The mutational landscape of early- and typical-onset oral tongue squamous cell carcinoma

Large-Scale Cancer Genomic Analysis Reveals Significant Disparities between Microsatellite Instability and Tumor Mutational Burden

BACKGROUND

Microsatellite instability (MSI) and tumor mutational burden (TMB) are predictive biomarkers for pan-cancer immunotherapy. The interrelationship between MSI-high (MSI-H) and TMB-high (TMB-H) in human cancers and their predictive value for immunotherapy in lung cancer remain unclear.

METHODS

We analyzed somatic mutation data from the Genomics Evidence Neoplasia Information Exchange (n = 46,320) to determine the relationship between MSI-H and TMB-H in human cancers using adjusted multivariate regression models. Patient survival was examined using the Cox proportional hazards model. The association between MSI and genetic mutations was assessed.

RESULTS

Patients (31-89%) with MSI-H had TMB-low phenotypes across 22 cancer types. Colorectal and stomach cancers showed the strongest association between TMB and MSI. TMB-H patients with lung cancer who received immunotherapy exhibited significantly higher overall survival [HR, 0.61; 95% confidence interval (CI), 0.44-0.86] and progression-free survival (HR, 0.65; 95% CI, 0.47-0.91) compared to the TMB-low group; no significant benefit was observed in the MSI-H group. Patients with TMB and MSI phenotypes showed further improvement in overall survival and PFS. We identified several mutated genes associated with MSI-H phenotypes, including known mismatch repair genes and novel mutated genes, such as ARID1A and ARID1B.

CONCLUSIONS

Our results demonstrate that TMB-H and/or a combination of MSI-H can serve as biomarkers for immunotherapies in lung cancer.

IMPACT

These findings suggest that distinct or combined biomarkers should be considered for immunotherapy in human cancers because notable discrepancies exist between MSI-H and TMB-H across different cancer types.

MicroRNAs targeting CDKN2A gene as a potential prognostic marker in head and neck squamous cell carcinoma

Epigenetic factors are known to markedly influence the functions of a gene by modification of transcripts, via methylation or acetylation and degradation of mRNA transcripts. The CDKN2A encodes cyclin-dependent kinase inhibitor 2A, a tumour suppressor protein. Genetic and epigenetic alterations in this gene have been demonstrated in several cancer types. The non-coding RNAs with a special emphasis on microRNAs have long been explored for their potential role in the epigenetic modification of gene expression. The present study aims to identify the microRNAs targeting CDKN2A gene transcripts and demonstrate their prognostic significance in head and neck squamous cell carcinoma (HNSCC). Computational approaches were employed to identify the microRNAs targeting CDKN2A. The gene and protein expression profile of CDKN2A was analyzed using UALCAN. A significant upregulation of CDKN2A was observed in the primary tumour tissues (p=<10-12). Interestingly, the protein expression, although found to be statistically significant (p=0.0129) did not correlate well with the gene expression profile. The microRNAs targeting CDKN2A were further analyzed to identify the possible reason for the decrease in protein expression. Among the 44 microRNAs targeting CDKN2A gene transcripts, hsa-miR-3681-3p, hsa-miR-542-5p, hsa-miR-4519 were found to be upregulated and hsa-miR-134-5p was found to be downregulated with a significant association with survival status of HNSCC patients. The hsa-miR-542-5p was found to correlate well with the survival and hence can be considered as the key microRNA associated with HNSCC. However, further validation of this microRNA is warranted to confirm its role in the process of carcinogenesis.

Molecular landscapes of oral cancers of unknown etiology

The incidence of the mobile tongue cancer in young patients has been rising. This oral cancer (OC) type has no identified risk factors (NIRF), no established molecular markers and is not yet recognized as a distinct clinical entity. To understand this emerging malignancy, we innovatively analyzed the public head and neck cancer multi-omics data. We identified mutational signatures that successfully stratified 307 OC and 109 laryngeal cancer cases according to their clinico-pathological characteristics. The NIRF OCs exhibited significantly increased activities of endogenous clock-like and APOBEC-associated mutagenesis, alongside specific cancer driver gene mutations, distinct methylome patterns and prominent antimicrobial transcriptomic responses. Furthermore, we show that mutational signature SBS16 in OCs reflects the combined effects of alcohol drinking and tobacco smoking. Our study characterizes the unique disease histories and molecular programs of the NIRF OCs revealing that this emerging cancer subtype is likely driven by increased endogenous mutagenesis correlated with responses to microbial insults.

