For each cancer type, between 5 and 10% of cases are attributable to a hereditary form. A tumor is called hereditary when its onset is due to a genetic mutation transmitted by the parents.

Mutations in parents have a 50% chance of being passed on to their children. The latter do not inherit the tumor itself, only the predisposition to develop that tumor more easily than the general population.

Individuals carrying a genetic mutation predisposing to a specific cancer are considered to be at high risk and must undergo appropriate prevention protocols.

Identifying and treating tumors with a familial origin is a challenge that requires special resources and skills. This is why IOV created the Hereditary Tumor and OncoEndocrinology unit, which works in synergy with the Unit of Immunology and Molecular Diagnostics, specializing in the following neoplasms:

  • familial colorectal cancer
  • hereditary endocrine / neuroendocrine tumors
  • hereditary breast and ovary cancer
  • familial melanoma
  • hereditary kidney cancer

Cancer genetic counseling and genetic testing

Cancer genetic counseling is available for people with suspected hereditary predisposition to develop cancer. Counseling is carried out by a multidisciplinary team that includes:

  • a geneticist
  • an oncologist and / or appropriate expert specialist
  • a psychologist

Patients or healthy individuals who undergo oncogenetic counseling are invited to provide data on their family, on their illness and that of their relatives. After drawing the family tree and an exhaustive analysis of the medical data, the geneticist verifies the presence or absence of criteria to perform a genetic test.

The choice to undergo a genetic test must be made independently and consciously after receiving, during consultation, all the available information on:

  • the disease and / or the risk of developing it
  • the genetic investigation and its limits
  • the risk of illness associated with the test results
  • the available preventive and / or therapeutic possibilities

Given the complexity of the topics covered and of the choice to undergo the test and / or undertake specific monitoring / risk reduction, psychological counseling is offered to ensure adequate support and to favor autonomy in decision-making.
After signing an informed consent form, the patient may decide to undergo the test, which requires a blood sample or a buccal swab. Molecular analysis of genes is performed in the Molecular Biology Laboratory of the Hereditary Tumor and Oncoendocrinology Unit.

Results of the genetic test

From the genetic test, it is possible to obtain:

  • an informative result (the predisposing mutation is identified);
  • a non-informative result (the predisposing mutation is not identified either because it is on a gene not yet known or because it is not identifiable by the currently available analysis);
  • a doubtful result, if a gene variant of which the pathogenetic effect is not known is identified.

The result of the test will be communicated in a subsequent consultation session, in which the molecular data will be interpreted and the most appropriate surveillance program and possible risk reduction options will be illustrated. While awaiting the test result, which may take a relatively long time (even longer than 6 months), the patient and family members will be provided with an appropriate surveillance protocol.

Only if the result is informative, can the genetic test be extended to other adult members of the family who wish to do so. In families where a mutation that predisposes to cancer is identified, the family members at risk will be recommended for genetic testing by the patient or family doctor with indications to contact the Hereditary Tumor and Oncoendocrinology Unit.

Genetic mutation

Cancer is now considered a disease with a genetic component characterized by uncontrolled cell growth. The cells of our body receive control signals that tell them when to grow, when to multiply and when growth must stop. In a tumor, cells do not respond to the control signals, due to alterations of their genetic heritage, and grow and multiply irregularly spreading in different parts of the body. The event that determines the alteration is called mutation. When a gene undergoes a mutation (due to biological, chemical and physical causes), the cell will receive improper information about its function.

Tumors, for the most part, are sporadic: the mutation develops randomly without a particular family predisposition. The mutation originates in the DNA of a small group of cells and determines a genetic error that will perpetuate in the descendants of those cells, which, accumulating in a specific organ, will initially replace the healthy tissue and then spread to nearby or distant organs ( metastases).

While in sporadic tumors, the genetic mutation is present only in the tumor cells, and therefore only in the area of the organ affected by the neoplasia, in the case of hereditary tumors, the mutation is present in all the patient’s cells. To demonstrate that the predisposition to the development of a tumor is hereditary and to be able to identify the associated DNA mutation provides the great advantage of being able to predict the evolution of the tumor in the affected subject and to eliminate or reduce the risk of cancer in relatives who are carriers of the mutation.

Gene alterations that may predispose to tumor development have been identified for some cancers (breast, colon, stomach, kidney, melanoma, thyroid, pancreas, parathyroid and adrenal gland) and many studies are underway for other types of cancer.