Henrik Hellquist

DNA methylation of tumour suppressor genes is the most well-studied epigenetic alterations in head and neck cancer. The tumour suppressor genes CDKN2A, RASSF1, and TIMP3 are the most frequently investigated, but the methylation status has been analysed in more than another dozen genes, for example MGMT . In oral squamous cell carcinoma (OSCC) methylation of MGMT, DAPK , and CDKN2A are promising biomarkers of prognostic value. Inhibition of LSD1 , encoding a histone demethylase, attenuates the development and growth of OSCC. Methylation of TIMP3 in sinonasal adenocarcinoma (intestinal type) is associated with a significant worse survival, an association not seen in sinonasal squamous cell carcinoma. Olfactory neuroblastoma can be distinguished into four unique subgroups by methylation profiling. Methylation of RASSF1 is seen in NUT carcinoma, and significantly higher RASSF1 methylation is found in SMARCB1/INI1-deficient tumours compared to the less aggressive SMARCB1/INI-proficient tumours. Genome-wide methylation profiling in combination with IDH2 mutation status suggests that tumours with undifferentiable SNUC morphology can be classified into for subgroups. Most salivary gland carcinoma subtypes have specific epigenetic signatures. Four of the most common subtypes, adenoid cystic carcinoma (ADCC), mucoepidermoid carcinoma (MEC), acinic cell carcinoma (ACC), and carcinoma ex pleomorphic adenoma (CXPA) have all methylation of RASSF1A , two (MEC and ADCC) also of TIMP3 and two (MEC and CXPA) of p16INK ^4a . A methylation landscape of 20 salivary gland tumours (SGTs) is nowadays available.

Background/Objectives: Premalignant laryngeal lesions carry a variable risk of malignant transformation to squamous cell carcinoma. Identifying reliable biomarkers that predict malignant transformation could improve patient management and surveillance strategies. The objective of this work is to perform a systematic review of the literature on biomarkers that predict malignant transformation of premalignant laryngeal lesions. Methods: We conducted a systematic review following PRISMA 2020 guidelines. The PubMed, Scopus and Embase databases, and Google Scholar were searched for studies published between January 2011 and November 2025. Studies investigating biomarkers that predict malignant transformation of histopathologically confirmed premalignant laryngeal lesions were included. Risk of bias was assessed using the ROBINS-I tool. Results: From 166 initially identified records, 11 studies met the inclusion criteria, including 730 patients. These studies investigated diverse biomarker categories such as protein markers (cortactin, FAK, NANOG, SOX2, CSPG4), immune markers (tumor-infiltrating lymphocytes, immune gene signatures), microRNAs (miR-183-5p, miR-155-5p, miR-106b-3p), and genetic markers (chromosomal instability, PIK3CA amplification and mutations, FGFR3 mutations). Five studies provided adequate follow-up data on transformation outcomes. Most studies showed a moderate to serious risk of bias primarily due to limited confounder control and incomplete reporting. Conclusions: While several promising biomarker candidates have been identified, the evidence base remains limited due to small sample sizes, heterogeneous methodologies, and inadequate follow-up data. Cortactin/FAK protein expression and immune signatures are the most promising but require validation in larger, well-designed prospective cohorts.

Benign and malignant head and neck tumors are common worldwide and cause mortality and morbidity with variations in population prevalence

Background/Objectives: The methylation of the hypermethylated oncological region (THOR) of human telomerase reverse transcriptase (hTERT) may forecast tumour aggressiveness. This pilot study aimed to evaluate THOR methylation as a potential biomarker for recurrence/malignant transformation in salivary gland pleomorphic adenomas (PA). Methods: THOR methylation was assessed by quantitative pyrosequencing in 96 parotid tissue samples (benign and malignant), including non-neoplastic parotid tissue, PA, recurrent PA (rPA), and carcinomas, along with their adjacent tissues. TERT promoter mutations (TPMs) were analysed by Sanger sequencing. Results: THOR methylation significantly differed across the seven groups. Malignant tissues showed higher THOR methylation than non-neoplastic tissues, whereas benign tumours showed no significant difference from non-neoplastic tissue. THOR methylation in rPA was closer to carcinoma than to normal tissue, similar in rPA and tissues adjacent to rPA, and higher in tissues adjacent to carcinomas than in non-neoplastic tissues. A subset of PA-adjacent tissues showed epigenetic alterations, suggesting an increased risk of recurrence or malignant transformation (5–15%). No TPMs were detected. Conclusions: THOR methylation may add information to differentiate normal from carcinogenic tissues and, as such, may be included in a biomarkers panel. Epigenetic alterations in PA-adjacent tissues with normal histology highlight the need for improved diagnostic markers.