Methods for the study of mast cells in cancer

Tumor growth requires interactions of tumor cells with a receptive and inductive microenvironment. Two major populations of tumor-infi ltrating cells are considered to be essential for producing such a microenvironment: (1) proinfl ammatory cells that nurture the tumor with growth factors and facilitate invasion and metastasis by secreting proteases and (2) immune suppressive leukocytes including T-regulatory cells (Treg) that hinder tumor-specifi c CD8 T-cell responses, which otherwise could potentially reject the tumor. Among the proinfl ammatory cells, accumulation of mast cells (MCs) in human tumors is frequently recorded and was recently linked with poor prognosis. Causative links between mast cell infi ltration and tumor progression can be deduced from animal studies. There is an interesting link between mast cells and Treg. The adoptive transfer of Treg from healthy syngeneic mice to mice susceptible to colon cancer suppresses focal mastocytosis and hinders tumor progression. Furthermore, T-cell-defi cient mice susceptible to colon cancer show enhanced focal mastocytosis and tumor invasion. Here, we describe methods to assess MCs in mouse models of cancer and to investigate how MCs affect tumor epithelium. Additionally, we will detail methods used to investigate how T cells infl uence MCs and how MCs infl uence T cells.