A diagnostic test that carries out a multiple genetic analysis aimed at evaluating the susceptibility to the development of Colorectal cancer or Familial Adenomatous Polyposis

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What is a tumour?

Cancer nowadays is considered a pathology with a genetic component that occurs when cellular growth is out of control. Our body cells receive signals telling them when to grow and multiply and when such growth must stop. In a tumour, such cells do not respond to control signals and grow and multiply abnormally, spreading to different parts of the body, due to changes in their DNA. The event leading to the alteration of genetic functions is called “mutation”. When a gene is affected by mutation for different causes (biological, chemical and physical), information to the cell will not be adequate for its functions.

Is cancer hereditary?

Neoplasms are mostly pathologies caused by multiple factors generated by genetic and environmental risk factors. Most tumours are “sporadic”, that is, they arise in the general population without any clear signs of a genetic susceptibility. In these types of tumours, DNA alterations (mutations) randomly develop in somatic cells, namely, those cells creating every organ and system of our body. These mutations develop in the DNA of a small group of cells and generate the genetic error that is perpetrated in the descendants of those cells. After having accumulated in an organ, they initially replace the healthy cells of that organ and then spread to other organs, both nearby and distant (metastasis).
There are forms of tumour called "familial", when people affected by cancer in the family are close relatives. Cancer familiarity is a significant risk factor, especially when common environmental risk factors are also shared (lifestyles, diet, polluting agents, etc.) without a specific genetic alteration that makes the subject more susceptible to the disease.
Only a small, but significant, percentage of tumours are “hereditary”. Estimates say that around 5-10% of breast cancers and 10-25% of ovarian cancers have a hereditary component. In these tumours, DNA mutations occur in germ or reproductive cell and, therefore, may be passed on to the person's offspring. At birth, the child will show the genetic defect in one or more genes in all cells of the body and, therefore, will be susceptible to the development of a neoplasm when, during his/her life, other mutations occur.

When a new person is conceived, s/he acquires two pairs of each gene, one pair from the father and one from the mother. Any genetic mutations in the DNA of the parents are, therefore, passed on to children. If one of the parents has a mutation in one of the cancer-generating genes (hereditary tumour), the offspring has a 50% chance of inheriting that mutation. People inheriting a germ cell mutation are born with a copy of the mutated gene. These people do not inherit the tumour, but only the susceptibility to develop that type of cancer more easily, compared to the general population.

ColonScreen® Test

ColonScreen® is a diagnostic test developed by GENOMA Group that carries out a multiple genetic analysis aimed at evaluating the susceptibility to the development of Colorectal cancer or Familial Adenomatous Polyposis. Therefore, the test identifies patients with the risk of developing the aforesaid neoplasms by analysing their DNA.

The genetic susceptibility test is addressed to people who from a thorough family history, show a high and concrete incidence of neoplasms in previous generations and, therefore, have a high risk of carrying a germinal mutation.

A hereditary form of cancer may be present when the family has:
• Several individuals affected by the same type of cancer or correlated cancers,
• Individuals affected by multiple tumours,
• Tumours that arise at a young age.


In particular:
• Colorectal cancer diagnosed ≤ 50 years;
• Endometrial or ovarian cancer with a family history of gastrointestinal cancer;
• Subjects with more than one cancer associated to the Lynch syndrome (e.g. colorectal and endometrial cancer);
• Three or more cases of colorectal, ovarian, endometrial, gastric cancer or other types of cancer associated with the Lynch syndrome in the family;
• Results of the Microsatellite or immunohistocemical instability test in the cancer showing a lower capacity of repairing DNA replication errors;
• Multiple primary tumours in the same patient;
• Several members of the family (on the same side) with colorectal cancer or other types of cancer.
• A known mutation in the family in one of the genes associated with colorectal cancer/polyposis susceptibility.


The geneticist, with the informed consensus of the person, will decide whether a DNA mutation diagnostic test is necessary.


