SDC4 and cancer: Given that the majority of cancer types that shown a significant positive ratio of expression of Sdc-3 and Sdc-4 on malignant versus normal or adjacent tissue are solid tumors (Figures 1A,B), and solid tumors are known to be hypoxic, we interrogated the data for potential correlations between SDC3 or SDC4 genes and a hypoxia signature comprised of 15 genes including LDHA, VEGFA, and others (see section “Materials and Methods”).