Distinctive chromosomal instability patterns in oral verrucous and squamous cell carcinomas detected by high-resolution DNA flow cytometry

BACKGROUND:

Oral verrucous carcinomas (OVCs) are characterized by better prognosis than oral squamous cell carcinomas (OSCCs). Because chromosomal instability (CIN) in solid tumors is indicative of prognosis, this study investigated whether OVCs and OSCCs were characterized by differences in CIN biomarkers.

METHODS:

Fresh or frozen multiple tissue samples were submitted to high‐resolution DNA flow cytometry (hr DNA‐FCM).

RESULTS:

DNA aneuploid sublines were detected in 6 of 9 OVCs (66.7%) and in 20 of 25 OSCCs (80.0%). Multiple DNA aneuploid sublines were observed, respectively, in 2 of 6 (33.3%) DNA aneuploid OVCs and in 14 of 20 (70%) DNA aneuploid OSCCs (P = .163). OVCs were mainly characterized by DNA Index (DI) values in the near‐diploid region (DI≠1 and DI < 1.4), whereas aneuploid OSCCs carried most frequently multiple aneuploid sublines with high DI values (DI ≥ 1.4). DNA near‐diploid and high aneuploid sublines were, respectively, 87.5% and 12.5% for the OVCs versus 30% and 70% for the OSCCs (P = .004).

CONCLUSIONS:

Present data suggest that OVCs are characterized by a lower degree of CIN and tumor heterogeneity than OSCCs, such that they appear as “frozen” in an early stage of DNA near‐diploid aneuploidy, as previously observed for oral preneoplastic lesions. These DI characteristics, which can easily be obtained by hr DNA‐FCM, appear to reflect the well‐known differences in aggressiveness and prognosis of OVCs and OSCCs. Cancer 2011;. © 2011 American Cancer Society.     

Aberrant DNA methylation of tumor-related genes in oral rinse: a noninvasive method for detection of oral squamous cell carcinoma

BACKGROUND:

The early detection of oral squamous cell carcinoma (OSCC) is important, and a screening test with high sensitivity and specificity is urgently needed. Therefore, in this study, the authors investigated the methylation status of tumor‐related genes with the objective of establishing a noninvasive method for the detection of OSCC.

METHODS:

Oral rinse samples were obtained from 34 patients with OSCC and from 24 healthy individuals (controls). The methylation status of 13 genes was determined by using methylation‐specific polymerase chain reaction analysis and was quantified using a microchip electrophoresis system. Promoter methylation in each participant was screened by receiver operating characteristic analysis, and the utility of each gene's methylation status, alone and in combination with other genes, was evaluated as a tool for oral cancer detection.

RESULTS:

Eight of the 13 genes had significantly higher levels of DNA methylation in samples from patients with OSCC than in controls. The genes E‐cadherin (ECAD), transmembrane protein with epidermal growth factor‐like and 2 follistatin‐like domains 2 (TMEFF2), retinoic acid receptor beta (RARβ), and O‐6 methylguanine DNA methyltransferase (MGMT) had high sensitivity (>75%) and specificity for the detection of oral cancer. OSCC was detected with 100% sensitivity and 87.5% specificity using a combination of ECAD, TMEFF2, RARβ, and MGMT and with 97.1% sensitivity and 91.7% specificity using a combination of ECAD, TMEFF2, and MGMT.

CONCLUSIONS:

The aberrant methylation of a combination of marker genes present in oral rinse samples was used to detect OSCC with >90% sensitivity and specificity. The detection of methylated marker genes from oral rinse samples has great potential for the noninvasive detection of OSCC. Cancer 2012. © 2012 American Cancer Society.     

Different miRNA signatures of oral and pharyngeal squamous cell carcinomas: a prospective translational study

Background:

MicroRNAs (miRNAs) are small non-coding RNAs, which regulate mRNA translation/decay, and may serve as biomarkers. We characterised the expression of miRNAs in clinically sampled oral and pharyngeal squamous cell carcinoma (OSCC and PSCC) and described the influence of human papilloma virus (HPV).

Methods:

Biopsies obtained from 51 patients with OSCC/PSCC and 40 control patients were used for microarray analysis. The results were correlated to clinical data and HPV status. Supervised learning by support vector machines was employed to generate a diagnostic miRNA signature.

