Nanomedicine approaches to improve cancer immunotherapy

Immune-related adverse events and immune checkpoint inhibitors: a focus on neurotoxicity and clinical management

INTRODUCTION

Immune checkpoint inhibitors (ICIs) represent an innovative therapeutic approach of oncologic diseases. In Europe, this therapeutic class currently includes eight agents: ipilimumab, pembrolizumab, nivolumab, atezolizumab, avelumab, cemiplimab, durvalumab and dostarlimab. Despite their proved clinical benefits, they can induce immune related adverse events (irADRs), that can also involve the nervous system.

AREAS COVERED

Despite their rarity, neurological irADRs related to ICI-treatments can lead to serious and dangerous complications, highlighting the importance of a strict monitoring of patients. This review aims to summarize the safety profile of ICIs, focusing on their possible neurotoxicity and their management.

EXPERT OPINION

Considering the clinical relevance of ICIs-induced irADRs and that the underlying mechanisms are still not completely understood, the use of ICIs requires extensive safety monitoring. Before to prescribe immunotherapy, oncologists should identify possible individual risk factors that may favor the onset of irADRs. Oncologists and general practitioners should inform and educate patients about the specific toxicities of immunological checkpoint inhibitors, including nervous ones. They should be carefully monitored at least 6 months after the end of treatment. ICIs-related nervous toxicities require a multidisciplinary management, in which neurologists and clinical pharmacologists should participate.

Solid Lipid Nanoparticles: Multitasking Nano-Carriers for Cancer Treatment

Despite all the advances seen in recent years, the severe adverse effects and low specificity of conventional chemotherapy are still challenging problems regarding cancer treatment. Nanotechnology has helped to address these questions, making important contributions in the oncological field. The use of nanoparticles has allowed the improvement of the therapeutic index of several conventional drugs and facilitates the tumoral accumulation and intracellular delivery of complex biomolecules, such as genetic material. Among the wide range of nanotechnology-based drug delivery systems (nanoDDS), solid lipid nanoparticles (SLNs) have emerged as promising systems for delivering different types of cargo. Their solid lipid core, at room and body temperature, provides SLNs with higher stability than other formulations. Moreover, SLNs offer other important features, namely the possibility to perform active targeting, sustained and controlled release, and multifunctional therapy. Furthermore, with the possibility to use biocompatible and physiologic materials and easy scale-up and low-cost production methods, SLNs meet the principal requirements of an ideal nanoDDS. The present work aims to summarize the main aspects related to SLNs, including composition, production methods, and administration routes, as well as to show the most recent studies about the use of SLNs for cancer treatment.

Activation of cancer immunotherapy by nanomedicine

Cancer is one of the most difficult diseases to be treated in the world. Immunotherapy has made great strides in cancer treatment in recent years, and several tumor immunotherapy drugs have been approved by the U.S. Food and Drug Administration. Currently, immunotherapy faces many challenges, such as lacking specificity, cytotoxicity, drug resistance, etc. Nanoparticles have the characteristics of small particle size and stable surface function, playing a miraculous effect in anti-tumor treatment. Nanocarriers such as polymeric micelles, liposomes, nanoemulsions, dendrimers, and inorganic nanoparticles have been widely used to overcome deficits in cancer treatments including toxicity, insufficient specificity, and low bioavailability. Although nanomedicine research is extensive, only a few nanomedicines are approved to be used. Either Bottlenecks or solutions of nanomedicine in immunotherapy need to be further explored to cope with challenges. In this review, a brief overview of several types of cancer immunotherapy approaches and their advantages and disadvantages will be provided. Then, the types of nanomedicines, drug delivery strategies, and the progress of applications are introduced. Finally, the application and prospect of nanomedicines in immunotherapy and Chimeric antigen receptor T-cell therapy (CAR-T) are highlighted and summarized to address the problems of immunotherapy the overall goal of this article is to provide insights into the potential use of nanomedicines and to improve the efficacy and safety of immunotherapy.

