Histologic and Genomic Analysis of Conjunctival SCC in African and American Cohorts Reveal UV Light and HPV Signatures and High Tumor Mutation Burden.

Purpose: Conjunctival squamous cell carcinoma (conjSCC) is more prevalent and aggressive in sub-Saharan African countries compared with the rest of the world. This study aims to compare the genomic, immunophenotypic, and histologic features between patients from the United States and Ethiopia, to identify etiopathogenic mechanisms and unveil potential treatment strategies. Methods: We compared histologic features and mutational profiles using whole exome sequencing, high-risk human papillomavirus (HPV) status, PD-L1 expression, and tumor-infiltrating lymphocytes in conjSCC tumors of patients from Ethiopia (ETH; n = 25) and the United States (from MD Anderson [the MDA cohort]; n = 29). Genomic alterations were compared with SCCs from other anatomic sites using data from The Cancer Genome Atlas. Results: Solar elastosis was seen in 78% of ETH and 10% of MDA samples. Thicker tumors had higher density of CD8+ and CD3+ cells. HPV status was similar between the cohorts (ETH = 21% and MDA = 28%). The mean tumor mutation burden (TMB) was significantly higher in conjSCC (3.01/Mb, log10) and cutaneous SCC compared other SCC subtypes. ETH samples had higher TMB compared to the MDA cohort (3.34 vs. 2.73). Mutations in genes associated with ultraviolet light (UV) signature were most frequently encountered (SBS7b = 74% and SBS7a = 72%), with higher prevalence in the ETH cohort, whereas SBS2 and SBS13 signatures were more common among MDA HPV+ conjSCCs. Conclusions: Our findings suggest that UV exposure may play a major role in conjSCC, with a higher prevalence in the ETH cohort compared with the MDA cohort, where HPV also contributes.

Immune infiltration at the primary tumor is associated with clinical outcome of patients with extranodal extension of lymph node metastasis in oral cancer.

BACKGROUND: Extranodal extension (ENE) of lymph node metastasis is one of the most reliable prognostic indicators for patients with locally advanced oral cancer. Although multiple reports have found a close relationship between immune infiltration of tumors and patient clinical outcomes, its association with ENE is unknown. METHODS: We identified 234 human papillomavirus-negative (HPV-) oral cavity squamous cell carcinoma (OSCC) patients in The Cancer Genome Atlas and investigated the immune infiltration profiles of primary tumors and their association with survival. RESULTS: Hierarchical clustering analysis clearly classified the overall immune infiltration status in OSCC into high immune or low immune groups. The combination of ENE positivity and low immune infiltration was strongly associated with poor overall survival (OS) compared to the combination of ENE positivity and high immune infiltration [hazard ratio 2.04 (95 %CI, 1.08-3.83); p = 0.024]. The immune infiltration status was not associated with OS rates in patients with ENE-negative or node negative tumors. CONCLUSION: Overall Immune infiltration at the primary site was significantly associated with clinical outcome of OSCC patients with ENE.

Mutant p53 gains oncogenic functions through a chromosomal instability-induced cytosolic DNA response.

Inactivating TP53 mutations leads to a loss of function of p53, but can also often result in oncogenic gain-of-function (GOF) of mutant p53 (mutp53) proteins which promotes tumor development and progression. The GOF activities of TP53 mutations are well documented, but the mechanisms involved remain poorly understood. Here, we study the mutp53 interactome and find that by targeting minichromosome maintenance complex components (MCMs), GOF mutp53 predisposes cells to replication stress and chromosomal instability (CIN), leading to a tumor cell-autonomous and cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING)-dependent cytosolic DNA response that activates downstream non-canonical nuclear factor kappa light chain enhancer of activated B cell (NC-NF-κB) signaling. Consequently, GOF mutp53-MCMs-CIN-cytosolic DNA-cGAS-STING-NC-NF-κB signaling promotes tumor cell metastasis and an immunosuppressive tumor microenvironment through antagonizing interferon signaling and regulating genes associated with pro-tumorigenic inflammation. Our findings have important implications for understanding not only the GOF activities of TP53 mutations but also the genome-guardian role of p53 and its inactivation during tumor development and progression.

