Reverse-phase protein array profiling of oropharyngeal cancer and significance of PIK3CA mutations in HPV-associated head and neck cancer

HPV and coronary diseases in menopausal women: an integrative review

High-risk human papillomavirus (HPV) infection is associated with cervical cancer while low-risk HPV strains mostly cause benign lesions. Multiple studies have also associated HPV with coronary artery (CAD) disease in women. Furthermore, the climacteric period in women, triggers chronic inflammation and has major implications for CAD and associated lipid disorders. The association of HPV with coronary artery disease in climacteric women has few studies, and the objective of this review is to gather and analyse scientific data on the subject. This is an integrative review performed on PubMed and Google Scholar using the keywords "HPV", "coronary heart disease" and "climacteric", among these keywords the boolean operator AND and the publication date filter. (2018 onwards). Five articles were found, whose main results show presence of high-risk vaginal HPV in climacteric women. Climacterium and HPV were associated with a three-fold increased risk of CAD, as well as with factors related to menopause that promote atheroma formation, lipid disorders and chronic inflammation. Thus, these results support the association between HPV infection and CAD in climacteric women, possibly via chronic inflammation, hormonal factors related to menopause and dyslipidemia.

Human papillomavirus (HPV) load is higher in HPVDNA/p16 positive than in HPVDNA positive/p16 negative oropharyngeal squamous cell carcinoma but does not differ significantly between various subsites or correlate to survival

OBJECTIVE

Patients with human papillomavirus DNA positive (HPVDNA+) and p16ink4a overexpressing (p16+) oropharyngeal squamous cell carcinoma (OPSCC), especially those with cancer in the tonsillar and base of tongue subsites as compared to other OPSCC subsites have a better outcome than those with only HPVDNA+ or only p16+ cancer. Likewise having a high viral load has been suggested to be a positive prognostic factor. We therefore hypothesized, that HPV viral load could vary depending on OPSCC subsite, as well as with regard to whether the cancer was HPVDNA+ and p16+, or only HPVDNA+, or only p16+ and that this affected outcome.

MATERIAL AND METHODS

To address these issues HPV viral load was determined by HPV digital droplet (dd) PCR in tumor biopsies with previously known HPVDNA/p16 status from 270 OPSCC patients diagnosed 2000-2016 in Stockholm, Sweden. More specifically, of these patients 235 had HPVDNA+/p16+, 10 had HPVDNA+/p16-, 13 had HPVDNA-/p16+ and 12 had HPVDNA-/p16- cancer.

RESULTS

We found that HPVDNA+/p16+ OPSCC had a significantly higher viral load than HPVDNA+/p16- OPSCC. Moreover, there was a tendency for a higher viral load in the tonsillar and base of tongue OPSCC subsites compared to the other subsites and for a low viral load to correlate to a better clinical outcome but none of these tendencies reached statistical significance.

CONCLUSION

To conclude, the mean viral load in HPVDNA+/p16+ OPSCC was higher than in HPVDNA+/p16- OPSCC, but there was no statistically significant difference in viral load depending on OPSCC subsite or on clinical outcome.

Genetic Mutations Associated with Inflammatory Response Caused by HPV Integration in Oropharyngeal Squamous Cell Carcinoma

(1) Background: Head and neck cancer (HNC) ranks as the sixth most prevalent cancer in the world. In addition to the traditional risk factors such as alcohol and tobacco consumption, the implication of the human papillomavirus (HPV) is becoming increasingly significant, particularly in oropharyngeal cancer (OPC). (2) Methods: This study is based on a review analysis of different articles and repositories investigating the mutation profile of HPV-related OPC and its impact on patient outcomes. (3) Results: By compiling data from 38 datasets involving 8311 patients from 12 countries, we identified 330 genes that were further analyzed. These genes were enriched for regulation of the inflammatory response (RB1, JAK2, FANCA, CYLD, SYK, ABCC1, SYK, BCL6, CEBPA, SRC, BAP1, FOXP1, FGR, BCR, LRRK2, RICTOR, IGF1, and ATM), among other biological processes. Hierarchical cluster analysis showed the most relevant biological processes were linked with the regulation of mast cell cytokine production, neutrophil activation and degranulation, and leukocyte activation (FDR < 0.001; p-value < 0.05), suggesting that neutrophils may be involved in the development and progression of HPV-related OPC. (4) Conclusions: The neutrophil infiltration and HPV status emerge as a potential prognostic factor for OPC. HPV-infected HNC cells could potentially lead to a decrease in neutrophil infiltration. By gaining a better molecular understanding of HPV-mediated neutrophil immunosuppression activity, it is possible to identify a meaningful target to boost antitumor immune response in HNC and hence to improve the survival of patients with HNC.

The SGK3-Catalase antioxidant signaling axis drives cervical cancer growth and therapy resistance

Cancer cells frequently exhibit aberrant redox homeostasis and adaptation to oxidative stress. Hence abrogation of redox adaptation in cancer cells can be exploited for therapeutic benefit. Here we report SGK3 functions as an anti-oxidative factor to promote cell growth and drug resistance in cervical cancers harboring PIK3CA helical domain mutations. Mechanistically, SGK3 is activated upon oxidative stress and exerts anti-ROS activity by stabilizing and activating the antioxidant enzyme catalase. SGK3 interacts with and phosphorylates catalase, promoting its tetrameric state and activity. Meanwhile, SGK3 phosphorylates GSK3β and protects catalase from GSK3β-β-TrCP mediated ubiquitination and proteasomal degradation. Furthermore, SGK3 inhibition not only potentiates CDK4/6 inhibitor Palbociclib-mediated cytotoxicity, but also overcomes cisplatin resistance through ROS-mediated mechanisms. These data uncover the role of SGK3 in maintaining redox homeostasis and suggest that the SGK3-catalase antioxidant signaling axis may be therapeutically targeted to improve treatment efficacy for cervical cancers carrying PIK3CA helical domain mutations.

Assessment of the Mutation Profile of Tonsillar Squamous Cell Carcinomas Using Targeted Next-Generation Sequencing

Data regarding driver mutation profiles in tonsillar squamous cell carcinomas (TSCCs) remain scarce, limiting the understanding of its pathogenesis and unexpected behavior in the updated staging system. We investigated the incidence of clinically relevant mutations and their contribution in the prognosis of the condition, and their association with human papillomavirus (HPV) infection and adjuvant therapy. We subjected 43 surgically resected TSCC samples to targeted next-generation sequencing, determined their HPV status using polymerase chain reaction, and performed The Cancer Genomic Atlas and Gene Set Enrichment analyses. Thirty-five TSCC samples (81.4%) showed at least one oncogenic/likely oncogenic mutation among twenty-nine cancer-related genes. The top five mutated genes were TP53 (46.5%), PIK3CA (25.6%), PTEN (18.6%), EGFR (16.3%), and SMAD4 (14.0%). The EGFR pathway was the most frequently affected (51.2%), followed by the p53 (48.8%), PI3K (39.5%), and RTK (34.9%) pathways. The gene set enrichment analysis confirmed that the genes involved in signal transduction, such as growth factor receptors and second messengers, EGFR tyrosine kinase inhibitors, and PI3K signaling pathways, were mostly related with TSCCs. TP53 mutation was an independent prognostic factor predicting worse overall survival in the adjuvant therapy group. RTK mutations were related to survival in all patients and in the HPV-positive group, but multivariate analyses showed no significance. In conclusion, oncogenic/likely oncogenic mutations were relatively high in TSCCs, and TP53 and RTK mutations may be candidate predictors for poor prognosis in the adjuvant therapy and HPV-positive groups, respectively, under the updated staging system.