Critical clinical gaps in cancer precision nanomedicine development

Active targeting strategy is adopted in nanomedicine for cancer treatment. Personalizing the nanomedicine in accordance with patients' omics, under the precision medicine platform, is met with challenges in targeting ligand and matrix material selection at nanoformulation stage. The past 5-year literatures show that the nanoparticulate targeting ligand and matrix material are not selected based upon the cancer omics profiles of patients. The expression of cancer cellular target receptors and metabolizing enzymes is primarily influenced by age, gender, race/ethnic group and geographical origin of patients. The personalized perspective of a nanomedicine cannot be realised with premature digestion of matrix and targeting ligand by specific metabolizing enzymes that are overexpressed by the patients, and unmatched targeting ligand to the majority of cell surface receptors overexpressed in cancer. Omics analysis of individual metabolizing enzyme and cancer cell surface receptor expressed in cancer facilitates targeting ligand and matrix material selection in nanomedicine development.

Harnessing the Immunogenic Potential of Gold Nanoparticle-Based Platforms as a Therapeutic Strategy in Breast Cancer Immunotherapy: A Mini Review

Breast cancer remains the most common malignancy among women worldwide. Although the implementation of mammography has dramatically increased the early detection rate, conventional treatments like chemotherapy, radiation therapy, and surgery, have significantly improved the prognosis for breast cancer patients. However, about a third of treated breast cancer patients are known to suffer from disease recurrences and progression to metastasis. Immunotherapy has recently gained traction due to its ability to establish long-term immune surveillance, and response for the prevention of disease recurrence and extension of patient survival. Current research findings have revealed that gold nanoparticles can enhance the safety and efficacy of cancer immunotherapy, through their unique intrinsic properties of good biocompatibility, durability, convenient surface modification, as well as enhanced permeability and retention effect. Gold nanoparticles are also able to induce innate immune responses through the process of immunogenic cell death, which can lead to the establishment of lasting adaptive immunity. As such gold nanoparticles are considered as good candidates for next generation immunotherapeutic strategies. This mini review gives an overview of gold nanoparticles and their potential applications in breast cancer immunotherapeutic strategies.

Nanomedicine as a Promising Tool to Overcome Immune Escape in Breast Cancer

Breast cancer is the most common type of malignancy and leading cause of cancer death among women worldwide. Despite the current revolutionary advances in the field of cancer immunotherapy, clinical response in breast cancer is frequently below expectations, in part due to various mechanisms of cancer immune escape that produce tumor variants that are resistant to treatment. Thus, a further understanding of the molecular events underlying immune evasion in breast cancer may guarantee a significant improvement in the clinical success of immunotherapy. Furthermore, nanomedicine provides a promising opportunity to enhance the efficacy of cancer immunotherapy by improving the delivery, retention and release of immunostimulatory agents in targeted cells and tumor tissues. Hence, it can be used to overcome tumor immune escape and increase tumor rejection in numerous malignancies, including breast cancer. In this review, we summarize the current status and emerging trends in nanomedicine-based strategies targeting cancer immune evasion and modulating the immunosuppressive tumor microenvironment, including the inhibition of immunosuppressive cells in the tumor area, the activation of dendritic cells and the stimulation of the specific antitumor T-cell response.

Advances in Engineered Polymer Nanoparticle Tracking Platforms towards Cancer Immunotherapy-Current Status and Future Perspectives

Engineering polymeric nanoparticles for their shape, size, surface chemistry, and functionalization using various targeting molecules has shown improved biomedical applications for nanoparticles. Polymeric nanoparticles have created tremendous therapeutic platforms, particularly applications related to chemo- and immunotherapies in cancer. Recently advancements in immunotherapies have broadened this field in immunology and biomedical engineering, where "immunoengineering" creates solutions to target translational science. In this regard, the nanoengineering field has offered the various techniques necessary to manufacture and assemble multifunctional polymeric nanomaterial systems. These include nanoparticles functionalized using antibodies, small molecule ligands, targeted peptides, proteins, and other novel agents that trigger and encourage biological systems to accept the engineered materials as immune enhancers or as vaccines to elevate therapeutic functions. Strategies to engineer polymeric nanoparticles with therapeutic and targeting molecules can provide solutions for developing immune vaccines via maintaining the receptor storage in T- and B cells. Furthermore, cancer immunotherapy using polymeric nanomaterials can serve as a gold standard approach for treating primary and metastasized tumors. The current status of the limited availability of immuno-therapeutic drugs highlights the importance of polymeric nanomaterial platforms to improve the outcomes via delivering anticancer agents at localized sites, thereby enhancing the host immune response in cancer therapy. This review mainly focuses on the potential scientific enhancements and recent developments in cancer immunotherapies by explicitly discussing the role of polymeric nanocarriers as nano-vaccines. We also briefly discuss the role of multifunctional nanomaterials for their therapeutic impacts on translational clinical applications.