A Deep Learning Onion Peeling Approach to Measure Oral Epithelium Layer Number.

Head and neck squamous cell carcinoma (HNSCC), specifically in the oral cavity (oral squamous cell carcinoma, OSCC), is a common, complex cancer that significantly affects patients' quality of life. Early diagnosis typically improves prognoses yet relies on pathologist examination of histology images that exhibit high inter- and intra-observer variation. The advent of deep learning has automated this analysis, notably with object segmentation. However, techniques for automated oral dysplasia diagnosis have been limited to shape or cell stain information, without addressing the diagnostic potential in counting the number of cell layers in the oral epithelium. Our study attempts to address this gap by combining the existing U-Net and HD-Staining architectures for segmenting the oral epithelium and introducing a novel algorithm that we call Onion Peeling for counting the epithelium layer number. Experimental results show a close correlation between our algorithmic and expert manual layer counts, demonstrating the feasibility of automated layer counting. We also show the clinical relevance of oral epithelial layer number to grading oral dysplasia severity through survival analysis. Overall, our study shows that automated counting of oral epithelium layers can represent a potential addition to the digital pathology toolbox. Model generalizability and accuracy could be improved further with a larger training dataset.

Inflammation induced by tumor-associated nerves promotes resistance to anti-PD-1 therapy in cancer patients and is targetable by interleukin-6 blockade.

While the nervous system has reciprocal interactions with both cancer and the immune system, little is known about the potential role of tumor associated nerves (TANs) in modulating anti-tumoral immunity. Moreover, while peri-neural invasion is a well establish poor prognostic factor across cancer types, the mechanisms driving this clinical effect remain unknown. Here, we provide clinical and mechniastic association between TANs damage and resistance to anti-PD-1 therapy. Using electron microscopy, electrical conduction studies, and tumor samples of cutaneous squamous cell carcinoma (cSCC) patients, we showed that cancer cells can destroy myelin sheath and induce TANs degeneration. Multi-omics and spatial analyses of tumor samples from cSCC patients who underwent neoadjuvant anti-PD-1 therapy demonstrated that anti-PD-1 non-responders had higher rates of peri-neural invasion, TANs damage and degeneration compared to responders, both at baseline and following neoadjuvant treatment. Tumors from non-responders were also characterized by a sustained signaling of interferon type I (IFN-I) - known to both propagate nerve degeneration and to dampen anti-tumoral immunity. Peri-neural niches of non-responders were characterized by higher immune activity compared to responders, including immune-suppressive activity of M2 macrophages, and T regulatory cells. This tumor promoting inflammation expanded to the rest of the tumor microenvironment in non-responders. Anti-PD-1 efficacy was dampened by inducing nerve damage prior to treatment administration in a murine model. In contrast, anti-PD-1 efficacy was enhanced by denervation and by interleukin-6 blockade. These findings suggested a potential novel anti-PD-1 resistance drived by TANs damage and inflammation. This resistance mechanism is targetable and may have therapeutic implications in other neurotropic cancers with poor response to anti-PD-1 therapy such as pancreatic, prostate, and breast cancers.

Beta-Blocker Use Is Associated With Worse Relapse-Free Survival in Patients With Head and Neck Cancer.

