The percent of CD44+ cells from each PDX tumor varied slightly, although none had significant differences in the percent of CD44+ cells under different oxygen conditions; there was an average of 62% CD44+ cells in hypoxic, 64% in physoxic and 60% in hyperoxic conditions (F2,36=1.32, p=.28) from live cells (Fig. 1a,d). This evidence concerns the gene CD44 and neoplasm.