GI tract cancers are an enormous public health issue, and together are responsible for more deaths than any other form of cancer. One of the major difficulties with diagnosing and treating these cancers, especially when localized to the intestine, is access to the tumour - patients often do not exhibit obvious symptoms until the later stages, when treatment options are limited.

We looked into a few different ways of tackling this issue, from improving existing diagnostic methods to developing new avenues for treatment. One of the consistent themes that came up in our brainstorming process was the potential for us to use the host's cell-mediated immune response to fight cancer. Cancer immunotherapy is a rapidly growing field, and clinical trials for certain forms of leukemia are already underway.

Thus, this year, McMaster iGEM sought to augment the power of the host immune system to fight against GI tract cancers, using a specially engineered strain of commensal lactobacillus bacteria. When completed, our bacteria will be able to sense the presence of tumours in the gut, bind to specific receptors on tumour cells, and begin secreting pro-inflammatory cytokines in this tumour microenvironment. This will recruit T cells to the site of the tumour and elicit an anti-cancer response, effectively stopping the cancerous growth using the body's own toolkits. This summer, we aim to develop a proof-of-concept of our idea, and create a bacterial strain that can secrete IL-2 under tightly controlled, tumour-specific conditions.