PROM1 and gastric adenocarcinoma: The gastric adenocarcinoma with positive expression of CD133 was 41.2% (7 out of 17) at grade 1, 46.2% (30 out of 65) at grade 2 and 61.4% (156 out of 254) at grade 3, respectively, thus the association between expression of CD133 and histological grade was statistically significant (P = 0.032) (Table 1).