PURPOSE: Although beta-blockers (BBs) have been hypothesized to exert a beneficial effect on cancer survival through inhibition of beta-adrenergic signaling pathways, clinical data on this issue have been inconsistent. We investigated the impact of BBs on survival outcomes and efficacy of immunotherapy in patients with head and neck squamous cell carcinoma (HNSCC), non-small-cell lung cancer (NSCLC), melanoma, or squamous cell carcinoma of the skin (skin SCC), independent of comorbidity status or cancer treatment regimen. METHODS: Patients (N = 4,192) younger than 65 years with HNSCC, NSCLC, melanoma, or skin SCC treated at MD Anderson Cancer Center from 2010 to 2021 were included. Overall survival (OS), disease-specific survival (DSS), and disease-free survival (DFS) were calculated. Kaplan-Meier and multivariate analyses adjusting for age, sex, TNM staging, comorbidities, and treatment modalities were performed to assess the effect of BBs on survival outcomes. RESULTS: In patients with HNSCC (n = 682), BB use was associated with worse OS and DFS (OS: adjusted hazard ratio [aHR], 1.67; 95% CI, 1.06 to 2.62; P = .027; DFS: aHR, 1.67; 95% CI, 1.06 to 2.63; P = .027), with DSS trending to significance (DSS: aHR, 1.52; 95% CI, 0.96 to 2.41; P = .072). Negative effects of BBs were not observed in the patients with NSCLC (n = 2,037), melanoma (n = 1,331), or skin SCC (n = 123). Furthermore, decreased response to cancer treatment was observed in patients with HNSCC with BB use (aHR, 2.47; 95% CI, 1.14 to 5.38; P = .022). CONCLUSION: The effect of BBs on cancer survival outcomes is heterogeneous and varies according to cancer type and immunotherapy status. In this study, BB intake was associated with worse DSS and DFS in patients with head and neck cancer not treated with immunotherapy, but not in patients with NSCLC or skin cancer.

Deep learning-based pathology image analysis predicts cancer progression risk in patients with oral leukoplakia.

BACKGROUND: Oral leukoplakia (OL) is associated with an increased risk for oral cancer (OC) development. Prediction of OL cancer progression may contribute to decreased OC morbidity and mortality by favoring early intervention. Current OL progression risk assessment approaches face large interobserver variability and is weakly prognostic. We hypothesized that convolutional neural networks (CNN)-based histology image analyses could accelerate the discovery of better OC progression risk models. METHODS: Our CNN-based oral mucosa risk stratification model (OMRS) was trained to classify a set of nondysplastic oral mucosa (OM) and a set of OC H&E slides. As a result, the OMRS model could identify abnormal morphological features of the oral epithelium. By applying this model to OL slides, we hypothesized that the extent of OC-like features identified in the OL epithelium would correlate with its progression risk. The OMRS model scored and categorized the OL cohort (n = 62) into high- and low-risk groups. RESULTS: OL patients classified as high-risk (n = 31) were 3.98 (95% CI 1.36-11.7) times more likely to develop OC than low-risk ones (n = 31). Time-to-progression significantly differed between high- and low-risk groups (p = 0.003). The 5-year OC development probability was 21.3% for low-risk and 52.5% for high-risk patients. The predictive power of the OMRS model was sustained even after adjustment for age, OL site, and OL dysplasia grading (HR = 4.52, 1.5-13.7). CONCLUSION: The ORMS model successfully identified OL patients with a high risk of OC development and can potentially benefit OC early diagnosis and prevention policies.

Mildly dysplastic oral lesions with optically-detectable abnormalities share genetic similarities with severely dysplastic lesions.

OBJECTIVE: Optical imaging studies of oral premalignant lesions have shown that optical markers, including loss of autofluorescence and altered morphology of epithelial cell nuclei, are predictive of high-grade pathology. While these optical markers are consistently positive in lesions with moderate/severe dysplasia or cancer, they are positive only in a subset of lesions with mild dysplasia. This study compared the gene expression profiles of lesions with mild dysplasia (stratified by optical marker status) to lesions with severe dysplasia and without dysplasia. MATERIALS AND METHODS: Forty oral lesions imaged in patients undergoing oral surgery were analyzed: nine without dysplasia, nine with severe dysplasia, and 22 with mild dysplasia. Samples were submitted for high throughput gene expression analysis. RESULTS: The analysis revealed 116 genes differentially expressed among sites without dysplasia and sites with severe dysplasia; 50 were correlated with an optical marker quantifying altered nuclear morphology. Ten of 11 sites with mild dysplasia and positive optical markers (91%) had gene expression similar to sites with severe dysplasia. Nine of 11 sites with mild dysplasia and negative optical markers (82%) had similar gene expression as sites without dysplasia. CONCLUSION: This study suggests that optical imaging may help identify patients with mild dysplasia who require more intensive clinical follow-up. If validated, this would represent a significant advance in patient care for patients with oral premalignant lesions.

