For the first time, the mechanism that allows cancer cells to escape the action of the immune system has been identified. A group of researchers from the National Cancer Centre Singaporepublishing a scientific survey in the journal “Nature Communications”.
The professor Gopal Iyer, lead author of the study and head of the Department of Head and Neck Surgery at the National Cancer Center in Singapore, said the immune system detects and destroys abnormal cells such as cancer cells, but in some cases, cancer cells ” evade” immune action. This is made possible by the mechanism of metastasis, the process by which cancer cells break away from the primary tumor and regenerate in other parts of the body, making cancer more difficult to treat.
For this reason, the team set out to study the early onset of metastases, which typically occurs when cancer cells are detected in lymph nodes in close proximity to the primary tumour. Scientists then identified, within the tumors, the presence of pre-metastatic cells, able to move from the area of origin to other parts of the body passing through lymph nodes.
The researchers then observed that a substantial proportion of the CD8+ lymphocytes – cells in charge of identifying and eliminating the abnormal ones (including cancer cells) – were “depleted” and unable to perform their protective role. This is because after being repeatedly exposed to cancer they had lost their effectiveness.
The explanation of the scientists
“Like an employer who forces their employees to work non-stop grueling shifts, cancer forces the immune cells to work overtime and the immune cells become depleted, becoming unable to function normally,” said Prof. Iyer.
The researchers also found that when cancer cells and immune cells communicate with each other through special receptors, the infected cells emit a signal that is read by the latter as “don’t eat me.”
Immune cells – always refers to the author of the study – can be partially “reactivated” by means of PD-1 class inhibitor drugs. But despite this treatment, many of them were still too “tired” to continue destroying the infected cells.
The importance of the discovery of the National Cancer Center Singapore lies in the demonstration of the fact that, despite the action of cancer, the body’s immune system still continues its activity, even if with little effectiveness. Research has therefore highlighted that immune cells can always be reactivated, even in secondary moments.
“Our investigations indicate that we can fight cancer with a larger arsenal of ‘weapons’,” concluded Iyer.