation analyses was identified. During the first six months of our study period, material from 25 of 66 NSCLC patients (38%) was not tested, whereas only six of the 118 patients (5%) in 2013 were not tested. For 34 patients, the first tissue specimen contained too few tumour cells and a new sample was sent for EGFR analyses for 11 of these. EGFR mutation was detected in 7.1% of the analysed NSCLC and in 9.4% of adenocarcinomas.

DISCUSSION

Especially for patients with advanced stages of NSCLC, EGFR mutation status is necessary for treatment stratification. Our results show that the guidelines were followed increasingly over time for patients diagnosed with NSCLC at the Vestfold Hospital Trust. The establishment of interdisciplinary meetings has improved the diagnostic routines.

Tumor Suppressor Function of the SEMA3B Gene in Human Lung and Renal Cancers

The SEMA3B gene is located in the 3p21.3 LUCA region, which is frequently affected in different types of cancer. The objective of our study was to expand our knowledge of the SEMA3B gene as a tumor suppressor and the mechanisms of its inactivation. In this study, several experimental approaches were used: tumor growth analyses and apoptosis assays in vitro and in SCID mice, expression and methylation assays and other. With the use of the small cell lung cancer cell line U2020 we confirmed the function of SEMA3B as a tumor suppressor, and showed that the suppression can be realized through the induction of apoptosis and, possibly, associated with the inhibition of angiogenesis. In addition, for the first time, high methylation frequencies have been observed in both intronic (32-39%) and promoter (44-52%) CpG-islands in 38 non-small cell lung carcinomas, including 16 squamous cell carcinomas (SCC) and 22 adenocarcinomas (ADC), and in 83 clear cell renal cell carcinomas (ccRCC). Correlations between the methylation frequencies of the promoter and the intronic CpG-islands of SEMA3B with tumor stage and grade have been revealed for SCC, ADC and ccRCC. The association between the decrease of the SEMA3B mRNA level and hypermethylation of the promoter and the intronic CpG-islands has been estimated in renal primary tumors (P < 0.01). Using qPCR, we observed on the average 10- and 14-fold decrease of the SEMA3B mRNA level in SCC and ADC, respectively, and a 4-fold decrease in ccRCC. The frequency of this effect was high in both lung (92-95%) and renal (84%) tumor samples. Moreover, we showed a clear difference (P < 0.05) of the SEMA3B relative mRNA levels in ADC with and without lymph node metastases. We conclude that aberrant expression and methylation of SEMA3B could be suggested as markers of lung and renal cancer progression.

The 46359CT polymorphism of DNMT3B is associated with the risk of cervical cancer

Abnormal methylation is related to cancer development. Since DNMT3B is an enzyme that modulates genomic methylation, we hypothesized that genetic variants of the promoter DNMT3B may be associated with an increased risk of developing cervical cancer. Our aim was to investigate the association between -579GT and 46359CT polymorphisms of DNMT3B and cervical cancer, high-grade squamous intraepithelial lesions (HSIL), and low-grade squamous intraepithelial lesions (LSIL). Samples from 200 healthy women and 130 women with squamous intraepithelial lesions (70 with cervical cancer, 30 with HSIL, and 30 with LSIL) were analyzed. Polymorphism genotyping was performed using PCR and restriction fragment length polymorphism. The -579GT polymorphism was not associated with cervical cancer, HSIL, or LSIL. The CT genotype of 46359CT polymorphism was significantly associated with cervical cancer risk (OR 8.75, CI 1.27-374.1), whereas the TT genotype was associated with a significantly decreased risk of HSIL (OR 0.66, CI 0.01-0.32) and LSIL (OR 0.11, CI 0.026-0.45). Our results suggest that genotyping the 46359CT polymorphism in DNMT3B may help identify women who are genetically susceptible to cervical cancer development. Additional studies with larger sample sizes are necessary to confirm our findings.

Genomics of squamous cell lung cancer

Approximately 30% of patients with non-small cell lung cancer have the squamous cell carcinoma (SQCC) histological subtype. Although targeted therapies have improved outcomes in patients with adenocarcinoma, no agents are currently approved specifically for use in SQCC. The Cancer Genome Atlas (TCGA) recently published the results of comprehensive genomic analyses of tumor samples from 178 patients with SQCC of the lung. In this review, we briefly discuss key molecular aberrations reported by TCGA and other investigators and their potential therapeutic implications. Carefully designed preclinical and clinical studies based on these large-scale genomic analyses are critical to improve the outcomes of patients with SQCC of lung in the near future.

DNA methylation profiling across the spectrum of HPV-associated anal squamous neoplasia

BACKGROUND

Changes in host tumor genome DNA methylation patterns are among the molecular alterations associated with HPV-related carcinogenesis. However, there is little known about the epigenetic changes associated specifically with the development of anal squamous cell cancer (SCC). We sought to characterize broad methylation profiles across the spectrum of anal squamous neoplasia.

METHODOLOGY/PRINCIPAL FINDINGS

Twenty-nine formalin-fixed paraffin embedded samples from 24 patients were evaluated and included adjacent histologically normal anal mucosa (NM; n = 3), SCC-in situ (SCC-IS; n = 11) and invasive SCC (n = 15). Thirteen women and 11 men with a median age of 44 years (range 26-81) were included in the study. Using the SFP(10) LiPA HPV-typing system, HPV was detected in at least one tissue from all patients with 93% (27/29) being positive for high-risk HPV types and 14 (93%) of 15 invasive SCC tissues testing positive for HPV 16. Bisulfite-modified DNA was interrogated for methylation at 1,505 CpG loci representing 807 genes using the Illumina GoldenGate Methylation Array. When comparing the progression from normal anal mucosa and SCC-IS to invasive SCC, 22 CpG loci representing 20 genes demonstrated significant differential methylation (p<0.01). The majority of differentially methylated gene targets occurred at or close to specific chromosomal locations such as previously described HPV methylation "hotspots" and viral integration sites.