Recent Advances in Nanomaterials Development for Nanomedicine and Cancer

Cancer is considered one of the leading causes of death, with a growing number of cases worldwide. However, the early diagnosis and efficient therapy of cancer have remained a critical challenge. The emergence of nanomedicine has opened up a promising window to address the drawbacks of cancer detection and treatment. A wide range of engineered nanomaterials and nanoplatforms with different shapes, sizes, and composition has been developed for various biomedical applications. Nanomaterials have been increasingly used in various applications in bioimaging, diagnosis, and therapy of cancers. Recently, numerous multifunctional and smart nanoparticles with the ability of simultaneous diagnosis and targeted cancer therapy have been reported. The multidisciplinary attempts led to the development of several exciting clinically approved nanotherapeutics. The nanobased materials and devices have also been used extensively to develop point-of-care and highly sensitive methods of cancer detection. In this review article, the most significant achievements and latest advances in the nanomaterials development for cancer nanomedicine are critically discussed. In addition, the future perspectives of this field are evaluated.

Design and Encapsulation of Immunomodulators onto Gold Nanoparticles in Cancer Immunotherapy

The aim of cancer immunotherapy is to reactivate autoimmune responses to combat cancer cells. To stimulate the immune system, immunomodulators, such as adjuvants, cytokines, vaccines, and checkpoint inhibitors, are extensively designed and studied. Immunomodulators have several drawbacks, such as drug instability, limited half-life, rapid drug clearance, and uncontrolled immune responses when used directly in cancer immunotherapy. Several strategies have been used to overcome these limitations. A simple and effective approach is the loading of immunomodulators onto gold-based nanoparticles (GNPs). As gold is highly biocompatible, GNPs can be administered intravenously, which aids in increasing cancer cell permeability and retention time. Various gold nanoplatforms, including nanospheres, nanoshells, nanorods, nanocages, and nanostars have been effectively used in cancer immunotherapy. Gold nanostars (GNS) are one of the most promising GNP platforms because of their unusual star-shaped geometry, which significantly increases light absorption and provides high photon-to-heat conversion efficiency due to the plasmonic effect. As a result, GNPs are a useful vehicle for delivering antigens and adjuvants that support the immune system in killing tumor cells by facilitating or activating cytotoxic T lymphocytes. This review represents recent progress in encapsulating immunomodulators into GNPs for utility in a cancer immunotherapeutic regimen.

Toxicity of gold nanoparticles (AuNPs): A review

Gold nanoparticles are a kind of nanomaterials that have received great interest in field of biomedicine due to their electrical, mechanical, thermal, chemical and optical properties. With these great potentials came the consequence of their interaction with biological tissues and molecules which presents the possibility of toxicity. This paper aims to consolidate and bring forward the studies performed that evaluate the toxicological aspect of AuNPs which were categorized into in vivo and in vitro studies. Both indicate to some extent oxidative damage to tissues and cell lines used in vivo and in vitro respectively with the liver, spleen and kidney most affected. The outcome of these review showed small controversy but however, the primary toxicity and its extent is collectively determined by the characteristics, preparations and physicochemical properties of the NPs. Some studies have shown that AuNPs are not toxic, though many other studies contradict this statement. In order to have a holistic inference, more studies are required that will focus on characterization of NPs and changes of physical properties before and after treatment with biological media. So also, they should incorporate controlled experiment which includes supernatant control Since most studies dwell on citrate or CTAB-capped AuNPs, there is the need to evaluate the toxicity and pharmacokinetics of functionalized AuNPs with their surface composition which in turn affects their toxicity. Functionalizing the NPs surface with more peculiar ligands would however help regulate and detoxify the uptake of these NPs.

The Application of and Strategy for Gold Nanoparticles in Cancer Immunotherapy

Immunotherapy of malignant tumor is a verified and crucial anti-tumor strategy to help patients with cancer for prolonging prognostic survival. It is a novel anticancer tactics that activates the immune system to discern and damage cancer cells, thereby prevent them from proliferating. However, immunotherapy still faces many challenges in view of clinical efficacy and safety issues. Various nanomaterials, especially gold nanoparticles (AuNPs), have been developed not only for anticancer treatment but also for delivering antitumor drugs or combining other treatment strategies. Recently, some studies have focused on AuNPs for enhancing cancer immunotherapy. In this review, we summarized how AuNPs applicated as immune agents, drug carriers or combinations with other immunotherapies for anticancer treatment. AuNPs can not only act as immune regulators but also deliver immune drugs for cancer. Therefore, AuNPs are candidates for enhancing the efficiency and safety of cancer immunotherapy.

