Tuning cancer fate: the unremitting role of host immunity

Abstract

Host immunity plays a central and complex role in dictating tumour progression. Solid tumours are commonly infiltrated by a large number of immune cells that dynamically interact with the surrounding microenvironment. At first, innate and adaptive immune cells successfully cooperate to eradicate microcolonies of transformed cells. Concomitantly, surviving tumour clones start to proliferate and harness immune responses by specifically hijacking anti-tumour effector mechanisms and fostering the accumulation of immunosuppressive immune cell subsets at the tumour site. This pliable interplay between immune and malignant cells is a relentless process that has been concisely organized in three different phases: elimination, equilibrium and escape. In this review, we aim to depict the distinct immune cell subsets and immune-mediated responses characterizing the tumour landscape throughout the three interconnected phases. Importantly, the identification of key immune players and molecules involved in the dynamic crosstalk between tumour and immune system has been crucial for the introduction of reliable prognostic factors and effective therapeutic protocols against cancers.

Keywords: cancer; immune cells; immunotherapy.

Figure 1.

Immune cells contributing to the tumour editing. At the tumour site, the dynamic interplay between immune and malignant cells is characterized by three different phases: elimination (left), equilibrium (middle) and escape (right) [16]. Immune players dictating the three interconnected phases are indicated with lower case labels in the figure and throughout the text.