By comparing the blood donors with the patients with gastric cancer (Table 2 and Table 3), a significant difference was observed in the frequency of CagA positive status (p < 0.001; OR = 8.54; 95 % CI = 4.99 – 14.76) and in the distribution of the STAT3 genotypes (χ2 = 10.86, 2 degrees of freedom, p = 0.004). Here, STAT3 is linked to gastric cancer.