ABSTRACT
Cancer immunoediting is crucial to understand the success or failure of a tumor. Immune system plays dual roles in tumor development and progression, promoting or suppressing tumor depending on tumor microenvironment and the events that lead to initiation of carcinogenesis. The immune system has potential to recognize and destroy tumors, and thus function as a primary defense mechanism against cancer. On the other hand, unresolved immune responses can result in the growth and progression of cancer. Objectives: The host immune system determines tumour fate in three phases (Elimination, Equilibrium and Escape) and ac- cording to this theory, it blocks adaptive and innate tumour responses or promotes conditions that favour tumour progression. Conclusion: The purpose of this review is to emphasise the importance of immunity in tumour promotion and suppression.