Associations among smoking, MGMT hypermethylation, TP53-mutations, and relapse in head and neck squamous cell carcinoma

Saliva as a potential non-invasive liquid biopsy for early and easy diagnosis/prognosis of head and neck cancer

Head and neck squamous cell carcinomas (HNSCCs) are the most devastating diseases in India and southeast Asia. It is a preventable and curable disease if detected early. Tobacco and alcohol consumption are the two major risk-factors but infection of high-risk HPVs are also associated with development of predominantly oral and oropharyngeal carcinomas. Interestingly, unlike cervical cancer, HPV-induced HNSCCs show good prognosis and better survival in contrast, majority of tobacco-associated HPV-ve HNSCCs are highly aggressive with poor clinical outcome. Biomarker analysis in circulatory body-fluids for early cancer diagnosis, prognosis and treatment monitoring are becoming important in clinical practice. Early diagnosis using non-invasive saliva for oral or other diseases plays an important role in successful treatment and better prognosis. Saliva mirrors the body's state of health as it comes into direct contact with oral lesions and needs no trained manpower to collect, making it a suitable bio-fluid of choice for screening. Saliva can be used to detect not only virus, bacteria and other biomarkers but variety of molecular and genetic markers for an early detection, treatment and monitoring cancer and other diseases. The performance of saliva-based diagnostics are reported to be highly (≥95 %) sensitive and specific indicating the test's ability to correctly identify true positive or negative cases. This review focuses on the potentials of saliva in the early detection of not only HPV or other pathogens but also identification of highly reliable gene mutations, oral-microbiomes, metabolites, salivary cytokines, non-coding RNAs and exosomal miRNAs. It also discusses the importance of saliva as a reliable, cost-effective and an easy alternative to invasive procedures.

Targeting DNA damage response as a potential therapeutic strategy for head and neck squamous cell carcinoma

Cells experience both endogenous and exogenous DNA damage daily. To maintain genome integrity and suppress tumorigenesis, individuals have evolutionarily acquired a series of repair functions, termed DNA damage response (DDR), to repair DNA damage and ensure the accurate transmission of genetic information. Defects in DNA damage repair pathways may lead to various diseases, including tumors. Accumulating evidence suggests that alterations in DDR-related genes, such as somatic or germline mutations, single nucleotide polymorphisms (SNPs), and promoter methylation, are closely related to the occurrence, development, and treatment of head and neck squamous cell carcinoma (HNSCC). Despite recent advances in surgery combined with radiotherapy, chemotherapy, or immunotherapy, there has been no substantial improvement in the survival rate of patients with HNSCC. Therefore, targeting DNA repair pathways may be a promising treatment for HNSCC. In this review, we summarized the sources of DNA damage and DNA damage repair pathways. Further, the role of DNA damage repair pathways in the development of HNSCC and the application of small molecule inhibitors targeting these pathways in the treatment of HNSCC were focused.

A Prognostic Gene Signature for Hepatocellular Carcinoma

Hepatocellular carcinoma is the third most common cause of cancer-related deaths in China and immune-based therapy can improve patient outcomes. In this study, we investigated the relationship between immunity-associated genes and hepatocellular carcinoma from the prognostic perspective. The data downloaded from The Cancer Genome Atlas Liver Hepatocellular Carcinoma (TCGA-LIHC) and the Gene Expression Omnibus (GEO) was screened for gene mutation frequency using the maftools package. Immunity-associated eight-gene signature with strong prognostic ability was constructed and proved as an independent predictor of the patient outcome in LIHC. Seven genes in the immune-related eight-gene signature were strongly associated with the infiltration of M0 macrophages, resting mast cells, and regulatory T cells. Our research may provide clinicians with a quantitative method to predict the prognosis of patients with liver cancer, which can assist in the selection of the optimal treatment plan.

Salivary DNA Methylation as an Epigenetic Biomarker for Head and Neck Cancer. Part II: A Cancer Risk Meta-Analysis

Aberrant methylation of tumor suppressor genes has been reported as an important epigenetic silencer in head and neck cancer (HNC) pathogenesis. Here, we performed a comprehensive meta-analysis to evaluate the overall and specific impact of salivary gene promoter methylation on HNC risk. The methodological quality was assessed using the Newcastle–Ottawa scale (NOS). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the strength of the association and Egger’s and Begg’s tests were applied to detect publication bias. The frequency of salivary DNA promoter methylation was significantly higher in HNC patients than in healthy controls (OR: 8.34 (95% CI = 6.10–11.39; p < 0.01). The pooled ORs showed a significant association between specific tumor-related genes and HNC risk: p16 (3.75; 95% CI = 2.51–5.60), MGMT (5.72; 95% CI = 3.00–10.91), DAPK (5.34; 95% CI = 2.18–13.10), TIMP3 (3.42; 95% CI = 1.99–5.88), and RASSF1A (7.69; 95% CI = 3.88–15.23). Overall, our meta-analysis provides precise evidence on the association between salivary DNA promoter hypermethylation and HNC risk. Thus, detection of promoter DNA methylation in saliva is a potential biomarker for predicting HNC risk.

Improved local control in p16 negative oropharyngeal cancers with hypermethylated MGMT

INTRODUCTION

Patients with oropharyngeal cancers that are p16 negative (p16-) have worse outcomes than those who are p16 positive (p16+) and there is an unmet need for prognostic markers in this population. O6-Methylguanine (O6-MG)-DNA-methyltransferase (MGMT) gene methylation has been associated with response to chemoradiotherapy (CRT) in glioblastoma. We sought to find if MGMT promoter methylation was associated with outcomes of locally advanced oropharyngeal and oral cavity squamous cell carcinoma (OOSCC) in patients treated with definitive concurrent CRT.

METHODS

Patients were identified with primary OOSCC, known p16 status, retrievable pre-treatment biopsies, and at least 6 months of follow-up who received definitive concurrent CRT from 2004 to 2015. Biopsies were tested for MGMT hypermethylation (MGMT+) using a Qiagen pyrosequencing kit (Catalog number 970061). Outcomes were subsequently recorded and analyzed.

RESULTS

Fifty-eight patients were included with a median follow up of 78 (range 6-196) months. Fourteen patients (24.1%) had oral cavity cancer and 44 (75.9%) had oropharyngeal cancer. A significant difference was found for local recurrence free survival (LRFS) by combined MGMT and p16 status (p = 0.0004). Frequency of LR in MGMT+/p16+, MGMT+/p16-, MGMT-/p16+, and MGMT-p16- patients was 14.3%, 14.3%, 13.0%, and 69.2%, respectively (p = 0.0019). A significant difference was not found for distant recurrence free survival (p = 0.6165) or overall survival (p = 0.1615). LRFS remained significant on analysis restricted to oropharyngeal cancer patients (p-value = 0.0038).

CONCLUSION

Patients who are p16- and MGMT+ with oropharyngeal and oral cavity squamous cell carcinoma have significantly better LC with definitive CRT than those who are p16- and MGMT-. Prospective studies are needed to verify these findings.