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Cidon. J Unexplored Med Data 2018;3:8 I http://dx.doi.org/10.20517/2572-8180.2018.03 Page 13 of 16

antigen-recognition domain of an antibody and intracellular signaling domains of T cell receptor which will
recognize a tumor antigen, and the T cells will activate and change to cytolytic.

For this therapy one of the key points is the production of antibodies to bind to the tumours but not to
[74]
healthy tissues, and also to select the antigens. The tumour associated form of MUC1 seems to be a
[74]
relevant antigen and MUC1-CAR-T cell treatment has shown benefits but needs further evaluation .
A trial assessing CEA-redirected-CAR-T cells in CEA transgenic mice demonstrated regression of CEA
positive cancers as primary treatment and also a good recall response after the second challenge with these
[75]
tumours . A CEA-T cell receptor therapy assessed in a small study showed objective response in metastatic
[76]
colon cancer in three patients .
+
A phase I/II study is assessing an anti-MUC1 CAR-T cell therapy in patients with a MUC1 tumor and
includes patients with colon cancer amonth othes (NCT02617134). This trial is recruiting patients at this time.

CONCLUSION
Immunotherapy is a breakthrough in cancer therapy and several agents are already approved to be used
routinely in clinical practice, however, much remains to be done to be able to select the optimal population
to achieve maximum responses.

A group of colon cancer patients, those with MSI-H, seems to be the target for immunotherapy as the
highest responses to PD-1/PD-L1 inhibition are shown in highly mutated tumours.

Moreover, the identification of tumours significantly infiltrated by cytotoxic T-cells, is a predictive factor for
benefit from PD-1/PD-L1 inhibitors.

Although all these data are promising, we need to remind that only 30% of MSI-H patients, show a benefit
with immunotherapy and thus research should continue to find other options to maximise the benefit.

Here is where the treatments that stimulate antigen presentation and boost T-cell priming (i.e. chemotherapy,
radiation and monoclonal antibodies) can help transform a non-immunogenic tumour to an immunogenic
one.

Perhaps combining immunotherapies between them or with other drugs could increase the benefits without
increasing the side-effects significantly.

Unfortunately, no definite agent has been found yet for MSS and non-hypermutated tumours. However,
MEK inhibitors combined with anti-PD-L1 are under investigation with some positive results so far.

It seems that we are now advancing at good speed in the understanding of immunotherapy and great
optimism should remain.

DECLARATIONS
Authors’ contributions
The author contributed solely to the article.

Availability of data and materials
The data were strictly obtained from medical literature according to the privacy policy and ethics code of our
institute.