Gastric adenocarcinoma follows a 5-step process, the first few steps of which involve a severe inflammatory response, initiated by H. pylori. The third step, known as precancer or gastric intestinal metaplasia (GIM), is when ‘micro-intestines’ are formed in the stomach. Essentially, the stem cells that rejuvenate the stomach lining differentiate into intestinal cells. Steps 4 and 5 are the final stages of precancer and cancer, respectively.
Patients with symptoms at steps 1 or 2 are treated to eradicate H. pylori and this significantly reduces the risk of developing stomach cancer. However, antibiotic treatment of patients with precancer is not as effective at reducing the risk of developing cancer. In the UK, patients with precancer are placed on a surveillance list for endoscopy to monitor precancerous changes every 3 years. We urgently need prevention, rather than management, strategies.
Enter the microbiome…
So, why does a state of chronic inflammation turn to precancer in some people? We think the answer lies in our microbiome.
From the ‘gum to the bum’, the amount – and diversity – of bacteria making up the microbiome changes. In recent years, DNA sequencing has become the most powerful tool that scientists can use to identify the, “Who’s, who?” of the gastrointestinal microbiome. Interestingly, much of our biological variation is due to our microbiome, rather than our human cells. However, in the case of the stomach, the number of bacteria are so low that it can be hard to spot variation and patterns. Nonetheless, there was a striking and consistent observation made by several independent researchers – once a healthy stomach turns diseased or cancerous, the number of H. pylori decline. In parallel, the number of other bacteria increases.
Source link