How does the ColonScreen® test work?

ColonScreen® test is carried out with a blood sample. The DNA is isolated from the nucleated cells through a complex laboratory analysis and amplified via PCR. Then, with a state-of-the art technological massive parallel sequencing (MPS) process that uses Next Generation Sequencing (NGS) techniques with ILLUMINA sequencers, 12 genes (exons and adjacent intrionic regions, ± 5 nucleotides) are completely sequenced at high reading depth (Table 1). The chosen genes are often involved in hereditary susceptibility to the formation of Colorectal cancer or Familial Adenomatous Polyposis.

The resulting genetic sequences are analysed with an advanced bioinformatics analysis, to find mutations of the examined genes, if present.

Accuracy of the ColonScreen® test

Present DNA sequencing techniques produce results with more than 99% accuracy. Even though this test is very accurate, the limits of the examination need to be considered.



Test Limits

This examination analyses only genetic diseases and genes listed in Table 1 and cannot detect:

 • Mutations positioned in the intrionic regions beyond ± 5 nucleotides from the breakpoints;
 • Deletions, inversions, or duplications with a value of more than 20 bps;
 • Germline mosaicism (i.e. mutations only in the gametes).

A “NEGATIVE” - No mutations result for the examined genes does not exclude the possibility that mutations are not present in a region of the genome that was not explored during the examination. Some regions of our DNA may not be sequenced or have a lower coverage than the limitations set by GENOMA Group experts to guarantee an accurate examination of gene variations. These regions, therefore, are not included in the examination if they do not meet the requested qualitative standards. In some cases the result of genome testing may reveal DNA variations or mutations with an unknown or unclassifiable clinical meaning within the current medical and scientific knowledge. The interpretation of genetic variations is based upon the most updated knowledge available upon examination. Such interpretation may change in the future, when new scientific and medical information on the structure of the genome are acquired and may affect the evaluation of the genetic variations themselves.



What are the benefits of the ColonScreen® test?

The possibility to detect subjects at risk of developing a neoplasm is the best way for an early diagnosis of cancer and, therefore, to decrease mortality in that type of disease. Members of families with high risks of inheriting cancer and especially those that were directly affected by a neoplasm, genetic counselling and may discuss his/her clinical and genetic situation with the geneticist. This assessment may lead to a genetic test to evaluate whether the patient is a carrier of a mutation that increases susceptibility to the development of a specific tumour. If the test result is positive, the analysis may be extended to the relatives of the patient, in order to find those at risk.

The information from the genetic test may offer several benefits, such as:

  • Finding family members with a high risk of developing cancer;
  • The development of an adequate medical check plan for high-risk subjects, in order to promote early diagnosis of cancer;
  • Awareness that the genetic mutations may be transferred to the offspring and the detection of high-risk offspring with germinal genetic mutations;
  • The possibility to undergo prevention therapies.

Results of the ColonScreen® test


“POSITIVE“

Presence of one or more mutations:
the result shows that there are one or more mutations in one (or more) genes leading to hereditary susceptibility to the development of colon cancer; the test, therefore, shows a mutated copy of the gene. During a genetic consultancy session, our geneticist thoroughly explains the test results and calculates the likelihood of developing the specific cancer associated to that mutation detected in a specific gene.

Risk Tables

A positive result does not necessarily mean that the patient with a mutation will develop a tumour; it only shows susceptibility to developing that type of tumour in the patient, or rather, the person has a higher risk level compared to a person without that specific mutation. In fact, not all people carrying mutations develop neoplasms. Although such mutations significantly increase the chance of developing a tumour, the cancer does not develop until the normal copy of the corresponding gene is mutated during the life of the person. Since everyone inherits two pairs of the same gene, a mutation must occur in each pair to cancel the function of such gene. The acquisition of a new mutation may, therefore, directly lead to a tumour. Identifying cancer-susceptibility mutation allows us to develop an intense clinical check plan and evaluate preventive surgery. A mutation also leads to the examination of other relatives at risk if they want to check their situation. In relatives the test is a predictive analysis, because it detects, within these families, the carriers of the mutation and people that do not carry the mutation, finding exactly those people with a high chance of developing a tumour and those whose risk is at the same level as the general population. That way, carriers can start specific check protocols for early diagnosis or prevention, while the latter will be screened with the same protocols as the general population.


