The history and advances in cancer immunotherapy: understanding the characteristics of tumor-infiltrating immune cells and their therapeutic implications

Abstract

Immunotherapy has revolutionized cancer treatment and rejuvenated the field of tumor immunology. Several types of immunotherapy, including adoptive cell transfer (ACT) and immune checkpoint inhibitors (ICIs), have obtained durable clinical responses, but their efficacies vary, and only subsets of cancer patients can benefit from them. Immune infiltrates in the tumor microenvironment (TME) have been shown to play a key role in tumor development and will affect the clinical outcomes of cancer patients. Comprehensive profiling of tumor-infiltrating immune cells would shed light on the mechanisms of cancer-immune evasion, thus providing opportunities for the development of novel therapeutic strategies. However, the highly heterogeneous and dynamic nature of the TME impedes the precise dissection of intratumoral immune cells. With recent advances in single-cell technologies such as single-cell RNA sequencing (scRNA-seq) and mass cytometry, systematic interrogation of the TME is feasible and will provide insights into the functional diversities of tumor-infiltrating immune cells. In this review, we outline the recent progress in cancer immunotherapy, particularly by focusing on landmark studies and the recent single-cell characterization of tumor-associated immune cells, and we summarize the phenotypic diversities of intratumoral immune cells and their connections with cancer immunotherapy. We believe such a review could strengthen our understanding of the progress in cancer immunotherapy, facilitate the elucidation of immune cell modulation in tumor progression, and thus guide the development of novel immunotherapies for cancer treatment.

Alteration in Gene Pair Correlations in Tryptophan Metabolism as a Hallmark in Cancer Diagnosis

“… 5 Furthermore, cancer cells can express abnormal antigens to evade host immunosurveillance. 6 Being the building blocks of proteins, amino acids are of a high demand in fast proliferating cancer cells. Therapies targeting amino acid metabolism have been investigated.…”

­­Prognostic analysis of tumor mutation burden combined with immune infiltration of Thymic epithelial tumors

“…The tumor microenvironment, especially tumor immune in ltration affects the effects of tumor immunotherapy [29]. And interestingly, this effect plays a dual role in cancer, which can inhibit tumor growth or promote tumor growth [30].So far, there have been many studies on the relationship between immune cells and tumor immunotherapy.…”

Single-Cell Transcriptome Profiling Reveals Intratumoral Heterogeneity in Human Chordomas

“…Single-cell RNA sequencing (scRNA-seq) may provide elucidation of the mechanisms underlying carcinogenesis and of the molecular features of cancers. It may provide a clearer description of the TME at the single cell level and potentially allow for more effective therapeutic strategies for tumors [15].…”