Abstract
Methylation of CpG islands in the promoter region of genes acts as a significant mechanism of epigenetic gene silencing in head and neck cancer. In the present study, we assessed the association of epigenetic alterations of a panel of 12 genes [nucleolar protein 4 (NOL4), iroquois homeobox 1 (IRX1), SLC5A8, LRRC3B, FUSSEL18, EBF3, GBX2, HMX2, SEPT9, ALX3, SOCS3 and LHX6] with head and neck squamous cell carcinoma (HNSCC) via a candidate gene approach. After the initial screening of methylated CpG islands on the promoter regions by bisulfite sequencing using salivary rinse samples, only two genes had methylated CpG dinucleotides on their promoter regions in tumor samples and absence of methylated CpGs were found in normal salivary rinse samples after bisulfite modification and bisulfite sequencing. We then performed real-time quantitative methylation-specific PCR (QMSP) on 16 salivary rinse and 14 normal mucosal samples from healthy subjects and 33 HNSCC tumor samples for the two genes selected. After validation with QMSP, one gene, NOL4, was highly methylated (91%) in tumor samples and unmethylated in normal salivary rinses and minimally methylated in normal mucosal samples demonstrating cancer-specific methylation in HNSCC tissues. Although the IRX1 gene was observed as methylated in normal mucosal and salivary rinse samples, the methylation values of these normal samples were very low (<10%). In conclusion, we identified NOL4 as a highly specific promoter methylated gene associated with HNSCC. IRX1 may have potential as a biomarker for HNSCC and should be assessed in a larger cohort.
Highlights
Head and neck cancer, which is the sixth most common cancer in the world among human malignant disorders, is an aggressive and life-threatening disease with poor prognosis, morbidity and high mortality in advanced disease
From a previous study using the gene expression profiling via oligonucleotide microarray-based approach to discover the new cancer-specific methylated genes [6], in the present study, we evaluated the hypermethylation of 10 genes [nucleolar protein 4 (NOL4), iroquois homeobox 1 (IRX1), sodiumcoupled monocarboxylate transporter 1 (SLC5A8), leucine rich repeat containing 3B (LRRC3B), functional smad-suppressing element on chromosome 18 (FUSSEL18), early B-cell factor 3 (EBF3), gastrulation brain homeobox 2 (GBX2), H6 family
To determine if the methylated genes in tumor samples were cancer-specific, we investigated promoter methylation in 16 normal saliva, 14 age‐matched normal mucosa from healthy individuals that were analyzed as a control, to investigate the normal promoter methylation status of two newly identified candidate genes (NOL4, IRX1) and in 33 head and neck squamous cell carcinoma (HNSCC) tumor samples by quantitative methylation-specific PCR (QMSP)
Summary
Head and neck cancer, which is the sixth most common cancer in the world among human malignant disorders, is an aggressive and life-threatening disease with poor prognosis, morbidity and high mortality in advanced disease. Survival rates have not improved significantly for patients with head and neck squamous cell carcinoma (HNSCC) in the past 30 years despite active clinical and basic research addressing this issue. More than 40,000 new cases of HNSCC are diagnosed in the United States each year, with a mortality rate of 12,000 in the USA annually [1]. Cancer-specific molecular biomarkers, which have the ability to warn the clinicians in the earlier stage before the disease advances, or to provide insight regarding the prognosis of the disease or outcome of the patients, are required. It is important to develop new methods that provide sensitive and reliable biomarkers of HNSCC for detection, treatment response and prognosis
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
