Medicina de precisão do Hospital Israelita Albert Einstein

Oncogenetics: Genes and Cancer

oncogenetica - a área da medicina que combate o câncer

Oncogenetics emerged from the union between the areas of oncology and genomics. This union became essential for categorizing the knowledge about cancer, since the mechanisms that govern the development of these diseases are contained in human genetic material.

Want to know more about oncogenetics? Keep reading to understand what oncogenetics is, how oncogeneticists work and how they can help us prevent cancer!

What is oncogenetics?

Oncogenetics is the science responsible for relating cancer to certain alterations present in the genetic material of human beings. Thus, oncogenetics is a field of research and a branch of ​​medicine that operates at the intersection between oncology and genetics/genomics. 

This branch of medicine takes advantage of the fact that genetic variability offers information that can be used to increase the accuracy of diagnosis , prognosis and therapeutic strategies to be used.

What is the role of oncogenetics?

Investigate pathogenic genetic variants capable of influencing the development of cancer; understand the ways in which changes in the epigenome and transcriptome influence the onset of cancer.

Thus, by employing knowledge of genomics and oncology, arising from Genome-Wide Association Studies (GWAS), oncogenetics contributes to the prevention of many types of cancer based on the analysis of each individual’s DNA.

What is the roles of an oncogeneticist?

The oncogeneticist is the professional responsible for understanding how the patient’s genetic alterations can influence the development of cancer and assisting them with prevention strategies.

Cancer is a set of diverse diseases characterized by the presence of one or more malignant tumors. Such tumors are caused by the uncompensated division of cells, resulting in pathological cell clusters.

When we understand that our genome has all the information necessary for cells to carry out division, it is not difficult to understand the genetic implications that exist in the origin of cancer.

Despite this, most forms of cancer are not monogenic. This means that these diseases are not caused by a single genetic variant, but rather by a collection of them.

It is precisely in this collection of alterations that the oncogeneticist’s work is concentrated. By analyzing the genetic material, this professional is able to draw conclusions about: 

  • Increased risks of developing cancer; 
  • Predisposition; 
  • Early detection of cancer;
  • Personalized therapeutic strategies.

Oncogenetics in cancer prevention

The medical evaluation carried out by the oncologist or geneticist oncogeneticist, with the aim of preventing cancer, is developed through a methodology called genetic counseling .

With the Hereditary Cancer Predisposition Gene Panel exam, the physician can understand his patient’s risk for developing cancer. Based on this data, specific prevention strategies are established for each case.

Being a carrier of a cancer-related variant does not determine the development of the disease, but having a predisposition to develop it. In Hereditary Cancer Predisposition Syndrome (HCPS) , for example, an individual inherits certain genetic characteristics that increase the risk of developing cancer.

People with a family history of cancer, therefore, are especially benefited by genetic counseling performed by the oncogeneticist, since certain alterations identified by the physician may constitute a SPHC.

Additionally, it is important to emphasize that some of the habits, as well as the environment in which we are inserted, can generate harmful changes to the DNA. Consequently, all individuals have a potential benefit to be gained from genetic counseling.

This information can be used by the oncogeneticist to carry out screening and early diagnosis , mitigating the risk that a tumor is discovered in advanced stages, and reducing the mortality rate.

The development of malignant tumors is associated with the presence of changes in two classes of genes : proto-oncogenes and Tumor Suppressor Genes (GST), both involved in the expression of proteins that regulate cell proliferation.

Proto-oncogenes express proteins related to the up-regulation of cell division. 

In events where these genes are mutated or even with an abnormal number of copies , cell division happens in an unbridled way, generating cancer. In these cases, the proto-oncogenes are called oncogenes .

On the other hand, tumor suppressor genes perform the opposite function. Thus, the proteins expressed by this class of genes work by restricting cell proliferation, losing or decreasing this function ( down-regulation ) when the genes suffer mutations or find themselves with a smaller number of copies.

Additionally, modification of the expression of these genes can occur due to mutations of various types in promoter regions and also through epigenetic mechanisms .

Therefore, mutations in genes that predispose to the risk of developing cancer can be inherited , although most of them are acquired throughout life, through contact with mutagenic agents.

Some of the oncogenes associated with the onset of cancer are:

  • Epidermal Growth Factor Receptor Gene: this oncogene is commonly found in cases of glioblastomas and head and neck cancer ;
  • Ras gene family: are the most commonly found oncogenes in malignant tumors in humans;
  • ABL-BCR gene: its translocation from chromosome 9 to chromosome 22 is related to the development of Chronic Myeloid Leukemia .

Mutations in Tumor Suppressor Genes, however, are more commonly found in cancer than mutations in proto-oncogenes. Examples of GST related to the development of cancer are:

  • TP53 : called by some authors the “guardian of the genome”, the mutation of this gene is the most commonly found in human cancer. When mutations occur in germline cell lines, patients develop the so-called Li-Fraumeni Syndrome, which increases the risk of developing several types of cancer, especially breast cancer;
  • BRCA gene family : these are some of the genes most commonly associated with breast cancer and ovarian cancer;
  • CDK2A : responsible for encoding the INK4K and ARF proteins, the mutation of this gene is present in about 40% of all cases of melanoma skin cancer;
  • Retinoblastoma gene (RB1) : the proteins encoded by this gene inhibit the action of transcription factors responsible for initiating the S phase of the cell cycle. As its name suggests, mutations in this gene are implicated in the development of retinoblastoma.

What are some of the tools of oncogenetics?

Next-generation sequencing has opened doors for many questions about our genome to be answered and also for many others to be asked at all. Some of these questions were directly related to oncogenetics.

In parallel to genomics, other omics sciences have also developed, such as proteomics, metabolomics and transcriptomics, which have generated immense amounts of data about how our organism works and which aspects are involved with the emergence of pathological conditions.

To deal with this large amount of information, bioinformatics has developed methodologies that have enabled large-scale data collection and analysis , as occurs in genomic association studies.

In addition to promoting research initiatives, it allowed physicians to use the information made available by researchers at extremely high speed. Thanks to this, the use of genetic information in personalized medicine has become a reality and no longer just an idealization.

With these tools, oncogeneticists can currently perform genetic counseling based on methodologies such as genetic mapping (which involves, for example, the whole genome or whole exome sequencing of a patient) and analysis of hereditary risk panels , which compile data on specific genes .


Oncogenetics is the area of ​​knowledge dedicated to understanding the genetic mechanisms underlying the development of cancer. In precision medicine, oncogenetics is used to perform early diagnosis and prevention, as well as to establish personalized therapeutic strategies.

Cancer-related genes can be divided into two categories: oncogenes and Tumor Suppressor Genes. When mutated, these genes have their expression modified, resulting in the development of cancer. 

Furthermore, mutations in promoter regions and epigenetic mechanisms can also generate similar results.

In addition to genetic sequencing, the clinical use of oncogenetics was made possible by the emergence of bioinformatics pipelines, which facilitate the organization and analysis of this information. This allows for personalized decision-making by physicians when faced with cancer cases.