Molecular Targets and Cancer Therapeutics (Part 2)

Normally, to replace damaged cells or for the purpose of growth, healthy cells can divide according to the proliferation potency, in a systematic and controlled manner. When this mechanism is interfered with in such a way that the cell multiplies beyond the control system, a neoplasm may originate. The name (neoplasm) comes from the ancient Greek words neo, which means “new,” and plasma, which means “creation, formation.”. Even after the underlying trigger is removed, a neoplasm's growth is disorganized with that of the healthy surrounding tissue, and it continues to grow abnormally. When this abnormal neoplastic growth creates a mass, it is referred to as a ” tumor”. There are four primary types of neoplasms (tumor): benign (noncancerous), in situ, malignant (cancerous), and neoplasms of unclear or unidentified behaviour, which follow the pattern of cell development. Oncology is concerned with malignant neoplasms, which are commonly known as malignancies or cancers. In Oncology, many cancer classifications emerged, however, the most notable of which is based on the nomenclature by the type of tissue from which it arises, or by the primary site in the body where it originally appeared. Herein, this chapter will go over the definition of cancer, classifications as well as the key differences between the types of cancers. This chapter will also cover the pathophysiology and epidemiology of the many types of cancers.

Cancer has a higher chance of being cured when it is diagnosed, detected, and treated early. Diagnosis of cancer in its early stages also results in the highest chance of survival with the improvement of lifestyle of cancer patients. A comprehensive physical exam and a full family medical history are needed before a cancer diagnosis can be made. Self-examination or other screening procedures will normally detect visible forms of cancers, such as melanoma and breast cancer, before the condition progresses. However, several forms of other types of cancer are discovered and diagnosed after disease development and severe signs have already occurred. This chapter discusses the diagnostic approaches that are often utilized to aid in the diagnosis of cancer.

Surgery, the oldest cancer treatment, is a mainstay in the cure and control of most cancers. Indeed, for many patients, surgery, usually in combination with chemotherapy, is the only hope for long-term survival or cure. But surgery can do more than treat cancer; it can also diagnose cancer (diagnostic surgery), investigate cancer further (staging surgery), debulk tumors (debulking surgery), relieve pain (palliative surgery), prevent cancer from occurring in the first place (preventative surgery), restore the appearance or function of the body after cancer surgery (reconstructive surgery) and help medical staff to administer chemotherapy (access surgery). This chapter looks at each of these purposes of cancer surgery in detail. 

Immunotherapy is one of the important modalities in the treatment of cancer since it can directly target the tumor and its microenvironment with lesser side effects and cytotoxicity. The main goal of immunotherapy in the treatment of cancer is the reactivation of the immune system against cancer cells. In this way, the body fights against cancer using its immune system rather than relying on external agents which might be harmful to other healthy parts of the body. The development of monoclonal antibodies (Mabs) has delivered a significant therapeutic effect. Mab therapy is one of the most evolving techniques in cancer immunotherapy and has shown efficacy in controlling several types of malignancies. There are several other methods by which the activation of the immune system can be achieved, such as by using small molecules or by targeting ligands. Interestingly, studies have demonstrated that cancer stem cells have also been found as a target for effective immunotherapy. Additionally, the complete elimination of the cancer cells requires longer sustainability of tumor-specific T cells. Primitive results suggest that these T cells can be localized to tumor cells, mediating highly effective immunotherapy. However, despite these huge successes, several problems still persist and must be overcome. This chapter discusses the current and cutting-edge immunotherapeutic approaches to fight against cancer cells.

Nanoscience and Nanotechnology are now almost in every field of Science. The field has been growing since it was started in 1959 when the Nobel Prize American physicist, Richard Feynman introduced the concept of nanotechnology; since then, it has involved in almost every field of Science, including chemistry, biology, computer science, physics, and engineering. Nanoscience and nanotechnology are now at the frontline of modernistic research. The term 'nano' referred to a Greek prefix meaning “dwarf” with a scale of one thousand millionths of a meter (10-9 m). Nanoscience is the study of particles and structures on the scale of nanometers. Early detection of cancer plays an important role in successful treatment. The detection of cancer in the early stage has been delayed by the limits of conventional cancer detection methods. Recently, the uprising in the use of Nanomedicine and nanotechnology in health care offers hope for the detection, prevention, and treatment of cancer. Nanomedicine drugs have been observed to be involved in the treatment of solid tumors. Also, it is based on enhanced Permeability and Retention (EPR). The main characteristics of EPR are related to tumor vessel permeability which allows enhanced permeability (EP) of large particles (macro molecules proteins, micelles & liposomes). Nanomedicine transport can be hindered from Tumor-associated microphage (TAM) by poor blood perfusion, high Extracellular Matrix (ECM) dense and high tumor stromal cells. Electrochemotherapy is commonly used in palliative settings for the treatment of patients with unresectable tumors to relieve pain and improve the quality of life. It is also frequently used in the treatment of neoplasia at a late stage and when comprehensive surgical treatment is not possible due to the size, location, and the number of the lesion. As the treatment does not involve tissue heating, so Electrochemotherapy is used for the treatment of tumors near or close to important structures like vessels and nerves. Electrochemotherapy has a favorable side effect in the form of local and transient, moderate local pain, edema, erythema, and muscle contractions during electroporation.

Surveillance against tumors is governed by both intrinsic (non-immune) and extrinsic (immune) surveillance. While research on non-immune surveillance started as early as the 1960s when it was demonstrated that cell environment within and around can induce tumor-suppressing mechanisms, a major part of the progress is missing compared to immune surveillance. Part of the reason could be due to the fact that immune surveillance is seen to have more potential in therapeutic application in curing cancerous tumors compared to non-immune surveillance mechanisms. Many of the non-immune mechanisms are still under investigation as theories, although a few studies have shown their possibility. Contrary to this, there is a plethora of studies on immune surveillance. The immune system has been proven to have a role in the surveillance against tumors, thus conferring a certain degree of protection. However, not all tumor cells are successfully detected by innate immunity, and many of them have developed strategic ways of escaping adaptive immunity. The immunosurveillance in both animal models and humans shows overwhelmingly that cells with immunodeficiencies are more susceptible to tumor development. However, it is confounding that even immune-competent individuals develop tumors, and thus a significant process is responsible. Thus, immunoediting was proposed as a theory to explain why tumors can escape immunosurveillance. This chapter provides detailed evidence from animal and human tumors and analyses the mechanisms, pathways, and components implicated in tumor immune surveillance. The findings suggest that while immune surveillance could be the key to promoting immune function against the development of tumors, there is more research and understanding needed in the various mechanisms and cells implicated. This is because most, if not all, of the therapeutic studies using immune effectors have proved to be poor in preventing, treating, or regulating the development of tumors.