Results:

One hundred and fourteen miRNAs were differentially expressed between OSCC and normal oral epithelium, with the downregulation of miR-375 and upregulation of miR-31 as the most significant aberrations. Pharyngeal squamous cell carcinoma exhibited 38 differentially expressed miRNAs compared with normal pharyngeal epithelium. Differences in the miRNA expression pattern of both normal epithelium and SCC were observed between the oral cavity compared with the pharynx. Human papilloma virus infection revealed perturbations of 21 miRNAs, most significantly in miR-127-3p and miR363. A molecular classifier including 61 miRNAs was generated for OSCC with an accuracy of 93%.

Conclusion:

MicroRNAs may serve as useful biomarkers in OSCC and PSCC. The influence of HPV on miRNA may provide a mechanism for the distinct clinical behaviour of HPV-infected tumours.     

Stratification of HPV-associated and HPV-negative oropharyngeal squamous cell carcinomas based on DNA methylation epigenotypes

While the incidence of oropharyngeal squamous cell carcinoma (OPSCC) has been increasing in these two decades, primarily due to human papillomavirus (HPV), stratification of OPSCC into molecular subgroups showing different clinicopathological features has not been fully investigated. We performed DNA methylome analysis using Infinium 450k for 170 OPSCC cases, including 89 cases in our cohort and 81 cases reported by The Cancer Genome Atlas, together with targeted exon sequencing analysis. We stratified OPSCC by hierarchical clustering analysis using methylome data. Methylation levels of classifier markers were validated quantitatively using pyrosequencing, and area under the curve (AUC) values of receiver operating characteristics (ROC) curves were calculated. OPSCC was stratified into four epigenotypes: HPV(+) high-methylation (OP1), HPV(+) intermediate-methylation (OP2), HPV(−) intermediate-methylation (OP3) and HPV(−) low-methylation (OP4). Ten methylation marker genes were generated: five to classify HPV(+) cases into OP1 and OP2, and five to classify HPV(−) cases into OP3 and OP4. AUC values of ROC curves were 0.969 and 0.952 for the two marker panels, respectively. While significantly higher TP53 mutation and CCND1 copy number gains were observed in HPV(−) than in HPV(+) groups (p < 0.01), no significant difference of genomic aberrations was observed between OP1 and OP2, or OP3 and OP4. The four epigenotypes showed significantly different prognosis (p = 0.0006), distinguishing the most favorable OPSCC subgroup (OP1) among generally favorable HPV(+) cases, and the most unfavorable OPSCC subgroup (OP3) among generally unfavorable HPV(−) cases. HPV(+) and HPV(−) OPSCC are further divided into distinct DNA methylation epigenotypes, showing significantly different prognosis.     

Treatment of squamous carcinoma in mice with a vaccine enriched for cells that induce immunity to squamous carcinoma--a new vaccination strategy

We report a new vaccination strategy for squamous cell carcinoma (SCC). The vaccine was prepared by transfer of unfractionated DNA‐fragments (25 kb) from squamous carcinoma cells (KLN205, DBA/2 origin (H‐2^d)) into LM mouse fibroblasts (C3H/He origin; H‐2^k), a highly immunogenic cell line. To enhance their nonspecific immunogenic properties, the fibroblasts were modified before DNA transfer to secrete IL‐2 and to express additional allogeneic MHC class I determinants. As the transferred DNA integrates into the genome of the recipient cells, and is replicated as the cells divide, sufficient DNA to prepare the vaccine could be obtained from as few as 10⁷ squamous carcinoma cells (4 mm tumor). Since only a small proportion of the transfected cell‐population was expected to have incorporated genes specifying antigens associated with the squamous carcinoma cells (TAA), we devised a novel approach to enrich the vaccine for cells that induce immunity to the SCC. Aliquots of the transfected population were divided into 10 small pools (initial inoculums = 1 × 10³). We reasoned that if the starting inoculums were sufficiently small, then the distribution of highly immunogenic and weakly immunogenic cells in each pool would not be the same. Cells from individual pools were allowed to increase in number. A portion of the expanded cell populations were maintained frozen/viable for later recovery. The remaining portions were used to immunize naïve DBA/2 mice. Pools containing greater numbers of immunogenic cells were identified by 2 independent assays. Frozen aliquots of cells from the pool that stimulated immunity to the squamous carcinoma to the greatest extent were recovered and subdivided for additional rounds of immune selection. Enhanced immunity to squamous carcinoma mediated by CD8+ T cells was induced in tumor‐bearing mice treated solely by immunization with the enriched cell‐population. © 2006 Wiley‐Liss, Inc.     

