ISG15 and esophageal cancer: In our study we found that while depletion of both IGS15 and UBE2L6 elevates autophagy, only those esophageal cancer cells with ISG15 knockdown showed a decrease in sensitivity to 5-FU, consistent with the effects of ISG15 silencing reported by Desai et al. In contrast, sensitivity of esophageal cells to 5-FU was unaffected by UBE2L6 knockdown.