One of the current challenges and failures of immunotherapy is in part due to the complex tumor microenvironment (TME) that provides a formidable barrier to immune infiltration and function. The TME consists of various cell types (tumor cells, fibroblasts, endothelial cells, and immune cells), soluble signaling molecules (cytokines, growth factors, and chemokines), and extracellular matrix. On another note, metabolic disturbances in various TME components, such as hypoxia, acidosis, lactate accumulation, and nutrient deprivation, can play a critical role in the tumor progression. Furthermore, genetic and epigenetic dysfunctions are known to be part of the characteristics of cancer development. The immune cells could have a pro- or anti-tumor role in the TME, and their activity might vary in the context of different cancers. Both innate and adaptive immune cells interact with tumor cells through direct contact or through chemokines and cytokines signaling, shaping the tumor's activity and response to therapy.

Tumor microenvironment (TME) plays an important role in immunosuppressive mechanisms that result in immune editing and treatment resistance. Elucidating the diversity of stromal and immune cell distribution, polarization, and changes in their gene expression signatures will enable a better understanding of key events to improve treatment and prognosis. With the onset of immune checkpoint inhibitors (ICIs) in clinics for patients with solid tumors and hematologic malignancies, immunotherapy has taken a new direction in cancer management, especially as combination therapies. However, limitations encountered with the use of ICIs, including toxicity and immune-related adverse events (irAE) indicate the need to understand multiple regulatory mechanisms at both cellular and molecular levels that alter the immune landscape of the TME. Since predominant changes in the immune landscape occur at the TME, focussed deliberation on these events will provide a comprehensive understanding on this topic for scientists in the fields of basic, translational, and clinical cancer immunology. The heterogeneity of TME and complex immune landscape pose major challenges in the treatment of solid tumors. Thus, integrative approaches, which relate immune mechanisms in the TME to that of peripheral and systemic immune signatures are essential to improve our understanding of the disease complexity and possibly improve immunotherapy outcomes. Such multiparametric studies should combine advances in current understanding of cancer immunobiology with powerful technologies, such as single-cell and spatial transcriptomics, and high dimensional flow cytometry that rapidly expand our ability to explore these interactions. Notably, tumor heterogeneity and inflammatory mediators in the TME vary significantly in neoplasms based on mutational load, lymphocyte infiltration, expression of checkpoint molecules, soluble inhibitors, and tumor cell metabolism. Overall, connecting key events to immune signatures that conform to a consensus will provide a benchmark to delve further into this important topic. Other parameters such as myeloid and lymphoid cell polarization to alter the immune homeostasis at the TME, favoring a tumor-supportive milieu would provide a macroscopic picture that may help guide treatment choices for more refined personalized tumor immunotherapy.

The book starts with an introduction to and history of myeloid-derived suppressor cells (MDSCs), followed by a description of their differentiation, their role in the tumour microenvironment and their therapeutic targeting. It closes with an outlook on future developments. In cancer patients, myelopoiesis is perturbed and instead of generating immunogenic myeloid cells (such as dendritic cells, inflammatory macrophages and granulocytes), there is an increase in highly immature MDSCs. These cells are distributed systemically, resulting in general immunosuppression. They also infiltrate tumours, promoting their progression and metastasis by inhibiting the natural anti-tumour immune response. As these cells also interact with classical anti-neoplastic treatments, they have become major therapeutic targets in the pharmaceutical industry and in oncology research.

Tumor-associated immune cells, in particular myeloid cells, have opposing roles during cancer development by facilitating antitumor immune responses and driving cancer-promoting inflammation. Defective antitumor immunity is prevalent in cancers, and it is now clear that overcoming the myeloid cell-mediated immunosuppressive microenvironment poses tremendous interest for future cancer therapies. JAK/STAT signaling has come to the forefront as a crucial pathway to induce immunosuppression and procancer inflammation. Specifically, STAT3 activation is critical for the phenotype of myeloid cells by regulating immunosuppressive and prometastatic factors, thereby providing myeloid cells with a multitude of tumor-promoting functions. Genetic ablation of STAT3 in the myeloid compartment induces potent innate and adaptive antitumor immunity along with an inhibition of tumor growth and metastasis. Recently, therapeutic targeting of JAK/STAT3 has shown great promise in blocking immunosuppression in preclinical models. One such example is the use of novel siRNA to selectively target STAT3 in myeloid cells, through conjugation to CpG oligonucleotides that agonize Toll receptor TLR9 on myeloid cells. Along with other novel therapeutic strategies to inhibit JAK/STAT signaling, it seems likely that future efforts to target this pathway will be made in single and combination approaches for effective anticancer immunotherapy.

