In support of this hypothesis, LY6D has indeed been shown to confer chemoresistance in head and neck squamous cell carcinoma [19, 20], and Rubinstein et al. demonstrated that LY6D was consistently up-regulated in colorectal cancer xenografts grown in mice upon treatment with irinotecan, and that treatment with a combination of LY6D-targeting antibody and irinotecan led to complete tumour regression [21]. This evidence concerns the gene LY6D and head and neck squamous cell carcinoma.