Role of Immunity in Spontaneous Cure of Cancer

Review Article

Abstract

This review article provides a brief overview of recent developments in a particular topic. In general, this article summarizes the current knowledge on the subject. This provides the reader with an understanding of the subject by discussing the results of a recent research paper.

Interestingly, some cancers have a particular tendency to regress spontaneously. There are several examples of such referrals. Among them, metastatic melanoma (MM), leukemia, lung cancer, and Merkel cell carcinoma deserve special mention. MM is fascinating because it can regress in the final stage of the disease. [42] The significant contribution of host immunity to early tumor genesis has recently been recognized due to our better understanding of the molecular pathways that regulate tumor cell biology and tumor-lymphocyte interactions. [3]

Targeted therapies designed to target oncogenic pathways in tumor cells may also up-regulate the endogenous immune response and tumor microenvironment. [3]Identifying T-cell inhibitory signals has led to the development of immune checkpoint inhibitors, which specifically impede the inhibition of immune effectors, amplifying and potentially expanding the pre-existing immune response against cancer. [3] This immunity against cancer can be enhanced through immunotherapies, mainly in vaccines, which stimulate natural T lymphocyte clones that specifically recognize tumor antigens. [3] Consequently, a promising anticancer therapy will aim to activate patients' natural anticancer immunity, either to eliminate residual tumor cells or to extend the dormancy period in metastatic tumor cells. Such endogenous cancer immunity plays an essential role in controlling the balance between dormant tumor cells and tumor leakage and in limiting metastasis. [3] 

Malignant melanoma (MM) is the most aggressive and difficult-to-treat form of skin cancer. It is estimated that up to 90% of deaths from skin tumors are due to this malignancy. [8] Regression is more common in melanoma than in other types of tumors; it would be six times higher than in other malignant tumors. Up to 50% of primary MM undergo spontaneous regression. However, spontaneous regression of the metastatic form of the tumor is a rare phenomenon observed in only 0.23% of cases. [8]The most frequently mentioned factors leading to spontaneous regression of MM are surgical trauma, infection, vaccination (BCG and rabies vaccines), and immunological factors. Other well-documented conditions associated with the regression of metastatic MM are blood transfusion and various endocrine factors. [8] 

Among the New Age methods, auto fiction, alternative gene therapy, combined bacteriolytic therapy, and enzyme-prodrug therapy targeting bacteria are some of the potential cancer treatment modalities that use microorganisms. There is an interconnection between microorganisms, the response of the immune system, and possible mechanisms involved in spontaneous tumor regression. [33] The role of NK cells evolves with tumor progression. It offers new opportunities to manipulate NK cell function to improve response rates to cancer immunotherapy in a broader range of cancers. [23] 

Self-recognition of missing target cells. Signaling from activating and inhibitory receptors regulates the activation of natural killer (NK) cells. Stressed cells, such as tumor cells, lose their MHC class I molecules, a ligand for inhibitory receptors on NK cells. At the same time, they acquire stress-associated molecules that act as ligands for receptor activation. Thus, the absence of inhibitory signaling combined with the induction of activating signaling shifts the balance towards the activation of NK cells, leading to the secretion of cytokines and the destruction of tumor cells.