CONCLUSIONS

We have identified a panel of differentially methlylated CpG loci across the spectrum of HPV-associated squamous neoplasia of the anus. To our knowledge, this is the first reported application of large-scale high throughput methylation analysis for the study of anal neoplasia. Our findings support further investigations into the role of host-genome methylation in HPV-associated anal carcinogenesis with implications towards enhanced diagnosis and screening strategies.

Oral carcinogenesis is not achieved in different carcinogen-treated PAI-1 transgenic and wild-type mouse models

AIM

In an effort to assess the role of plasminogen activator inhibitor-1 (PAI-1) in oral squamous cancer development and progression, two different carcinogen treatment protocols were conducted.

MATERIALS AND METHODS

Protocol I included mice from a PAI-1 transgenic (Tg) breed (n=56) and their wild-type (WT) counterparts (n=56), divided into one control group and two main experimental groups, treated with 7,12-dimethylbenz[a]anthracene (DMBA) for 8 and 16 weeks, respectively. Protocol II included the same number and types of animals and groups, which were similarly treated with 4-Nitroquinoline 1-oxide (4-NQO) in drinking water. Two drugs that affect plasma PAI-1 levels, enalapril and pravastatin, were administered to certain subgroups of animals in both protocols.

RESULTS

None of the animals developed macroscopically-visible oral cancer lesions. Eleven animals under Protocol I and 52 animals under Protocol II died. Skin lesions were noted only in DMBA-treated animals (n=9). Almost all animals administered with 4-NQO developed alopecia and lost weight, while two of them developed stomach tumours, and one female mouse developed a large ovarian cyst.

CONCLUSION

Transgenic mice may respond differently when used in well-established carcinogen models and oral carcinogenesis is hard to achieve in these rodents.

Euphorbia mauritanica and Kedrostis hirtella extracts can induce anti-proliferative activities in lung cancer cells

Cancer is a public health problem in the world accounting for most of the deaths. Currently, common treatment of cancer such as chemotherapy works by killing fast-growing cancer cells. Unfortunately, chemotherapy cannot tell the difference between cancer cells and fast-growing healthy cells, including red and white blood cells. As a result, one of the most serious potential side effects of some types of chemotherapy is a low white blood cell count that makes it unreliable (Parkin et al. [34]; Pauk et al. [3]). Even though intense research has been going on in recent years, successful therapeutic targets against this disease have been elusive. In this study, we evaluate the anti-proliferative activity of Euphorbia mauritanica and Kedrostis hirtella in lung cancer. In our assessment it was observed that E. mauritanica and K. hirtella were able to induce cell death at 5 μg/ml in A549 cells over 22 h and at 10 μg/ml over 24 h in the Lqr1 cell line. Molecular analysis of DNA fragmentation and Annexin V were used to examine the type of cell death induced by E. mauritanica and K. hirtella extracts. These results showed an increase in necrotic and apoptotic characteristics with both nuclear DNA fragmentation and smear. Therefore, these results suggest that E. mauritanica and K. hirtella may play a role in inducing cell death in lung cancer cells. However, further studies need to be conducted to ascertain these results.

XAF1 as a prognostic biomarker and therapeutic target in squamous cell lung cancer

BACKGROUND

X-linked inhibitor of apoptosis (XIAP)-associated factor 1 (XAF1) is a new tumor suppressor. Low expression of XAF1 is associated with poor prognosis of human cancers. However, the effect of XAF1 on lung cancer remains unknown. In this study, we investigated the expression of XAF1 and its role in squamous cell lung cancer.

METHODS

Cancer tissues, cancer adjacent tissues and normal lung tissues were collected from 51 cases of squamous cell lung cancer. The expression of XAF1 mRNA was determined by reverse transcription-polymerase chain reaction (RT-PCR). The expression of XAF1 protein was determined by Western blotting and immunohistochemical staining. Ad5/F35-XAF1 virus was generated. Cell proliferation and apoptosis were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method and flow cytometry (FACS), respectively.

RESULTS

The levels of XAF1 protein and mRNA in cancer tissues were significantly lower than those in cancer adjacent and normal lung tissues (P < 0.05). The low expression of XAF1 was associated with tumor grade, disease stage, differentiation status and lymph node metastasis in squamous cell lung cancer patients. The restoration of XAF1 expression mediated by Ad5/F35-XAF1 virus significantly inhibited cell proliferation and induced apoptosis in a dose- and time-dependent manner.

CONCLUSION

XAF1 is a valuable prognostic marker in squamous cell lung cancer and may be a potential candidate gene for lung cancer therapy.

The mutational landscape of head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a common, morbid, and frequently lethal malignancy. To uncover its mutational spectrum, we analyzed whole-exome sequencing data from 74 tumor-normal pairs. The majority exhibited a mutational profile consistent with tobacco exposure; human papillomavirus was detectable by sequencing DNA from infected tumors. In addition to identifying previously known HNSCC genes (TP53, CDKN2A, PTEN, PIK3CA, and HRAS), our analysis revealed many genes not previously implicated in this malignancy. At least 30% of cases harbored mutations in genes that regulate squamous differentiation (for example, NOTCH1, IRF6, and TP63), implicating its dysregulation as a major driver of HNSCC carcinogenesis. More generally, the results indicate the ability of large-scale sequencing to reveal fundamental tumorigenic mechanisms.

Exome sequencing of head and neck squamous cell carcinoma reveals inactivating mutations in NOTCH1

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide. To explore the genetic origins of this cancer, we used whole-exome sequencing and gene copy number analyses to study 32 primary tumors. Tumors from patients with a history of tobacco use had more mutations than did tumors from patients who did not use tobacco, and tumors that were negative for human papillomavirus (HPV) had more mutations than did HPV-positive tumors. Six of the genes that were mutated in multiple tumors were assessed in up to 88 additional HNSCCs. In addition to previously described mutations in TP53, CDKN2A, PIK3CA, and HRAS, we identified mutations in FBXW7 and NOTCH1. Nearly 40% of the 28 mutations identified in NOTCH1 were predicted to truncate the gene product, suggesting that NOTCH1 may function as a tumor suppressor gene rather than an oncogene in this tumor type.