Polymeric Micelles in Cancer Immunotherapy

Cancer immunotherapies have generated some miracles in the clinic by orchestrating our immune system to combat cancer cells. However, the safety and efficacy concerns of the systemic delivery of these immunostimulatory agents has limited their application. Nanomedicine-based delivery strategies (e.g., liposomes, polymeric nanoparticles, silico, etc.) play an essential role in improving cancer immunotherapies, either by enhancing the anti-tumor immune response, or reducing their systemic adverse effects. The versatility of working with biocompatible polymers helps these polymeric nanoparticles stand out as a key carrier to improve bioavailability and achieve specific delivery at the site of action. This review provides a summary of the latest advancements in the use of polymeric micelles for cancer immunotherapy, including their application in delivering immunological checkpoint inhibitors, immunostimulatory molecules, engineered T cells, and cancer vaccines.

Targeting the "Sweet Side" of Tumor with Glycan-Binding Molecules Conjugated-Nanoparticles: Implications in Cancer Therapy and Diagnosis

Nanotechnology is in the spotlight of therapeutic innovation, with numerous advantages for tumor visualization and eradication. The end goal of the therapeutic use of nanoparticles, however, remains distant due to the limitations of nanoparticles to target cancer tissue. The functionalization of nanosystem surfaces with biological ligands is a major strategy for directing the actions of nanomaterials specifically to tumor cells. Cancer formation and metastasis are accompanied by profound alterations in protein glycosylation. Hence, the detection and targeting of aberrant glycans are of great value in cancer diagnosis and therapy. In this review, we provide a brief update on recent progress targeting aberrant glycosylation by functionalizing nanoparticles with glycan-binding molecules (with a special focus on lectins and anti-glycan antibodies) to improve the efficacy of nanoparticles in cancer targeting, diagnosis, and therapy and outline the challenges and limitations in implementing this approach. We envision that the combination of nanotechnological strategies and cancer-associated glycan targeting could remodel the field of cancer diagnosis and therapy, including immunotherapy.

Enhancing Combined Immunotherapy and Radiotherapy through Nanomedicine

Radiotherapy and immunotherapy are two key treatments for cancer. There is growing evidence that they are also synergistic, and combination treatments are being studied extensively in the clinical setting. In addition, there is emerging evidence that nanotechnology-enabled therapeutics can potentiate both radiotherapy and immunotherapy, in turn improving both treatments. This is an exciting new area of interdisciplinary science and has significant potential for major clinical impact. Some of the approaches in this area have already reached the clinical stage. In this review, we will discuss recent advances in the interface between radiotherapy, immunotherapy, and nanomedicine. We plan to review the many approaches to combine these three fields for cancer treatment.

Nanoparticles for "two color" 19F magnetic resonance imaging: Towards combined imaging of biodistribution and degradation

The use of polymeric nanoparticles (NPs) as therapeutics has been steadily increasing over past decades. In vivo imaging of NPs is necessary to advance the therapeutic performance. 19F Magnetic Resonance Imaging (19F MRI) offers multiple advantages for in vivo imaging. However, design of a probe for both biodistribution and degradation has not been realized yet. We developed polymeric NPs loaded with two fluorocarbons as promising imaging tools to monitor NP biodistribution and degradation by 19F MRI. These 200 nm NPs consist of poly(lactic-co-glycolic acid) (PLGA) loaded with perfluoro-15-crown-5 ether (PFCE) and PERFECTA. PERFECTA/PFCE-PLGA NPs have a fractal sphere structure, in which both fluorocarbons are distributed in the polymeric matrix of the fractal building blocks, which differs from PFCE-PLGA NPs and is unique for fluorocarbon-loaded colloids. This structure leads to changes of magnetic resonance properties of both fluorocarbons after hydrolysis of NPs. PERFECTA/PFCE-PLGA NPs are colloidally stable in serum and biocompatible. Both fluorocarbons show a single resonance in 19F MRI that can be imaged separately using different excitation pulses. In the future, these findings may be used for biodistribution and degradation studies of NPs by 19F MRI in vivo using "two color" labeling leading to improvement of drug delivery agents.

