Stromal cells can contribute oncogenic signals

The majority of studies of neoplastic transformation have focused attention on events that occur within transformed cells. These cells autonomous even ts result in the disruption of molecular pathways that regulate basic activ ities of the cells such as proliferation, death, movement and genomic integ rity. Other studies have addressed the microenvironment of tumor cells and documented its importance in supporting tumor progression. Recent work has begun to expand on these initial studies of tumor microenvironment and now provide novel insights into the possible initiation and progression of mali gnant cells. This review will address the transforming effect of stromal ce lls on epithelial components.