TERT promoter mutation positive oral cavity carcinomas, a clinically and genetically distinct subgroup of head and neck squamous cell carcinomas

BACKGROUNDS

The importance of TERT promoter (pTERT) mutation of oral cavity squamous cell carcinoma (OCSCC) with clinical features and genetic alterations are not well recognized.

METHODS

We retrospectively analyzed genetic data from multiple databases, including 260 cases from the C-CAT database, 407 cases from the MSK-MetTropism database, and 40 OCSCC datasets from in-house clinical samples.

RESULTS

From C-CAT database, TP53 (66%), CDKN2A (51%), and pTERT (29%) were the most frequent mutations observed. pTERT mutations were more prevalent in OCSCC (63%), younger individuals, and women (46%), with lower rates of alcohol abuse and smoking and co-mutated with TP53, HRAS, and CASP8. MSK-MetTroposim data validated with the enrichment of pTERT mutations in OCSCC, among women and Asian individuals. In-house datasets OCSCC with pTERT mutation (50%) characterized by fewer recurrent neck metastases.

CONCLUSION

The study suggests that OCSCC with pTERT mutation represents a distinct subgroup with unique clinical and genetic characteristics.

hsa_circ_0005991 promotes epithelial-mesenchymal transition by regulating miR-30b-3p/Cdc42EP1 axis in ovary endometriosis

Endometriosis is a common gynecological disease with an enigmatic pathogenesis. This work explored the function of hsa_circ_0005991 in ovarian endometriosis. High-throughput RNA-Seq was conducted in five matched ectopic (EC) and eutopic (EU) samples. Further, several types of cell function experiments were conducted. According to bioinformatics analysis, a competing endogenous RNA network was established. It included 5 circRNAs, 13 miRNAs, and 551 mRNAs. The expression levels of hsa_circ_0005991 and Cdc42EP1 were significantly elevated, while miR-30b-3p was reduced in the EC group. Upregulation of hsa_circ_0005991 raised Cdc42EP1 levels, induced EMT, and boosted Ishikawa cell proliferation, migration, and invasion. hsa_circ_0005991 knockdown indicated the opposite effects. When co-transfected with miR-30b-3p mimics or inhibitors, these effects could be reversed, respectively. Western blot assays showed alterations of EMT markers in EC samples. hsa_circ_0005991/miR-30b-3p/Cdc42EP1 axis promotes the EMT process in endometriosis, which may offer a theoretical foundation for the mechanism exploration and therapy of this disease.

Recent and Projected Trends in Oral Tongue Cancer in the United States: A Demographic Shift in Case Burden as Early Onset Increases Among Females Subside

Background

Oral tongue cancer (OTC) incidence has increased rapidly among young (< 50 years) non-Hispanic White (NHW) individuals in the United States (U.S.) over the last two decades; however, it is unknown if age-associated trajectories have persisted. Furthermore, incidence trends for all 50 U.S. states and the District of Columbia have never been investigated.

Materials and methods

Using U.S. Cancer Statistics data, we investigated incidence trends from 2001-2019, overall and according to age, sex, race/ethnicity, and state of residence. We used age-period-cohort analysis to explore temporal patterns among birth cohorts and to project future trends and case counts.

Results

OTC incidence increased across all age, sex, and racial/ethnic groups, with marked increases observed among the NHWs (2.9%/year; 95%CI, 2.2%-3.7%). Incidence among NHWs increased in most U.S. states, particularly in the Southeast. Increases were significantly greater among NHW females compared to males (3.6%/year vs 2.6%/year; P = 0.022). Increases among females aged 50-59 years were most notable and significantly outpaced increases among younger females (4.8%/year [95% CI, 4.1%-5.4%] vs. 3.3%/year [95% CI, 2.7%-3.8%]; P < .001). While both NHW male and female birth cohorts from 1925 to 1980 saw sustained increases, rates stabilized among females born after 1980. Should trends continue, the burden of new OTC cases among NHWs in the U.S. is projected to shift to older individuals (33.1% versus 49.3% aged ≥ 70) and females (86% case increase versus 62% among males).