Plasma cell-free DNA methylome profiling in pre- and post-surgery oral cavity squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC), a highly heterogeneous disease that involves multiple anatomic sites, is a leading cause of cancer-related mortality worldwide. Although the utility of noninvasive biomarkers based on circulating cell-free DNA (cfDNA) methylation profiling has been widely recognized, limited studies have been reported so far regarding the dynamics of cfDNA methylome in oral cavity squamous cell carcinoma (OCSCC). It is hypothesized in this study that comparison of methylation profiles in pre- and postsurgery plasma samples will reveal OCSCC-specific prognostic and diagnostic biomarkers. As a strategy to further prioritize tumor-specific targets, top differential methylated regions (DMRs) were called by reanalyzing methylation data from paired tumor and normal tissue collected in the the cancer genome atlas head-neck squamous cell carcinoma (TCGA) head and neck cancer cohort. Matched plasma samples from eight patients with OCSCC were collected at Moffitt Cancer Center before and after surgical resection. Plasma-derived cfDNA was analyzed by cfMBD-seq, which is a high-sensitive methylation profiling assay. Differential methylation analysis was then performed based on the matched samples profiled. In the top 200 HNSCC-specific DMRs detected based on the TCGA data set, a total of 23 regions reached significance in the plasma-based DMR test. The top five validated DMR regions (ranked by the significance in the plasma study) are located in the promoter regions of genes PENK, NXPH1, ZIK1, TBXT, and CDO1, respectively. The genome-wide cfDNA DMR analysis further highlighted candidate biomarkers located in genes SFRP4, SOX1, IRF4, and PCDH17. The prognostic relevance of candidate genes was confirmed by survival analysis using the TCGA data. This study supports the utility of cfDNA-based methylome profiling as a promising noninvasive biomarker source for OCSCC and HNSCC.     

Monitoring of circulating tumour-associated DNA as a prognostic tool for oral squamous cell carcinoma

Frequent allelic imbalances (AIs) including loss of heterozygosity and microsatellite instability on a specific chromosomal region have been identified in a variety of human malignancies. The objective of our study was to assess the possibility of prognostication and monitoring of oral squamous cell carcinoma (SCC) by microsatellite blood assay. DNA from normal and tumorous tissues and serum DNA obtained at three time points (preoperatively, postoperatively, and 4 weeks postoperatively) from 64 patients with oral SCC was examined at nine microsatellite loci. In all, 38 (59%) DNA samples from tumorous tissues and 52% from serum showed AIs in at least one locus. Patterns of AIs in the serum DNA were matched to those detected in tumour DNA. Of them, AIs were frequently detected preoperatively (44%, 28 of 64), and postoperatively (20%, 13 of 64). Moreover, among 12 cases with AIs during the postoperative period, six had no evidence of an AI 4 weeks postoperatively, and they had no recurrence and were disease free. In contrast, six patients with AI-positive DNA 4 weeks postoperatively have died with distant metastasis within 44 weeks. Thus, our results suggest that the assessment of microsatellite status in the serum DNA could be a useful predictive tool to monitor disease prognosis.     

Inhibition of ICAM2 induces radiosensitization in oral squamous cell carcinoma cells

We recently identified genes and molecular pathways related to radioresistance of oral squamous cell carcinoma (OSCC) using Affymetrix GeneChip. The current study focused on the association between one of the target genes, intercellular adhesion molecule 2 (ICAM2), and resistance to X-ray irradiation in OSCC cells, and evaluated the antitumor efficacy of combining ICAM2 small interfering RNA (siRNA) and X-ray irradiation. Downregulation of ICAM2 expression by siRNA enhanced radiosensitivity of OSCC cells with the increased apoptotic phenotype via phosphorylation (ser473) of AKT and activation of caspase-3. Moreover, overexpression of ICAM2 induced greater OSCC cell resistance to the X-ray irradiation with the radioresistance phenotype. These results suggested that ICAM2 silencing is closely related to sensitivity of OSCC cells to radiotherapy, and that ICAM2 may be an effective radiotherapeutic target for this disease.     

