M1 macrophages also amplify Th1 responses, providing a positive feedback loop in anti-tumor response, while M2 macrophages (“healing” phenotype) are mainly stimulated by interleukin-4 (IL-4) or IL-13, inclined to facilitate tumor growth and progression (Murray & Wynn, 2011; Shi et al., 2015; Martinez & Gordon, 2014; Solinas et al., 2009; Mantovani et al., 2002). The gene discussed is IL13; the disease is neoplasm.