In which cases is the genetic study useful?

MADRID, April 23 (EDIZIONS) –

That our mother or grandmother had bad cancer does not mean we are going to develop it, yes or yes. However, we may be more likely to have this disease than anyone. It all depends on whether it is a hereditary cancer or not, and even then it is not mandatory.

As the Spanish Society of Medical Oncology (SEOM) has explained, the hereditary cancer is a cancer that has its origin in a genetic mutation. "It is estimated that 5 to 10% of bad cancers are hereditary." 20 to 25% of the mutations responsible for hereditary bad cancers occur in the BRCA 1 and BRCA 2 genes. The risk of developing bad cancer during life, it is about 60% in BRCA carriers 1 and 50% in BRCA 2 carriers, "he said.

But to better understand, in an interview with Infosalus, Dr. Teresa Ramón y Cajal, coordinator of the hero-family working group of the GEICAM Breast Cancer Research Group, recalls that even though she is alone, there is no reason to worry. is a "multifactorial" disease, it recognizes that inheritance may represent "a significant factor of weight" for some people to develop it, because they have inherited an alteration of their genes (the predisposition to cancer), through the egg or sperm of their parents.

Of course, this oncologist points out that even if one of these altered genes is inherited, it does not mean that this person will develop the disease itself. In the specific case of bad cancer, Ramón y Cajal states that "the greater the number of family members diagnosed with bad cancer, the lower the age of diagnosis, the greater the suspicion that the tumor is hereditary ".

GENETIC STUDY, YES OR NO?

At this point, he specifies that there is a set of specific, varying criteria that are used to recommend a genetic study based on families. GEICAM points out that there is a series of frequently repeated clinical data in people with such a mutation who may raise suspicions about their presence.

Among these, he enumerates: a diagnosis before the 40; the badociation of bad cancer and ovarian cancer in the same patient or in the family; if it exists in the family

some cases of bad cancer in men; the subtype of diagnosed bad cancer is triple negative (the most aggressive); and if the diagnosed bad cancer is bilateral (affects both bads).

Since the genetic badysis of BRCA1 and BRCA2 is "complex and expensive," says SEOM, it is therefore necessary to make a very precise selection of the families that can be considered high risk and for whom the L & # 39; genetic study is indicated.

From the scientific badociation GEICAM also considers that knowing the carrier status of a person, both in good health and having already developed the disease, involves possible changes in the medical and surgical management of the tumor and opens the door. other therapeutic possibilities specific to these patients. .

GENES INVOLVED IN HERCEDITARY CANCER MAM: BRCA 1 AND BRCA 2

Dr. Ramón y Cajal indicates that the genes most frequently impaired in bad cancer with BRCA 1 and BRCA 2, as mentioned above, but points out that it is about genes of "incomplete penetrance" , ie their alteration is synonymous with high risk of bad cancer, but that does not mean that the disease will be generated at 100%.

"Your grandmother may have had bad cancer, not your mother, but you, but keep in mind that, depending on the type of bad cancer transmission, the larger your mother is and if she has not presented the disease, it is less likely that it has transmitted a genetic alteration because, being the issuer of the predisposition, the normal thing is that it has already manifested, "says-t- he.

However, these alterations are detected in about less than 30% of women meeting clinical criteria presumed to be prone to bad cancer "so we know that there must be more genes involved," adds GEICAM.

He explains that the BRCA1 and BRCA2 genes produce tumor suppressor proteins that help repair damaged DNA. Of course, when one of these genes contains alterations, its function is not fulfilled and DNA damage is not repaired properly, so cells are more likely to exhibit additional genetic alterations that can lead to the development of cancer.

"Women carrying a mutation in these genes have a higher risk of developing bad cancer and ovarian cancer than the general population, but that does not mean that the disease will develop. involved, such as PTEN, CDH1, TP53, PALB2, CHEK2 or ATM, among others, "he adds.

Surgical or medical treatment options in these patients with a BRCA1 or BRCA2 mutation have been studied in recent years. They personalize their treatment by knowing the underlying molecular alterations and the risks of developing another tumor.

Specifically, knowledge of mutations in the BRCA1 and BRCA2 genes, badociated with a defect in one of the DNA repair mechanisms, has allowed the development of specific targeted therapies for hereditary bad cancer, as is the case of PARP inhibitors. (protein also involved in the repair of DNA). Some of these drugs have already been approved in Spain for patients with ovarian cancer and continue their clinical development in patients with bad cancer.

Finally, the oncologist mentions the case of bad cancer in humans, which is also possible because they have bads. In these cases, he says you should suspect a hereditary predisposition, especially if you are having other family members in whom bad or ovarian cancer has been diagnosed.

"If one in 100 men can have bad cancer, carriers of a BRCA 2 gene mutation are 6 out of 100. Other factors must occur throughout life for a woman predisposed to the disease, such as There are no human hormonal and reproductive histories, which has a lesser incidence, but this carrier will be able to transmit to his children this genetic alteration by the sperm, with a probability of 50% " , adds the expert.