口腔鳞状细胞癌中TSLC1基因启动子甲基化状态检测的临床意义

目的:探讨肺癌抑癌基因1(TSLC1)在口腔鳞状细胞癌组织中基因启动子甲基化状态及其与临床病理参数的联系.方法:应用甲基化特异性PCR检测TSLC1基因启动子在55例口腔鳞状细胞癌组织及10例正常组织中的甲基化状态并结合临床病理资料进行分析.结果:在癌组织中TSLC1基因甲基化阳性率为76.4％(42/55),正常组织未出现TSLC1基因甲基化.TSLC1基因甲基化与口腔鳞状细胞癌临床分期显著相关(P=0.008).结论:TSLC1基因甲基化与口腔鳞状细胞癌临床分期密切相关,可能是参与口腔鳞状细胞癌发展的重要分子事件.     

Oral cavity squamous cell carcinomas in young patients in a selected Malaysian centre

Aim:   This study aims to evaluate the demographics, to analyze the clinical and pathological findings, treatment and the outcome of oral cavity squamous cell carcinomas (OSCC) in patients aged 40-years old and below in our centre.
Methods:   Records of patients who were diagnosed with OSCC in the Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, from 1998 to 2003 were analyzed. Their socioeconomic data such as their age, gender and race, risk factors, family history and genetic predisposition were assessed. Other data examined included the sites and stage of the tumor, histopathology results, treatment modality and outcome of OSCC.
Results:   There were 19 patients with no gender predilection. Malays made up most patients diagnosed with OSCC, followed by Chinese and Indians. There was no significant high-risk habit in this group. Most of the sites involved were the tongue (73.7%), buccal mucosa (15.8%) and alveolus (10.5%). Most of the patients (57.9%) were diagnosed with stage IV disease. Eighteen patients underwent treatment consisting of surgery or radiotherapy or in combination. A 5-year follow up revealed that nine patients (47.3%) survived and remain well, four patients (21.1%) had a recurrence, two patients (10.5%) died of the disease.
Conclusion:   The majority of patients presented with stage IV disease without any significant high-risk habit. Surgery remains the mainstay of treatment, however, 5-year follow-up showed a less than 50% survival rate.     

Arsenic-related DNA copy-number alterations in lung squamous cell carcinomas

Background:

Lung squamous cell carcinomas (SqCCs) occur at higher rates following arsenic exposure. Somatic DNA copy-number alterations (CNAs) are understood to be critical drivers in several tumour types. We have assembled a rare panel of lung tumours from a population with chronic arsenic exposure, including SqCC tumours from patients with no smoking history.

Methods:

Fifty-two lung SqCCs were analysed by whole-genome tiling-set array comparative genomic hybridisation. Twenty-two were derived from arsenic-exposed patients from Northern Chile (10 never smokers and 12 smokers). Thirty additional cases were obtained for comparison from North American smokers without arsenic exposure. Twenty-two blood samples from healthy individuals from Northern Chile were examined to identify germline DNA copy-number variations (CNVs) that could be excluded from analysis.

Results:

We identified multiple CNAs associated with arsenic exposure. These alterations were not attributable to either smoking status or CNVs. DNA losses at chromosomes 1q21.1, 7p22.3, 9q12, and 19q13.31 represented the most recurrent events. An arsenic-associated gain at 19q13.33 contains genes previously identified as oncogene candidates.

Conclusions:

Our results provide a comprehensive approach to molecular characteristics of the arsenic-exposed lung cancer genome and the non-smoking lung SqCC genome. The distinct and recurrent arsenic-related alterations suggest that this group of tumours may be considered as a separate disease subclass.     

