| Laryngeal squamous cell carcinoma(LSCC),as one of the most common malignant tumors in head and neck,accounts for 5.7%?7.6% of systemic malignancies,and is characterised by high mortality and poor prognosis.Although great progress has been made in chemotherapy,radiotherapy,and molecular targeted therapy in recent years,the 5-year survival rate and quality of life for LSCC patients remain low and incidence rate of LSCC has increased year by year.As LSCC patients are trending younger,it seriously impairs swallowing,respiration and phonation function.Moreover,LSCC drastically impacts the quality of life and survival of patients.Evidence suggests that life elongation has been at the expanse of laryngeal function for patients with advanced LSCC.The pathogenesis of LSCC is complicated and still not very clear so far.Currently,there is a lack of universally accepted biomarkers for early diagnosis and therapeutic targets for LSCC.Therefore,a better understanding of the molecular mechanisms of LSCC and a uncover novel biomarkers are in urgent demand.Genetic instability such as chromosomal instability is associated with the tumorigenesis of LSCC.Copy-number variations(CNVs),refers to DNA fragment copy number variations in the human genome,ranging from 1 KB to several Mb,including deletion,insertion,replication and duplication.CNVs are widely distributed throughout the human genome and are one of the major contributors to genetic diversity and phenotypic variation.In addition,CNVs are important reasons for the activation of proto-oncogenes and the inactivation of tumor suppressor genes which play crucial roles in regulating cell growth,proliferation,apoptosis and metastasis in a variety of human tumors.Array comparative genomic hybridization(array-CGH)has emerged as a high-throughput genomic technology to screen variation of chromosome,such as microduplication,microdeletion and aneuploidy.Array-CGH facilitates the aggregation of high resolution data of the cancer-related genomic imbalances and detection of proto-oncogenes and tumor-suppressor genes,aiming at monitoring the process of oncogenesis and cancer progression.In this study,we investigated the whole genome deletion and amplification profiling of LSCC by array-CGH and the relationships between chromosomal aberrations and clinicopathological characteristics.Meanwhile,microarray datasets from the GEO database were analyzed to obtain differentially expressed genes(DEGs)and provide relevant candidate genes related to the occurrence and development of LSCC.ObjectiveThe present study was designed to explore chromosome CNVs of LSCC by array-CGH and analyze the relationship between chromosome CNVs and clinical-pathological characteristics.Microarray datasets from the GEO database were analyzed to obtain DEGs and provide relevant candidate genes related to the occurrence and development of LSCC.MethodAfter obtaining the patients' signed consent forms,total genomic DNA of66 LSCC cases was isolated.Then array-CGH which was provided by Agilent company was performed to detect whole genomic chromosome CNVs and analyzed by cytogenomics 4.0.The relationship between chromosome CNVs and clinical-pathological characteristics were analyzes and the DEGs were obtained by integration and analysis data from GEO database.Immunohistochemical analysis was used to analyze the difference expression of candidate genes in cancer and adjacent tissues,and the correlations between candidate genes and clinicopathological parameters were analyzed.Results(1)In present study,different numbers and sizes of genomic CNVs(amplification,loss,duplication and homozygous deletion)were detected by array-CGH in 66 LSCC samples.The chromosomal segments with high frequency of genomic imbalance detected included nine repeated segments:3q26.1-qter,5pter-p12,7p22.3p14.1,8p12p11.22,8q24.13 q 24.3,11q13.2q13.4,12pter-p12.2,18pter-p11.31 and 20p13p12.1,and five loss fragments:3pter-p21.32,4q28.1-q35.2,5q13.2-qter,9pter-p21.3 and 13 monosomy.3q26.32q27.2 was the fragment with the highest repeated frequency,which contained SOX2,EIF4G1,FXR1,DVL3,DCUN1D1 and IGF2BP2 genes in the smallest region of overlap(SRO).There were two highly amplified fragments on chromosome 8p11.2 and 8q24.21,which contained ADAM2 and CCDC26 genes respectively.In our study,four homozygous deletions were detected,which included some possible tumor suppressor genes,such as NEIL3,CSMD1,CDKN2 A and PCDH20.(2)According to the clinical and pathological characteristics,there was no correlation between the high frequency CNV segments with lymph node stage and tumor stage.The repetition of 3q26.1-qter,5pter-p12 and the loss of5q13.2-qter in smoking group indicated a statistically significant difference compared with non-smoking group(P < 0.05);(3)Candidate genes such as SOX2,EIF4G1,FXR1,DVL3,DCUN1D1,IGF2BP2,CCDC26 and CDKN2 A,SPINK5,PCDH20,CSMD1,NEIL3 were identified by integrating analysis of gene differential expression with GEO database.(4)The overexpression rates of PCDH20?NEIL3?DCUN1D1?EIF4G1 and IGF2BP2 in laryngeal carcinoma were statistically significant comparing with adjacent tissues.PCDH20 was negatively correlated with lymph node metastasis and smoking history,NEIL3 expression was negatively correlated with lymph node metastasis,however,DCUN1D1 expression was positively correlated with TNM stage,EIF4G1 and IGF2BP2 expression were positively correlated with lymph node metastasis.Conclusion(1)In present study,different numbers and sizes of genomic CNVs(amplification,loss,duplication and homozygous deletion)were detected by array-CGH in all 66 LSCC samples.(2)The high frequency CNV fragments which detected in LSCC contained important related oncogenes and tumor suppressor genes.(3)The duplication and deletion of specific chromosome fragments were correlated with smoking history,and some gene expression was correlated with clinicopathological parameters.(4)By integration analysis of DEGs in GEO database,LSCC related candidate genes could be inferred,which provided a reference for molecular mechanisms underlying the pathogenesis of LSCC. |
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