Phase I trial of everolimus in combination with thoracic radiotherapy in non-small-cell lung cancer

Targeting mTOR and Survivin Concurrently Potentiates Radiation Therapy in Renal Cell Carcinoma by Suppressing DNA Damage Repair and Amplifying Mitotic Catastrophe

Background

Renal cell carcinoma (RCC) was historically considered to be less responsive to radiation therapy (RT) compared to other cancer indications. However, advancements in precision high-dose radiation delivery through single-fraction and multi-fraction stereotactic ablative radiotherapy (SABR) have led to better outcomes and reduced treatment-related toxicities, sparking renewed interest in using RT to treat RCC. Moreover, numerous studies have revealed that certain therapeutic agents including chemotherapies can increase the sensitivity of tumors to RT, leading to a growing interest in combining these treatments. Here, we developed a rational combination of two radiosensitizers in a tumor-targeted liposomal formulation for augmenting RT in RCC. The objective of this study is to assess the efficacy of a tumor-targeted liposomal formulation combining the mTOR inhibitor everolimus (E) with the survivin inhibitor YM155 (Y) in enhancing the sensitivity of RCC tumors to radiation.

Experimental Design

We slightly modified our previously published tumor-targeted liposomal formulation to develop a rational combination of E and Y in a single liposomal formulation (EY-L) and assessed its efficacy in RCC cell lines in vitro and in RCC tumors in vivo. We further investigated how well EY-L sensitizes RCC cell lines and tumors toward radiation and explored the underlying mechanism of radiosensitization.

Results

EY-L outperformed the corresponding single drug-loaded formulations E-L and Y-L in terms of containing primary tumor growth and improving survival in an immunocompetent syngeneic mouse model of RCC. EY-L also exhibited significantly higher sensitization of RCC cells towards radiation in vitro than E-L and Y-L. Additionally, EY-L sensitized RCC tumors towards radiation therapy in xenograft and murine RCC models. EY-L mediated induction of mitotic catastrophe via downregulation of multiple cell cycle checkpoints and DNA damage repair pathways could be responsible for the augmentation of radiation therapy.

Conclusion

Taken together, our study demonstrated the efficacy of a strategic combination therapy in sensitizing RCC to radiation therapy via inhibition of DNA damage repair and a substantial increase in mitotic catastrophe. This combination therapy may find its use in the augmentation of radiation therapy during the treatment of RCC patients.

Non-Small Cell Lung Cancer Treatment with Molecularly Targeted Therapy and Concurrent Radiotherapy—A Review

Lung cancer is the leading cause of death worldwide for both men and women. Surgery can be offered as a radical treatment at stages I and II and selected cases of stage III (III A). Whereas at more advanced stages, combined modalities of treatment are applied: radiochemotherapy (IIIB) and molecularly targeted treatment (small molecule tyrosine kinase inhibitors, VEGF receptor inhibitors, monoclonal antibodies, and immunological treatment with monoclonal antibodies). Combination treatment, composed of radiotherapy and molecular therapy, is increasingly employed in locally advanced and metastatic lung cancer management. Recent studies have indicated a synergistic effect of such treatment and modification of immune response. The combination of immunotherapy and radiotherapy may result in the enhancement of the abscopal effect. Anti-angiogenic therapy, in combination with RT, is associated with high toxicity and should be not recommended. In this paper, the authors discuss the role of molecular treatment and the possibility of its concurrent use with radiotherapy in non-small cell lung cancer (NSCLC).

The PIK3CA-E545K-SIRT4 signaling axis reduces radiosensitivity by promoting glutamine metabolism in cervical cancer

The mutation of glutamic acid 545 to lysine (E545K) in PIK3CA, as the most common missense mutation of this gene in various cancer types, is frequently observed in cervical cancer and has been shown to reduce cervical cancer radiosensitivity. However, the underlying mechanisms remain unclear. Here, we implicate the alterations of glutamine metabolism in PIK3CA-E545K-mediated radioresistance of cervical cancer. Specifically, PIK3CA mutation negatively regulated the expression of SIRT4 via the epigenetic regulator EP300 independently of the canonical mTORC1 pathway. PIK3CA-E545K-induced SIRT4 downregulation promoted cell proliferation, migration, and radiation-induced DNA repair and apoptosis, while SIRT4 overexpression reversed the radioresistance phenotype mediated by PIK3CA mutation. Mechanistically, SIRT4 modulated glutamine metabolism and thus cellular apoptosis by negatively regulating a glutamate pyruvate transaminase GPT1. Moreover, the PI3K inhibitor BYL719, but not mTOR inhibitors, exerted remarkable synergistic effects with radiotherapy by inhibiting glutamine metabolism in vitro and in vivo. Collectively, this study reveals the role of PIK3CA-E545K-SIRT4 axis in regulating glutamine metabolism and the radioresistance in cervical cancer, which provides a necessary preliminary basis for clinical research of PI3K inhibitors as radiosensitizing agents.

Radiation therapy-induced left vocal cord paralysis following lung stereotactic body radiation therapy: A case report and review of the literature

We report the case of a 50-year old women with an oncological history of metastatic breast carcinoma who underwent lung stereotactic body radiation therapy (SBRT) of 60Gy in 8 fractions for a left upper lobe metastatic lesion. Seven months later, she complains about hoarseness and weakness of voice. Tumoral relapse and other frequent etiologies were excluded. The diagnosis of radiation induced left recurrent laryngeal nerve paralysis causing left vocal cord paralysis (VCP) was made. The symptomatology did not improve till the disease progression and death of the patient 29 months after SBRT. VCP after lung SBRT is a rare adverse event that has not yet been well described in the medical literature.

Histone lysine methyltransferase SETDB2 suppresses NRF2 to restrict tumor progression and modulates chemotherapy sensitivity in lung adenocarcinoma

OBJECTIVE

Aberrant epigenetic remodeling represents a molecular hallmark in lung adenocarcinoma (LUAD). We aim to investigate the biological roles of SETDB2 and its underlying associations with oxidative stress, providing therapeutic targets for individualized treatment of LUAD.

METHODS

Differential analysis was conducted via Limma package, and Kaplan-Meier analysis was performed with survival package. CCK-8, cell proliferation assay, transwell assay, and in vivo assays were conducted to assess the function of SETDB2. Western blot assay, RT-qPCR, and immunohistochemistry (IHC) were conducted to assess the expression levels of SETDB2/NRF2. Chromatin immunoprecipitation (ChIP) assay and ChIP-qPCR were conducted to assess the epigenetic roles of SETDB2.

