SULF1 and cancer: The in situ hybridization clearly shows that SULF1-expressing cells are more common in the stroma (mean 24.9% stroma vs. 8.4% tumor, p < 0.001) while SULF2 expression is higher in the cancer cells (mean 22.7% stroma vs. 52.5% tumor, p < 0.001) (Supplemental Table S5).