LGALS9 and nasopharyngeal carcinoma: Although galectin-9 has been detected on exosomes in Epstein-Barr virus-infected nasopharyngeal carcinoma cells51 and its secretion is inhibited by exosome formation blockers52, knockdown of exosome pathway regulators has minimal impact on galectin-9 secretion in HeLa cells (Fig. 2k, l, and Supplementary Figs. 4c, d and 8g, h).