Over the next ten years, twenty-thousand Australians will be diagnosed with stomach cancer. Despite treatment, more than half of those patients will die less than two years later.
Most of these cancers will be caused by infection with carcinogenic variants of Helicobacter pylori – the “CagA positive” strains that express the protein CagA.
By using a test to detect carcinogenic H. pylori infections, patients could be treated with antibiotics to clear their infection before cancer begins to develop. Within five years after being successfully treated, a patient’s risk of developing stomach cancer returns to normal.
Biotome is on the path to develop the world’s first test for gastric cancer risk with high enough accuracy and at a low enough cost to be used for public health screening.
Existing serology tests for CagA+ H. pylori are not clinically useful, due to low specificity. There are high levels cross-reactivity with other antigens indicating widespread antibody reactivity to CagA-like proteins even in individuals not infected with H. pylori, or in individuals infected with the commonly occurring H. pylori variants that lack CagA.
Our approach is to build a precision-serology ELISA that unlike conventional serology tests uses antibody epitopes (i.e. peptides) to catch antibodies. By carefully screening all linear epitopes of the CagA protein using peptide arrays expressing short peptides, we have identified peptides to which there are no cross-reactive antibody-responses and which therefore can form the basis of a highly accurate serology test.
Our approach is also useful to create precision-serology tests to other serology-relevant diseases, including chronic infections, post-infection diseases as well as autoimmune diseases.