Nanomedicine for improvement of dendritic cell-based cancer immunotherapy

Dendritic cell (DC)-based cancer immunotherapy has shown impressive outcomes, including the development of the first FDA-approved anti-cancer vaccine. However, the clinical application of DC-based cancer immunotherapy is associated with various challenges. Promising novel tools for the administration of cancer vaccines has emerged from recent developments in nanoscale biomaterials. One current strategy to enhance targeted drug delivery, while minimizing drug-related toxicities, is the use of nanoparticles (NPs). These can be utilized for antigen delivery into DCs, which have been shown to provide potent T cell-stimulating effects. Therefore, NP delivery represents one promising approach for creating an effective and stable immune response without toxic side effects. The current review surveys cancer immunotherapy with particular attention toward NP-based delivery methods that target DCs.

ENS, Boer JC, Ferji K, Six JL, Chen X, Elkord E, Plebanski M, Mohamud R. Synergistic Effects of Nanomedicine Targeting TNFR2 and DNA Demethylation Inhibitor-An Opportunity for Cancer Treatment

Tumor necrosis factor receptor 2 (TNFR2) is expressed on some tumor cells, such as myeloma, Hodgkin lymphoma, colon cancer and ovarian cancer, as well as immunosuppressive cells. There is increasingly evidence that TNFR2 expression in cancer microenvironment has significant implications in cancer progression, metastasis and immune evasion. Although nanomedicine has been extensively studied as a carrier of cancer immunotherapeutic agents, no study to date has investigated TNFR2-targeting nanomedicine in cancer treatment. From an epigenetic perspective, previous studies indicate that DNA demethylation might be responsible for high expressions of TNFR2 in cancer models. This perspective review discusses a novel therapeutic strategy based on nanomedicine that has the capacity to target TNFR2 along with inhibition of DNA demethylation. This approach may maximize the anti-cancer potential of nanomedicine-based immunotherapy and, consequently, markedly improve the outcomes of the management of patients with malignancy.

Gold nanoparticles in chemo-, immuno-, and combined therapy: review [Invited]

Functionalized gold nanoparticles (GNPs) with controlled geometrical and optical properties have been the subject of intense research and biomedical applications. This review summarizes recent data and topical problems in nanomedicine that are related to the use of variously sized, shaped, and structured GNPs. We focus on three topical fields in current nanomedicine: (1) use of GNP-based nanoplatforms for the targeted delivery of anticancer and antimicrobial drugs and of genes; (2) GNP-based cancer immunotherapy; and (3) combined chemo-, immuno-, and phototherapy. We present a summary of the available literature data and a short discussion of future work.

Mannose functionalized plain and endosomolytic nanocomposite(s)-based approach for the induction of effective antitumor immune response in C57BL/6 mice melanoma model

The goal of present study to assess the antigen specific immunopotentiation effect of mannose functionalized endosomolytic and conventional nanocomposite(s) based combination approach using C57BL/6 mice melanoma model. Endosomolytic and conventional nanocomposite(s) were prepared by double emulsification method. The optimized formulation was extensively characterized for average particle size, zeta potential and PDI of nanocomposite(s) which were measured in range of ≈200 nm, 0.111 ± 0.024, -23.4 ± 2.0 mV, respectively. pH-dependent morphological changes in the surface of MRPRPNs and PRPNs were analyzed by using surface electron microscopy at different time intervals. The cellular uptake assessment of developed formulations were followed by using RAW 264.7 macrophage cell lines. Results revealed that after immunizing B16F10 melanoma cells implanted C57BL/6 mice with combination [endosomolytic and conventional nanocomposite(s)] of nanocomposite(s), a significant increase in the interleukins level i.e. IL-2, IFN-ϒ, IL-12 and IL-6 and OVA Ag(s) specific antibody responses were recorded. Consequently, a strong immunological response was elicited with specific polarization contributing to humoral and activation of CD8⁺ to cellular responses. Finding of histological examination also support the potential of therapeutic outcome. The present approach based on mannose surface functionalization for targeting to antigen presenting cells and pH-dependent prompt endosomal release and escape can be a promising system for efficient cancer immunotherapy.

