Regulatory proteins SOCS 1-7 (suppressors of cytokine signaling), CIS (cytokine-inducible SH 2 protein) and other intracellular molecules such as JAKs (Janus tyrosine kinases), STATs family (signal transducers and activators of transcription), which participate in immunological response, could influence differentiation and proliferation, cell apoptosis, cell-cycle progression, cytokines and growth factors secretion by regulation of proper genes which determine these process in neoplasm cells and blood cells. The aim of this study was to introduce the latest knowledge of the SOCS/CIS family function in regulation of these processes. In this study the characterization of SOCS/CIS proteins and role in immu- nocompetent cells activation, their differentiation, proliferation, cytokines secretion and regulatory me- chanisms of carcinogenesis and neoplasm progression as well as interactions between SOCS1-7, CIS and proteins which determine regulation of lymphocytes T activity (ZAP70, Gfi-1, p27kip1) and oncogenesis (JAKs, STATs, p65, FAK, c-kit i IRS1/2) were introduced. Knowledge of mechanisms of activation by SOCS/CIS family, both in neoplasm cells and immunocompetent cells, could allow to understand intracel- lular interactions between these molecules, learn dominate processes in cancer disease and use new therapeutic methods (immunotherapy, new criterions for operations).