IL-6 antisense-mediated growth inhibition in a head and neck squamous cell carcinoma cell line

The growth of tumor cells can be regulated by a variety of cytokines. To investigate the pathogenesis of head and neck cancer and explore a new therapeutic approach for the carcinoma, the role of interleukin-6 (IL-6) in the growth of a human head and neck squamous cell carcinoma (HNSCC) cell line was examined. Whether or not IL-6 is increased in HNSCC and whether or not IL-6 antisense oligonucleotide treatment could decrease proliferation and angiogenic activity of HNSCC cell lines, was determined. Established human HNSCC cell lines were screened for IL-6 expression at both mRNA and protein levels. By using a 15-mer antisense phosphorothioate oligonucleotide targeting a sequence in the second exon of the IL-6 gene, modulation of IL-6 and vascular endothelial growth factor (VEGF) expression was examined in UMSCC IIA in cell supernatants by capture enzyme-linked immunosorbent assay (ELISA), and in cell lysates by reverse transcriptase-polymerase chain reaction (RT-PCR). In addition, cell growth was determined by cell count. Endothelial cell migration was measured using a modified Boyden chamber. IL-6 was identified in the supernatant of the cell culture medium, indicating that these cells secreted IL-6, and the mRNAs of IL-6 were shown to be present in the cell lysates. IL-6 antisense oligonucleotide treatment resulted in a significant reduction of IL-6 protein expression compared to the sense control. The antisense oligonucleotides targeting IL-6 mRNA, also, inhibited cell growth and IL-6 production as well as VEGF expression. The addition of conditioned medium from IL-6 antisense-treated tumor cells resulted in decreased endothelial cell migration and tubule formation. Taken together, these findings indicate that endogenous IL-6 plays an important role in the growth of HNSCC and exerts its action by an autocrine growth mechanism, and that therapeutic trials with antisense oligonucleotides targeted to IL-6 mRNA may have some value for the treatment of HNSCC due to a decrease of neovascularization.

Mammalian target of rapamycin and head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC), a significant cause of cancer deaths worldwide, has multiple stepwise malignant evolutions. Mammalian target of rapamycin (mTOR) plays a critical role in tumor development, invasion, metastasis and angiogenesis that impact local recurrence and survival. mTOR can also act as a biomarker for personalized adjuvant therapy. In in vivo and in vitro studies, mTOR inhibitor suppresses tumor growth and sensitizes HNSCC to radiation, cytotoxic agents and epidermoid growth factor receptor inhibitors. We have reviewed the pathogenesis of HNSCC, mTOR pathway, mTOR inhibitor and the role of mTOR in HNSCC.

Suicide gene therapy in head and neck carcinoma cells: an in vitro study

The aim of gene therapy includes the tight spatial and temporal control of transgenic expression. There are several approaches concerning the externally inducible gene promoters used for the control of suicide genes. We have tested the mifepristone-dependent system GeneSwitch to regulate the expression of a deletion mutant of Pseudomonas exotoxin A in the hypopharyngeal carcinoma cell line, FADU. The GeneSwitch system consists of two plasmids, the regulatory plasmid, pSwitch, and the pGene/V5-His plasmid, in which we cloned the toxin mutant (pGene/V5-His-ETA). We stably transfected FADU cells with pSwitch and subsequently transiently separated pSwitch clones with pGene/V5-His-ETA. We tested the inductive capacities of single pSwitch clones, the influence of experimental variations in transfection, the inductive capacities without antibiotic selection pressure, the inductive capacity after re-induction, as well as the background expression levels. In FADU cells the GeneSwitch-ETA combination worked precisely and effectively. Our in vitro study revealed that the use of toxin genes in combination with the GeneSwitch system is a promising approach for gene therapy in head and neck cancer.

Genetic risk of DNA repair gene polymorphisms (XRCC1 and XRCC3) for high risk human papillomavirus negative cervical cancer in Northeast Thailand

To identify risk factors other than high risk human papillomavirus infection for the development of cervical cancer, functional polymorphisms of DNA repair genes, XRCC1 Arg399Gln and Arg194Trp and XRCC3 Thr241Met, were studied among Northeastern Thai women. Cases (n=111) were defined as squamous cell cervical cancer and controls (n=118) were recruited from healthy women without cervical abnormalities. The XRCC1 194Trp/Trp genotype significantly increased the risk for cervical cancer (OR=5.52; 95%CI=1.14-26.64; p=0.03). Among the HPV infection negative group, significantly higher risks for cervical cancer were visualized for XRCC1 399Arg/Gln (adjusted OR=3.69; 95%CI=1.04-13.06; p=0.04) and XRCC1 194Arg/Trp (adjusted OR=4.13; 95%CI=1.13-15.12; p=0.03). This study indicates that variant types of DNA repair genes play partial roles in modifying individual susceptibility to cervical cancer. Since cervical cancer is a multi-factorial disease, the contribution of DNA repair enzymes to the development of cervical cancer, if it exists may be concealed by HPV infection.

[Genes responsible for etiopathogenesis in esophageal squamous cell carcinoma]

Esophageal squamous cell carcinoma is a very important cancer type, not only because of its frequent cases around the world but also because of its high mortality rate. Despite of the fact that this is a very rare cancer in Poland (around 2% of patients), we need to know more about this disease in order to find better ways to fight it. Epidemiological factors: smoking and use of psychoactive substances like alcohol and drugs, poor diet as well as changes in expression of genes may have influence on this cancer. During last years there has been a lot of researche on the role of GEAC1, which seems to play a very important role in normal and cancer cells. Perhaps the protein coded by this gene is an important part in cancer development, also being an important element in processes in normal tissues.