RESULTS

We found that SETDB2 expression is decreased in tumor samples versus normal tissues in TCGA-LUAD cohort, LUAD-EAS cohort, GSE72094 dataset, and independent Soochow-LUAD dataset. Patients with low SETDB2 levels had a worse prognosis relative to those with high SETDB2. SETDB2 inhibition could significantly promote cell growth, migration ability, and stemness maintenance. Gene set enrichment analysis (GSEA) suggested that SETDB2 correlated with oxidative stress crosstalk and regulated NRF2 mRNA levels. ChIP assay suggested that SETDB2 mainly recruited the H3K9me3 enrichment at the NRF2 promoter region to suppress the mRNA levels of NRF2. Downregulated SETDB2 could activate NRF2 transcription and expression, thereby promoting its downstream targets, like NQO1, FTH1, and ME1. Functional experiments demonstrated that low SETDB2 allowed NRF2 to drive malignant processes of LUAD. SETDB2 overexpression attenuated the ability of NRF2 signaling to neutralize cellular reactive oxygen species (ROS) levels, leading to enhanced cell apoptosis. Overexpressed SETDB2 could inhibit tumor progression in vivo and further render LUAD cells sensitive to chemotherapy.

CONCLUSIONS

In conclusion, these findings uncovered the suppressive role of SETDB2 in LUAD. SETDB2 negatively regulates NRF2 signaling to modulate tumor progression, which creates a therapeutic vulnerability in LUAD.

Imaging of Drug-Related Pneumonitis in Oncology

Clinical applications of novel anticancer agents in the past few decades brought marked advances in cancer treatment, enabling remarkable efficacy and effectiveness; however, these novel agents are also associated with toxicities. Among various toxicities, drug-related pneumonitis is one of the major clinical challenges in the management of cancer patients. Imaging plays a key role in detection, diagnosis, and monitoring of drug-related pneumonitis during cancer treatment. In the current era of precision oncology, pneumonitis from molecular targeted therapy and immune-checkpoint inhibitors (ICI) has been recognized as an event of clinical significance. Additionally, further advances of therapeutic approaches in cancer have brought several emerging issues in diagnosis and monitoring of pneumonitis. This article will describe the computed tomography (CT) pattern-based approach for drug-related pneumonitis that has been utilized to describe the imaging manifestations of pneumonitis from novel cancer therapies. Then, we will discuss pneumonitis from representative agents of precision cancer therapy, including mammalian target of rapamycin inhibitors, epidermal growth factor receptor inhibitors, and ICI, focusing on the incidence, risk factors, and the spectrum of CT patterns. Finally, the article will address emerging challenges in the diagnosis and monitoring of pneumonitis, including pneumonitis from combination ICI and radiation therapy and from antibody conjugate therapy, as well as the overlapping imaging features of drug-related pneumonitis and coronavirus disease 2019 pneumonia. The review is designed to provide a practical overview of drug-related pneumonitis from cutting-edge cancer therapy with emphasis on the role of imaging.

Targeting Epithelial-to-Mesenchymal Transition in Radioresistance: Crosslinked Mechanisms and Strategies

Radiotherapy exerts a crucial role in curing cancer, however, its treatment efficiency is mostly limited due to the presence of radioresistance. Epithelial-to-mesenchymal transition (EMT) is a biological process that endows the cancer cells with invasive and metastatic properties, as well as radioresistance. Many potential mechanisms of EMT-related radioresistance being reported have broaden our cognition, and hint us the importance of an overall understanding of the relationship between EMT and radioresistance. This review focuses on the recent progresses involved in EMT-related mechanisms in regulating radioresistance, irradiation-mediated EMT program, and the intervention strategies to increase tumor radiosensitivity, in order to improve radiotherapy efficiency and clinical outcomes of cancer patients.

The PI3K/AKT/mTOR signaling pathway inhibitors enhance radiosensitivity in cancer cell lines

INTRODUCTION

Radiotherapy is one of the most common types of cancer treatment modalities. Radiation can affect both cancer and normal tissues, which limits the whole delivered dose. It is well documented that radiation activates phosphatidylinositol 3-kinase (PI3K) and AKT signaling pathway; hence, the inhibition of this pathway enhances the radiosensitivity of tumor cells. The mammalian target of rapamycin (mTOR) is a regulator that is involved in autophagy, cell growth, proliferation, and survival.

CONCLUSION

The inhibition of mTOR as a downstream mediator of the PI3K/AKT signaling pathway represents a vital option for more effective cancer treatments. The combination of PI3K/AKT/mTOR inhibitors with radiation can increase the radiosensitivity of malignant cells to radiation by autophagy activation. Therefore, this review aims to discuss the impact of such inhibitors on the cell response to radiation.

Everolimus-induced pneumonitis in neuroendocrine neoplasms: correlation of CT findings and clinical signs

BACKGROUND

Everolimus, a mammalian target of rapamycin (mTOR)-inhibitor, is approved for the treatment of advanced neuroendocrine neoplasms (NEN). A rare major adverse event is the occurrence of drug-induced pneumonitis.

PURPOSE

To evaluate the correlation between clinical signs and computed tomography (CT) findings in everolimus-induced pneumonitis in patients with NEN.

MATERIAL AND METHODS

Ninety patients with NEN treated with everolimus were retrospectively enrolled (approved by our Institutional Review Board). All patients received chest CTs before the initiation of everolimus and during the treatment along with physical examinations. Clinical signs of pneumonitis were scored (symptomatic score) according to CTCAE v5.0. Pulmonary function tests (PFT) were evaluated if available. CT images were analyzed based on the severity of interstitial lung disease (ILD), the overall pneumonitis extent (PnE), and regarding presence of typical lung opacification patterns. Follow-up examinations of patients with pneumonitis were analyzed.

RESULTS

Pneumonitis was diagnosed in 18 (20%) patients. There was no significant correlation between symptomatic score or PFT and ILD score or PnE. In case of a cryptogenic organizing pneumonia pattern (n = 14), symptomatic scores were significantly lower (P = 0.035) than in case of other opacification patterns (n = 4). In the follow-up analysis, we could identify four different clinical courses.

