“…This chemoresistance may be produced by the tumor host factors [103] or factors associated with tumor-tumor microenvironment interactions [104]. The implication of the tumor microenvironment on the progression of the tumor and the chemoresistance nowadays is widely recognized [105][106][107][108][109][110]. The tumor microenvironment consists of tumor cells, vasculature, extracellular matrix (ECM), non-malignant cells, such as, stromal cells, tumor associated fibroblast (CAFs), immune cells and a complex signaling molecule network which include growth factors, cytokines, chemokines, and exosomes that sustain the internal connections of the microenvironment, [111,112].…”