Clinical significance of human telomerase RNA gene (hTERC) amplification in cervical squamous cell lesions detected by fluorescence in situ hybridization

BACKGROUND

Genomic amplification of the human telomerase RNA gene (hTERC), located in the chromosome 3q26 region, has been documented in tumorigenesis. The present study was designed to detect hTERC amplification in cervical lesions and evaluate whether this might serve as a supportive biomarker to cytopathology or histopathology in the diagnosis of cervical lesions.

METHODS

Liquid-based thin-layer cytopathologic examination and detection of amplification by fluorescence in situ hybridization (FISH) was conducted in 130 women, along with assessment of human papillomavirus DNA, colposcopy with biopsy, and histopathologic examination.

RESULTS

In cytopathologic examinations, hTERC amplification rates for negative for intraepithelial lesion or malignancy (NILM),atypical squamous cells of undetermined significance (ASCUS), low-grade squamous intraepithelial lesion (LSIL), high-grade squamous intraepithelial lesion (HSIL) and squamous cell carcinoma (SCC) cases were 0% (0/10), 4% (1/25), 20% (6/30), 77% (27/35), and 100% (10/10), respectively. The difference among abnormal cellular change groups was statistically significant (P< 0.05). In histopathologic examinations, hTERC amplification rates in normal squamous cell with or without inflammatory, cervical intraepithelial neoplasia 1 (CIN 1), CIN 2, CIN 3 and SCC cases were 3.8% (2/52), 18.2% (6/33), 66.7% (6/9), 84.6% (22/26), 100% (10/10), respectively. There were significant differences among CIN1, CIN2, CIN3 and SCC cases (P< 0.05). The hTERC amplification was more specific than HPV positivity in differentiating lowgrade from high-grade cervical disorders (specificity: 88.5% vs. 70.8%, P< 0.05).

CONCLUSIONS

FISH detection of hTERC amplification could be an effective adjunct to cytopathologic or histopathologic examination for differential diagnosis of low- and high-grade cervical squamous cell disorders.

Caveolin-1 mediates tumor cell migration and invasion and its regulation by miR-133a in head and neck squamous cell carcinoma

MicroRNAs (miRNAs) are small non-coding RNAs of approximately 22 nucleotides that can function as oncogenes or tumor suppressors in human cancer. Down-regulation of the miRNA miR-133a in many type of cancers, and a reduction of cell proliferation, migration, and invasion upon over-expression, suggests that miR-133a is a tumor suppressor. In this study, genome-wide gene expression analysis of HNSCC cells that over-express miR-133a showed that caveolin-1 (CAV1), a multifunctional scaffolding protein, is down-regulated, a result that was confirmed by real-time PCR and Western blot analysis. A luciferase reporter assay revealed that miR-133a is directly bound to CAV1 mRNA. Cancer cell migration and invasion were significantly inhibited in HNSCC cells transfected with si-CAV1. Therefore, CAV1 functions as an oncogene in HNSCC. The identification of tumor suppressive miRNAs and their target genes could provide new insights into potential mechanism of HNSCC carcinogenesis.

Epigenetic silencing of MAL, a putative tumor suppressor gene, can contribute to human epithelium cell carcinoma

BACKGROUND

To identify new and useful candidate biomarkers in head and neck squamous cell carcinoma (HNSCC), we performed a genome-wide survey and found that Myelin and lymphocyte-associated protein (MAL) was a gene that was markedly down-regulated in HNSCC. Hence, we investigated the mechanism of MAL silencing and the effects of MAL on the proliferation, invasion, and apoptotic potential in HNSCC.

RESULTS

MAL was significantly down-regulated in 91.7% of HNSCC specimens at the mRNA level as compared with adjacent normal tissues (P = 0.0004). Moreover, the relative transcript levels of the MAL gene were remarkably decreased by five-fold in nine HNSCC cell lines as compared with normal head and neck epithelium cells. MAL gene expression was restored in 44%, 67%, and 89% in HNSCC cell lines treated with TSA, 5-Aza-dC, and TSA plus 5-Aza-dC, respectively. Furthermore, bisulfate-treated DNA sequencing demonstrated that the two CpG islands (that is, M1 and M2) located in MAL promoter region were completely methylated in the HNSCC cell lines (CpG methylated ratio was more than 90%), and only one CpG island (that is, M1) was partially methylated in HNSCC tissues (CpG methylated ratio between 20% and 90%). A significant reduction in cell proliferation and a change in the cell cycle profile were also observed in MAL transfectants. Matrigel assay demonstrated that the invasiveness of HNSCC cells significantly decreased. A significant increase in the population of apoptotic cells was observed in MAL transfected cells. The exogenous expression of the MAL gene suppressed malignant phenotypes, while the cell death induced by MAL gene transfer was a result of apoptosis as demonstrated by the induction of cleavage of the poly (that is, ADP-ribose) polymerase. Additionally, tumor growth was suppressed in cells expressing MAL as compared with cells not expressing MAL.

CONCLUSION

Our data suggest that the epigenetic inactivation of MAL, as a candidate tumor suppressor gene, can contribute to human epithelial cell carcinoma and may be served as a biomarker in HNSCC.

B7-H3 and CD133 expression in non-small cell lung cancer and correlation with clinicopathologic factors and prognosis

OBJECTIVE

To detect the expression of B7-H3 and CD133 in human non-small cell lung cancer (NSCLC) specimens and lung benign lesions, and to evaluate the correlation between the 2 biomarkers and clinicopathologic features.

METHODS

This is a case-control study of 102 tissue specimens collected from NSCLC participants undergoing thoracic surgery in the Second Affiliated Hospital of Soochow University, Suzhou, China, between January 2006 and December 2008. From the 102 patients, 25 adjacent non-cancer samples were verified pathologically as normal tissue (positive group), and 24 benign inflammatory lesion tissues were used as control (negative group). Specimens from 126 participants were stained immunohistochemically using Image-Pro Plus software, and the cell number was measured in each section.