“NEGATIVE”
No mutations:
the results show no mutations in the examined genes. However, a negative result does not necessarily mean that the patient does not risk developing a tumour. These people have the same chance of developing cancer as the general population because most of these types of tumours are sporadic in nature.

Downloads

Technical Information
(PDF file; 150 Kb)
Genes Investigated
(PDF file; 266 Kb)
ColonScreen Bibliography
(PDF file; 280 Kb)





About us

GENOMA: a rich heritage combining technologies and people, a model for quality, professional expertise and competencies.

GENOMA is a highly specialised diagnostic centre in Italy, renowned for its contribution to the advancement of molecular diagnostics. The laboratory is also renowned internationally thanks to its collaboration with scientific networks and prestigious research projects.

GENOMA, incorporated in 1997, is the point of reference for high-tech examinations. It is mainly a "service" centre for highly specialised prenatal and postnatal genetic, cytogenetic and molecular examinations.

GENOMA is considered as one of the most advanced molecular diagnostics centre in Europe and its head offices are in Rome and Milan. The laboratories are in a modern, high-tech building and cover a surface of more than 4,000 sqm. The centre uses state-of-the-art instruments and technologies and works at high quality levels.

GENOMA professionals have been working in genetics for more than 20 years. A team of more than 100 professionals, including geneticists, molecular biologists, gynaecologists, researches and laboratory technicians work together operating in the field of cytogenetic and molecular diagnostics for clinical applications and research and are led by Dr. Francesco Fiorentino inside a centre with very high technical and scientific standards.

GENOMA works all over Italy and abroad in Europe, the United States and the Middle East, providing specialised diagnostic support for public and private health clinics, examination laboratories, health centres, hospitals, private clinics, general outpatients' clinics, medically assisted procreation centres and physicians specialising in different fields.
Our laboratories receive biological samples from more than 5,000 health centres and hospitals every day. The integrated approach of the Centre is aimed at performing extremely high volumes of examinations; more than 100,000 genetic tests, constantly increasing, are carried out every year.

One of the features of the Group is a well-organised network of services, one of the most comprehensive in Italy and abroad, allowing the centre to offer its patients and their physicians innovative diagnostic solutions for any clinical need. With a list of more than 1,500 genetic tests available directly in our laboratories and divided into 20 areas of application, GENOMA is able to meet increasingly specialised requests in cytogenetic and molecular diagnostics, providing its customers with a highly specialised, precise, effective and rapid service.

GENOMA is a laboratory with one of the longest, wide-ranging experience in Europe in prenatal diagnostics. Thanks to this heritage, the Group can offer expectant mothers and their physicians state-of-the art technologies for foetal chromosome and genetic diseases diagnostics.

The laboratory in figures

2 main offices (Rome and Milan)
5,000 sqm dedicated to laboratories
100,000 genetic tests every year
1,500 types of genetic examinations
100 employees
20 areas of application
2,000 customers

Contact us

If you want additional information on the ColonScreen® test fill out the on-line form prepared by the GENOMA laboratory and please do talk to one of the staff in charge.

info@laboratoriogenoma.eu

Via Castel Giubileo, 11 - 00138 Roma (RM)
Tel. : + (39) 06.8811270 (6 linee)
Fax : +(39) 06 64492025

www.laboratoriogenoma.eu

Via Enrico Cialdini, 16 (Affori Centre)
20161 Milano (MI)
Tel. : + (39) 0239297626 (12 linee PBX)
Fax : + (39) 02392976261

www.genomamilano.it

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