A Tale of 2 Tumor Environments (IMAGE) Cold Spring Harbor Laboratory Caption Mikala Egeblad's team showed in mice that the progression of different types of breast cancer was influenced differently by the tissue -- the so-called tumor microenvironment -- in which the tumor is embedded. The tumor microenvironment contains many factors, including immune cells and blood vessels, that communicate with cancer cells and can promote tumor growth. On the left, a breast cancer type called luminal; on the right, a type called triple-negative/basal. The luminal microenvironment has less fibrosis (scar tissue, colored purple) and contains few inflammatory cells embedded within these fibrotic areas or in the surrounding fatty tissue (white). The triple-negative microenvironment contains more inflammatory cells and more fibrosis. Targeting a protein called MMP9, which promotes cancer and is linked with poor prognosis, slowed the course of the triple-negative/basal breast cancer, the one with the more profoundly altered microenvironment, but had no impact on the luminal cancer. Credit Egeblad Lab, CSHL Usage Restrictions please give credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.