RESULTS

Of the 102 specimens, 71 expressed B7-H3, and 51 expressed CD133, higher than that in benign lesions (p<0.001) or non-cancer tissues (p<0.001). B7-H3 expression in squamous cell carcinoma (SCC) was significantly higher than those in adenocarcinoma (p=0.048), while CD133 expression in large cell lung carcinoma was higher than that in SCC (p=0.023). The mean number of tumor-infiltrating lymphocytes (TILs) in the B7-H3-positive group was lower than that in the B7-H3-negative group (p=0.026). The mean TILs in the CD133-positive group was significantly lower than that in CD133-negative group (p=0.029). We found that CD133 was related to tumor cell differentiation degree and CD133 expression was negatively correlated with B7-H3 expression. The CD133 positive or B7-H3 negative was associated with poor prognosis of NSCLC patients by Cox regression analysis.

CONCLUSION

Both CD133 and B7-H3 might induce apoptosis of TILs in NSCLC and tumor evading host immune surveillance. Either CD133 or B7-H3 might be an independent risk factor of NSCLC participants.

Genetic alterations in a telomerase-immortalized human esophageal epithelial cell line: implications for carcinogenesis

Ectopic expression of viral oncoproteins disrupts cellular functions and limits the value of many existing immortalization models as models for carcinogenesis, especially for cancers without definitive viral etiology. Our newly established telomerase-immortalized human esophageal epithelial cell line, NE2-hTERT, retained nearly-diploid and non-tumorigenic characteristics, but exhibited genetic and genomic alterations commonly found in esophageal cancer, including progressive loss of the p16(INK4a) alleles, upregulation of anti-apoptotic proteins, epithelial-mesenchymal transition, whole-chromosome 7 gain and duplicated 5q arm. Our data also revealed a novel positive regulation of p16(INK4a) on cyclin D1. These findings probably represent early crucial events and mechanisms in esophageal carcinogenesis.

Human rhomboid family-1 gene RHBDF1 participates in GPCR-mediated transactivation of EGFR growth signals in head and neck squamous cancer cells

Epidermal growth factor receptor (EGFR) is an activated oncogene in many cancers. It can be transactivated by ligands of G protein-coupled receptors (GPCRs). We show here that a novel gene, human rhomboid family-1 (RHBDF1), which was recently reported to have a pivotal role in epithelial cancer cell growth in culture and in xenograft tumors, participates in the modulation of GPCR-mediated EGFR transactivation. The RHBDF1 protein localizes mainly in the endoplasmic reticulum. Silencing the RHBDF1 gene in head and neck squamous cancer cell line 1483 cells with siRNA causes an inhibition of gastrin-releasing peptide (GRP) -induced phosphorylation of EGFR and EGFR-dependent signaling proteins p44/42 MAPK and AKT, accompanied by an inhibition of GRP-induced survival, proliferation, and invasion of the cells. The EGFR signaling pathway itself remains intact, however, as the cells remain responsive to exogenous EGF. In addition, RHBDF1 gene silencing disrupts GRP-stimulated secretion of EGFR ligand TGF-alpha, but not the production of latent TGF-alpha, whereas engineered overexpression of RHBDF1 markedly accelerates the secretion of TGF-alpha. These findings are consistent with the view that RHBDF1 is critically involved in a GPCR ligand-stimulated process leading to the activation of latent EGFR ligands.

Prevention of KLF4-mediated tumor initiation and malignant transformation by UAB30 rexinoid

The transcription factor KLF4 acts in post-mitotic epithelial cells to promote differentiation and functions in a context-dependent fashion as an oncogene. In the skin KLF4 is co-expressed with the nuclear receptors RARgamma and RXRalpha, and formation of the skin permeability barrier is a shared function of these three proteins. We utilized a KLF4-transgenic mouse model of skin cancer in combination with cultured epithelial cells to examine functional interactions between KLF4 and retinoic acid receptors. In cultured cells, activation of a conditional, KLF4-estrogen receptor fusion protein by 4-hydroxytamoxifen resulted in rapid upregulation of transcripts for nuclear receptors including RARgamma and RXRalpha. We tested retinoids in epithelial cell transformation assays, including an RAR-selective agonist (all-trans RA), an RXR-selective agonist (9-cis UAB30, rexinoid), and a pan agonist (9-cis RA). Unlike for several other genes, transformation by KLF4 was inhibited by each retinoid, implicating distinct nuclear receptor heterodimers as modulators of KLF4 transforming activity. When RXRalpha expression was suppressed by RNAi in cultured cells, transformation was promoted and the inhibitory effect of 9-cis UAB30 was attenuated. Similarly as shown for other mouse models of skin cancer, rexinoid prevented skin tumor initiation resulting from induction of KLF4 in basal keratinocytes. Rexinoid permitted KLF4 expression and KLF4-induced cell cycling, but attenuated the KLF4-induced misexpression of cytokeratin 1 in basal cells. Neoplastic lesions including hyperplasia, dysplasia and squamous cell carcinoma-like lesions were prevented for up to 30 days. Taken together, the results identify retinoid receptors including RXRalpha as ligand-dependent inhibitors of KLF4-mediated transformation or tumorigenesis.

[Significance of Arg554Lys AHR gene polymorhism an survival of in squamous cell carcinoma laryngeal cancer in relation to tobacco smoking--preliminary study]

Initiation and progression of laryngeal cancer is associated with tobacco smoking and abusing of strong alcoholic beverages. A significance of genetic factor, although not defined sufficiently yet has been raised as well. The studies were focused on an influence of AHR gene polymorphism on survival of squamous cell carcinoma laryngeal subjects. The study material was 65 archival DNA samples analyzed by RLP-PCR. The samples varying with electrophoretic mobility were DNA sequenced. In the study group 9 heterozygotic variants Arg554Lys (codon 554) were detected. One case was a carrier of two other mutations in codon: 490 (1468 A > G) and 570 (1708 G > A). Survival time, metastasis and occurrence of second primary tumors were compared in carriers of wild type and Arg554Lys variant AHR. Preliminary results indicate for a necessity of further studies as until now the study group is too small to find a conclusive association.