Distinct immune signature predicts progression of vestibular schwannoma and unveils a possible viral etiology.

BACKGROUND: The management of sub-totally resected sporadic vestibular schwannoma (VS) may include observation, re-resection or irradiation. Identifying the optimal choice can be difficult due to the disease's variable progression rate. We aimed to define an immune signature and associated transcriptomic fingerprint characteristic of rapidly-progressing VS to elucidate the underpinnings of rapidly progressing VS and identify a prognostic model for determining rate of progression. METHODS: We used multiplex immunofluorescence to characterize the immune microenvironment in 17 patients with sporadic VS treated with subtotal surgical resection alone. Transcriptomic analysis revealed differentially-expressed genes and dysregulated pathways when comparing rapidly-progressing VS to slowly or non-progressing VS. RESULTS: Rapidly progressing VS was distinctly enriched in CD4+, CD8+, CD20+, and CD68+ immune cells. RNA data indicated the upregulation of anti-viral innate immune response and T-cell senescence. K - Top Scoring Pair analysis identified 6 pairs of immunosenescence-related genes (CD38-KDR, CD22-STAT5A, APCS-CXCR6, MADCAM1-MPL, IL6-NFATC3, and CXCL2-TLR6) that had high sensitivity (100%) and specificity (78%) for identifying rapid VS progression. CONCLUSION: Rapid progression of residual vestibular schwannoma following subtotal surgical resection has an underlying immune etiology that may be virally originating; and despite an abundant adaptive immune response, T-cell immunosenescence may be associated with rapid progression of VS. These findings provide a rationale for clinical trials evaluating immunotherapy in patients with rapidly progressing VS.

Mutant p53 drives an immune cold tumor immune microenvironment in oral squamous cell carcinoma.

The critical role of the tumor immune microenvironment (TIME) in determining response to immune checkpoint inhibitor (ICI) therapy underscores the importance of understanding cancer cell-intrinsic mechanisms driving immune-excluded ("cold") TIMEs. One such cold tumor is oral cavity squamous cell carcinoma (OSCC), a tobacco-associated cancer with mutations in the TP53 gene which responds poorly to ICI therapy. Because altered TP53 function promotes tumor progression and plays a potential role in TIME modulation, here we developed a syngeneic OSCC models with defined Trp53 (p53) mutations and characterized their TIMEs and degree of ICI responsiveness. We observed that a carcinogen-induced p53 mutation promoted a cold TIME enriched with immunosuppressive M2 macrophages highly resistant to ICI therapy. p53-mutated cold tumors failed to respond to combination ICI treatment; however, the combination of a programmed cell death protein 1 (PD-1) inhibitor and stimulator of interferon genes (STING) agonist restored responsiveness. These syngeneic OSCC models can be used to gain insights into tumor cell-intrinsic drivers of immune resistance and to develop effective immunotherapeutic approaches for OSCC and other ICI-resistant solid tumors.

Induction chemotherapy with or without erlotinib in patients with head and neck squamous cell carcinoma amenable for surgical resection.

