CD44 and cancer: Using the fluorescent immunostaining of CD44 at the sites of cancer cell engraftment in vascular ECs, we observed a robust positivity for CD44 in the regions where cancer cells had adhered (Figure 7D), as illustrated in Figure 7G. Additionally, fluorescent immunostaining images of CD44 expression from frozen tumor tissue sections in Figure 2 revealed reduced CD44 expression in the blood vessels within the tumor tissue (Figure 7E).