DNA Damage Response Mechanisms in Head and Neck Cancer: Significant Implications for Therapy and Survival

Head and neck cancer (HNC) is a term collectively used to describe a heterogeneous group of tumors that arise in the oral cavity, larynx, nasopharynx, oropharynx, and hypopharynx, and represents the sixth most common type of malignancy worldwide. Despite advances in multimodality treatment, the disease has a recurrence rate of around 50%, and the prognosis of metastatic patients remains poor. HNCs are characterized by a high degree of genomic instability, which involves a vicious circle of accumulating DNA damage, defective DNA damage repair (DDR), and replication stress. Nonetheless, the damage that is induced on tumor cells by chemo and radiotherapy relies on defective DDR processes for a successful response to treatment, and may play an important role in the development of novel and more effective therapies. This review summarizes the current knowledge on the genes and proteins that appear to be deregulated in DDR pathways, their implication in HNC pathogenesis, and the rationale behind targeting these genes and pathways for the development of new therapies. We give particular emphasis on the therapeutic targets that have shown promising results at the pre-clinical stage and on those that have so far been associated with a therapeutic advantage in the clinical setting.

EGFR pathway targeting drugs in head and neck cancer in the era of immunotherapy

Receptor tyrosine kinases (RTKs) are cell surface receptors that bind growth factor ligands and initiate cellular signaling. Of the 20 classes of RTKs, 7 classes, I-V, VIII, and X, are linked to head and neck cancers (HNCs). We focus on the first class of RTK, epidermal growth factor receptor (EGFR), as it is the most thoroughly studied class. EGFR overexpression is observed in 20% of tumors, and expression of EGFR variant III is seen in 15% of aggressive chemoradiotherapy resistant HNCs. Currently, the EGFR monoclonal antibody (mAb) cetuximab is the only FDA approved RTK-targeting drug for the treatment of HNCs. Clinical trials have also included EGFR mAbs, with tyrosine kinase inhibitors, and small molecule inhibitors targeting the EGFR, MAPK, and mTOR pathways. Additionally, Immunotherapy has been found to be effective in 15 to 20% of patients with recurrent or metastatic HNC as a monotherapy. Thus, attempts are underway for the combinatorial treatment of immunotherapy and EGFR mAbs to determine if the recruitment of immune cells in the tumor microenvironment can overcome EGFR resistance.

Targeting mTOR as a Cancer Therapy: Recent Advances in Natural Bioactive Compounds and Immunotherapy

The mammalian target of rapamycin (mTOR) is a highly conserved serine/threonine-protein kinase, which regulates many biological processes related to metabolism, cancer, immune function, and aging. It is an essential protein kinase that belongs to the phosphoinositide-3-kinase (PI3K) family and has two known signaling complexes, mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). Even though mTOR signaling plays a critical role in promoting mitochondria-related protein synthesis, suppressing the catabolic process of autophagy, contributing to lipid metabolism, engaging in ribosome formation, and acting as a critical regulator of mRNA translation, it remains one of the significant signaling systems involved in the tumor process, particularly in apoptosis, cell cycle, and cancer cell proliferation. Therefore, the mTOR signaling system could be suggested as a cancer biomarker, and its targeting is important in anti-tumor therapy research. Indeed, its dysregulation is involved in different types of cancers such as colon, neck, cervical, head, lung, breast, reproductive, and bone cancers, as well as nasopharyngeal carcinoma. Moreover, recent investigations showed that targeting mTOR could be considered as cancer therapy. Accordingly, this review presents an overview of recent developments associated with the mTOR signaling pathway and its molecular involvement in various human cancer types. It also summarizes the research progress of different mTOR inhibitors, including natural and synthetised compounds and their main mechanisms, as well as the rational combinations with immunotherapies.

Comprehensive Viral Genotyping Reveals Prognostic Viral Phylogenetic Groups in HPV16-Associated Squamous Cell Carcinoma of the Oropharynx

Human papillomavirus-positive (HPV+) squamous cell carcinoma of the oropharynx (OPSCC) is the most prevalent HPV-associated malignancy in the United States and is primarily caused by HPV subtype 16 (HPV16). Favorable treatment outcomes have led to increasing interest in treatment deescalation to reduce treatment-related morbidity. Prognostic biomarkers are needed to identify appropriately low-risk patients for reduced treatment intensity. Targeted DNA sequencing including all HPV16 open reading frames was performed on tumors from 104 patients with HPV16+ OPSCC treated at a single center. Genotypes closely related to the HPV16-A1 reference were associated with increased numbers of somatic copy-number variants in the human genome and poor recurrence-free survival (RFS). Genotypes divergent from HPV16-A1 were associated with favorable RFS. These findings were independent of tobacco smoke exposure. Total RNA sequencing was performed on a second independent cohort of 89 HPV16+ OPSCC cases. HPV16 genotypes divergent from HPV16-A1 were again validated in this independent cohort, to be prognostic of improved RFS in patients with moderate (less than 30 pack-years) or low (no more than 10 pack-years) of tobacco smoke exposure. In summary, we show in two independent cohorts that viral sequence divergence from the HPV16-A1 reference is correlated with improved RFS in patients with moderate or low tobacco smoke exposure.

IMPLICATIONS

HPV16 genotype is a potential biomarker that could be easily adopted to guide therapeutic decision-making related to deescalation therapy.

PIK3CA Gene Mutations in HNSCC: Systematic Review and Correlations with HPV Status and Patient Survival

PIK3CA mutations are believed to contribute to the pathogenesis of human papillomavirus (HPV)-associated head and neck squamous cell carcinomas (HNSCC). This study aims to establish the frequency of PIK3CA mutations in a Portuguese HNSCC cohort and to determine their association with the HPV status and patient survival. A meta-analysis of scientific literature also revealed widely different mutation rates in cohorts from different world regions and a trend towards improved prognosis among patients with PIK3CA mutations. DNA samples were available from 95 patients diagnosed with HNSCC at the Portuguese Institute of Oncology in Lisbon between 2010 and 2019. HPV status was established based on viral DNA detected using real-time PCR. The evaluation of PIK3CA gene mutations was performed by real-time PCR for four mutations (H1047L; E542K, E545K, and E545D). Thirty-seven cases were found to harbour PIK3CA mutations (39%), with the E545D mutation (73%) more frequently detected. There were no significant associations between the mutational status and HPV status (74% WT and 68% MUT were HPV (+); p = 0.489) or overall survival (OS) (3-year OS: WT 54% and MUT 65%; p = 0.090). HPV status was the only factor significantly associated with both OS and disease-free survival (DFS), with HPV (+) patients having consistently better outcomes (3-year OS: HPV (+) 65% and HPV (-) 36%; p = 0.007; DFS HPV (+) 83% and HPV (-) 43%; p = 0.001). There was a statistically significant interaction effect between HPV status and PIK3CA mutation regarding DFS (Interaction test: p = 0.026). In HPV (+) patients, PIK3CA wild-type is associated with a significant 4.64 times increase in the hazard of recurrence or death (HR = 4.64; 95% CI 1.02-20.99; p = 0.047). Overall, PIK3CA gene mutations are present in a large number of patients and may help define patient subsets who can benefit from therapies targeting the PI3K pathway. The systematic assessment of PIK3CA gene mutations in HNSCC patients will require further methodological standardisation.

Whole-Exome Sequencing of HPV Positive Tonsillar and Base of Tongue Squamous Cell Carcinomas Reveals a Global Mutational Pattern along with Relapse-Specific Somatic Variants

Simple Summary

To better prevent/combat recurrence and identify predictive/targetable markers upon diagnosis, we performed whole-exome sequencing (WES) of primary tumours and relapses of human papillomavirus positive (HPV⁺) tonsillar and base of tongue cancer (TSCC/BOTSCC) on patients treated with curative intent, with and without relapse. A specific deletion in the CDC27 gene was observed only in the primaries of 5/17 patients that recurred but in none of the 18 patients without recurrence. Furthermore, three specific variants and 26 mutated genes enriched in mucins were identified in at least 30% of all primaries irrespective of recurrence. To conclude, a specific CDC27 deletion could be specific for recurrent HPV⁺ TSCC/BOTSCC, while BCLAF1, AQP7 and other globally mutated genes could be of significance for further investigation.