Conclusion

The period of rapidly increasing OTC incidence among younger NHW females in the U.S. is tempering and giving way to greater increases among older females, suggesting that a birth cohort effect may have influenced previously observed trends. Recent increases among NHWs aged ≥ 50 of both sexes have matched or outpaced younger age groups. Continuing increases among older individuals, particularly females, will lead to a shift in the OTC patient profile over time.

BORG family proteins in physiology and human disease

The binder of rho GTPases (BORG)/Cdc42 effector proteins (Cdc42EP) family is composed of five Rho GTPase binding proteins whose functions and mechanism of actions are of emerging interest. Here, we review recent findings pertaining to the family as a whole and consider how these change our understanding of cellular organization. Recent studies have implicated BORGs in both fundamental physiology and in human diseases, mainly cancers. An emerging pattern suggests that BORG family members cancer-promoting properties are related to their ability to regulate the cytoskeleton, with many impacting the organization of acto-myosin stress fibers. This is consistent with the broader literature indicating that BORG family members are regulators of both the septin and actin cytoskeleton networks. The exact mechanism through which BORGs modify the cytoskeleton is not clear, but we consider here a few data-supported and speculative possibilities. Finally, we delve into how the Rho GTPase Cdc42 modifies BORG function in cells. This remains open-ended as Cdc42's effects on BORGs appear cell type- and cell state-dependent. Collectively, these data point to the importance of the BORG family and suggest broader themes in their function and regulation.

Genetic characteristics of advanced oral tongue squamous cell carcinoma in young patients

OBJECTIVES

We aimed to investigate genetic alterations in oral tongue squamous cell carcinoma (OTSCC) based on age and the clinical significance of these alterations in young OTSCC patients.

MATERIALS AND METHODS

We detected genetic alterations in 44 cases of advanced OTSCC through next-generation sequencing and analyzed and compared patients either younger or older than 45 years. Further analysis was conducted on a validation group of 96 OTSCC patients aged ≤ 45 years to examine the clinical and prognostic associations of TERT promoter (TERTp) mutations.

RESULTS

TP53 mutation was the most common genetic alteration in advanced OTSCC (88.6%), followed by TERTp mutation (59.1%), CDKN2A mutation (31.8%), FAT1 mutation (9.1%), NOTCH1 mutation (9.1%), EGFR amplification (18.2%), and CDKN2A homozygous deletion (4.5%). TERTp mutation was the only genetic alteration significantly enriched in young patients (81.3% in young versus 46.4% in older; P < 0.024). Within the validation group of young patients, TERTp mutation was identified in 30 cases (30/96, 31.3%) and tended to be related to both smoking and alcohol consumption (P = 0.072), higher stage (P = 0.002), more frequent perineural invasion (P = 0.094), and worse overall survival (P = 0.012) than wild type.

CONCLUSION

Our findings suggest that TERTp mutation is more frequent in young patients with advanced OTSCC and is associated with worse clinical outcomes. Therefore, TERTp mutation may serve as a prognostic biomarker for OTSCC in young patients. The findings of this study may help in developing personalized treatment strategies for OTSCC based on age and genetic alterations.

Circulating Tumor DNA in Head and Neck Squamous Cell Carcinoma

Tumors shed cell-free DNA (cfDNA) into the plasma. “Liquid biopsies” are a diagnostic test to analyze cfDNA in order to detect minimal residual cancer, profile the genomic tumor landscape, and monitor cancers non-invasively over time. This technique may be useful in patients with head and neck squamous cell carcinoma (HNSCC) due to genetic tumor heterogeneity and limitations in imaging sensitivity. However, there are technical challenges that need to be overcome for the widespread use of liquid biopsy in the clinical management of these patients. In this review, we discuss our current understanding of HNSCC genetics and the role of cfDNA genomic analyses as an emerging precision diagnostic tool.