MicroRNA and oral cancer: future perspectives

MicroRNAs (miRNAs) are small non-coding RNAs that mediate gene expression at the post-transcriptional level by degrading or repressing target messenger RNAs (mRNA). They are about 22 nucleotides in length and regulate mRNA translation by base pairing to partially complementary sites, predominantly in the 3' untranslated region (3' UTR) of mRNA. In this review, we discuss miRNA biogenesis and function, together with its possible involvement in oral cancer. Despite its great importance in normal cell development and diseases, a small number of studies have attempted to investigate miRNA in oral cancer. Overexpression of oncogenic miRNA may reduce protein products of tumor-suppressor genes. On the other hand, loss of tumor-suppressor miRNA expression may cause elevated levels of oncogenic protein. One or both of these alterations could represent new targets for cancer diagnosis and treatment in the future. Many researchers have focused on genetic and epigenetic alterations in oral squamous cell carcinoma cells. The emergence of miRNA knowledge, and its potential interactive action with such alterations, therefore creates a new understanding of cell transformation.

[Increase of BIRC5 gene expression in non-small cell lung cancer and esophageal squamous cell carcinoma does not correlate with expression of genes SMAC/DIABLO and PML encoding its inhibitors]

Survivin (BIRC5) is one of the members of IAP-family apoptosis inhibitors. The BIRCS gene is expressed in most human embryonic tissues and malignant tumors but not in normal differentiated tissues of adult human. It was suggested that BIRC5 proteins inhibit apoptosis and play an essential role in tumorigenesis, makings surviving an attractive target for anticancer therapy. The mechanisms regulating level of survivin are not completely understood. It was supposed that natural inhibitors of survivin, namely SMAC and PML, play an important role in these processes. Using RT-PCR and immunoblotting we analyzed the transcription level of BIRC5, SMAC and PML genes and content of corresponding proteins in normal and tumor human tissues in non-small cell lung cancer and esophageal squamous cell carcinoma. It was demonstrated that BIRC5 is transcribed only in tumor tissues, whereas expression levels of SMAC and PML are the same in normal and tumor tissues. The contents of proteins correspond to levels of mRNA of the respective genes. Thus the increase of level of survivin in tumor tissues is not the result of decrease in content of its inhibitors SMAC and PML, as their content in tumor and normal cells is the same.

Atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion: cytohistologic correlation study with diagnostic pitfalls

OBJECTIVE

In the current study, we explore the diagnostic parameters and pitfalls in the follow-up of 123 cases of Pap smears diagnosed as high-grade atypical squamous cells (ASC-H) at our institution.

STUDY DESIGN

A computer database search was performed from the archives of the Ottawa Hospital Cytopathology Service for cases diagnosed with ASC-H between January 2003 and July 2005.

RESULTS

Follow-up of the 123 cases of ASC-H showed high grade squamous intraepithelial lesion (HSIL) in 73 patients (59.4%), low grade squamous intraepithelial lesion (LSIL) in 11 (8.9%), immature squamous metaplasia in 23 (18.7%), reactive squamous cell changes in 12 (9.8%), benign glandular lesions (endocervical atypia, degenerated glandular cells) in 2 (1.6%) and atrophy in 2 (1.6%). In our study, 83 patients were younger than 40 years (67.4%), with biopsy-proven HSIL found in 54 patients (65.1%). The remaining 40 patients (32.6%) were older than 40 years of age, and follow-up biopsies showed HSIL in 19 patients (47.5%).

CONCLUSION

In our study, 59.4% of the cases that were diagnosed cytologically as ASC-H were found to have HSIL on subsequent biopsies. This correlation was stronger in patients below the age of 40 years (65.1% vs. 47.5%). The cytopathologic feature most strongly associated with HSIL was the presence of coarse nuclear chromatin (84%).

Insulin-like growth factor system gene expression in cervical scrapes from women with squamous intraepithelial lesions and cervical cancer

BACKGROUND

There is ample evidence that the insulin-like growth factors (IGF) system is involved in the development of several types of cancer. The aim of this study was to evaluate the expression levels of IGF-I, IGF-II, IGF binding protein 3 (IGFBP-3) and IGF-I receptor (IGF-IR) in exfoliated cervical cells in cervical carcinogenesis.

METHODS

mRNA levels of IGF-I, IGF-II, IGFBP-3 and IGF-IR were assessed by real-time PCR in 105 cervical scrapes obtained from 16 patients diagnosed with low-grade squamous intraepithelial lesions (LSIL), 24 with high-grade SIL (HSIL), 23 with cervical cancer, and 42 from controls with normal Papanicolau (Pap) test.

RESULTS

IGF-I mRNA levels were very low and no significant differences were seen between control and other groups. IGF-II mRNA levels were significantly lower in LSIL than in control group (median [arbitrary units]: 0.38 vs. 2.42, P=0.006) but its expression in HSIL and cervical cancer was similar to the one observed in controls. IGFBP-3 mRNA levels were significantly lower in cancer than in controls (median [arbitrary units]: 0.43 vs. 0.73, P=0.03). We observed a decrease in IGF-IR gene expression as the SIL degree increased (median for controls, LSIL, HSIL, and cervical carcinoma [arbitrary units]: 31.24, 9.08, 8.95, and 3.56, respectively). IGF-IR mRNA levels were significantly lower in HSIL and cervical cancer in comparison with controls (P=0.043 and P<0.001, respectively).

CONCLUSIONS

The present observations suggest that a reduced expression of IGFBP-3 and IGF-IR can be associated with progression to cervical cancer; the specific role played by the IGF-IR in this process remains unclear.