CONCLUSION

CT detects everolimus-induced pneumonitis at a subclinical stage. In this setting, CT findings, clinical severity, and PFT do not clearly correlate. Opacification pattern analysis seems to be of importance when assessing the severity of CT findings. Asymptomatic patients with positive CT findings should be closely monitored to timely initiate specific treatment.

mTOR pathway and DNA damage response: A therapeutic strategy in cancer therapy

The mammalian target of rapamycin (mTOR) is a conserved serine/threonine-protein kinase, comprising two subunit protein complexes: mTORC1 and mTORC2. In response to insult and cancer, the mTOR pathway plays a crucial role in regulating growth, metabolism, cell survival, and protein synthesis. Key subunits of mTORC1/2 catalyze the phosphorylation of various molecules, including eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1), ribosomal protein S6 kinase β-1 (S6K1). The DNA damage response (DDR) maintains genomic stability and provides an opportunity for treating tumors with defects caused by DNA damaging agents. Many mTOR inhibitors are utilized for the treatment of cancers. However, several clinical trials are still assessing the efficacy of mTOR inhibitors. This paper discusses the role of the mTOR signaling pathway and its regulators in developing cancer. In the following, we will review the interaction between DDR and mTOR signaling and the innovative therapies applied in preclinical and clinical trials for treating cancers.

High in vitro and in vivo synergistic activity between mTORC1 and PLK1 inhibition in adenocarcinoma NSCLC

Significant rational is available for specific targeting of PI3K/AKT/mTOR pathway in the treatment of non-small cell lung cancer (NSCLC). However, almost all clinical trials that have evaluated Pi3K pathway-based monotherapies/combinations did not observe an improvement of patient’s outcome. The aim of our study was therefore to define combination of treatment based on the determination of predictive markers of resistance to the mTORC1 inhibitor RAD001/Everolimus. An in vivo study showed high efficacy of RAD001 in NSCLC Patient-Derived Xenografts (PDXs). When looking at biomarkers of resistance by RT-PCR study, three genes were found to be highly expressed in resistant tumors, i.e., PLK1, CXCR4, and AXL. We have then focused our study on the combination of RAD001 + Volasertib, a PLK1 inhibitor, and observed a high antitumor activity of the combination in comparison to each monotherapy; similarly, a clear synergistic effect between the two compounds was found in an in vitro study. Pharmacodynamics study demonstrated that this synergy was due to (1) tumor vascularization decrease, increase of the HIF1 protein expression and decrease of the intracellular pH, and (2) decrease of the Carbonic Anhydrase 9 (CAIX) protein that could not correct intracellular acidosis. In conclusion, all these preclinical data strongly suggest that the inhibition of mTORC1 and PLK1 proteins may be a promising therapeutic approach for NSCLC patients.

Phase I trial of the MEK inhibitor selumetinib in combination with thoracic radiotherapy in non-small cell lung cancer

Background

The RAS/RAF/MEK/ERK signalling pathway has a pivotal role in cancer proliferation and modulating treatment response. Selumetinib inhibits MEK and enhances effects of radiotherapy in preclinical studies.

Patients and methods

Single-arm, single-centre, open-label phase I trial. Patients with stage III NSCLC unsuitable for concurrent chemo-radiotherapy, or stage IV with dominant thoracic symptoms, were recruited to a dose-finding stage (Fibonacci 3 + 3 design; maximum number = 18) then an expanded cohort (n = 15). Oral selumetinib was administered twice daily (starting dose 50 mg) commencing 7 days prior to thoracic radiotherapy, then with radiotherapy (6-6.5 weeks; 60-66 Gy/30-33 fractions). The primary objective was to determine the recommended phase II dose (RP2D) of selumetinib in combination with thoracic radiotherapy.

Results

21 patients were enrolled (06/2010-02/2015). Median age: 62y (range 50-73). M:F ratio 12(57%):9(43%). ECOG PS 0:1, 7(33%):14(67%). Stage III 16(76%); IV 5(24%). Median GTV 64 cm³ (range 1-224 cm³). 15 patients comprised the expanded cohort at starting dose. All 21 patients completed thoracic radiotherapy as planned and received induction chemotherapy. 13 (62%) patients received the full dose of selumetinib.In the starting cohort no enhanced radiotherapy-related toxicity was seen. Two patients had dose-limiting toxicity (1x grade 3 diarrhoea/fatigue and 1x pulmonary embolism). Commonest grade 3-4 adverse events: lymphopaenia (19/21 patients) and hypertension (7/21 patients). One patient developed grade 3 oesophagitis. No patients developed grade ≥3 radiation pneumonitis. Two patients were alive at the time of analysis (24 and 26 months follow-up, respectively). Main cause of first disease progression: distant metastases ± locoregional progression (12/21 [57.1%] patients). Six patients had confirmed/suspected pneumocystis jiroveci pneumonia.

Conclusion

We report poor outcome and severe lymphopenia in most patients treated with thoracic radiotherapy and selumetinib at RP2D in combination, contributing to confirmed/clinically suspected pneumocystis jiroveci pneumonia. These results suggest that this combination should not be pursued in a phase II trial.ClinicalTrials.gov reference: NCT01146756.

Comparative Effectiveness of Proton vs Photon Therapy as Part of Concurrent Chemoradiotherapy for Locally Advanced Cancer

Importance

Concurrent chemoradiotherapy is the standard-of-care curative treatment for many cancers but is associated with substantial morbidity. Concurrent chemoradiotherapy administered with proton therapy might reduce toxicity and achieve comparable cancer control outcomes compared with conventional photon radiotherapy by reducing the radiation dose to normal tissues.

Objective

To assess whether proton therapy in the setting of concurrent chemoradiotherapy is associated with fewer 90-day unplanned hospitalizations (Common Terminology Criteria for Adverse Events, version 4 [CTCAEv4], grade ≥3) or other adverse events and similar disease-free and overall survival compared with concurrent photon therapy and chemoradiotherapy.

Design, Setting, and Participants

This retrospective, nonrandomized comparative effectiveness study included 1483 adult patients with nonmetastatic, locally advanced cancer treated with concurrent chemoradiotherapy with curative intent from January 1, 2011, through December 31, 2016, at a large academic health system. Three hundred ninety-one patients received proton therapy and 1092, photon therapy. Data were analyzed from October 15, 2018, through February 1, 2019.

Interventions

Proton vs photon chemoradiotherapy.