Escape from Cellular Senescence Is Associated with Chromosomal Instability in Oral Pre-Malignancy

An escape from cellular senescence through the development of unlimited growth potential is one of the hallmarks of cancer, which is thought to be an early event in carcinogenesis. In this review, we propose that the molecular effectors of senescence, particularly the inactivation of TP53 and CDKN2A, together with telomere attrition and telomerase activation, all lead to aneuploidy in the keratinocytes from oral potentially malignant disorders (OPMD). Premalignant keratinocytes, therefore, not only become immortal but also develop genotypic and phenotypic cellular diversity. As a result of these changes, certain clonal cell populations likely gain the capacity to invade the underlying connective tissue. We review the clinical implications of these changes and highlight a new PCR-based assay to identify aneuploid cell in fluids such as saliva, a technique that is extremely sensitive and could facilitate the regular monitoring of OPMD without the need for surgical biopsies and may avoid potential biopsy sampling errors. We also draw attention to recent studies designed to eliminate aneuploid tumour cell populations that, potentially, is a new therapeutic approach to prevent malignant transformations in OPMD.

Aberrant Expression and Prognostic Potential of IL-37 in Human Lung Adenocarcinoma

Interleukin-37 (IL-37) is a relatively new IL-1 family cytokine that, due to its immunoregulatory properties, has lately gained increasing attention in basic and translational biomedical research. Emerging evidence supports the implication of this protein in any human disorder in which immune homeostasis is compromised, including cancer. The aim of this study was to explore the prognostic and/or diagnostic potential of IL-37 and its receptor SIGIRR (single immunoglobulin IL-1-related receptor) in human tumors. We utilized a series of bioinformatics tools and -omics datasets to unravel possible associations of IL-37 and SIGIRR expression levels and genetic aberrations with tumor development, histopathological parameters, distribution of tumor-infiltrating immune cells, and survival rates of patients. Our data revealed that amongst the 17 human malignancies investigated, IL-37 exhibits higher expression levels in tumors of lung adenocarcinoma (LUAD). Moreover, the expression profiles of IL-37 and SIGIRR are associated with LUAD development and tumor stage, whereas their high mRNA levels are favorable prognostic factors for the overall survival of patients. What is more, IL-37 correlates positively with a LUAD-associated transcriptomic signature, and its nucleotide changes and expression levels are linked with distinct infiltration patterns of certain cell subsets known to control LUAD anti-tumor immune responses. Our data indicate the potential value of IL-37 and its receptor SIGIRR to serve as biomarkers and/or immune-checkpoint therapeutic targets for LUAD patients. Further, the data highlight the urgent need for further exploration of this cytokine and the underlying pathogenetic mechanisms to fully elucidate its implication in LUAD development and progression.

Fusobacterium is enriched in oral cancer and promotes induction of programmed death-ligand 1 (PD-L1)

Recently, increased number of studies have demonstrated a relationship between the oral microbiome and development of head and neck cancer, however, there are few studies to investigate the role of oral bacteria in the context of the tumor microenvironment in a single head and neck subsite. Here, paired tumor and adjacent normal tissues from thirty-seven oral tongue squamous cell carcinoma (SCC) patients were subjected to 16S rRNA gene sequencing and whole exome sequencing (WES), in addition to RNA sequencing for tumor samples. We observed that Fusobacterium was significantly enriched in oral tongue cancer and that Rothia and Streptococcus were enriched in adjacent normal tissues. A decrease in alpha diversity was found in tumor when compared to adjacent normal tissues. While increased Fusobacterium in tumor samples was not associated with changes in immune cell infiltration, it was associated with increased PD-L1 mRNA expression. Therefore, we examined the effects of Fusobacterium on PD-L1 expression in head and neck SCC cell lines. We demonstrated that infection with Fusobacterium species can increase both PD-L1 mRNA and surface PD-L1 protein expression on head and neck cancer cell lines. The correlation between Fusobacterium and PD-L1 expression in oral tongue SCC, in conjunction with the ability of the bacterium to induce PD-L1 expression in vitro suggests a potential role for Fusobacterium on modulation of the tumor immune microenvironment in head and neck cancer.

