Figure 1. Osteoblasts prime neutrophils that promote tumor growth in the lung.

The relationship between the lung tumor and its surroundings plays a pivotal role in determining whether and how malignant cancer cells grow. The study of Engblom and colleagues now reveals a novel very important function of systemic cross-talk between lung tumor and the bone that regulates cancer progression [42]. Lung tumors increase the number of osteocalcin (Ocn)expressing osteoblasts through tumor-secreted factors. These osteoblasts prime SiglecF^high– expressing neutrophils, which in turn expand lung tumor growth in vivo. With the appearance of state-of-art techniques, future studies will reveal in detail the cellular and molecular components that regulate the lung tumor microenvironment.