First, bacteria other than Hp in the gastric mucosa of nongastric cancer patients were analyzed under the premise of the existence of Hp, and it was found that the dominant bacterial species were Neisseria flavescens (13.7%), Streptococcus salivarius (9.5%), Rothia mucilaginosa (8.9%) and Streptococcus pneumonia (6.6%) (Hu et al., 2012). Here, HP is linked to cancer.