FAT1 Upregulates in Oral Squamous Cell Carcinoma and Promotes Cell Proliferation via Cell Cycle and DNA Repair

Objective

Previous studies have revealed that FAT atypical cadherin 1 (FAT1) plays a tumor-suppressive or oncogenic role in a context-dependent manner in various cancers. However, the functions of FAT1 are ambiguous in tumorigenesis owing to inconsistent research in oral squamous cell carcinoma (OSCC). The present study aimed at gaining an insight into the role of FAT1 in the tumor genesis and development.

Methods

The expression, mutant, and survival data analyses were done using data from The Cancer Genome Atlas (TCGA), the Gene Expression Omnibus (GEO), and the Clinical Proteomic Tumor Analysis Consortium (CPTAC) database, verified with clinical samples via real-time polymerase chain reaction (qRT-PCR), Western blot (WB), and immunohistochemical (IHC) staining. OSCC cells transfected with siRNA were employed for in vitro assessment in cell proliferation, apoptosis, and migration ability in appropriate ways. The underlying mechanism was explored by RNA sequencing after FAT1 silencing.

Results

Overall, FAT1 significantly increased in OSCC with a poor prognosis outcome. The in vitro experiment showed the promoting effect of FAT1 in the proliferation and migration of OSCC cells. FAT1 can also inhibit both the early and late apoptosis of OSCC cells. RNA-sequencing analysis of FAT1 silencing revealed that the cell cycle, DNA replication, and some core genes (MCM2, MCM5, CCNE1 SPC24, MYBL2, KIF2C) may be the potential mechanism in OSCC.

Conclusions

FAT1 may act as an oncogene in OSCC with potential mechanism influencing the cell cycle and DNA repair.

Early-onset oral cancer as a clinical entity: aetiology and pathogenesis

Oral squamous cell carcinoma (OSCC) is one of the most important medical and socio-economic problems in many of the developed countries worldwide, due to the high mortality. The incidence of OSCC among individuals under 45 years of age is growing every year; however, the aetiological factors and pathogenetic mechanisms are poorly understood. This review summarizes the available information regarding clinicopathological features, extrinsic and intrinsic aetiological factors, and the molecular and immune landscape of early-onset OSCC. This cancer shows high recurrence rates and is not associated with the aetiological factors specific to adult-onset OSCC. Young adults with OSCC are not infected with human papillomavirus and rarely consume alcohol or tobacco, but more frequently use smokeless tobacco. Data from single studies indicate the hereditary nature of early-onset OSCC: the KIR2DL1⁺-HLA-C2⁺ genotype and MMP-1 2 G allele are frequently detected in young patients. Early-onset OSCC shows specific genetic, epigenetic, transcriptomic, and proteomic changes. The tumour microenvironment in early-onset OSCC is tolerogenic rather than immunogenic. All of the data suggest that OSCC in young patients is a separate clinical entity with a specific aetiology and pathogenesis. Further studies are needed to reveal the causes and molecular targets of early-onset OSCC for the development of preventive and therapeutic strategies.

Young non-smokers with oral cancer: What are we missing and why?

OBJECTIVES

There has been an increase in young non-smokers (YNS) who develop oral cavity squamous cell carcinomas (OSCC). Oncological outcomes in YNS are controversial and etiology has not been well-defined. We hypothesize that the etiology of cancer development in YNS and their poor outcome is related to an impaired immune system.

MATERIALS AND METHODS

From a database of 2073 OSCC patients treated with primary surgery between 1985 and 2015, 9% were young patients. We categorized patients as: ≤40 years-old/non-smokers (n = 100), ≤40 years-old/smokers (n = 80), >40 years-old/non-smokers (n = 595) and >40 years-old/smokers (n = 1298). Patient and tumor variables were used to calculate propensity scores and stabilized inverse probability of treatment weights were calculated. Weighted proportional hazard models were performed. Survival and recurrence outcomes of YNS were compared to the other 3 groups. Host immune status of YNS measured by peripheral blood neutrophil-to-lymphocyte ratio (NLR) was compared to 2 control groups (YNS with thyroid cancer and YNS with benign pathologies).

RESULTS

After adjusting for tumor and host factors, YNS had a higher probability of death compared to young smokers. This was driven by a higher incidence of regional and distant recurrences. Host factors showed a strong association with outcomes suggesting YNS may have an impaired immune system. Compared to the control cohorts YNS with OSCC had a higher NLR (p = .006).

