Cardiac tumors, both primary tumors and metastasis are extremely rare. If this is intuitive for cardiomyocytes, which early after birth exit the cell cycle and terminally stop dividing, the heart contains many other cell types which have the potential to proliferate. Angiogenesis is a key causative factor in the pathogenesis of any tumor, as in the absence of vascular support tumors become necrotic and apoptotic. The main goal of this project was to compare tumor growth and angiogenesis in the myocardium and in the right tibialis anterior muscle. Mices were subjected to intracardiac and intramuscular injection of different quantities of Lewis lung carinoma cells. Tumor masses were harvested and used for immunohistochemistry, immunofluorescence and dextran assays. Results show higher tumor cell growth in the muscular tissue compared to the cardiac tissue, higher percentage of positive αSMA/lectin tumor cells, as well as higher percentage of Edu positive cells in muscular tumor tissues compared to the untreated tissue. Results from dextran assays show higher vascular permeability and perfusion of the cardiac tumor compared to the muscle. This project provide evidence that experimental tumors in the heart are less invasive then tumor in the muscle, although the main reason why cardiac tumor almost never occur still remain unexplored.