A new study concluded that the residual cancer cells that survived the initial anticancer treatment could exploit our immune system leading to cancer recurrence. The study, jointly-funded by European Research Council, the Richard M Schulze Family Foundation, the Mayo Foundation, Cancer Research UK, and the US National Institutes of Health was recently published in the journal of Cancer Immunology Research.
The study was carried out in mice where researchers investigated the immune response after cancer treatment in order to unravel the mechanisms underlying cancer recurrence. It was later revealed that residual cancer cells that survived the initial treatment can subsequently undermine the immune surveillance by disrupting the functions of natural killer cells (NK-cells) and the tumour necrosis factor alpha (TNF-α). These are two key elements in the immune system which are important to keep both infections and cancer growth in check.
The residual cancer cells could modify the anticancer effect of TNF-α in such a way that it actually supported the growth of cancer cells instead of eliminating them. Moreover, these cancer cells also expressed high level of PD-L1 molecules on their surface which camouflaged themselves from the killing effects of NK-cells and T-cells.
These methods of circumventing the immune system allowed the resurgent cancer cells to progress unchecked leading to cancer recurrence after initial therapy.
Interestingly, researchers also found that immunotherapies (which target the T-cells, TNF-α or NK cells) could actually delay or prevent cancer recurrence.
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Taken together, these findings suggested the important role of our immune system in cancer treatment as well as the potential of immunotherapies that can prevent cancer recurrence by blocking the methods used by residual cancer cells to avoid the immune system. This is corroborated by the data from other clinical trials which also pointed to the potential of immunotherapies in reducing the risk of relapse in cancer treatment.
John Tiong Jeh Lung
MPharm, PhD, RPh
- Kottke et. al. (2017). Subversion of NK Cell and TNF-alpha Immune Surveillance Drives Tumor Recurrence. Cancer Immunology Research. DOI: 10.1158/2326-6066.CIR-17-0175