Toll-like receptor 2 is present in the microenvironment of oral squamous cell carcinoma

Background:

The aim of this study was to investigate the expression of toll-like receptor 2 (TLR2) on cells associated with oral squamous cell carcinoma, epithelial dysplasia and irritative hyperplasia, using immunohistochemistry.

Results:

More immune cells expressed TLR2 in carcinoma and dysplasia than in hyperplasia (P<0.001). No hyperplastic samples showed positive TLR2 staining on keratinocytes, whereas keratinocytes in 64% of cases of carcinoma and 74% of cases of dysplasia were TLR2 positive.

Conclusion:

Positive TLR2 expression in the microenvironment suggests activation of immune surveillance against the altered epithelium, whereas TLR2 expression by malignant keratinocytes may be indicative of resistance to apoptosis as a pro-survival mechanism.     

Functional characterization of p53 molecules expressed in human squamous cell carcinomas of the head and neck

Mutation of the p53 tumor suppressor gene has been demonstrated in a large proportion of human head and neck squamous cell carcinomas (HNSCCs) and has been assumed to play a role in the pathogenesis of these tumors, although no formal evidence of functional aberration has been demonstrated. In this study, we isolated cDNA clones encoding the entire p53 coding region from six human HNSCC cell lines that showed aberrant patterns of p53 expression in the parental cells, analyzed their nucleotide sequences, and characterized their function in vivo. cDNAs cloned from four cell lines harbored alterations within the p53 coding sequence (one missense mutation, one missense mutation plus in-frame deletion, one splice donor mutation, and a 1-nt insertion). HN30 cells, which contained wild-type p53 nucleotide sequences, showed a high constitutive level of protein expression. HN26 cells contained wild-type coding sequences but did not express the 53-kDa protein, although the mRNA was transcribed and a molecule of increased molecular mass (70 kDa) was observed by western blotting. Functional studies revealed that none of the four proteins encoded by mutant cDNAs were able to transactivate expression of a reporter plasmid containing a wild-type p53 consensus binding site when cotransfected into p53-null cells, whereas molecules encoded by wild-type p53 cDNAs increased reporter gene expression about a hundredfold over uninduced levels. Co-expression of each mutant cDNA with wild-type p53 cDNA and a wild-type p53-responsive reporter gene demonstrated that each of the proteins encoded by mutant cDNAs harbored some degree of inhibitory activity that varied depending on the mutation present. Thus, aberrant p53 function as a result of mutation or altered expression characterizes oral squamous cell carcinomas. The inhibitory activity of these molecules may be a mechanism for deregulation of the function of co-expressed wild-type p53 that may be of importance during the early stages of tumor development. Mol. Carcinog. 18:89–96, 1997. © 1997 Wiley-Liss, Inc.     

Immunohistochemical expression of EGFR and p-EGFR in oral squamous cell carcinomas

Epidermal growth factor receptor (EGFR) is a tyrosine kinase receptor of the ErbB family, which is expressed or highly expressed in a variety of solid tumors, including oral cancers. High EGFR expression has been correlated with tumor size, metastasis and survival. In recent years, EGFR has been considered a promising target for monoclonal antibody therapy. A total of 52 patients with oral squamous cell carcinoma (OSCC) were selected for EGFR and phosphorylated EGFR (p-EGFR) detection. Immunohistochemical staining was performed to evaluate EGFR and p-EGFR expression. Positive EGFR and p-EGFR staining was present in 92.3% (48/52) and 98.0% (51/52) of all cases, respectively. High EGFR and p-EGFR expression was present in 63.4% (33/52) and 69.2% (36/52) of all cases, respectively. EGFR and p-EGFR expression did not correlate with the clinical factors tumor stage, regional lymph node metastasis, or distant metastasis. However, a statistically significant correlation was identified between high EGFR expression and the pathologic factor tumor invasion. As a conclusion, the majority of OSCCs highly express EGFR and p-EGFR, indicating the importance of studying the efficacy of anticancer therapy targeting these signal factors.(Pathology Oncology Research Vol 12, No 2, 87–91)     

