LGALS4 and chordoma: Compared with control notochords from 4465:Gal4 embryos (Fig. 1F), the malformed notochords from both double-transgenic notochord-Gal4;UAS:HRASV12 combinations had histological characteristics that were highly similar to those of human chordomas: the developing masses consisted of plump cells with focally prominent nuclear pleomorphism (variation in size and shape) and hyperchromasia (dark staining with hematoxylin).