CONCLUSION

When adjusted by relevant covariates, YNS with OSCC have poorer survival than their young smoker counterparts. Our results suggest that an impaired immune system may be partly responsible for OSCC development and poorer outcomes in YNS.

A robust and interpretable gene signature for predicting the lymph node status of primary T1/T2 oral cavity squamous cell carcinoma

Oral cavity squamous cell carcinoma (OSCC) affects more than 30 000 individuals in the United States annually, with smoking and alcohol consumption being the main risk factors. Management of early-stage tumors usually includes surgical resection followed by postoperative radiotherapy in certain cases. The cervical lymph nodes (LNs) are the most common site for local metastasis, and elective neck dissection is usually performed if the primary tumor thickness is greater than 3.5 mm. However, postoperative histological examination often reveals that many patients with early-stage disease are negative for neck nodal metastasis, posing a pressing need for improved risk stratification to either avoid overtreatment or prevent the disease progression. To this end, we aimed to identify a primary tumor gene signature that can accurately predict cervical LN metastasis in patients with early-stage OSCC. Using gene expression profiles from 189 samples, we trained K-top scoring pairs models and identified six gene pairs that can distinguish primary tumors with nodal metastasis from those without metastasis. The signature was further validated on an independent cohort of 35 patients using real-time polymerase chain reaction (PCR) in which it achieved an area under the receiver operating characteristic (ROC) curve and accuracy of 90% and 91%, respectively. These results indicate that such signature holds promise as a quick and cost effective method for detecting patients at high risk of developing cervical LN metastasis, and may be potentially used to guide the neck treatment regimen in early-stage OSCC.

Distinct Genomic Landscapes in Early-Onset and Late-Onset Endometrial Cancer

PURPOSE

The spectrum of somatic mutations among women with endometrial cancer (EC) younger than 50 years (early-onset EC) remains unknown. We investigated distinct somatic mutation patterns among early-onset and late-onset (age ≥ 50 years) EC patients.

METHODS

This cohort study included individuals age 18+ years diagnosed with pathologically confirmed EC in the American Association of Cancer Research (AACR) Genomics Evidence Neoplasia Information Exchange (GENIE, v9.1) consortium. We explored tumor mutational burden (TMB) and genomic patterns of EC by age at clinical sequencing using multivariable regression models adjusted for race, ethnicity, histology, sequencing assay, sample type, and TMB.

RESULTS

Among 2,425 women with EC, 176 (7.3%) had early-onset EC and 1,923 (79.3%) had nonhypermutated (< 17.78 mutations/Mb) tumors. TMB significantly differed across age and histology groups. Among nonhypermutated ECs, early-onset patients had significantly lower odds of presenting with nonsilent FGFR2 and PIK3R1 somatic mutations compared with late-onset EC patients in adjusted models (FGFR2: odds ratio [OR] = 0.18, 95% CI, 0.04 to 0.76; PIK3R1: OR = 0.54, 95% CI, 0.31 to 0.92). By contrast, early-onset EC patients had increased odds of presenting with nonsilent CTNNB1 and BRCA2 mutations compared with late-onset patients (CTNNB1: OR = 3.32, 95% CI, 2.14 to 5.16; BRCA2: OR = 4.01, 95% CI, 1.55 to 10.38). Subsequent analyses stratified by race, ethnicity, and tumor histology identified distinct patterns of APC, KMT2D, KMT2C, and KRAS by race, ethnicity, and PTEN and APC patterns by histologic subtypes.

CONCLUSION

Early-onset EC harbors a unique genomic landscape compared with late-onset disease. A distinct molecular phenotype of early-onset EC provides novel insights into a unique etiology and may yield clinical implications for developing targeted treatment modalities for younger patients.