Abstract

To identify predictive/targetable markers in human papillomavirus positive (HPV⁺) tonsillar and base of tongue cancer (TSCC/BOTSCC), whole-exome sequencing (WES) of tumours of patients with/without recurrence was performed. Forty primary tumours and adjacent normal tissue were separated by micro-dissection from formalin-fixed paraffin-embedded tissue from patients treated with curative intent 2000–2014 at Karolinska University Hospital. Successful sequencing was obtained in primary tumours of 18 patients without and primaries of 17 with local or distant recurrence, as well as in 10 corresponding recurrences (i.e., five local relapses and five distant metastases) from these 17 patients. One variant—a high-impact deletion in the CDC27 gene—was observed only in primaries of 5/17 patients that had a recurrence after full treatment but in none of those without recurrence. In addition, 3 variants and 26 mutated genes, including CDC27, BCLAF1 and AQP7, were present in at least 30% of all primary tumours independent of prognosis. To conclude, a CDC27 deletion was specific and found in ~30% of samples from patients with a local relapse/distant metastasis and could, therefore, potentially be a prospective marker to predict prognosis. Commonly mutated genes, such as BCLAF1, should be further studied in the context of targeted therapy.

Prognostic and Predictive Clinical and Biological Factors in HPV Malignancies

Human papillomavirus (HPV) causes the majority of oropharyngeal, cervical, and anal cancers, among others. These HPV-associated cancers cause substantial morbidity and mortality despite ongoing vaccination efforts. Aside from the earliest stage tumors, chemoradiation is used to treat most HPV-associated cancers across disease sites. Response rates are variable, and opportunities to improve oncologic control and reduce toxicity remain. HPV malignancies share multiple commonalities in oncogenesis and tumor biology that may inform personalized methods of screening, diagnosis, treatment and surveillance. In this review we discuss the current literature and identify promising molecular targets, prognostic and predictive clinical factors and biomarkers in HPV-associated oropharyngeal, cervical and anal cancer.

Biology of the Radio- and Chemo-Responsiveness in HPV Malignancies

In multiple anatomic sites, patients with cancers associated with the Human Papillomavirus (HPV) experience better locoregional control and overall survival after radiotherapy and/or chemoradiotherapy than patients with HPV-negative cancers. These improved outcomes suggest that relatively unique biological features in HPV-positive cancers may increase sensitivity to DNA damaging agents as well as an impaired DNA damage response. This review will address potential biological mechanisms driving this increased sensitivity of HPV-positive cancer to radiation and/or chemotherapy. This review will discuss the clinical and preclinical observations that support the intrinsic radiosensitivity and/or chemosensitivity of HPV-positive cancers. Furthermore, this review will highlight the molecular mechanisms for increased radiation sensitivity using the classical "4 Rs" of radiobiology: repair, reassortment, repopulation, and reoxygenation. First, HPV-positive cancers have increased DNA damage due to increased oxidative stress and impaired DNA damage repair due to the altered activity TP53, p16, TIP60, and other repair proteins. Second, irradiated HPV-positive cancer cells display increased G2/M arrest leading to reassortment of cancer cells in more radiosensitive phases of the cell cycle. In addition, HPV-positive cancers have less radioresistant cancer stem cell subpopulations that may limit their repopulation during radiotherapy. Finally, HPV-positive cancers may also have less hypoxic tumor microenvironments that make these cancers more sensitive to radiation than HPV-negative cells. We will also discuss extrinsic immune and microenvironmental factors enriched in HPV-positive cancers that facilities responses to radiation. Therefore, these potential biological mechanisms may underpin the improved clinical outcomes often observed in these virally induced cancers.

Targeted Therapy as a Potential De-Escalation Strategy in Locally Advanced HPV-Associated Oropharyngeal Cancer: A Literature Review

The treatment landscape of locally advanced HPV-oropharyngeal squamous cell carcinoma (OPSCC) is undergoing transformation. This is because the high cures rates observed in OPSCC are paired with severe treatment-related, long-term toxicities. These significant adverse effects have led some to conclude that the current standard of care is over-treating patients, and that de-intensifying the regimens may achieve comparable survival outcomes with lower toxicities. Consequently, several de-escalation approaches involving locally advanced OPSCC are underway. These include the reduction of dosage and volume of intensive cytotoxic regimens, as well as elimination of invasive surgical procedures. Such de-intensifying treatments have the potential to achieve efficacy and concurrently alleviate morbidity. Targeted therapies, given their overall safer toxicity profiles, also make excellent candidates for de-escalation, either alone or alongside standard treatments. However, their role in these endeavors is currently limited, because few targeted therapies are currently in clinical use for head and neck cancers. Unfortunately, cetuximab, the only FDA-approved targeted therapy, has shown inferior outcomes when paired with radiation as compared to cisplatin, the standard radio-sensitizer, in recent de-escalation trials. These findings indicate the need for a better understanding of OPSCC biology in the design of rational therapeutic strategies and the development of novel, OPSCC-targeted therapies that are safe and can improve the therapeutic index of standard therapies. In this review, we summarize ongoing research on mechanism-based inhibitors in OPSCC, beginning with the salient molecular features that modulate tumorigenic processes and response, then exploring pharmacological inhibition and pre-clinical validation studies of candidate targeted agents, and finally, summarizing the progression of those candidates in the clinic.

Oropharyngeal Squamous Cell Carcinoma Treatment in the Era of Immune Checkpoint Inhibitors

While head and neck squamous cell carcinomas (HNSCC) are marginally decreasing due to the reduction in exposure to the major risk factors, tobacco and alcohol, the incidence of high-risk human papillomavirus (HPV)-positive oropharynx squamous cell carcinomas (OPSCC), especially those in the tonsil and base of tongue subsites, are increasing. Patients with the latter are younger, display a longer overall survival, and show a lower recurrence rate after standard-of-care treatment than those with HPV-negative OPSCC. This may reflect an important role for immune surveillance and control during the natural history of the virally driven tumour development. Immune deviation through acquisition of immune-suppressive factors in the tumour microenvironment (TME) is discussed in relation to treatment response. Understanding how the different immune factors are integrated in the TME battleground offers opportunities for identifying prognostic biomarkers as well as novel therapeutic strategies. OPSCC generally receive surgery or radiotherapy for early-stage tumour treatment, but many patients present with locoregionally advanced disease requiring multimodality therapies which can involve considerable complications. This review focuses on the utilization of newly emerged immune checkpoint inhibitors (PD-1/PD-L1 pathway) for treatment of HNSCC, in particular HPV-positive OPSCC, since they could be less toxic and more efficacious. PD-1/PD-L1 expression in the TME has been extensively investigated as a biomarker of patient response but is yet to provide a really effective means for stratification of treatment. Extensive testing of combinations of therapeutic approaches by types and sequencing will fuel the next evolution of treatment for OPSCC.

Molecular Tumor Subtypes of HPV-Positive Head and Neck Cancers: Biological Characteristics and Implications for Clinical Outcomes

Until recently, research on the molecular signatures of Human papillomavirus (HPV)-associated head and neck cancers mainly focused on their differences with respect to HPV-negative head and neck squamous cell carcinomas (HNSCCs). However, given the continuing high incidence level of HPV-related HNSCC, the time is ripe to characterize the heterogeneity that exists within these cancers. Here, we review research thus far on HPV-positive HNSCC molecular subtypes, and their relationship with clinical characteristics and HPV integration into the host genome. Different omics data including host transcriptomics and epigenomics, as well as HPV characteristics, can provide complementary viewpoints. Keratinization, mesenchymal differentiation, immune signatures, stromal cells and oxidoreductive processes all play important roles.