Nuclear imaging of liposomal drug delivery systems: A critical review of radiolabelling methods and applications in nanomedicine

The integration of nuclear imaging with nanomedicine is a powerful tool for efficient development and clinical translation of liposomal drug delivery systems. Furthermore, it may allow highly efficient imaging-guided personalised treatments. In this article, we critically review methods available for radiolabelling liposomes. We discuss the influence that the radiolabelling methods can have on their biodistribution and highlight the often-overlooked possibility of misinterpretation of results due to decomposition in vivo. We stress the need for knowing the biodistribution/pharmacokinetics of both the radiolabelled liposomal components and free radionuclides in order to confidently evaluate the images, as they often share excretion pathways with intact liposomes (e.g. phospholipids, metallic radionuclides) and even show significant tumour uptake by themselves (e.g. some radionuclides). Finally, we describe preclinical and clinical studies using radiolabelled liposomes and discuss their impact in supporting liposomal drug development and clinical translation in several diseases, including personalised nanomedicine approaches.

Selective Nanomechanics of Aromatic versus Aliphatic Thiolates on Gold Surfaces

Thiolated gold nanointerfaces play a key role in numerous fields of science, technology, as well as modern medicine to coat, functionalize, and protect. Our computational study reveals that the mechanical vs thermal stabilities of aliphatic thiolates on gold surfaces are strikingly different from those of aromatic thiolates. The aliphatic thiolates feature, at the same time, a higher thermal desorption energy but a lower mechanical rupture force than thiophenolates. Our analysis discloses that this most counterintuitive property is due to different mechanochemical detachment mechanisms. Electronic structure analyses along the detachment pathways trace this back to the distinct electronic properties of the S─Au bond in stretched nanojunctions. The discoveries that it is a higher thermal stability that entails a lower mechanical stability and that mechanical loads generate different local nanostructures depending on the nature of the thiolate are highly relevant for the rational design of improved thiol-gold nanocontacts.

Organosilica Nanoparticles and Medical Imaging

Medical imaging technology using nanoparticles has several advantages from it varies functional properties. As we described previous chapters, mesoporous silica nanoparticles demonstrated great contribution for nanomedicine progress and it has been expected to cause an innovation in medical field. Recently we developed a novel type of silica nanoparticles, organosilica nanoparticles. Organosilica nanoparticles are both structurally and functionally different from common silica nanoparticles by including mesoporous silica nanoparticles. The organosilica nanoparticles are inherent organic-inorganic hybrid nanomaterials. The interior and exterior functionalities of organosilica nanoparticles are effective for their internal and surface functionalization. Medical imaging using organosilica nanoparticles is making a new field of nano-medical imaging. Multifunctionalizations peculiar to organosilica nanoparticles enable to construct novel medical imaging system. In this chapter we will introduce organosilica nanoparticles, and its applications on advanced medical imaging.

Immunoengineering with biomaterials for enhanced cancer immunotherapy

Cancer immunotherapy has recently shown dramatic clinical success inducing durable response in patients of a wide variety of malignancies. Further improvement of the clinical outcome with immune related cancer treatment requests more exquisite manipulation of a patient's immune system with increased immunity against diseases while mitigating the toxicities. To meet this challenge, biomaterials applied to immunoengineering are being developed to achieve tissue- and/or cell-specific immunomodulation and thus could potentially enhance both the efficacy and safety of current cancer immunotherapies. Here, we review the recent advancement in the field of immunoengineering using biomaterials and their applications in promoting different modalities of cancer immunotherapies, with focus on cell-, antibody-, immunomodulator-, and gene-based immune related treatments and their combinations with conventional therapies. Challenges and opportunities are discussed in applying biomaterials engineering strategies in the development of future cancer immunotherapies. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies Implantable Materials and Surgical Technologies > Nanomaterials and Implants.

Bridging Bio-Nano Science and Cancer Nanomedicine

The interface of bio-nano science and cancer medicine is an area experiencing much progress but also beset with controversy. Core concepts of the field-e.g., the enhanced permeability and retention (EPR) effect, tumor targeting and accumulation, and even the purpose of "nano" in cancer medicine-are hotly debated. In parallel, considerable advances in neighboring fields are occurring rapidly, including the recent progress of "immuno-oncology" and the fundamental impact it is having on our understanding and the clinical treatment of the group of diseases collectively known as cancer. Herein, we (i) revisit how cancer is commonly treated in the clinic and how this relates to nanomedicine; (ii) examine the ongoing debate on the relevance of the EPR effect and tumor targeting; (iii) highlight ways to improve the next-generation of nanomedicines; and (iv) discuss the emerging concept of working with (and not against) biology. While discussing these controversies, challenges, emerging concepts, and opportunities, we explore new directions for the field of cancer nanomedicine.