PURPOSE: Neoadjuvant chemotherapy prior to definitive surgery has been utilized widely for locally advanced oral squamous cell carcinoma (OSCC). We evaluated neoadjuvant erlotinib with platinum-docetaxel vs. placebo with platinum-docetaxel in stage III-IVB OSCC patients. EXPERIMENTAL DESIGN: Patients with newly diagnosed stage III, IVA, IVB (AJCC 7th) OSCC amenable to surgical resection were included. Patients were randomized to receive up to 3 cycles of chemotherapy with concurrent erlotinib or placebo, followed by surgery. The primary endpoint was major pathologic response (MPR) rate, secondary endpoints included safety, overall (OS) and progression-free survival (PFS). RESULTS: Fifty-two patients received at least one cycle of treatment and 47 were evaluable with surgical resection. MPR rate was not different between erlotinib (30%, 7/23) and placebo arms (41.7%, 10/24) (p=0.55). At median follow up of 26.5 months, there was no difference on OS or PFS between groups. Patients who received erlotinib with chemotherapy and achieved MPR (n=7) had no recurrence. The treatment-related adverse event rates were not different between the two groups (96% vs. 96%). However, rash, mostly low grade, was more common in the erlotinib arm (79% vs. 50%). Transcriptomic analysis in the pre-treatment samples indicated that genes in protein glycosylation and Wnt signaling pathways were associated with benefit in those treated with erlotinib plus chemotherapy. CONCLUSIONS: The addition of erlotinib to platinum-taxane chemotherapy was well-tolerated but did not induce higher rates of MPR or PFS or OS survival benefit. Patients who received chemotherapy with erlotinib and achieved major pathological responses had excellent clinical outcome.

Nestin and NG2 transgenes reveal two populations of perivascular cells stimulated by photobiomodulation.

Pericytes and glial cells are known to collaborate in dental pulp tissue repair. Cell-based therapies that stimulate these stromal components may be of therapeutic relevance for partially vital dental pulp conditions. This study aimed to examine the early effect of photobiomodulation (PBM) in pericytes from experimentally injured pulp tissue. To accomplish this, we used the Nestin-GFP/NG2-DsRed mice, which could allow the identification of distinct pericyte phenotypes. We discovered the presence of two pericytes subsets within the dental pulp, the Nestin + NG2+ (type-2) and Nestin- NG2+ (type-1). Upon injury, PBM treatment led to a significant increase in Nestin+ cells and pericytes. This boost was mainly conferred by the more committed pericyte subset (NestinNG2+ ). PBM also stimulated terminal blood vessels sprouting adjacent to the injury site while maintaining signs of pulp vitality. In vitro, PBM induced VEGF upregulation, improved dental pulp cells proliferation and migration, and favored their mineralization potential. Herein, different subsets of perivascular cells were unveiled in the pulp tissue. PBM enhanced not only NG2+ cells but nestin-expressing progenitors in the injured dental pulp.

Elective neck dissection versus observation in patients with head and neck cutaneous squamous cell carcinoma.

BACKGROUND: The survival benefit of elective neck dissection (END) for patients with cutaneous squamous cell carcinoma (cSCC) of the head and neck and no evidence of regional metastasis (cN0) has never been reported. The aim of this study was to determine the effect of END on patient survival. METHODS: The authors included patients with head and neck cSCC who had undergone primary surgery from 1995 to 2017. The primary end point was survival, and the secondary end points were the incidence of occult regional disease and regional disease control. To assess the impact of END on survival, the authors used multivariable Cox proportional hazards models with propensity score and matching techniques for internal validation. RESULTS: A total of 1111 patients presented with no evidence of nodal disease; 173 had END, and 938 were observed. Adjuvant radiotherapy to the neck was administered to 101 patients (9%). END resulted in a 5-year overall survival rate of 52%, whereas the rate was 63% in the observation group (P = .003 [log-rank]). The 5-year disease-free survival rate for patients undergoing END was similar to that for the observation group (73% vs 75%; P = .429). A multivariate regression model showed that the performance of END was not associated with improved rates of overall, disease-specific, or disease-free survival; similarly, among patients with advanced disease (T3-4), those who underwent END did not have improved survival rates. CONCLUSIONS: Among patients with cSCC of the head and neck, observation of the neck nodes resulted in noninferior survival rates in comparison with END at the time of primary surgery. Further studies are required to elucidate the role of END in patients with advanced disease.