Main Outcomes and Measures

The primary end point was 90-day adverse events associated with unplanned hospitalizations (CTCAEv4 grade ≥3). Secondary end points included Eastern Cooperative Oncology Group (ECOG) performance status decline during treatment, 90-day adverse events of at least CTCAEv4 grade 2 that limit instrumental activities of daily living, and disease-free and overall survival. Data on adverse events and survival were gathered prospectively. Modified Poisson regression models with inverse propensity score weighting were used to model adverse event outcomes, and Cox proportional hazards regression models with weighting were used for survival outcomes. Propensity scores were estimated using an ensemble machine-learning approach.

Results

Among the 1483 patients included in the analysis (935 men [63.0%]; median age, 62 [range, 18-93] years), those receiving proton therapy were significantly older (median age, 66 [range, 18-93] vs 61 [range, 19-91] years; P < .01), had less favorable Charlson-Deyo comorbidity scores (median, 3.0 vs 2.0; P < .01), and had lower integral radiation dose to tissues outside the target (mean [SD] volume, 14.1 [6.4] vs 19.1 [10.6] cGy/cc × 107; P < .01). Baseline grade ≥2 toxicity (22% vs 24%; P = .37) and ECOG performance status (mean [SD], 0.62 [0.74] vs 0.68 [0.80]; P = .16) were similar between the 2 cohorts. In propensity score weighted-analyses, proton chemoradiotherapy was associated with a significantly lower relative risk of 90-day adverse events of at least grade 3 (0.31; 95% CI, 0.15-0.66; P = .002), 90-day adverse events of at least grade 2 (0.78; 95% CI, 0.65-0.93; P = .006), and decline in performance status during treatment (0.51; 95% CI, 0.37-0.71; P < .001). There was no difference in disease-free or overall survival.

Conclusions and Relevance

In this analysis, proton chemoradiotherapy was associated with significantly reduced acute adverse events that caused unplanned hospitalizations, with similar disease-free and overall survival. Prospective trials are warranted to validate these results.

Combined Radiotherapy and New Systemic Therapies - Have We Moved Beyond Palliation?

The new systemic therapies for cancer are having major impacts on the prognosis of patients with advanced cancers, some achieving long-term survival with targeted therapy or immune checkpoint inhibitors. Interactions of radiotherapy with the new systemic therapies are reviewed. Many agents increase radiosensitivity and particular caution is required combining BRAF inhibitors and radiotherapy because of significant toxicity. Most new systemic therapies can be used safely with palliative doses of radiotherapy, but it is important to be aware of overlapping toxicities depending on the site treated. DNA damage response modulators increase radiosensitivity and may potentially increase radiation toxicity but are at an earlier stage of development. Stereotactic ablative radiotherapy may produce further survival gains in patients responding to targeted therapy and immunotherapy.

Is Host Metabolism the Missing Link to Improving Cancer Outcomes?

For the past 100 years, oncologists have relentlessly pursued the destruction of tumor cells by surgical, chemotherapeutic or radiation oncological means. Consistent with this focus, treatment plans are typically based on key characteristics of the tumor itself such as disease site, histology and staging based on local, regional and systemic dissemination. Precision medicine is similarly built on the premise that detailed knowledge of molecular alterations of tumor cells themselves enables better and more effective tumor cell destruction. Recently, host factors within the tumor microenvironment including the vasculature and immune systems have been recognized as modifiers of disease progression and are being targeted for therapeutic gain. In this review, we argue that—to optimize the impact of old and new treatment options—we need to take account of an epidemic that occurs independently of—but has major impact on—the development and treatment of malignant diseases. This is the rapidly increasing number of patients with excess weight and its’ attendant metabolic consequences, commonly described as metabolic syndrome. It is well established that patients with altered metabolism manifesting as obesity, metabolic syndrome and chronic inflammation have an increased incidence of cancer. Here, we focus on evidence that these patients also respond differently to cancer therapy including radiation and provide a perspective how exercise, diet or pharmacological agents may be harnessed to improve therapeutic responses in this patient population.

Mannose shows antitumour properties against lung cancer via inhibiting proliferation, promoting cisplatin‑mediated apoptosis and reducing metastasis

It has been reported that mannose exerts antitumour effects against certain types of cancer. The present study was designed to evaluate whether mannose exerted potential anticancer effects on A549 and H1299 non-small cell lung cancer (NSCLC) cells in vitro, which has not been reported previously. A Cell Counting Kit-8 cell viability assay was used to assess the antiproliferative effects of mannose on NSCLC cells. Flow cytometry-based methods were used to evaluate the effects of mannose on the cell cycle distribution and cisplatin-mediated apoptosis of NSCLC cells. Transwell migration and invasion assays were conducted to examine whether mannose could inhibit the invasive abilities of NSCLC cells. The effects of mannose on the PI3K/AKT and ERK signalling pathways were explored through western blot analysis assessing the expression of phosphorylated (p)-AKT and p-ERK1/2. It was found that mannose showed potential anticancer effects against NSCLC cells in vitro by inhibiting proliferation, inducing G0/G1 cell cycle arrest, promoting cisplatin-induced apoptosis and decreasing the invasive abilities. These data indicate the potential anticancer properties of mannose and suggest the application of mannose-based therapies to treat NSCLC.

Augmenting the therapeutic window of radiotherapy: A perspective on molecularly targeted therapies and nanomaterials

Radiation therapy is a cornerstone of modern cancer therapy alongside surgery, chemotherapy, and immunotherapy, with over half of all cancer patients receiving radiation therapy as part of their treatment regimen. Development of novel radiation sensitizers that can improve the therapeutic window of radiation therapy are sought after, particularly for tumors at an elevated risk of local and regional recurrence such as locally-advanced lung, head and neck, and gastrointestinal tumors. This review discusses clinical strategies to enhance radiotherapy efficacy and decrease toxicity, hence, increasing the overall therapeutic window. A focus is given to the molecular targets that have been identified and their associated mechanisms of action in enhancing radiotherapy. Examples include cell survival and proliferation signaling such as the EGFR and PI3K/AKT/mTOR pathways, DNA repair genes including PARP and ATM/ATR, angiogenic growth factors, epigenetic regulators, and immune checkpoint proteins. By manipulating various mechanisms of tumor resistance to ionizing radiation (IR), targeted therapies hold significant value to increase the therapeutic window of radiotherapy. Further, the use of novel nanoparticles to enhance radiotherapy is also reviewed, including nanoparticle delivery of chemotherapies, metallic (high-Z) nanoparticles, and nanoparticle delivery of targeted therapies - all of which may improve the therapeutic window of radiotherapy by enhancing the tumor response to IR or reducing normal tissue toxicity.

