CLEC2D expression has been immunohistochemically examined in several human malignancies including glioma, prostate cancer, head and neck cutaneous squamous cell carcinoma (HNcSCC), clear cell renal cell carcinoma (ccRCC), and oral squamous cell carcinoma, where CLEC2D is often overexpressed and identified as a poor prognostic factor [11–13]. This evidence concerns the gene CLEC2D and prostate cancer.