Epigenetic silencing of CDX2 is a feature of squamous esophageal cancer

CDX2, a mammalian homologue of the homeobox gene 'caudal,' is expressed in gut epithelia and plays an important role in establishing the intestinal phenotype during development. Mice heterozygously disrupted for CDX2 develop disorganized polypoid hamartomas with glandular epithelium and stratified squamous metaplasia resembling foregut mucosa. Since no genetic disruptions of CDX2 have been reported to explain loss of gene function, we examined whether epigenetic mechanisms altered CDX2 expression. Eleven of 17 squamous esophageal cancer cell lines lacked expression of CDX2 that was restored following treatment with 5-aza-2'-deoxycytidine, while all colorectal cancer cell lines expressed CDX2. Loss of expression was associated with DNA methylation in the 5' region of CDX2 determined by methylation specific PCR and bisulfite sequencing. Methylation of CDX2 was rare in primary colorectal (1 of 44 tumors, 2%) and esophageal adenocarcinoma neoplasms (2 of 43 tumors, 5%), but was common in esophageal squamous carcinoma (24 of 45 tumors, 49%). No CDX2 methylation was found in normal tissues. Using semi-quantitative RT-PCR, expression of CDX2 was found in low level in normal esophagus, at higher levels in primary adenocarcinoma of the esophagus, but not in primary squamous cancers of the esophagus. Restoration of CDX2 in silenced cell lines resulted in expression of the CDX2 target gene MUC2, a gene important in glandular differentiation. Our results suggest that the inactivation of CDX2 in esophageal cancer associated with DNA methylation may be an important determinant of the squamous or non-adenomatous phenotype.

[Association between genetic polymorphism in DNA repair genes XRCC3 and risks of laryngeal and hypopharyngeal carcinomas]

OBJECTIVE

To study the association between polymorphism of DNA repair gene XRCC3 Thr 241 Met and the risks of developing laryngeal and hypopharyngeal carcinomas.

METHODS

One hundred and seventy five patients with laryngeal or hypopharyngeal carcinoma and 525 cancer-free controls were genotyped for the polymorphism by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using unconditional logistic regression model.

RESULTS

The XRCC3 241 Met allele increased the risk of developing laryngeal carcinoma and hypopharyngeal carcinoma. Comparing with subjects having the XRCC3 241 Thr/Thr genotype, the subjects at least having one XRCC3 241 Met allele had OR of 2. 26 (95% CI 1.33 -3.82). Respectively analyzing the risks of laryngeal carcinoma and hypopharyngeal carcinoma, The allele XRCC3 241 Met increased the risks of developing both laryngeal and hypopharyngeal carcinoma. Comparing with the subjects having the XRCC3 241 Thr/Thr genotype, the subjects with laryngeal carcinoma at least having one XRCC3 241 Met genotype had OR of 2.27 (95% CI 1.26 - 4.09); the subjects with hypopharyngeal carcinoma at least having one XRCC3 241 Met genotype had OR of 2. 99 (95% CI 1.27 - 7.04). Smoking may increase the risk of developing laryngeal carcinoma and hypopharyngeal carcinoma. The interaction of smoking and XRCC3 Thr241 Met increased risk of laryngeal carcinoma and hypopharyngeal carcinoma in a super-multiplicative manner. The subjects with heavy smoking and at least having one XRCC3 241Met allele had OR of 19.09 (95% CI 7.38 -49.40) comparing with those having the XRCC3 241 Thr/ Thr genotype and no smoking, which was greater than the multiplication of ORs both of subjects at least having one 241 Met allele meanwhile without smoking (OR, 0.91; 95% CI, 0.20 - 4.21) and of subjects having XRCC3 241 Thr/Thr genotype meanwhile with smoking (OR, 4.13; 95% CI, 2.38 - 7.17).

CONCLUSIONS

XRCC3 Thr 241 Met plays an important role in the development of laryngeal and hypopharyngeal carcinoma.

Inactivation of the Wwox gene accelerates forestomach tumor progression in vivo

The WWOX gene encodes a tumor suppressor spanning the second most common human fragile site, FRA16D. Targeted deletion of the Wwox gene in mice led to an increased incidence of spontaneous and ethyl nitrosourea-induced tumors. In humans, loss of heterozygosity and reduced or loss of WWOX expression has been reported in esophageal squamous cell cancers (SCC). In the present study, we examined whether inactivation of the Wwox gene might lead to enhanced esophageal/forestomach tumorigenesis induced by N-nitrosomethylbenzylamine. Wwox+/- and Wwox+/+ mice were treated with six intragastric doses of N-nitrosomethylbenzylamine and observed for 15 subsequent weeks. Ninety-six percent (25 of 26) of Wwox+/- mice versus 29% (10 of 34) of Wwox+/+ mice developed forestomach tumors (P = 1.3 x 10(-7)). The number of tumors per forestomach was significantly greater in Wwox+/- than in Wwox+/+ mice (3.2 +/- 0.34 versus 0.47 +/- 0.17; P < 0.0001). In addition, 27% of Wwox+/- mice had invasive SCC in the forestomach, as compared with 0% of wild-type controls (P = 0.002). Intriguingly, forestomachs from Wwox+/- mice displayed moderately strong Wwox protein staining in the near-normal epithelium, but weak and diffuse staining in SCC in the same tissue section, a result suggesting that Wwox was haploinsufficient for the initiation of tumor development. Our findings provide the first in vivo evidence of the tumor suppressor function of WWOX in forestomach/esophageal carcinogenesis and suggest that inactivation of one allele of WWOX accelerates the predisposition of normal cells to malignant transformation.