CX-4945 and siRNA-Mediated Knockdown of CK2 Improves Cisplatin Response in HPV(+) and HPV(-) HNSCC Cell Lines

Head and neck squamous cell carcinoma (HNSCC) can be categorized into human papillomavirus (HPV) positive or negative disease. Elevated protein kinase CK2 level and activity have been historically observed in HNSCC cells. Previous studies on CK2 in HNSCC did not generally include consideration of HPV(+) and HPV(−) status. Here, we investigated the response of HPV(+) and HPV(−) HNSCC cells to CK2 targeting using CX-4945 or siRNA downregulation combined with cisplatin treatment. HNSCC cell lines were examined for CK2 expression levels and activity and response to CX-4945, with and without cisplatin. CK2 levels and NFκB p65-related activity were high in HPV(+) HNSCC cells relative to HPV(−) HNSCC cells. Treatment with CX-4945 decreased viability and cisplatin IC50 in all cell lines. Targeting of CK2 increased tumor suppressor protein levels for p21 and PDCD4 in most instances. Further study is needed to understand the role of CK2 in HPV(+) and HPV(−) HNSCC and to determine how incorporation of the CK2-targeted inhibitor CX-4945 could improve cisplatin response in HNSCC.

Prognostic Markers and Driver Genes and Options for Targeted Therapy in Human-Papillomavirus-Positive Tonsillar and Base-of-Tongue Squamous Cell Carcinoma

The incidence of Human-papillomavirus-positive (HPV⁺) tonsillar and base-of-tongue squamous cell carcinoma (TSCC and BOTSCC, respectively) is increasing epidemically, but they have better prognosis than equivalent HPV-negative (HPV⁻) cancers, with roughly 80% vs. 50% 3-year disease-free survival, respectively. The majority of HPV⁺ TSCC and BOTSCC patients therefore most likely do not require the intensified chemoradiotherapy given today to head and neck cancer patients and would with de-escalated therapy avoid several severe side effects. Moreover, for those with poor prognosis, survival has not improved, so better-tailored alternatives are urgently needed. In line with refined personalized medicine, recent studies have focused on identifying predictive markers and driver cancer genes useful for better stratifying patient treatment as well as for targeted therapy. This review presents some of these endeavors and briefly describes some recent experimental progress and some clinical trials with targeted therapy.

PIK3CA Mutation in HPV-Associated OPSCC Patients Receiving Deintensified Chemoradiation

PIK3CA is the most frequently mutated gene in human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC). Prognostic implications of such mutations remain unknown. We sought to elucidate the clinical significance of PIK3CA mutations in HPV-associated OPSCC patients treated with definitive chemoradiation (CRT). Seventy-seven patients with HPV-associated OPSCC were enrolled on two phase II clinical trials of deintensified CRT (60 Gy intensity-modulated radiotherapy with concurrent weekly cisplatin). Targeted next-generation sequencing was performed. Of the 77 patients, nine had disease recurrence (two regional, four distant, three regional and distant). Thirty-four patients had mutation(s) identified; 16 had PIK3CA mutations. Patients with wild-type-PIK3CA had statistically significantly higher 3-year disease-free survival than PIK3CA-mutant patients (93.4%, 95% confidence interval [CI] = 85.0% to 99.9% vs 68.8%, 95% CI = 26.7% to 89.8%; P = .004). On multivariate analysis, PIK3CA mutation was the only variable statistically significantly associated with disease recurrence (hazard ratio = 5.71, 95% CI = 1.53 to 21.3; P = .01). PIK3CA mutation is associated with worse disease-free survival in a prospective cohort of newly diagnosed HPV-associated OPSCC patients treated with deintensified CRT.

Genomic heterogeneity and copy number variant burden are associated with poor recurrence-free survival and 11q loss in human papillomavirus-positive squamous cell carcinoma of the oropharynx

BACKGROUND

Human papillomavirus-positive (HPV+) squamous cell carcinoma of the oropharynx (OPSCC) is the most prevalent HPV-associated malignancy in the United States. Favorable treatment outcomes have led to increased interest in treatment de-escalation to reduce treatment morbidity as well as the development of prognostic markers to identify appropriately low-risk patients. Intratumoral genomic heterogeneity and copy number alteration burden have been demonstrated to be predictive of poor outcomes in many other cancers; therefore, we sought to determine whether intratumor heterogeneity and genomic instability are associated with poor outcomes in HPV+ OPSCC.

METHODS

Tumor heterogeneity estimates were made based on targeted exome sequencing of 45 patients with HPV+ OPSCC tumors. Analysis of an additional cohort of HPV+ OPSCC tumors lacking matched normal sequencing allowed copy number analysis of 99 patient tumors.

RESULTS

High intratumorally genomic heterogeneity and high numbers of copy number alterations were strongly associated with worse recurrence-free survival. Tumors with higher heterogeneity and frequent copy number alterations were associated with loss of distal 11q, which encodes key genes related to double-strand break repair, including ATM and MRE11A.

CONCLUSIONS

Both intratumor genomic heterogeneity and high-burden copy number alterations are strongly associated with poor recurrence-free survival in patients with HPV+ OPSCC. The drivers of genomic instability and heterogeneity in these tumors remains to be elucidated. However, 11q loss and defective DNA double-strand break repair have been associated with genomic instability in other solid tumors. Copy number alteration burden and intratumoral heterogeneity represent promising avenues for risk stratification of patients with HPV+OPSCC.

Worldwide prevalence of PI3K-AKT-mTOR pathway mutations in head and neck cancer: A systematic review and meta-analysis

A systematic review (SR) and meta-analysis were conducted to determine the prevalence of PI3K-AKT-mTOR signaling pathway mutations in patients with head and neck cancer (HNC). Overall, 105 studies comprising 8630 patients and 1306 mutations were selected. The estimated mutations prevalence was 13 % for PIK3CA (95 % confidence interval [CI] = 11-14; I² = 82 %; p < 0.0001), 4% for PTEN (95 % CI = 3-5; I² = 55 %; p < 0.0001), 3% for MTOR (95 % CI = 2-4; I² = 5%; p = 0.40), and 2% for AKT (95 % CI = 1-2; I² = 50 %; p = 0.0001). We further stratified the available data of the participants according to risk factors and tumor characteristics, including HPV infection, tobacco use, alcohol exposure, TNM stage, and histological tumor differentiation, and performed subgroup analysis. We identified significant associations between PI3K-AKT-mTOR pathway-associated mutations and advanced TNM stage (odds ratio [OR] = 0.20; 95 % CI = 0.09-0.44; I² = 71 %; p = 0.0001) and oropharyngeal HPV-positive tumors and PIK3CA mutations (OR = 17.48; 95 % CI = 4.20-72.76; I² = 69 %; p < 0.0002). No associations were found between alcohol and tobacco exposure, and tumor differentiation grade. This SR demonstrated that the PI3K-AKT-mTOR pathway emerges as a potential prognostic factor and could offer a molecular basis for future studies on therapeutic targeting in HNC patients.

