The task of this paper is to describe an environment suitable for the tumor formation, the unavoidable part of which is an immune system, either as a disabling factor, slowing down and suppressing, or as a cause for tumor growth. In a large number of immune cells, such as neutrophiles, macrophagesandlymphocytes, as is observed, we find attributes that support growth of tumor and aggravation of tumor symptoms. Mediators released via immune cells (cytokines, chemokines, transcription factors etc.), in severe cases of inflammation, can be transformed into participants in the process of cancerogenesis. Excreted mediators can also be factors of suppression, i.e., they act twofold - as a factors of progression or regression in immunosurveillance of tumor. This paper gives an overview of the essential features of inflammation and tumor formation and the latest knowledge of the role of the immune system in the emergence and development of inflammation, as well as the role of inflammation in the development and metastasis of tumor cells. The paper will also provide a review of numerous therapeutic methods in suppressing tumor growth.