Study maps DNA of Brazilians and discovers risks of hereditary cancer

This research is the first in Brazil to analyze the complete DNA of these patients – that is, do the complete genome sequencing – organized in several centers and connected to our public health system.

The study, published in the scientific journal The Lancet Regional Health – Americasanalyzed 275 adults in nine health centers and compared genomic data with the lifestyle of patients before diagnosis. The project receives funding from Ministry of Health through the PROADI-SUS program.

The study analyzed the DNA of 275 volunteers diagnosed with breast (140 cases), prostate (65) or intestinal (70) tumors. The group reflects Brazilian diversity: the majority identifies as brown (58.9%)followed by whites (29.8%) and black (9.5%). The average age of these people when they discovered the disease was 58.4 years.

By reading the complete genetic code, scientists found answers on two fronts. In the first, the focus was on the inherited DNA (germinative). About 9.5% of patients carried mutations in genes known to increase cancer risk. In total, 12% of the group had genetic alterations considered pathogenic.

On the second front, the research looked at the DNA from the tumor itself (somatic). Sequencing identified 91 genetic variants high impact in 88 different tumors. These data show how the biology of cancer in Brazil can present specific characteristics in comparison to international data.

This is the first time that a Brazilian work combines genome sequencing with the life history of patients on a national scale. Before BGMO, genomic evidence in Brazil was scarce and rarely integrated blood DNA with tumor DNA in a harmonized way. The country now has a technical basis to understand the burden of these diseases in its population.

Family testing allows expanding cancer prevention in the public health system

The discovery of a mutation in the patient acts as an alert for the family nucleus. The study carried out the call cascade testingin which he invited first and second degree relatives for targeted examinations. Of the 50 family members who agreed to participate, 38% also carried the genetic variant of the family.

This working model proves that it is viable to carry out precision medicine within the public health system (SUS). The project created an operational path that connects the sequencing laboratory to the structured genetic counseling. This allows family members at risk to be identified and monitored early.

Discovery of a mutation in the patient can act as an alert for their family – Image: Lightspring/Shutterstock

The initiative’s difference is its integration with public reference centers in different regions. The methodology demonstrated that complete genome sequencing can be applied in the routine of the healthcare system. And the project lays the foundation for genetics to help guide large-scale medical decisions.

For the next phases, researchers plan to follow these patients and their families for long periods. The objective is to use genetic mapping to create strategies for personalized surveillance and more precise treatments. Com esses dados, o sistema de saúde poderá agir de forma preventiva em grupos de maior risco genético.