NK Cells in Cancer Immunotherapy: Successes and Challenges explains the latest immunotherapeutic strategies, focusing on NK cells to allow the best and precise combination treatments to cancer patients. The book provides existing background knowledge in the field of immunotherapy and discusses future areas of research required to carry out cutting-edge, validated therapies. Chapters cover advances in immunotherapeutic strategies, in particular, the use of NK cells with and without T-cell therapy in the treatment of cancer. The book is a valuable resource for cancer researchers, oncologists, graduate students and those interested in learning more about novel strategies to treat cancer patients. Immunotherapy is fast becoming the method of choice for cancer therapy. Although remarkable advances have been made in the field of immunotherapy, there are significant challenges and difficulties ahead since many of the current immunotherapeutic strategies do not provide long-lasting treatment strategies, and therefore are not very effective. - Covers CAR/T and CAR/NK and adoptive NK cell therapy with and without T cell therapies - Discusses basic biology of NK cells and mouse models of human cancers and the role of NK cells in metastatic cancer and in cancer stem cells - Encompasses information on combination therapies using check point inhibition, adoptive transfer of cytotoxic effector cells, chemotherapeutic drugs and activating and inhibitory antibodies

Revealing essential roles of the tumor microenvironment in cancer progression, this book focuses on the role of hematopoietic components of the tumor microenvironment. Further, it teaches readers about the roles of distinct constituents of the tumor microenvironment and how they affect cancer development. Topics include neutrophils, basophils, T helper cells, cytotoxic lymphocytes, fibrocytes, and myeloid-derived suppressor cells, and more. Taken alongside its companion volumes, these books update us on what we know about various aspects of the tumor microenvironment as well as future directions. Tumor Microenvironment: Hematopoietic Cells – Part A is essential reading for advanced cell biology and cancer biology students as well as researchers seeking an update on research in the tumor microenvironment.

The tumor microenvironment has become a very important and hot topic in cancer research within the past few years. The tumor microenvironment is defined as the normal cells, molecules, and blood vessels that surround and feed a tumor cell. As many scientists have realized, studying the tumor microenvironment has become critical to moving the field forward, since there are many players in a tumor’s localized and surrounding area, which can significantly change cancer cell behavior. There is a dual relationship wherein the tumor can change its microenvironment and the microenvironment can affect how a tumor grows and spreads. Tumor Microenvironment in Cancer Progression and Cancer Therapy aims to shed light on the mechanisms, factors, and mediators that are involved in the cancer cell environment. Recent studies have demonstrated that in addition to promoting tumor progression and protecting tumor cells from the spontaneous immune-mediated rejection and different forms of cancer therapeutics, tumor microenvironment can also be a target and mediator of both standard and newly-emerging forms of cancer therapeutics. Thus, the dual role of the tumor microenvironment is the integral focus of the volume. The volume highlights the bi-directional interactions between tumor cells and non-malignant tumor component during tumor progression and treatment. It also focuses on the three groups of the reactive tumor component: stromal cells, blood vessels and the infiltrating immune cells. These three groups are discussed under the lens of their role in promoting tumor growth, shielding the tumor from rejection and from standard forms of cancer therapies. They are emerging as targets and mediators of standard and new forms of potential therapy.

Taken together, these studies highlight the importance of cellular crosstalk in the immune response to anti-cancer therapies. The role of direct NK cell-monocyte interactions in the efficacy of mAb therapy for HER2-positive breast cancer has been described, and a potential nanoscale tool for targeting innate immune cells has been characterized. Additional studies to determine how to maximize NK cell activity and optimize signaling from myeloid cells in the tumor microenvironment will improve the effectiveness of mAb therapy and benefit cancer patients for years to come.

A link between inflammation and cancer has been established many years ago, yet it is only recently that the potential significance of this connection has become apparent. Although several examples of chronic inflammatory conditions, often induced by persistent irritation and/or infection, developing into cancer have been known for some time, there has been a notable resistance to contemplate the possibility that this association may apply in a causative way to other cancers. Examples for such progression from chronic inflammation to cancer are colon carcinoma developing with increased frequency in patients with ulcerative colitis, and the increased incidence of bladder cancer in patients suffering from chronic Schistosoma infection. Inflammation and cancer have been recognized to be linked in another context for many years, i.e., with regards to pathologies resembling chronic lacerations or 'wounds that do not heal.' More recently, the immunology of wound healing has given us clues as to the mechanistic link between inflammation and cancer, in as much as wounds and chronic inflammation turn off local cell-mediated immune responses and switch on growth factor release as well the growth of new blood vessels - angiogenesis. Both of these are features of most types of tumours, which suggest that tumours may require an immunologically shielded milieu and a growth factor-rich environment.