DDX4 and cyst: Moreover, similar immunohistochemical assays using an unrelated first antibody (i.e. a polyclonal α-DDX4/VASA), directed to a stem cell marker, resulted in an entirely different pattern of fluorescence in the cyst’s tissue when the same secondary antibody was applied (Additional file 3: Figure S3), excluding the possibility of unspecific anti-GFP fluorescence.