Low expression of reversion-inducing cysteine-rich protein with Kazal motifs (RECK) indicates a shorter survival after resection in patients with adenocarcinoma of the lung

It has been reported that an endogenous matrix metalloproteinase (MMP) inhibitor, reversion-inducing cysteine-rich protein with Kazal motifs (RECK), is able to inhibit tumour angiogenesis, invasion, and metastasis through inhibition of MMP-2, MMP-9, and membrane type-1 (MT1)-MMP (MMP-14) secretion and activity. In this study, using quantitative real-time reverse transcriptase polymerase chain reaction (RT-PCR), we have analysed RECK expression levels in resected non-small-cell lung cancer (NSCLC) tissue and compared these data with the clinicopathological features of these patients to investigate the role of RECK in NSCLC. We have also analysed the expression of MMP-2, MMP-9, and MMP-14 and compared the data with those for RECK expression. Tissue samples of primary lung cancers were obtained from a total of 83 patients [46 with adenocarcinomas (ADC) and 37 with squamous cell carcinomas (SCC)] who underwent curative resection. The samples were taken from 83 tumours and 20 matched normal lung tissue samples as controls. Expressions of RECK in ADC and SCC were significantly lower than in the control. In ADC tissue, the expression of RECK was higher in stage IA than in stage IB-IIIA. There was no such a correlation in SCC. In ADC, univariate analysis for relapse-free survival using Cox regression analysis identified low RECK expression (p=0.036), low MMP-14 expression (p=0.038), and tumour T2 (p=0.034) as significant negative prognostic predictors. However, in SCC, none of the clinicopathological factors assessed, including RECK expression, had prognostic value. In conclusion, our study suggests that suppression of RECK expression is involved in the progression of ADC of the lung and that RECK expression in resected ADC of the lung is a favorable predictor of patients' prognosis.

CYP1A1 and GSTP1 polymorphisms in an oral cancer case-control study

CYP1A1 and GSTP1 polymorphisms have been associated with a higher risk to develop several cancers, including oral squamous cell carcinoma (OSCC), which is closely related to tobacco and alcohol consumption. Both genes code for enzymes that have an important role in activating or detoxifying carcinogenic elements found in tobacco and other compounds, and polymorphic variants of these genes may result in alterations of the enzymatic activity. The CYP1A1 gene codes for the enzyme aryl hydrocarbon hydroxylase, which is responsible for the metabolism of polycyclic aromatic hydrocarbons. The investigated polymorphism, Ile/Val, seems to increase the activity of the enzyme in homozygous individuals, leading to an accumulation of carcinogens. The Ile/Val polymorphism occurs because of an A->G transition at exon 7, resulting in the CYP1A1*2B allele. The GSTP1*B variant shows an A->G transition at exon 5, changing the amino acid Ile to Val, with a reduced catalytic activity of the enzyme. Due to this reduction, the carriers of mutant alleles lost the capability to metabolize carcinogens, which could be responsible for a higher susceptibility to cancer. We conducted a case-control study in a group of 72 cases with newly diagnosed OSCC and 60 healthy controls matched for age, gender, smoking habits, and ethnicity. We used PCR methods to identify the allelic variants CYP1A1*2B and GSTP1*B. The data obtained showed no statistically significant association of allelic or genotypic variants of CYP1A1*2B (OR = 1.06; 95% CI = 0.49-2.29) and GSTP1*B (OR = 1.40; 95% CI = 0.70-2.79) with OSCC.

Frequency and phenotypic implications of mitochondrial DNA mutations in human squamous cell cancers of the head and neck

Mitochondrial genomic mutations are found in a variety of human cancers; however, the frequency of mitochondrial DNA (mtDNA) mutations in coding regions remains poorly defined, and the functional effects of mitochondrial mutations found in primary human cancers are not well described. Using MitoChip, we sequenced the whole mitochondrial genome in 83 head and neck squamous cell carcinomas. Forty-one of 83 (49%) tumors contained mtDNA mutations. Mutations occurred within noncoding (D-loop) and coding regions. A nonrandom distribution of mutations was found throughout the mitochondrial enzyme complex components. Sequencing of margins with dysplasia demonstrated an identical nonconservative mitochondrial mutation (A76T in ND4L) as the tumor, suggesting a role of mtDNA mutation in tumor progression. Analysis of p53 status showed that mtDNA mutations correlated positively with p53 mutations (P < 0.002). To characterize biological function of the mtDNA mutations, we cloned NADH dehydrogenase subunit 2 (ND2) mutants based on primary tumor mutations. Expression of the nuclear-transcribed, mitochondrial-targeted ND2 mutants resulted in increased anchorage-dependent and -independent growth, which was accompanied by increased reactive oxygen species production and an aerobic glycolytic metabolic phenotype with hypoxia-inducible factor (HIF)-1alpha induction that is reversible by ascorbate. Cancer-specific mitochondrial mutations may contribute to development of a malignant phenotype by direct genotoxic effects from increased reactive oxygen species production as well as induction of aerobic glycolysis and growth promotion.

Detection of non-diploid cells in premalignant and malignant oral lesions using combined morphological and FISH analysis - a new method for early detection of suspicious oral lesions

Alteration in DNA content is an early event in oral carcinogenesis. We have examined oral brush samples to detect non-diploid cells (NDC) using simultaneous morphological and cytogenetic analysis. The study included 8 oral squamous cell carcinomas (OSCC), 22 premalignant lesions (OPLs), and 25 control individuals. Slides stained with Giemsa followed by FISH using chromosome 2 centromeric DNA probe, were scanned and fluorescent signals were simultaneously analyzed in parallel with the morphology. The proportion of NDC increased with the severity of the diagnosis. In two control subjects, 1-1.5% of the examined cells were NDC. Over 2% NDC were present in all OSCC cases and in 11 of the OPLs, of which, in 8 the histologic diagnosis was either epithelial hyperplasia or mild dysplasia. A significant number of NDC had normal morphology when cytomorphology and FISH were compared. Two patients with OPLs developed OSCC these patients had a significant proportion of NDC. We suggest that the combined morphological and cytogenetic analysis of cells collected by a non-invasive brush sampling can enhance early detection of potentially malignant cells.