Cell death in head and neck cancer pathogenesis and treatment

Many cancer therapies aim to trigger apoptosis in cancer cells. Nevertheless, the presence of oncogenic alterations in these cells and distorted composition of tumour microenvironment largely limit the clinical efficacy of this type of therapy. Luckily, scientific consensus describes about 10 different cell death subroutines with different regulatory pathways and cancer cells are probably not able to avoid all of cell death types at once. Therefore, a focused and individualised therapy is needed to address the specific advantages and disadvantages of individual tumours. Although much is known about apoptosis, therapeutic opportunities of other cell death pathways are often neglected. Molecular heterogeneity of head and neck squamous cell carcinomas (HNSCC) causing unpredictability of the clinical response represents a grave challenge for oncologists and seems to be a critical component of treatment response. The large proportion of this clinical heterogeneity probably lies in alterations of cell death pathways. How exactly cells die is very important because the predominant type of cell death can have multiple impacts on the therapeutic response as cell death itself acts as a second messenger. In this review, we discuss the different types of programmed cell death (PCD), their connection with HNSCC pathogenesis and possible therapeutic windows that result from specific sensitivity to some form of PCD in some clinically relevant subgroups of HNSCC.

The PI3K/Akt/mTORC signaling axis in head and neck squamous cell carcinoma: Possibilities for therapeutic interventions either as single agents or in combination with conventional therapies

The latest advances in the sequencing methods in head and neck squamous cell carcinoma (HNSCC) tissues have revolutionized our understanding of the disease by taking off the veil from the most frequent genetic alterations in the components of the oncogenic pathways. Among all the identified alterations, aberrancies in the genes attributed to the phosphoinositide 3-kinases (PI3K) axis have attracted special attention as they were altered in more than 90% of the tissues isolated from HNSCC patients. In fact, the association between these aberrancies and the increased risk of cancer metastasis suggested this axis as an "Achilles Heel" of HNSCC, which may be therapeutically targeted. The results of the clinical trials investigating the therapeutic potential of the inhibitors targeting the components of the PI3K axis in the treatment of HNSCC patients, either alone or in a combined-modal strategy, opened a new chapter in the treatment strategy of this malignancy. The present study aimed to review the importance of the PI3K axis in the pathogenesis of HNSCC and also provide a piece of information about the breakthroughs and challenges of PI3K inhibitors in the therapeutic strategies of the disease.

Global Genome Demethylation Causes Transcription-Associated DNA Double Strand Breaks in HPV-Associated Head and Neck Cancer Cells

High levels of DNA methylation at CpG loci are associated with transcriptional repression of tumor suppressor genes and dysregulation of DNA repair genes. Human papilloma virus (HPV)-associated head and neck squamous cell carcinomas (HNSCC) have high levels of DNA methylation and methylation has been associated with dampening of an innate immune response in virally infected cells. We have been exploring demethylation as a potential treatment in HPV+ HNSCC and recently reported results of a window clinical trial showing that HNSCCs are particularly sensitive to demethylating agent 5-azacytidine (5-aza). Mechanistically, sensitivity is partially due to downregulation of HPV genes expression and restoration of tumor suppressors p53 and Rb. Here, for the first time, we show that 5-azaC treatment of HPV+ HNSCC induces replication and transcription-associated DNA double strand breaks (DSBs) that occur preferentially at demethylated genomic DNA. Blocking replication or transcription prevented formation of DNA DSBs and reduced sensitivity of HPV-positive head and neck cancer cells to 5-azaC, demonstrating that both replication and active transcription are required for formation of DSBs associated with 5-azaC.

An Immunocompetent Mouse Model of HPV16(+) Head and Neck Squamous Cell Carcinoma

The incidence of human papilloma virus (HPV)-associated head and neck squamous cell carcinoma (HNSCC) is increasing and implicated in more than 60% of all oropharyngeal carcinomas (OPSCCs). Although whole-genome, transcriptome, and proteome analyses have identified altered signaling pathways in HPV-induced HNSCCs, additional tools are needed to investigate the unique pathobiology of OPSCC. Herein, bioinformatics analyses of human HPV(+) HNSCCs revealed that all tumors express full-length E6 and identified molecular subtypes based on relative E6 and E7 expression levels. To recapitulate the levels, stoichiometric ratios, and anatomic location of E6/E7 expression, we generated a genetically engineered mouse model whereby balanced expression of E6/E7 is directed to the oropharyngeal epithelium. The addition of a mutant PIK3CA^E545K allele leads to the rapid development of pre-malignant lesions marked by immune cell accumulation, and a subset of these lesions progress to OPSCC. This mouse provides a faithful immunocompetent model for testing treatments and investigating mechanisms of immuno- suppression.

Carper et al. present the ‘‘iKHP’’ mouse, in which HPV16 oncogenes are inducibly activated in vivo in a tissue-specific and temporal manner. Oropharyngeal- specific expression of E6/E7 with PIK3CA^E545K in these mice promotes the development of premalignant lesions marked by immune cell infiltration, but only a subset spontaneously convert to OPSCC.

PIK3CA and p53 Mutations Promote 4NQO-Initated Head and Neck Tumor Progression and Metastasis in Mice

The PI3K signaling pathway is frequently mutated in head and neck squamous cell carcinoma (HNSCC), often via gain-of-function (GOF) mutations in the PIK3CA gene. Here, we present novel genetically engineered mouse models (GEMM) carrying a GOF allele Loxp-STOP-Loxp(LSL)-PIK3CAH1047R (E20) alone or in combination with heterozygous LSL-p53+/R172H (p53) mutation with tissue-specific expression to interrogate the role of oncogenic PIK3CA in transformation of upper aerodigestive track epithelium. We demonstrated that the GOF PIK3CA mutation promoted progression of 4-nitroquinoline 1-oxide-induced oral squamous cell carcinoma (OSCC) in both E20 single mutant and E20/p53 double mutant mice, with frequent distal metastasis detected only in E20/p53 GEMM. Similar to in human OSCC, loss of p16 was associated with progression of OSCC in these mice. RNA-seq analyses revealed that among the common genes differentially expressed in primary OSCC cell lines derived from E20, p53, and E20/p53 GEMMs compared with those from the wild-type mice, genes associated with proliferation and cell cycle were predominantly represented, which is consistent with the progressive loss of p16 detected in these GEMMs. Importantly, all of these OSCC primary cell lines exhibited enhanced sensitivity to BYL719 and cisplatin combination treatment in comparison with cisplatin alone in vitro and in vivo, regardless of p53 and/or p16 status. Given the prevalence of mutations in p53 and the PI3K pathways in HNSCC in conjunction with loss of p16 genetically or epigenetically, this universal increased sensitivity to cisplatin and BYL719 combination therapy in cancer cells with PIK3CA mutation represents an opportunity to a subset of patients with HNSCC. IMPLICATIONS: Our results suggest that combination therapy of cisplatin and PI3K inhibitor may be worthy of consideration in patients with HNSCC with PIK3CA mutation.

A global epidemic increase of an HPV-induced tonsil and tongue base cancer - potential benefit from a pan-gender use of HPV vaccine

In 2007, human papillomavirus (HPV) type 16 was finally recognized as a risk factor, besides smoking and alcohol, for oropharyngeal squamous cell carcinoma (OPSCC), including tonsillar squamous cell carcinoma (TSCC), by the International Agency for Research against Cancer. Just before, in 2006, the Food and Drug Administration had approved Gardasil, the first vaccine against HPV16, 18, 6 and 11, for preventive vaccination women against cervical cancer. Concurrently, some Western countries, where smoking was decreasing, disclosed an epidemic increase in the incidence of OPSCC, especially of TSCC and base of tongue cancer (BOTSCC), together accounting for 80-90% of all OPSCCs, and mainly affecting men. The epidemic was later revealed to be due to a rise in HPV-positive cases, and scientists in the field suggested HPV vaccination also of boys. Globally, there are roughly 96 000 incident OPSCC cases/year of which 20-24% are caused by HPV, thereby accounting for around 22 000 OPSCC cases annually. Of these cases, 80-90% are due to HPV16 infection and would be prevented with the presently registered HPV vaccines. In Western countries, such as Sweden (with almost 400 TSCC and BOTSCC cases per year) and the United States, HPV prevalence in OPSCC is higher and around 70%. HPV vaccination of girls has been initiated in many countries, and the vaccines have been efficient and their side effects limited. HPV vaccination of boys has, however, been the exception, but should definitely not be delayed any further. It would benefit both girls and boys directly, and result in better and more robust herd immunity. Today, we have the possibility to eliminate several high-risk HPV types in the younger generations and avoid more than 600 000 cancer cases annually worldwide, and this possibility should be embraced by offering global pan-gender HPV vaccination.