Phosphoglycerate kinase 1 (PGK1) in cancer: A promising target for diagnosis and therapy

Phosphoglycerate kinase 1 (PGK1) is the first critical enzyme to produce ATP in the glycolytic pathway. PGK1 is not only a metabolic enzyme but also a protein kinase, which mediates the tumor growth, migration and invasion through phosphorylation some important substrates. Moreover, PGK1 is associated with poor treatment and prognosis of cancers. This manuscript reviews the structure, functions, post-translational modifications (PTMs) of PGK1 and its relationship with tumors, which demonstrates that PGK1 has indispensable value in the tumor progression. The current review highlights the important role of PGK1 in anticancer treatments.

Novel PI3K/Akt/mTOR pathway inhibitors plus radiotherapy: Strategy for non-small cell lung cancer with mutant RAS gene

Non-small cell lung cancer (NSCLC) with RAS -mutant gene has been the most difficult obstacle to overcome. Over 25% of muted lung adenocarcinomas have RAS mutation. The prognosis of NSCLC patients with RAS-mutant genes is always poor because there is no effective drug to suppress RAS-mutant genes. NSCLC patients with RAS-mutant usually develop resistance to radiotherapy and chemotherapy, which in some cases leads to a 5-10% survival rate for non-small cell lung cancer (NSCLC). As little clinical symptom of NSCLC was presented at its early stages, thus it always brings in disappointing treatment outcome. Currently, NSCLC presents the highest morbidity and mortality all over the world. The combination of PI3K/AKT/mTOR pathway inhibitors with radiotherapy is a novel strategy to improve radiosensitivity and therapeutic outcome of NSCLC with a RAS-mutant gene. There have been many preclinical studies and clinical trials on the effect of PI3K/AKT/mTOR pathway inhibitors combined with radiotherapy in NSCLC with a RAS-mutant gene have been reported in the past years. This review provides current knowledge of the combination of PI3K/Akt/mTOR pathway inhibitors with radiotherapy, which prove to be a significant improvement for the treatment of NSCLC patients with RAS mutations and will benefit NSCLC patients with RAS mutations.

Radiosensitising Cancer Using Phosphatidylinositol-3-Kinase (PI3K), Protein Kinase B (AKT) or Mammalian Target of Rapamycin (mTOR) Inhibitors

Radiotherapy is routinely used as a neoadjuvant, adjuvant or palliative treatment in various cancers. There is significant variation in clinical response to radiotherapy with or without traditional chemotherapy. Patients with a good response to radiotherapy demonstrate better clinical outcomes universally across different cancers. The PI3K/AKT/mTOR pathway upregulation has been linked to radiotherapy resistance. We reviewed the current literature exploring the role of inhibiting targets along this pathway, in enhancing radiotherapy response. We identified several studies using in vitro cancer cell lines, in vivo tumour xenografts and a few Phase I/II clinical trials. Most of the current evidence in this area comes from glioblastoma multiforme, non-small cell lung cancer, head and neck cancer, colorectal cancer, and prostate cancer. The biological basis for radiosensitivity following pathway inhibition was through inhibited DNA double strand break repair, inhibited cell proliferation, enhanced apoptosis and autophagy as well as tumour microenvironment changes. Dual PI3K/mTOR inhibition consistently demonstrated radiosensitisation of all types of cancer cells. Single pathway component inhibitors and other inhibitor combinations yielded variable outcomes especially within early clinical trials. There is ample evidence from preclinical studies to suggest that direct pharmacological inhibition of the PI3K/AKT/mTOR pathway components can radiosensitise different types of cancer cells. We recommend that future in vitro and in vivo research in this field should focus on dual PI3K/mTOR inhibitors. Early clinical trials are needed to assess the feasibility and efficacy of these dual inhibitors in combination with radiotherapy in brain, lung, head and neck, breast, prostate and rectal cancer patients.

Methodological Development of Combination Drug and Radiotherapy in Basic and Clinical Research

Newer technical improvements in radiation oncology have been rapidly implemented in recent decades, allowing an improved therapeutic ratio. The development of strategies using local and systemic treatments concurrently, mainly targeted therapies, has however plateaued. Targeted molecular compounds and immunotherapy are increasingly being incorporated as the new standard of care for a wide array of cancers. A better understanding of possible prior methodology issues is therefore required and should be integrated into upcoming early clinical trials including individualized radiotherapy-drug combinations. The outcome of clinical trials is influenced by the validity of the preclinical proofs of concept, the impact on normal tissue, the robustness of biomarkers and the quality of the delivery of radiation. Herein, key methodological aspects are discussed with the aim of optimizing the design and implementation of future precision drug-radiotherapy trials.

PLK1 and EGFR targeted nanoparticle as a radiation sensitizer for non-small cell lung cancer

Radiation sensitizers that can selectively act on cancer cells hold great promise to patients who receive radiation therapy. We developed a novel targeted therapy and radiation sensitizer for non-small cell lung cancer (NSCLC) based on cetuximab conjugated nanoparticle that targets epidermal growth factor receptor (EGFR) and delivers small interfering RNA (siRNA) against polo-like kinase 1 (PLK1). EGFR is overexpressed in 50% of lung cancer patients and a mediator of DNA repair, while PLK1 is a key mitotic regulator whose inhibition enhances radiation sensitivity. The nanoparticle construct (C-siPLK1-NP) effectively targets EGFR + NSCLC cells and reduces PLK1 expression, leading to G2/M arrest and cell death. Furthermore, we show a synergistic combination between C-siPLK1-NP and radiation, which was confirmed in vivo in A549 flank tumors. We also demonstrate the translational potential of C-siPLK1-NP as a systemic therapeutic in an orthotopic lung tumor model, where administration of C-siPLK1-NP reduced tumor growth and led to prolonged survival. Our findings demonstrate that C-siPLK1-NP is effective as a targeted therapy and as a potent radiation sensitizer for NSCLC. Potential application to other EGFR + cancer types such as colorectal and breast cancer is also demonstrated.