Current Trends in Precision Medicine and Next-Generation Sequencing in Head and Neck Cancer

OPINION STATEMENT

As the field of oncology enters the era of precision medicine and targeted therapies, we have come to realize that there may be no single "magic bullet" for patients with head and neck cancer. While immune check point inhibitors and some targeted therapeutics have shown great promise in improving oncologic outcomes, the current standard of care in most patients with head and neck squamous cell carcinoma (HNSCC) remains a combination of surgery, radiation, and/or cytotoxic chemotherapy. Nevertheless, advances in precision medicine, next-generation sequencing (NGS), and targeted therapies have a potential future in the treatment of HNSCC. These roles include increased patient treatment stratification based on predictive biomarkers or targetable mutations and novel combinatorial regimens with existing HNSCC treatments. There remain challenges to precision medicine and NGS in HNSCC, including intertumor and intratumor heterogeneity, challenging targets, and need for further trials validating the utility of NGS and precision medicine. Additionally, there is a need for evidence-based practice guidelines to assist clinicians on how to appropriately incorporate NGS in care for HNSCC. In this review, we describe the current state of precision medicine and NGS in HNSCC and opportunities for future advances in this challenging but important field.

Age-specific oncogenic pathways in head and neck squamous cell carcinoma - are elderly a different subcategory?

BACKGROUND

In recent clinical practice, an increasing number of elderly patients suffering from head and neck squamous cell carcinoma (HNSCC) of unknown pathophysiology is observed. The majority of HNSCC patients can roughly be divided into three subcategories. First, a small group of young patients who present with variants of genomic aberrations and inheritable diseases like Fanconi anaemia. Second, an increasing population of HPV-related HNSCCs that are regarded as genomic stable tumours with a more favourable prognosis. Though HPV-related tumours used to be more common among younger males, a notable rise in the elderly population is observed. The third subcategory, that of HPV-negative tumours, has been shown to be more heterogeneous with involvement of a variety of oncogenic pathways related to lifestyle factors like smoking and alcohol consumption, often seen in middle-aged males. Some of these pathways could be related to age, such as TP53 alterations, EGFR activation, apoptotic pathway alterations and field cancerization.

CONCLUSIONS

In this narrative review, we provide an overview of established and newly discovered age-specific pathophysiological mechanisms underlying HNSCC. We propose a fourth subcategory of patients with a suspected different pathophysiology: elderly (HPV-negative) HNSCC patients without a history of tobacco and alcohol consumption. In this subcategory, carcinogenesis seems to be a multi-step process based on genomic instability, immunosenescence, cell cycle disruption and telomere shortening. To conclude, we discuss suggestions for future research to fill the knowledge gap about age-dependent HNSCC carcinogenesis.

Oral Squamous Cell Carcinoma in Young Patients Show Higher Rates of EGFR Amplification: Implications for Novel Personalized Therapy

There is an increasing worldwide incidence of patients under 50 years of age presenting with oral squamous cell carcinoma (OSCC). The molecular mechanisms driving disease in this emerging cohort remain unclear, limiting impactful treatment options for these patients. To identify common clinically actionable targets in this cohort, we used whole genome and transcriptomic sequencing of OSCC patient samples from 26 individuals under 50 years of age. These molecular profiles were compared with those of OSCC patients over 50 years of age (n=11) available from TCGA. We show for the first time that a molecular signature comprising of EGFR amplification and increased EGFR RNA abundance is specific to the young subset of OSCC patients. Furthermore, through functional assays using patient tumor-derived cell lines, we reveal that this EGFR amplification results in increased activity of the EGFR pathway. Using a panel of clinically relevant EGFR inhibitors we determine that an EGFR-amplified patient-derived cell line is responsive to EGFR inhibition, suggesting EGFR amplification represents a valid therapeutic target in this subset of OSCC patients. In particular, we demonstrate sensitivity to the second-generation EGFR tyrosine kinase inhibitor afatinib, which offers a new and promising therapeutic avenue versus current EGFR-targeting approaches. We propose that testing for EGFR amplification could easily be integrated into current diagnostic workflows and such measures could lead to more personalized treatment approaches and improved outcomes for this younger cohort of OSCC patients.