Clinical Development of Molecular Targeted Therapy in Head and Neck Squamous Cell Carcinoma

A better understanding of cancer biology has led to the development of molecular targeted therapy, which has dramatically improved the outcome of some cancer patients, especially when a biomarker of efficacy has been used for patients' selection. In head and neck oncology, cetuximab that targets epidermal growth factor receptor is the only targeted therapy that demonstrated a survival benefit, both in the recurrent and in the locally advanced settings, yet without prior patients' selection. We herein review the clinical development of targeted therapy in head and neck squamous cell carcinoma in light of the molecular landscape and give insights in on how innovative clinical trial designs may speed up biomarker discovery and deployment of new molecular targeted therapies. Given the recent approval of immune checkpoint inhibitors targeting programmed cell death-1 in head and neck squamous cell carcinoma, it remains to be determined how targeted therapy will be incorporated into a global drug development strategy that will inevitably incorporate immunotherapy.

Utility of a Reverse Phase Protein Array to Evaluate Multiple Biomarkers in Diffuse Large B-Cell Lymphoma

Purpose

Diffuse large B‐cell lymphoma (DLBCL), the most common non‐Hodgkin lymphoma, is a heterogeneous lymphoma with different clinical manifestations and molecular alterations, and several markers are currently being measured routinely for its diagnosis, subtyping, or prognostication by immunohistochemistry (IHC). Here, the utility of a reverse‐phase‐protein‐array (RPPA) as a novel supportive tool to measure multiple biomarkers for DLBCL diagnosis is validated.

Experimental design

The expression of seven markers (CD5, CD10, BCL2, BCL6, MUM1, Ki‐67, and C‐MYC) is analyzed by RPPA and IHC using 37 DLBCL tissues, and the correlation between the two methods is determined. To normalize tumor content ratio in the tissues, the raw RPPA values of each marker are adjusted by that of CD20 or PAX‐5.

Results

The CD20‐adjusted data for CD5, MUM1, BCL2, Ki‐67, and C‐MYC has better correlation with IHC results than PAX‐5‐adjusted data. Receiver operating characteristic (ROC) analysis reveals that CD5, MUM1, BCL2, and C‐MYC exhibit a better sensitivity and specificity >0.750. Furthermore, the CD20‐adjusted C‐MYC value strongly correlates with that of IHC, and has a particularly high specificity (0.882).

Conclusions and clinical relevance

Although further investigation using a large number of DLBCL specimens needs to be conducted, these results suggest that RPPA could be applicable as a supportive tool for determining lymphoma prognosis.

E6 Oncoproteins from High-Risk Human Papillomavirus Induce Mitochondrial Metabolism in a Head and Neck Squamous Cell Carcinoma Model

Head and neck squamous cell carcinoma (HNSCC) cells that are positive for human papillomavirus (HPV+) favor mitochondrial metabolism rather than glucose metabolism. However, the involvement of mitochondrial metabolism in HNSCC HPV+ cells is still unknown. The aim of this work was to evaluate the role of E6 oncoproteins from HPV16 and HPV18 in the mitochondrial metabolism in an HNSCC model. We found that E6 from both viral types abates the phosphorylation of protein kinase B-serine 473 (pAkt), which is associated with a shift in mitochondrial metabolism. E6 oncoproteins increased the levels of protein subunits of mitochondrial complexes (I to IV), as well as the ATP synthase and the protein levels of the voltage dependent anion channel (VDAC). Although E6 proteins increased the basal and leak respiration, the ATP-linked respiration was not affected, which resulted in mitochondrial decoupling. This increase in leak respiration was associated to the induction of oxidative stress (OS) in cells expressing E6, as it was observed by the fall in the glutathione/glutathione disulfide (GSH/GSSG) rate and the increase in reactive oxygen species (ROS), carbonylated proteins, and DNA damage. Taken together, our results suggest that E6 oncoproteins from HPV16 and HPV18 are inducers of mitochondrial metabolism.

Novel K6-K14 keratin fusion enhances cancer stemness and aggressiveness in oral squamous cell carcinoma

Keratin intermediate filament (IF) is one component of cellular architectures, which provides necessary mechanical support to conquer environmental stresses. Recent findings reveal its involvement in mechano-transduction and the associated stem cell reprogramming, suggesting the possible roles in cancer development. Here, we report t(12;17)(q13.13;q21.2) chromosomal rearrangement as the most common fusion event in OSCC, resulting in a variety of inter-keratin fusions. Junction site mapping verified 9 in-frame K6-K14 variants, three of which were correlated with lymph node invasion, late tumor stages (T3/T4) and shorter disease-free survival times. When expressed in OSCC cells, those fusion variants disturbed wild-type K14 organization through direct interaction or aggregate formation, leading to perinuclear structure loss and nuclear deformation. Protein array analyses showed the ability of K6-K14 variant 7 (K6-K14/V7) to upregulate TGF-β and G-CSF signaling, which contributed to cell stemness, drug tolerance, and cell aggressiveness. Notably, K6-K14/V7-expressing cells easily adapted to a soft 3-D culture condition in vitro and formed larger, less differentiated tumors in vivo. In addition to the anti-mechanical-stress activity, our data uncover oncogenic functionality of novel keratin filaments caused by gene fusions during OSCC development.

Combined Aurora Kinase A (AURKA) and WEE1 Inhibition Demonstrates Synergistic Antitumor Effect in Squamous Cell Carcinoma of the Head and Neck

PURPOSE

Human papillomavirus (HPV)-negative head and neck squamous cell carcinomas (HNSCC) commonly bear disruptive mutations in TP53, resulting in treatment resistance. In these patients, direct targeting of p53 has not been successful, but synthetic lethal approaches have promise. Although Aurora A kinase (AURKA) is overexpressed and an oncogenic driver, its inhibition has only modest clinical effects in HPV-negative HNSCC. We explored a novel combination of AURKA and WEE1 inhibition to overcome intrinsic resistance to AURKA inhibition.Experimental Design: AURKA protein expression was determined by fluorescence-based automated quantitative analysis of patient specimens and correlated with survival. We evaluated treatment with the AURKA inhibitor alisertib (MLN8237) and the WEE1 inhibitor adavosertib (AZD1775), alone or in combination, using in vitro and in vivo HNSCC models.

RESULTS

Elevated nuclear AURKA correlated with worse survival among patients with p16(-) HNSCC. Alisertib caused spindle defects, G₂-M arrest and inhibitory CDK1 phosphorylation, and cytostasis in TP53 mutant HNSCC FaDu and UNC7 cells. Addition of adavosertib to alisertib instead triggered mitotic entry and mitotic catastrophe. Moreover, in FaDu and Detroit 562 xenografts, this combination demonstrated synergistic effects on tumor growth and extended overall survival compared with either vehicle or single-agent treatment.

CONCLUSIONS

Combinatorial treatment with adavosertib and alisertib leads to synergistic antitumor effects in in vitro and in vivo HNSCC models. These findings suggest a novel rational combination, providing a promising therapeutic avenue for TP53-mutated cancers.