Cytogenetic characteristics of oral squamous cell carcinomas in Fanconi anemia

Fanconi anemia (FA) is an autosomal recessive syndrome with a marked predisposition to malignancies, in particular acute myeloid leukemia and squamous cell carcinoma of the oral cavity. We examined oral squamous cell carcinoma tissue from two FA patients (FA-A and FA-C) by comparative genomic hybridization. Both tumors, which were negative for human papilloma as well as Epstein-Barr viral sequences, showed multiple alterations with a high proportion of whole-arm chromosomal gains and losses. This combination of features as well as the sites involved in chromosomal breakage are very similar to what is typically observed in non-FA oral tumors. These results suggest that the process leading to early occurrence of oral cancer in FA patients follows a similar pathway as in non-FA cancer patients, which would support a caretaker function for FA genes in the protection against oral carcinogenesis. Since FA patients are uniquely hypersensitive to DNA cross-linking agents, while oral cancer in the general population is thought to be environmentally induced, these results also suggest that environmental DNA cross-linkers may be causally involved in oral carcinogenesis.     

喉鳞状细胞癌组织中线粒体基因4977bp缺失突变的检测

背景与目的:线粒体DNA4977bp缺失突变是机体衰老的分子生物学标志之一,已证实其存在于多种实体性肿瘤中,该突变与喉鳞状细胞癌之间的关系尚不明确。本文旨在探讨喉鳞状细胞癌组织中线粒体基因4977bp缺失突变的发生情况及其与喉癌组织分化水平之间的关系。方法:取喉癌组织35例,均经病理证实为喉鳞状细胞癌。提取肿瘤组织总DNA,利用聚合酶链反应(polymerasechainreaction,PCR)对线粒体基因4977bp缺失进行检测。PCR产物直接测序。结果:35例标本中有20例(57.14%)检测到线粒体基因4977bp缺失突变,其中7例高分化喉鳞癌中有5例,24例中分化喉鳞癌中有15例,4例低分化喉鳞癌未检测到该缺失突变。经统计学分析,高分化、中分化级别喉鳞癌组织4977bp缺失突变发生率与低分化相比有显著性差异(P<0.05),而高分化和中分化之间无显著性差异(P>0.05)。结论:喉鳞状细胞癌组织中存在线粒体DNA4977bp缺失突变,该突变的发生可能与肿瘤组织分化水平有关。     

Tie-2在口腔鳞状细胞癌侵犯颌骨过程中的作用机制研究

目的:研究酪氨酸激酶受体-2（tyrosinekinase receptor-2,Tie-2）在口腔鳞状细胞癌侵犯颌骨过程中的作用机制。方法:免疫组化SP法比较Tie-2在颌骨侵犯前沿的口腔鳞状细胞癌与其他部位的口腔鳞癌中的表达差异;构建3种针对Tie-2的siRNA慢病毒载体（662、663、664）为实验组、空载病毒429和生理盐水（NS）为对照组,并将各组转染至人舌鳞癌细胞系（Cal-27）中,应用qRT-PCR筛选出抑制效果最好的siRNA;CCK-8法检测细胞活性;将抑制效果最好的慢病毒载体转染至Cal-27后,将其培养基上清添加至人单核细胞系（THP-1）培养基中,qRT-PCR和Western blotting检测THP-1中的破骨细胞功能相关基因抗酒石酸酸性磷酸酶（tartrate resistant acid phosphatase,TRAP）和组织蛋白酶K（cathepsin K,CTSK）的mRNA和蛋白量在各组中的表达差异。结果:颌骨侵犯前沿的骨旁鳞癌组织染色比其他部位鳞癌组织显著加深,骨旁鳞癌组织MOD值显著增大（P＜0.000 1）;siRNA-664对Cal-27中Tie-2表达的抑制效果最佳（P＜0.000 1）;用慢病毒转染Cal-27和THP-1后,细胞活性无明显变化,差异无统计学意义;沉默Cal-27中Tie-2的表达后,THP-1的破骨细胞功能相关基因和蛋白表达显著降低（P＜0.000 1）。结论:下调Tie-2表达后,THP-1向破骨细胞分化的潜力降低,表现为破骨细胞功能相关基因和蛋白表达下调。OSCC可能通过激活Ang/Tie-2信号体系释放某些破骨细胞分化因子,促进破骨细胞分化,从而导致局部骨侵犯发生。