Combined Inhibition of Rad51 and Wee1 Enhances Cell Killing in HNSCC Through Induction of Apoptosis Associated With Excessive DNA Damage and Replication Stress.

Despite advances in surgery, chemotherapy, and radiation, there are limited treatment options for advanced head and neck squamous cell carcinoma (HNSCC) and survival remains very poor. Therefore, effective therapies are desperately needed. Recently, selective exploitation of DNA damage and replication stress responses has become a novel approach for cancer treatment. Wee1 kinase and Rad51 recombinase are two proteins involved in regulating replication stress and homologous recombination repair in cancer cells. In this study, we investigated the combined effect of Rad51 inhibitor (B02) and Wee1 inhibitor (AZD1775) in vitro and in vivo in various HNSCC cell lines. Clonogenic survival assays demonstrated that B02 synergized with AZD1775 in vitro in all HNSCC cell lines tested. The synergy between these drugs was associated with forced CDK1 activation and reduced Chk1 phosphorylation leading to induction of excessive DNA damage and replication stress, culminating in aberrant mitosis and apoptosis. Our results showed that elevated Rad51 mRNA expression correlated with worse survival in HNSCC patients with HPV-positive tumors. The combination of B02 and AZD1775 significantly inhibited tumor growth in vivo in mice bearing HPV-positive HNSCC tumors as compared to HPV-negative HNSCC. This differential sensitivity appears to be linked to HPV-positive tumors having more in vivo endogenous replication stress owing to transformation by E6 and E7 oncogenes. Furthermore, addition of B02 radiosensitized the HPV-negative HNSCC tumors in vitro and in vivo In conclusion, our data implicate that a novel rational combination with Rad51 and Wee1 inhibitors holds promise as synthetic lethal therapy, particularly in high-risk HPV-positive HNSCC.

Low doses of methylnaltrexone inhibits head and neck squamous cell carcinoma growth in vitro and in vivo by acting on the mu-opioid receptor.

The Mu-opioid receptor (MOR) has been implicated in tumorigenesis and metastasis. Methylnaltrexone (MNTX), an antagonist of MOR, has shown to inhibit tumor growth and metastasis in lung cancer cell lines. The effect of MNTX on other cell lines such as head and neck squamous cell carcinoma (HNSCC) has not been investigated. We measured the expression and activity of the receptor in different HNSCC cell lines. Then, we evaluated the impact of modulating the expression MOR and the effect of MNTX on the proliferation, clonogenic activity, invasion, and migration of two HNSCC (FaDu and MDA686Tu) cell lines expressing MOR and one cell line (UMSCC47) not expressing the receptor. We also evaluated the impact of MNTX on tumor growth and metastasis formation in vivo. Activation of the receptor with [d-Ala2,N-Me-Phe4, Gly5-ol] (DAMGO) caused a significant reduction in cyclic adenosine monophosphate levels in FaDu cells. Knockdown of MOR inhibited in vitro aggressive cell behaviors on FaDu and MDA686Tu cells and correlated with a reduction in markers of epithelial-mesenchymal transition. In vitro studies showed that MNTX strongly inhibited the proliferation, clonogenic activity, invasion, and migration of FaDu and MDA686Tu cells but has no effect on UMSCC47 cells. In vivo experiments demonstrated that MNTX suppresses tumor growth in HNSCC cell tumor-bearing mice. Our studies indicate that MOR could be considered as a therapeutic target to treat HNSCC.

Mu-opioid receptor activation promotes in vitro and in vivo tumor growth in head and neck squamous cell carcinoma.

