CD44 and breast cancer: As shown in Figure 3 and Additional file 6, Table S3, we collected 39 tumor tissues from the untreated breast cancer patients with different genotypes and found that the levels of CD44 protein of seven cases carrying the TT genotype (0.838 ± 0.127) and 17 cases carrying the TC genotype (0.465 ± 0.243) were significantly higher than that of other 15 cases carrying the CC genotype (0.238 ± 0.067) (ANOVA test: P < 0.001).