German scientists have identified the proteins inside colon cancer cells that trick the immune system from seeing them as a threat. But, in lab tests, once researchers blocked the signals from the cells, the immune systems began to attack them. The insight could help scientists develop new and highly targeted immunotherapies for one of the world's most common forms of cancer.

Cancer grows when damaged cells begin to grow uncontrollably in the body. In most cases, our immune systems hunt down and destroy mutated cells. Still, some are allowed to grow and can develop into cancer. But why do some cancer cells evade detection?

Scientists have established that these cancer cells give out molecular signals that stop the immune system from seeing them as threats. They're called "checkpoint proteins," and identifying them is critical to the future of cancer treatment. In a new paper published in the Cell journal, German scientists have identified two proteins, known as CB7H3 and B7H4, that were present in cancer cells but not in health cells nearby.

Could these proteins be the cause of cancer cells' growth? "We decided to block B7H3 and B7H4 in colon cancer cells," said co-author Professor Sebastian Zeissig. "Blocking these signals suddenly allowed the immune system to attack tumor cells", said Zeissig.

Previously experiments to identify target proteins had shown less than promising results, but this time it was different. "The result was startling," said Zeissig. "Tumor tissue in which these signals were disabled showed significantly slowed growth or even shrinking." In experiments, targeting B7H3 and B7H4 proteins also had a beneficial impact on secondary tumours that had spread to the lungs.

Identifying the proteins is essential in developing new treatments for colon cancer. Most colon cancer patients receive chemotherapy, but this has significant side effects and isn't always effective. Zeissig and colleagues believe the findings could accelerate the development of effective new treatments called immunotherapies.

Immunotherapies are personalised treatments that target cancer at a genetic level. They work by blocking the signals given off by proteins in cancer cells. Once these signals are inhibited, the immune system can target and destroy them.

While initial experiments were on mice, the results were encouraging. "Our analyses of human samples showed that B7H3 and B7H4 are also present in human colon cancer cells," says Zeissig." These proteins are also barely detectable in healthy tissues in humans, which suggests that their targeting may be safe."

At RGCC, we welcome the findings and are encouraged by the progress to identify new targets for immunotherapies. We're developing a range of cancer immunotherapies. One of them is VAXO-Q-RE, an advanced combination therapy that consists of five types of immune cells, including macrophages, NK cells, dendritic cells, cytotoxic T lymphocytes and antibody-producing plasma cells.

While immunotherapies hold great promise for tomorrow, receiving an accurate and early cancer diagnosis is the best way to improve outcomes. At RGCC, we offer a range of personalised genetic tests that can help your clinician diagnose your cancer. Tests, such as our Metastat RGCC, can accurately determine a secondary cancerous tumour, including its potential location. As a result, clinicians can use the critical insights to drive care and ensure the right combination of treatments.

You can learn more about RGCC's range of cancer tests, including how your clinician can arrange them, here.

You can read the full paper, Microbiota-dependent activation of the myeloid calcineurin-NFAT pathway inhibits B7H3- and B7H4-dependent anti-tumor immunity in colorectal cancer, here.