AIMS: In vitro and in vivo studies suggest that the mu-opioid receptor (MOR) is involved in tumorigenesis, and metastasis in cancer. In humans, the use of MOR agonists (opioids) is associated with head and neck squamous cell carcinoma (HNSCC) progression. In the present study, we aimed to examine the role of MOR activation in MOR (+) HNSCC. MAIN METHODS: FaDu, MDA686Tu and UMSCC47 cell lines were used in in vitro and in vivo experiments. Cells and animals were treated with a highly selective MOR agonist DAMGO, [D-Ala (2), Me Phe (4), Glycol (5)]-enkephalin] or saline 0.9%. KEY FINDINGS: MOR activation significantly increased the proliferation, colony formation, invasion, and migration of FaDu and MDA6868Tu cells and promoted tumor growth in vivo. SIGNIFICANCE: These findings suggest that MOR is implicated in tumorigenesis of HNSCC. Overall, our findings identify that MOR could be used as a potential therapeutic target in patients with MOR (+) HNSCC.

Whole-exome Sequencing in Penile Squamous Cell Carcinoma Uncovers Novel Prognostic Categorization and Drug Targets Similar to Head and Neck Squamous Cell Carcinoma.

PURPOSE: Penile squamous cell carcinoma (PSCC) is rare with limited treatment options. We report the first whole-exome sequencing (WES) analysis and compare the molecular landscape of PSCC with other squamous cell carcinomas (SCC), with the goal to identify common novel targets. EXPERIMENTAL DESIGN: PSCC and matched normal penile tissues from 34 prospectively followed patients, underwent genomic WES and human papilloma virus testing. We performed tumor mutation signature estimation by two methods, first to identify APOBEC-related mutation enrichments and second to classify PSCC-enriched mutational patterns based on their association with the Catalogue of Somatic Mutations in Cancer mutation signatures. We performed an extensive genomic comparison between our PSCC cohort and other SCCs in The Cancer Genome Atlas studies. RESULTS: We identified that most PSCC samples showed enrichment for Notch pathway (n = 24, 70.6%) alterations, comparable with head and neck squamous cell carcinoma (HNSC). PSCC mutation signatures are most comparable with HNSC signatures. PSCC samples showed an enrichment of two distinct mutational signatures, the first, associated with oncogenic activity of AID/APOBEC, and the second, associated with defective DNA mismatch repair and microsatellite instability. MP1 enrichment was positively correlated with increased tumor mutation burden (TMB; CC, 0.71; P < 0.0001) and correlated with significantly worse survival in comparison with those with the MP2 subset [HR, 10.2 (1.13-92.9); P = 0.039]. We show that a subset of PSCC (38%), with enrichment of APOBEC-related mutation signature, had significantly higher TMB and worse overall survival in comparison with non-APOBEC-enriched subset [HR, 2.41 (1.11-6.77); P = 0.042]. CONCLUSIONS: This study identified novel druggable targets and similarities in mutational signatures between PSCC and HNSC with potential clinical implications.See related commentary by McGregor and Sonpavde, p. 2375.

Inclusion of extranodal extension in the lymph node classification of cutaneous squamous cell carcinoma of the head and neck.

BACKGROUND: The prognostic performance of the recently updated American Joint Committee on Cancer lymph node classification of cutaneous head and neck squamous cell carcinoma (HNSCC) has not been validated. The objective of this study was to assess the prognostic role of extranodal extension (ENE) in cutaneous HNSCC. METHODS: This was a retrospective analysis of 1258 patients with cutaneous HNSCC who underwent surgery with or without adjuvant therapy between 1995 and 2019 at The University of Texas MD Anderson Cancer Center. The primary outcome was disease-specific survival (DSS). Local, regional, and distant metastases-free survival were secondary outcomes. Recursive partitioning analysis (RPA) and a Cox proportional hazards regression model were used to assess the fitness of staging models. RESULTS: No significant differences in 5-year DSS were observed between patients with pathologic lymph node-negative (pN0) disease (67.4%) and those with pN-positive/ENE-negative disease (68.2%; hazard ratio, 1.02; 95% CI, 0.61-1.79) or between patients with pN-positive/ENE-negative disease and those with pN-positive/ENE-positive disease (52.7%; hazard ratio, 0.57; 95% CI, 0.31-1.01). The RPA-derived model achieved better stratification between high-risk patients (category III, ENE-positive with >2 positive lymph nodes) and low-risk patients (category I, pN0; category II, ENE-positive/pN1 and ENE-negative with >2 positive lymph nodes). The performance of the RPA-derived model was better than that of the pathologic TNM classification (Akaike information criterion score, 1167 compared with 1176; Bayesian information criterion score, 1175 compared with 1195). CONCLUSIONS: The number of metastatic lymph nodes and the presence of ENE are independent prognostic factors for DSS in cutaneous HNSCC, and incorporation of these factors in staging systems improves the performance of the American Joint Committee on Cancer lymph node classification.