Autophagy Function and Dysfunction: Potential Drugs as Anti-Cancer Therapy

Autophagy is a highly conserved catabolic and energy-generating process that facilitates the degradation of damaged organelles or intracellular components, providing cells with components for the synthesis of new ones. Autophagy acts as a quality control system, and has a pro-survival role. The imbalance of this process is associated with apoptosis, which is a “positive” and desired biological choice in some circumstances. Autophagy dysfunction is associated with several diseases, including neurodegenerative disorders, cardiomyopathy, diabetes, liver disease, autoimmune diseases, and cancer. Here, we provide an overview of the regulatory mechanisms underlying autophagy, with a particular focus on cancer and the autophagy-targeting drugs currently approved for use in the treatment of solid and non-solid malignancies.

PTEN in Lung Cancer: Dealing with the Problem, Building on New Knowledge and Turning the Game Around

Lung cancer is the most common malignancy and cause of cancer deaths worldwide, owing to the dismal prognosis for most affected patients. Phosphatase and tensin homolog deleted in chromosome 10 (PTEN) acts as a powerful tumor suppressor gene and even partial reduction of its levels increases cancer susceptibility. While the most validated anti-oncogenic duty of PTEN is the negative regulation of the PI3K/mTOR/Akt oncogenic signaling pathway, further tumor suppressor functions, such as chromosomal integrity and DNA repair have been reported. PTEN protein loss is a frequent event in lung cancer, but genetic alterations are not equally detected. It has been demonstrated that its expression is regulated at multiple genetic and epigenetic levels and deeper delineation of these mechanisms might provide fertile ground for upgrading lung cancer therapeutics. Today, PTEN expression is usually determined by immunohistochemistry and low protein levels have been associated with decreased survival in lung cancer. Moreover, available data involve PTEN mutations and loss of activity with resistance to targeted treatments and immunotherapy. This review discusses the current knowledge about PTEN status in lung cancer, highlighting the prevalence of its alterations in the disease, the regulatory mechanisms and the implications of PTEN on available treatment options.

mTORC1 inhibitor RAD001 (everolimus) enhances non-small cell lung cancer cell radiosensitivity in vitro via suppressing epithelial-mesenchymal transition

Resistance to radiotherapy causes non-small cell lung cancer (NSCLC) treatment failure associated with local recurrence and metastasis. Thus, understanding the radiosensitization of NSCLC cells is crucial for developing new treatments and improving prognostics. mTORC1 has been shown to regulate tumor cell radiosensitivity, but the underlying mechanisms are unclear. Moreover, mTORC1 also regulates epithelial-mesenchymal transition (EMT) that is important to metastasis and recurrence. In this study we explored whether mTORC1 regulated NSCLC cell radiosensitivity by altering EMT. We performed immunohistichemical analysis using tumor, adjacent and normal tissues from 50 NSCLC patients, which confirmed significantly elevated mTOR protein expression in NSCLC tissue. Then we used NCI-H460 and NCI-H661 cell lines to examine the effects of the mTORC1 inhibitor RAD001 (everolimus) on in vitro radiosensitivity, protein expression and dose-survival curves. RAD001 (10 nmol/L) significantly inhibited the mTORC1 pathway in both the cell lines. Pretreatment with RAD001 (0.1 nmol/L) enhanced the radiosensitivity in NCI-H661 cells with wild-type PIK3CA and KRAS but not in NCI-H460 cells with mutant PIK3CA and KRAS; the sensitivity enhancement ratios in the two NSCLC cell lines were 1.40 and 1.03, respectively. Furthermore, pretreatment with RAD001 (0.1 nmol/L) significantly decreased the migration and invasion with altered expression of several EMT-associated proteins (significantly increased E-cadherin and decreased vimentin expression) in irradiated NCI-H661 cells. Publicly available expression data confirmed that irradiation affected mTOR and EMT-associated genes at the transcript level in NSCLC cells. These results suggest that mTORC1 inhibition enhances the in vitro radiosensitivity of NSCLC cells with wild-type PIK3CA and KRAS by affecting EMT. Our preclinical data may provide a potential new strategy for NSCLC treatment.

Phase IB Study of Induction Chemotherapy With XELOX, Followed by Radiation Therapy, Carboplatin, and Everolimus in Patients With Locally Advanced Esophageal Cancer

PURPOSE

Preclinical studies have shown synergy between everolimus, an mTOR inhibitor, radiation, and platinum agents. We conducted a phase IB trial to determine the recommended phase II dose of everolimus with carboplatin and radiation.

MATERIALS AND METHODS

Patients with stage II/III esophageal cancer were enrolled. Following 2 cycles of Capecitabine/Oxaliplatin (XELOX), patients with no disease progression, received 50.4 Gy in 28 fractions and concurrent weekly carboplatin (area under the curve=2), with escalating doses of everolimus. A standard 3+3 dose escalation design was used.

RESULTS

Nineteen patients were enrolled. Two patients were screen failures and 4 were removed due to poor tolerance to XELOX (n=2) or disease progression (n=2). All treated patients had adenocarcinoma. Median age was 58 (44 to 71 y) and 85% were male patients. One patient at dose level 1 was replaced due to ongoing anxiety. One of 6 patients had a dose-limiting toxicity of bowel ischemia that was fatal. At dose level 2, two of 6 patients had a dose-limiting toxicity (fever with neutropenia and nausea). The recommended phase II dose of everolimus was 2.5 mg QOD. Grade ≥3 toxicities included lymphopenia (11%), nausea (10%), low white blood cell (8.0%) vomiting (5.5%), decreased neutrophils (4.0%). All patients achieved an R0 resection with a pathologic response rate of 40% and a pathologic complete response (ypCR) rate of 23%. The 2-year progression-free survival and overall survival were 50% and 49.6%, respectively.

CONCLUSIONS

The recommended phase II dose of everolimus with concurrent weekly carboplatin and radiation is 2.5 mg QOD.

mTOR Signaling in Cancer and mTOR Inhibitors in Solid Tumor Targeting Therapy

The mammalian or mechanistic target of rapamycin (mTOR) pathway plays a crucial role in regulation of cell survival, metabolism, growth and protein synthesis in response to upstream signals in both normal physiological and pathological conditions, especially in cancer. Aberrant mTOR signaling resulting from genetic alterations from different levels of the signal cascade is commonly observed in various types of cancers. Upon hyperactivation, mTOR signaling promotes cell proliferation and metabolism that contribute to tumor initiation and progression. In addition, mTOR also negatively regulates autophagy via different ways. We discuss mTOR signaling and its key upstream and downstream factors, the specific genetic changes in the mTOR pathway and the inhibitors of mTOR applied as therapeutic strategies in eight solid tumors. Although monotherapy and combination therapy with mTOR inhibitors have been extensively applied in preclinical and clinical trials in various cancer types, innovative therapies with better efficacy and less drug resistance are still in great need, and new biomarkers and deep sequencing technologies will facilitate these mTOR targeting drugs benefit the cancer patients in personalized therapy.

