Activation of the JNK pathway following loss of apical polarity in somatic cyst cells may be due to mechanisms similar to those seen in columnar epithelia in mammals or Drosophila imaginal discs, when Par complex function has been lost in a single cell or clone of cells in the epithelium (Archibald et al., 2015; Warner et al., 2010). This evidence concerns the gene MAPK8 and cyst.