Fig. 3

Biological factors and their roles in cell-cell and cell-matrix cross talks for tissue homeostasis. Various cytokines are released by activated immune cells such as monocytes, macrophages, dendritic cells and granulocytes. These cytokines activate or regulate other cells depending upon the microenvironmental conditions to maintain tissue homeostasis through various signaling pathways. In addition, growth factors, hormones and metabolites are essential factors to balance the tissue physiological conditions and functions. Besides defensive functions, immune cells are also actively involved in tissue growth, repair and blood vessel formation via their growth, differentiation, migration, and apoptosis and by sending signals to tissue specific cells, fibroblasts, platelets, red blood cells, and plasma cells. Tumor development is coupled with failure in the surveillance systems of immune cells, which are seized by tumor cells to produce high amount of active biological factors in tumor microenvironment to increase cell-cell and cell-matrix cross-talks for tumor progression