Combination of novel systemic agents and radiotherapy for solid tumors - part I: An AIRO (Italian association of radiotherapy and clinical oncology) overview focused on treatment efficacy

Over the past century, technologic advances have promoted the evolution of radiation therapy into a precise treatment modality allowing for the maximal administration of dose to tumors while sparing normal tissues. In parallel with this technological maturation, the rapid expansion in understanding the basic biology and heterogeneity of cancer has led to the development of several compounds that target specific pathways. Many of them are in advanced steps of clinical development for combination treatments with radiotherapy, and can be incorporated into radiation oncology practice for a personalized approach to maximize the therapeutic gain. This review describes the rationale for combining novel agents with radiation, and provides an overview of the current landscape focused on treatment efficacy.

Combination of novel systemic agents and radiotherapy for solid tumors - Part II: An AIRO (Italian association of radiotherapy and clinical oncology) overview focused on treatment toxicity

Clinical development and use of novel systemic agents in combination with radiotherapy (RT) is at nowadays most advanced in the field of treatment of solid tumors. Although for many of these substances preclinical studies provide sufficient evidences on their principal capability to enhance radiation effects, the majority of them have not been investigated in even phase I clinical trials for safety in the context of RT. In clinical practice, unexpected acute and late side effects may emerge especially in combination with RT. As a matter of fact, despite combined modality treatment holds potential for enhancing the therapeutic ratio, some concerns are raised from the lack of high-quality clinical data to guide the care of patients who are treated with novel compounds in conjunction with RT. The aim of this review is to provide, from a radio-oncological point of view, an overview of the most advanced combined treatment concepts for solid tumors focusing on treatment toxicity.

Metformin for non-small cell lung cancer patients: Opportunities and pitfalls

Despite exciting advances of the anticancer armamentarium in the recent years, mortality of non-small cell lung cancer (NSCLC) remains high and novel treatments are requisite. Therapy intensification is explored with promising, but expensive and potentially toxic new compounds. Repositioning already existing drugs for cancer treatment could save money and improve patient outcomes in specific contexts. Observational data suggest that use of the standard antidiabetic agent metformin decreases lung cancer incidence and mortality. Several basic researches have shown various anticancer effects of metformin, acting both on the glycolytic metabolism and on the tumoral immune microenvironment. Synergistic actions of metformin with antitumoral agents in preclinical NSCLC models have then been highlighted. Recent retrospective studies advocated improved outcomes in NSCLC diabetic patients receiving metformin with chemoradiotherapy or systemic compounds (including conventional platinum-based chemotherapy and EGFR tyrosine kinase inhibitors). Several prospective randomized trials are therefore currently assessing the addition of metformin to standard therapy in non-diabetic lung cancer patients. This article reviews promises and possible limitations of concurrent metformin used as an anticancer agent in NSCLC patients.

Prognostic value of tumor mutations in radically treated locally advanced non-small cell lung cancer patients

Introduction

Chemo-radiation is standard treatment in locally advanced non-small cell lung cancers (NSCLC). The prognostic value of mutations has been poorly explored in this population.

RESULTS

Clinical data were collected from 190 patients and mutational profiles were obtained in 78 of them; 58 (74%) were males, 31 (40%) current smokers, 47/31 stage IIIA/IIIB and 40 (51%) adenocarcinoma. The following mutations were identified: EGFR 12% (9/78), KRAS 15% (12/78), BRAF 5% (3/65), PI3KCA 2% (1/57), NRAS 3% (1/32), and ALK+ (FISH) 4% (2/51). HER2 was not detected. Median follow-up was 3.1 years. Overall survival was evaluated by group; no significant differences were identified in median overall survival (p = 0.21), with 29.4 months for the EGFR/ALK group (n = 11), 12.8 months for other mutations (n = 17), and 23.4 months for wild-type (n = 50). The EGFR/ALK and other mutations groups had poorer median progression-free survival (9.6 and 6.0 months) compared to the wild-type group (12.0 months; multivariate hazard ratio 2.0 [95% CI, 0.9–4.2] and 2.8 [95% CI, 1.5–5.2] respectively, p = 0.003).

Materials and Methods

We retrospectively reviewed all patients receiving radical treatment for locally advanced NSCLC in a single institution between January 2002 and June 2013. Next generation sequencing was performed on DNA from paraffin-embedded tissue. ALK rearrangements were detected by immunohistochemistry and/or FISH. Mutational prognostic value for Kaplan-Meier survival parameters was determined by log-rank tests and Cox proportional hazards models.

Conclusions

Selected gene alterations may be associated with poorer progression-free survival in locally advanced radically treated NSCLC and their prognostic and/or predictive value merits further evaluation in a larger population.

A systematic review of targeted agents for non-small cell lung cancer

BACKGROUND

advanced-stage non-small cell lung cancer (NSCLC) is characterized by having limited treatment options and thus a poor prognosis. However, new treatment options, in the form of targeted agents (TA), have emerged during recent years. This systematic review aims to provide an overview of the accessible literature in PubMed evaluating TA used on NSCLC patients, and the resulting survival outcomes.

METHOD

this systematic literature review was conducted by reviewing all relevant literature in PubMed. Six separate searches were performed: Three searches where controlled entry terms were used and three free text searches. Furthermore, other relevant publications were included manually. A total of seventy-two studies met the search criteria and were thus further analyzed and evaluated.

RESULTS

In the included studies, various TAs and their effect on different molecular targets have been evaluated. Clinical responses vary considerably among the different genetic aberrations. The majority of studies evaluated TA for epidermal growth factor receptor (EGFR) mutations and TA for echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) rearrangements. Studies regarding the use of TA for Rat sarcoma (RAS), rapidly accelerated fibrosarcoma (RAF), ROS proto-oncogene 1 (ROS1) rearrangement, Receptor tyrosine-protein kinase erbB-2 (ERBB2), Phosphatidylinositol 3-kinase (PIK3CA)/v-akt murine thymoma viral oncogene homolog; protein kinase B(AKT)/Phosphatase and tensin homolog deleted on chromosome 10(PTEN), The mammalian target of rapamycin (mTOR), and Mesenchymal-epithelial transition factor (MET) were included as well. In general, studies comparing treatment outcomes in EGFR-mutated patients and EML4-ALK (ALK) rearranged patients after use of either TA or standard chemotherapy, present significant better results after TA.