Novel genetic alterations and their impact on target therapy response in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is highly variable by tumor site, histologic type, molecular characteristics, and clinical outcome. During recent years, emerging targeted therapies have been focused on driver genes. HNSCC involves several genetic alterations, such as co-occurrence, multiple feedback loops, and cross-talk communications. These different kinds of genetic alterations interact with each other and mediate targeted therapy response. In the current review, it is emphasized that future treatment strategy in HNSCC will not solely be based on "synthetic lethality" approaches directed against overactivated genes. More importantly, biologic, genetic, and epigenetic alterations of HNSCC will be taken into consideration to guide the therapy. The emerging genetic alterations in HNSCC and its effect on targeted therapy response are discussed in detail. Hopefully, novel combination regimens for the treatment of HNSCC can be developed.

HPV-driven oropharyngeal cancer: current knowledge of molecular biology and mechanisms of carcinogenesis

Understanding of oropharyngeal squamous cell carcinoma has significantly progressed over the last decades, and the concept that this disease can be subdivided into two distinct entities based on human papilloma virus (HPV) status has gained acceptance. To combat the constantly growing epidemic of HPV+ oropharyngeal cancer, further investigation and characterization the unique features of the disease, along with the development and implementation of new, targeted therapies, is crucial. In this review, we summarize the etiology, pathogenesis, diagnosis, treatment, and molecular characteristics of HPV-associated oropharyngeal squamous cell carcinoma.

Treatment Delays in Primarily Resected Oropharyngeal Squamous Cell Carcinoma: National Benchmarks and Survival Associations

OBJECTIVE

To characterize treatment delays in surgically treated oropharyngeal cancer, identify factors associated with delays, and associate delays with survival.

STUDY DESIGN

Retrospective cross-sectional analysis.

SETTING

Commission on Cancer-accredited institutions.

SUBJECTS AND METHODS

We identified patients in the National Cancer Database with surgically treated oropharyngeal cancer. We characterized the durations of diagnosis-to-treatment initiation, surgery-to-radiation treatment, radiation treatment duration, total treatment package, and diagnosis-to-treatment end intervals as medians. We associated delays with patient, tumor, and treatment factors via multivariable logistic regression analysis and with overall survival by Cox proportional hazards regression.

RESULTS

In total, 3708 patients met inclusion criteria. Median durations of diagnosis-to-treatment initiation, surgery-to-radiation treatment, radiation treatment duration, total treatment package, and diagnosis-to-treatment end intervals were 27, 42, 47, 90, and 106 days, respectively. Medicaid and human papillomavirus (HPV) negativity were associated with delays. Delayed total treatment package and diagnosis-to-treatment end intervals were associated with decreased survival (hazard ratio [HR] = 1.81 [1.29-2.54], P = .001 and HR = 1.97 [1.39-2.78], P < .001, respectively); this was maintained following HPV stratification. Delays in the surgery-to-radiation treatment interval were associated with decreased overall survival in HPV-negative but not HPV-positive patients (HR = 2.05 [1.19-3.52], P = .010 and HR = 1.15 [0.74-1.80], P = .535, respectively). Diagnosis-to-treatment initiation and radiation treatment duration were not associated with overall survival in the overall cohort (HR = 1.21 [0.86-1.72], P = .280 and HR = 1.40 [0.99-1.99], P = .061, respectively); however, following stratification, delayed radiation treatment duration approached significance in HPV-negative but not HPV-positive patients (HR = 1.60 [0.96-2.68], P = .072 and HR = 1.35 [0.84-2.18], P = .220).

CONCLUSION

Treatment durations identified here can serve as national benchmarks and for institutions to compare quality to their peers. Distinct benchmarks should be applied to HPV-negative and HPV-positive patients.

High-Throughput Phosphorylation Screening and Validation through Ti(IV)-Nanopolymer Functionalized Reverse Phase Phosphoprotein Array

Protein phosphorylation is one of the most important and widespread molecular regulatory mechanisms that controls almost all aspects of cellular functions in animals and plants. Here, we introduce a novel chemically functionalized reverse phase phosphoprotein array (RP3A) to capture and measure phosphoproteomes. RP3A uses polyamidoamine (PAMAM) dendrimer immobilized with Ti(IV) ions to functionalize nitrocellulose membrane, facilitating specific chelation of phosphoproteins from complex protein samples on the array. Globular, water-soluble Ti(IV)-dendrimer allows the RP3A surface to be highly accessible to phosphoproteins multidimensionally, and the captured phosphoproteins were subsequently detected using the same validated antibodies as in regular reverse-phase protein arrays. The novel chemical strategy demonstrated superior specificity (1:10 000), high sensitivity (fg level), and good quantitative nature ( R² = 0.99) for measuring phosphoproteins. We further applied quantitative phosphoproteomics followed by RP3A to validate the phosphorylation status of a panel of phosphoproteins in response to environmental stresses in Arabidopsis.

Comparison of PI3K Pathway in HPV-Associated Oropharyngeal Cancer With and Without Tobacco Exposure

Objectives

The aim of the study was to evaluate whether HPV associated OPSCC with tobacco exposure follows a different carcinogenic pathway compared to HPV associated OPSCC without tobacco exposure and to investigate its prognostic significance. The question was addressed with focus on components of the PI3K pathway.

Methods

184 patients with newly diagnosed OPSCC treated with curative intent were consecutively enrolled. The expression level of p16, p53, PI3K, mTOR, and PTEN was assessed by immunohistochemistry and analyzed in relation to the risk factors HPV status and tobacco exposure.

Results

94 of 184 (51%) patients were p16 positive, p53 overexpression was detected in 48 of 184 (26%) cases. PI3K overexpression with 70 of 184 (38%) cases was significantly higher in p16 positive tumors. mTOR overexpression was present in 90 of 184 (49%) cases and significantly higher in p16 negative tumors. PTEN loss was found in 42 of 184 (23%) cases without association to p16 expression. p16 positive OPSCC showed lower rates of p53 expression and mTOR expression as well as higher rates of PI3K expression irrespective of tobacco exposure. Survival analysis showed a distinct intermediate survival rate of p16 positive smokers. The markers PI3K, mTOR, and PTEN did not have a significant impact on survival.

Conclusion

HPV associated OPSCC with tobacco exposure follows the same expression level of the PI3K pathway as HPV associated OPSCC without tobacco exposure. The impaired survival rate of the intermediate risk group cannot be explained by different expression patterns of PI3K, mTOR, and PTEN.

Level of Evidence

2b

Targeting phosphoinositide 3-kinase (PI3K) in head and neck squamous cell carcinoma (HNSCC)

The landscape of head and neck squamous cell carcinoma (HNSCC) has been changing rapidly due to growing proportion of HPV-related disease and development of new therapeutic agents. At the same time, there has been a constant need for individually tailored treatment based on genetic biomarkers in order to optimize patient survival and alleviate treatment-related toxicities. In this regard, aberrations of PI3K pathway have important clinical implications in the treatment of HNSCC. They frequently constitute ‘gain of function’ mutations which trigger oncogenesis, and PI3K mutations can also lead to emergence of drug resistance after treatment with EGFR inhibitors. In this article, we review PI3K pathway as a target of treatment for HNSCC and summarize PI3K/mTOR inhibitors that are currently under clinical trials. In light of recent advancement of immune checkpoint inhibitors, consideration of PI3K inhibitors as potential immune modulators is also suggested.

