Figure 2.

Role of mast cells in breast cancer. (a) The influence of mast cells in breast cancer prognosis is still a matter of discussion. Mast cells contain a great variety of bioactive components that may exert both pro- and antitumor effects. On the one hand, in vitro and in vivo studies support that mast cells exhibit protumor activity through promotion of lymphatic and blood vessel formation, tumor growth, and metastasis (orange right side). On the other hand, several population studies also associate mast cells with a greater survival and favorable prognosis (green left side). (b) Some bioactive molecules of mast cells documented to have protumorigenic effects are tryptase through its receptor PAR-2 and histamine through H2 receptor. The cancer processes in which these compounds have been associated are indicated.