CONCLUSIONS

This systematic review provides an overview of available literature in PubMed regarding NSCLC and TA. Included studies point toward that TA appears to be a promising therapeutic tool in treating NSCLC patients and use of TA is expected to result in improved treatment outcomes.

A phase II open-label multicenter study of gefitinib in combination with irradiation followed by chemotherapy in patients with inoperable stage III non-small cell lung cancer

Background

Gefitinib is an oral EGFR tyrosine kinase inhibitors which may act as a radiosensitizer.

Patients and Methods

This phase II study evaluated the efficacy of gefitinib 250 mg once daily in combination with thoracic radiotherapy (66 Gy in 6.5 weeks, 2 Gy/day, 5 fractions/week) followed by consolidation chemotherapy (IV cisplatin and vinorelbine) as first line treatment in a population of unselected stage IIIB NSCLC patients according to EGFR mutation status.

Results

Due to a low accrual rate in this study, the sample size (n = 50) was not reached. Sixteen patients were included in four centers, 50% had adenocarcinoma and 75% were male. Genomic alterations (7 patients studied) retrieved TP53 mutation in 2 patients and no EGFR mutation. Four weeks after radiotherapy, 3 patients (19%) had a partial response, 6 (38%) had a stable disease, and 7 had a progression (44%). Median overall survival was 11 months and median progression-free survival was 5 months. At the time of the last contact, 5 patients (31%) were still alive. Main toxicities were gastrointestinal (81%), cutaneous (81%), general (56%), and respiratory (50%). There were 12>G3 adverse events in 7 (47%) patients, and there was one toxic-death during the concomitant period due to an interstitial pneumonitis. There were two possible adverse events-related deaths during the chemotherapy period (pulmonary embolism (n = 1) and sudden death after the administration of the 3^rd course of chemotherapy (n = 1)).

Conclusion

The benefit of Gefitinib-RT could not be confirmed due to premature trial discontinuation. Further evaluation is required, especially in patients with EGFR mutated NSCLC.

Nanoparticles for radiooncology: Mission, vision, challenges

Cancer is one of the leading non-communicable diseases with highest mortality rates worldwide. About half of all cancer patients receive radiation treatment in the course of their disease. However, treatment outcome and curative potential of radiotherapy is often impeded by genetically and/or environmentally driven mechanisms of tumor radioresistance and normal tissue radiotoxicity. While nanomedicine-based tools for imaging, dosimetry and treatment are potential keys to the improvement of therapeutic efficacy and reducing side effects, radiotherapy is an established technique to eradicate the tumor cells. In order to progress the introduction of nanoparticles in radiooncology, due to the highly interdisciplinary nature, expertise in chemistry, radiobiology and translational research is needed. In this report recent insights and promising policies to design nanotechnology-based therapeutics for tumor radiosensitization will be discussed. An attempt is made to cover the entire field from preclinical development to clinical studies. Hence, this report illustrates (1) the radio- and tumor-biological rationales for combining nanostructures with radiotherapy, (2) tumor-site targeting strategies and mechanisms of cellular uptake, (3) biological response hypotheses for new nanomaterials of interest, and (4) challenges to translate the research findings into clinical trials.

A phase I study of mTOR inhibitor everolimus in association with cisplatin and radiotherapy for the treatment of locally advanced cervix cancer: PHOENIX I

BACKGROUND

Cervix cancer (CC) represents the fourth most common cancer in women. Treatment involving cisplatin and radiotherapy has been the standard for locally advanced disease. Everolimus inhibits the aberrant activity of mTOR that is part of carcinogenesis in CC. Further everolimus inactivates the HPV E7 oncoprotein and inhibits its proliferation. Preclinical models have suggested that everolimus sensitizes tumoral cells and vasculature to cisplatin and radiotherapy.

METHODS

In a 3 + 3 design, the trial aimed to treat three dose levels of at least three patients with daily doses of everolimus (2.5, 5 and 10 mg/day), cisplatin and radiotherapy delivered in a 9-week interval in CC patients, stage IIB, IIIA or IIIB. Patients received everolimus from day -7 up to the last day of brachytherapy. Primary objective was to evaluate safety, toxicity and the maximum-tolerated dose (MTD) of everolimus in association with cisplatin and radiotherapy. Pharmacokinetic (PK) parameters and response rates were analyzed as secondary objectives.

RESULTS

Thirteen patients were enrolled, 6 at 2.5 mg, 3 at 5 mg and 4 at 10 mg. Four patients did not complete the planned schedule, 1 at 2.5 mg presented grade 4 acute renal failure interpreted as dose-limiting toxicity (DLT) and 3 at 10 mg: 1 with disease progression, and 2 with DLTs-1 grade 3 rash and 1 grade 4 neutropenia. PK results were characterized by dose-dependent increases in AUC and C max.

CONCLUSIONS

The MTD of everolimus in combination with cisplatin and radiotherapy has been defined as 5 mg/day. The data regarding safety and response rates support further studies.

Increased radiosensitivity of HPV-positive head and neck cancers: Molecular basis and therapeutic perspectives

Human papillomavirus driven head and neck squamous cell carcinoma (HNSCC), particularly oropharyngeal squamous cell carcinoma (OPSCC), are characterized by a significant survival advantage over their HPV-negative counterparts. Although the reasons behind this are still not fully elucidated, it is widely accepted that these tumors have a higher response to ionizing radiation that might explain their favorable outcomes. Potential underlying intrinsic mechanisms include impaired DNA repair abilities, differences in activated repopulation-signaling pathways and cell cycle control mechanisms. The role of the microenvironment is increasingly highlighted, particularly tumor oxygenation and the immune response. Recent studies have shown a distinct pattern of intratumoral immune cell infiltrates, according to HPV status, and have suggested that an increased cytotoxic T-cell based antitumor immune response is involved in improved prognosis of patients with HPV-positive OPSCC. These significant milestones, in the understanding of HPV-induced HNSCC, pave the way to new therapeutic opportunities. This article reviews the current evidence on the biological basis of increased radiosensitivity in HPV-positive HNSCC and discusses potential therapeutic implications.