The molecular landscape of head and neck cancer

Head and neck squamous cell carcinomas (HNSCCs) arise in the mucosal linings of the upper aerodigestive tract and are unexpectedly heterogeneous in nature. Classical risk factors are smoking and excessive alcohol consumption, and in recent years, the role of human papillomavirus (HPV) has emerged, particularly in oropharyngeal tumours. HPV-induced oropharyngeal tumours are considered a separate disease entity, which recently has manifested in an adapted prognostic staging system while the results of de-intensified treatment trials are awaited. Carcinogenesis caused by HPV in the mucosal linings of the upper aerodigestive tract remains an enigma, but with some recent observations, a model can be proposed. In 2015, The Cancer Genome Atlas (TCGA) consortium published a comprehensive molecular catalogue on HNSCC. Frequent mutations of novel druggable oncogenes were not demonstrated, but the existence of a subgroup of genetically distinct HPV-negative head and neck tumours with favourable prognoses was confirmed. Tumours can be further subclassified based on genomic profiling. However, the amount of molecular data is currently overwhelming and requires detailed biological interpretation. It also became apparent that HNSCC is a disease characterized by frequent mutations that create neoantigens, indicating that immunotherapies might be effective. In 2016, the first results of immunotherapy trials with immune checkpoint inhibitors were published, and these may be considered as a paradigm shift in head and neck oncology.

Protein Expression in Tonsillar and Base of Tongue Cancer and in Relation to Human Papillomavirus (HPV) and Clinical Outcome

Human papillomavirus (HPV) is a major etiological factor for tonsillar and the base of tongue cancer (TSCC/BOTSCC). HPV-positive and HPV-negative TSCC/BOTSCC present major differences in mutations, mRNA expression and clinical outcome. Earlier protein studies on TSCC/BOTSCC have mainly analyzed individual proteins. Here, the aim was to compare a larger set of cancer and immune related proteins in HPV-positive and HPV-negative TSCC/BOTSCC in relation to normal tissue, presence of HPV, and clinical outcome. Fresh frozen tissue from 42 HPV-positive and 17 HPV-negative TSCC/BOTSCC, and corresponding normal samples, were analyzed for expression of 167 proteins using two Olink multiplex immunoassays. Major differences in protein expression between TSCC/BOTSCC and normal tissue were identified, especially in chemo- and cytokines. Moreover, 34 proteins, mainly immunoregulatory proteins and chemokines, were differently expressed in HPV-positive vs HPV-negative TSCC/BOTSCC. Several proteins were potentially related to clinical outcome for HPV-positive or HPV-negative tumors. For HPV-positive tumors, these were mostly related to angiogenesis and hypoxia. Correlation with clinical outcome of one of these, VEGFA, was validated by immunohistochemistry. Differences in immune related proteins between HPV-positive and HPV-negative TSCC/BOTSCC reflect the stronger activity of the immune defense in the former. Angiogenesis related proteins might serve as potential targets for therapy in HPV-positive TSCC/BOTSCC.

Metastatic model of HPV+ oropharyngeal squamous cell carcinoma demonstrates heterogeneity in tumor metastasis

Human papillomavirus induced (HPV+) cancer incidence is rapidly rising, comprising 60–80% of oropharyngeal squamous cell carcinomas (OPSCCs); while rare, recurrent/metastatic disease accounts for nearly all related deaths. An in vivo pre-clinical model for these invasive cancers is necessary for testing new therapies. We characterize an immune competent recurrent/metastatic HPV+ murine model of OPSSC which consists of four lung metastatic (MLM) cell lines isolated from an animal with HPV+ OPSCC that failed cisplatin/radiation treatment. These individual metastatic clonal cell lines were tested to verify their origin (parental transgene expression and define their physiological properties: proliferation, metastatic potential, heterogeneity and sensitivity/resistance to cisplatin and radiation. All MLMs retain expression of parental HPV16 E6 and E7 and degrade P53 yet are heterogeneous from one another and from the parental cell line as defined by Illumina expression microarray. Consistent with this, reverse phase protein array defines differences in protein expression/activation between MLMs as well as the parental line. While in vitro growth rates of MLMs are slower than the parental line, in vivo growth of MLM clones is greatly enhanced. Moreover, in vivo resistance to standard therapies is dramatically increased in 3 of the 4 MLMs. Lymphatic and/or lung metastasis occurs 100% of the time in one MLM line. This recurrent/metastatic model of HPV+ OPSCC retains the characteristics evident in refractory human disease (heterogeneity, resistance to therapy, metastasis in lymph nodes/lungs) thus serving as an ideal translational system to test novel therapeutics. Moreover, this system may provide insights into the molecular mechanisms of metastasis.

Impact of PI3K/AKT/mTOR pathway activation on the prognosis of patients with head and neck squamous cell carcinomas

The PI3K/AKT/mTOR signaling pathway has emerged as one of the most frequently deregulated in head and neck squamous cell carcinomas (HNSCC). Numerous alterations of various upstream and downstream components have been described; however, their prognostic significance and impact on HNSCC patient survival remains to be established. This was addressed using an unbiased cohort of 93 consecutive and homogeneous surgically treated HNSCC patients and results confirmed in 432 HNSCC patients. Our findings reveal the high prevalence of S6 phosphorylation, a surrogate marker of mTORC1 activation, in HNSCC specimens (>70%) and, more importantly, demonstrate its relevance on clinical outcome. Phosphorylation of ribosomal protein S6 on either Ser235/236 or Ser240/244 was consistently and significantly correlated with favorable prognosis, although with differences depending on the tumor site. Thus, p-S6 expression was significantly correlated with better disease-specific survival specifically in the subgroup of laryngeal carcinoma patients (P< 0.001). In addition, multivariate regression models revealed p-S6 to be an inverse and independent predictor of lymph-node metastasis (P= 0.004) and distant metastasis (P= 0.006). Taken together, this study unveils an unprecedented correlation of mTOR activation with improved clinical outcome in patients with laryngeal carcinomas and uncovers the potential of p-S6 expression as a good prognostic biomarker and an inverse predictor of lymph node and distant metastases. These results should be of broad interest as immunohistochemical detection of p-S6 may help to stratify patients and guide treatment decisions.

Therapeutic Implications of the Genetic Landscape of Head and Neck Cancer

Large-scale sequencing studies of head and neck squamous cell carcinoma (HNSCC) have elucidated the genetic changes that characterize HNSCC. These findings have supported the development of therapeutic strategies that target key components of aberrant signaling pathways and immune dysregulation. Cumulative evidence suggests that these agents in combination with radiotherapy may have synergistic effects. This review highlights the predictive biomarkers that have been identified from HNSCC genomic studies and implications on the development of molecular-targeting agents that may effectively treat patients with HNSCC, especially when used in combination with radiation.

Role of the Akt/mTOR signaling pathway in human papillomavirus-associated nasal and sinonasal inverted papilloma

Nasal and sinonasal inverted papilloma (NSIP) is a benign tumor in which surface epithelial cells grow downward into the underlying supportive tissue with varying degrees of metaplasia. Human papillomavirus (HPV) has been proposed as the causal agent in the pathogenesis of this disease. Many studies have shown that HPV can activate the Akt/mechanistic target of rapamycin (mTOR) signaling pathway, but the role of this pathway in HPV-associated NSIP is largely unknown. In this study, we enrolled 40 control tissue samples and 80 NSIP tissue samples. HPV genotyping showed that 47 of the 80 examined cases of NSIP were HPV-positive (58.8%), and the most common subtype was HPV11 (20/53, 37.7%). The immunohistochemistry showed statistically significant differences in phosphorylated Akt and phosphorylated S6 ribosomal protein staining among control samples, HPV-positive NSIP and HPV-negative NSIP. The HPV11 L1-L2 plasmid increased the proliferation of normal human nasopharyngeal epithelial NP69-SV40T cells and human nasopharyngeal cancer CNE1 cells. Meanwhile, rapamycin, an mTOR inhibitor, reversed the increased cell proliferation induced by the HPV11 L1-L2 plasmid. Western blot analysis showed that Akt/mTOR/S6 were overexpressed in NP69-SV40T cells and CNE1 cells infected with the HPV11 L1-L2 plasmid. These data demonstrate that HPV promotes cell proliferation through the Akt/mTOR signaling pathway in NSIP.