Hidden keys in stroma: Unlocking the tumor progression

Malignancy is considered as a pathological imbalance of tissue-cell societies, a state that emerges from tumor-host microenvironment in which host participates in induction, selection and expansion of the neoplastic cells. Invasion of these malignancies can be viewed as a derangement in the proper sorting of cell populations, causing a violation of normal tissue boundaries. This violation is carried out by certain stromal cells like carcinoma associated fibroblasts (CAFs), tumor associated macrophage (TAMs), endothelial cells (ECs) leucocytes, bone marrow derived cells, etc. Tumor cells may alter the surrounding stroma and in turn, stromal cells may promote cancer progression and invasion. Thus, this review compares the role of CAFs, TAMs and ECs in tumor microenvironment towards tumor progression. This compilation aims to collate existing literature on stromal cell with particular emphasis on their role in tumor invasiveness and summarize experimental studies, trials and literature of last 10 years collected from pubmed central indexed journals.