Multidimensional Mutational Profiling of the Indian HNSCC Sub-Population Provides IRAK1, a Novel Driver Gene and Potential Druggable Target

Head and neck squamous cell carcinomas (HNSCC) include heterogeneous group of tumors, classified according to their anatomical site. It is the sixth most prevalent cancer globally. Among South Asian countries, India accounts for 40% of HNC malignancies with significant morbidity and mortality. In the present study, we have performed exome sequencing and analysis of 51 Head and Neck squamous cell carcinoma samples. Besides known mutations in the oncogenes and tumour suppressors, we have identified novel gene signatures differentiating buccal, alveolar, and tongue cancers. Around 50% of the patients showed mutation in tumour suppressor genes TP53 and TP63. Apart from the known mutations, we report novel mutations in the genes AKT1, SPECC1, and LRP1B, which are linked with tumour progression and patient survival. A highly curated process was developed to identify survival signatures. 36 survival-related genes were identified based on the correlation of functional impact of variants identified using exome-seq with gene expression from transcriptome data (GEPIA database) and survival. An independent LASSO regression analysis was also performed. Survival signatures common to both the methods led to identification of 4 dead and 3 alive gene signatures, the accuracy of which was confirmed by performing a ROC analysis (AUC=0.79 and 0.91, respectively). Also, machine learning-based driver gene prediction tool resulted in the identification of IRAK1 as the driver (p-value = 9.7 e-08) and also as an actionable mutation. Modelling of the IRAK1 mutation showed a decrease in its binding to known IRAK1 inhibitors.

The Proteomic Landscape of Growth Factor Signaling Networks Associated with FAT1 Mutations in Head and Neck Cancers

FAT1 is frequently mutated in head and neck squamous cell carcinoma (HNSCC), but the biological and clinical effects of FAT1 mutations in HNSCC remain to be fully elucidated. We investigated the landscape of altered protein and gene expression associated with FAT1 mutations and clinical outcomes of patients with HNSCC. FAT1 mutation was stratified with clinical information from The Cancer Genome Atlas HNSCC databases with more than 200 proteins or phosphorylated sites. FAT1 mutation was significantly more prevalent among HPV(-), female, and older patients and was enriched in oral, larynx, and hypopharynx primary tumors. FAT1 mutation was also significantly associated with lower FAT1 gene expression and increased protein expression of HER3_pY1289, IRS1, and CAVEOLIN1. From an independent International Cancer Genome Consortium dataset, FAT1 mutation in oral cancer co-occurred with top mutated genes TP53 and CASP8. Poorer overall survival or progression-free survival was observed in patients with FAT1 mutation or altered HER3_pY1289, IRS1, or CAVEOLIN1. Pathway analysis revealed dominant ERBB/neuregulin pathways linked to FAT1 mutations in HNSCC, and protein signature panels uncovered the heterogeneity of patient subgroups. Decreased pEGFR, pHER2, and pERK and upregulated pHER3 and HER3 proteins were observed in two FAT1 knockout HNSCC cell lines, supporting that FAT1 alterations lead to altered EGFR/ERBB signaling. In squamous cancers of the lung and cervix, a strong association of FAT1 and EGFR gene expressions was identified. Collectively, these results suggest that alteration of FAT1 appears to involve mostly HPV(-) HNSCC and may contribute to resistance to EGFR-targeted therapy. SIGNIFICANCE: Integrative bioinformatics and statistical analyses reveal a panel of genes and proteins associated with FAT1 mutation in HNSCC, providing important insights into prospective clinical investigations with targeted therapies.

High-risk early-stage oral tongue squamous cell carcinoma, when free margins are not enough: Critical review

Oral tongue squamous cell carcinoma (OTSCC) is a quite peculiar disease from an anatomical and biological standpoint. An increasing amount of literature highlights the existence of a small subset of T1-T2N0 OTSCC, properly resected on a margin-dependent basis, which conversely proved higher than expected rates of loco-regional/distant failure and disease-specific mortality. These specific high-risk tumors might not have a margin-dependent disease and could possibly benefit from a more aggressive upfront loco-regional treatment, especially addressing the so-called T-N tract. Widespread adoption of a histopathological risk model would allow early recognition of these high-risk diseases and, consequently, intensification of the traditional treatment strategies in that specific niche. We reviewed the available knowledge trying to shed light on the potential determinants of the dismal prognosis of these high-risk OTSCC, with special reference to the role of overlooked T-N tract involvement and possible alternatives in terms of elective neck management and risk stratification.