Caspase-8 loss radiosensitizes head and neck squamous cell carcinoma to SMAC mimetic-induced necroptosis.

Caspase-8 (CASP8) is one of the most frequently mutated genes in head and neck squamous carcinomas (HNSCCs), and CASP8 mutations are associated with poor survival. The distribution of these mutations in HNSCCs suggests that they are likely to be inactivating. Inhibition of CASP8 has been reported to sensitize cancer cells to necroptosis, a regulated cell death mechanism. Here, we show that knockdown of CASP8 renders HNSCCs susceptible to necroptosis by a second mitochondria-derived activator of caspase (SMAC) mimetic, birinapant, in combination with pan-caspase inhibitors Z-VAD-FMK or emricasan and radiation. In a syngeneic mouse model of oral cancer, birinapant, particularly when combined with radiation, delayed tumor growth and enhanced survival under CASP8 loss. Exploration of molecular underpinnings of necroptosis sensitivity confirmed that the level of functional receptor-interacting serine/threonine protein kinase 3 (RIP3) determines susceptibility to this mode of death. Although an in vitro screen revealed that low RIP3 levels rendered many HNSCC cell lines resistant to necroptosis, patient tumors maintained RIP3 expression and should therefore remain sensitive. Collectively, these results suggest that targeting the necroptosis pathway with SMAC mimetics, especially in combination with radiation, may be relevant therapeutically in HNSCC with compromised CASP8 status, provided that RIP3 function is maintained.

Functionally impactful TP53 mutations are associated with increased risk of extranodal extension in clinically advanced oral squamous cell carcinoma.

BACKGROUND: The treatment of advanced oral squamous cell carcinoma (OSCC) is a clinical challenge because it is unclear which therapeutic approaches are the best for this highly heterogeneous group of patients. Because TP53 mutations are the most common genetic event in these tumors, the authors investigated whether they could represent an ancillary biomarker in the management of advanced OSCC. METHODS: The TP53 gene was sequenced in 78 samples from patients with advanced OSCC who received treatment at 2 institutions located in the United States and Brazil. TP53 mutations were classified according to an in-silico impact score (the evolutionary action score of p53 [EAp53]), which identifies mutations that have greater alterations of p53 protein function (high-risk). Associations between TP53 mutation status/characteristics and clinicopathologic characteristics were investigated. The relevant findings were validated in silico by analyzing 197 samples from patients with advanced OSCC from The Cancer Genome Atlas. RESULTS: No differences in clinical outcomes were detected between patients with TP53-mutant and wild-type TP53 disease. However, patients who had tumors carrying high-risk TP53 mutations had a significantly increased risk of developing extranodal extension (ENE) compared with those who had wild-type TP53-bearing tumors. The increased chances of detecting ENE among patients who had high-risk TP53 mutations was validated among patients with advanced OSCC from The Cancer Genome Atlas cohort. CONCLUSIONS: High-risk TP53 mutations are associated with an increased chance of detecting ENE in patients with advanced OSCC. Because ENE is 1 of the major factors considered for OSCC patient management, TP53 mutation status may represent a potential ancillary biomarker for treatment decisions regarding postoperative adjuvant therapy.