In cancer treatment, avoiding patient relapses is essential to improve the prognosis of the disease.. In colon cancer, various adjuvant treatments have been approved that seek to prevent the reappearance of tumor cells; Some prognostic factors help identify which cases are at highest risk.
However, there are still no tools that are sufficiently precise to identify in the best possible way which patients will need chemotherapy after surgery and those who will not.. It is not a trivial question if we take into account the toxicities associated with oncological treatments and the way in which they affect people's quality of life.
A study that has been presented at the congress of the Spanish Society of Medical Oncology (SEOM), which is being held these days in Barcelona, points to the possibility of using the microbiota as a new prognostic factor that helps to be even more precise in the selection of patients with the highest risk of colon cancer relapse.
“We already know that the microbiota plays a fundamental role in the incidence of colon cancer, but until now we were unaware of its role as a prognostic factor. For this reason, our research has focused on knowing whether some bacteria in the microbiota increase the risk of relapse in certain patients with localized colon cancer,” explains Daniel Martínez, medical oncologist at the Central University Hospital of Asturias (HUCA) and the lead author. of the investigation that was presented today, Friday, in the plenary session of Congress.
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Tumor cell proteomics
To answer this question, we have turned to proteomics, which is the area of Biology that studies the set of proteins expressed by a genome and which in recent years has been demonstrating its usefulness in the analysis of many diseases such as cancer.
“The study of proteins offers us complementary information to what we can obtain from genomic and transcriptomic studies, and can help us understand how a cell is functioning at a given time,” adds Martínez.
Thus, the proteins of tumor samples from 158 colorectal cancer patients in stages II and III that were preserved at the La Paz University Hospital in Madrid were studied.. “Performing the proteomic analysis was very complex, since there is a lot of data: in a first screen, 19 microbiota proteins and 2,698 human proteins were found.. After applying quality criteria, 13 microbiota proteins and 1,940 human proteins were obtained.. Finally, the Kaplan-Meier analysis determined that three microbiota proteins are related to disease-free survival,” details the oncologist.
Novel relationship with prognosis
Specifically, it was found that the greater presence of two of these proteins represented an increase in the risk of recurrence, while the lesser presence of the third represented a decrease.. The combination of the three proteins may serve as a biomarker of relapse risk.
These proteins help us identify three genera of bacteria that in previous studies had already been linked to an increase in the incidence of colon cancer, such as Fusobacterium nucleatum.. But now, for the first time, we see that they also play a role in the prognosis of relapses,” explains Martínez.
These data, in his opinion, are “quite promising.”. The next step is to validate the data that has been achieved in another independent cohort of patients.
On the other hand, a complete analysis of the proteome of tumor cells is being carried out, which he hopes will help to better understand colorectal cancer.. “If we can confirm these results that we have now obtained, it will help us a lot to properly select patients, but it would also be necessary to make an investment to be able to perform these types of proteomic tests in clinical practice, something that could not be done today” .
A microbiota 'panel'
The three specific proteins of the microbiome identified as a prognostic factor could be very useful in that sense.. Just as there are now genetic panels that look for specific mutations related to cancer, in the future, tests could be designed that look for these three proteins.
“In the end we would get a tool that would allow us not only to identify those people who do not need adjuvant treatment, because they do not have a risk of relapse, but also to know who truly needs it and who currently, perhaps with current prognostic factors, we do not know how to identify” , concludes this expert.