The JAK-STAT and EGFR pathways in ISCs and the EGFR pathway in enterocytes are indispensable for maintaining homeostasis, as flies lacking those pathways in the corresponding cells are highly susceptible to infection (Buchon et al., 2009a, 2010; Jiang et al., 2009; Osman et al., 2012). This evidence concerns the gene EGFR and infection.