Cancer is a multifactorial disease. The formation of cancer is depended on both internal (genetic) and external factors. Breakthroughs in the fields of genetics have demonstrated the important role genes play in cancer development as well as help us provide more precise tests. Almost all forms of cancer are caused due to genetic abnormalities. These abnormalities can be spontaneous or can be induced by mutagens. All external factors which can potentially cause or accelerate the development of cancer are called carcinogenic mutagens, these include: viruses, chemicals, tobacco, pollution, radiation and so on. The goal of genetics in cancer is to improve the diagnostic and therapeutic procedures.

“The inheritance of cancer”

Even though the vast majority of cancer cases are sporadic in nature (spontaneous mutations in somatic cells which are not passed down to the patient’s offspring), it is a well-known fact that certain forms of cancer run in families. In some families the pattern of cancer cases is easily noticed, while in others, due to the size of the family or lack of data, the pattern of cancer inheritance may not be easily noticed.

The characteristics of inherited cancer are as follows:

in the patient

-multiple primary tumors in the same organs;

-multiple primary tumors in different organs;

-bilateral primary tumors in paired organs (breast, kidneys, lungs…);

-early diagnosis of cancer (earlier than the population average);

-tumors in men/women that are not characteristic of their sex (breast cancer in men as an example);

-the link between cancer and other conditions;

-the link between cancer and congenital defects.

in the patient’s family

-the same of type of cancer appearing in relatives;

-frequent cases of cancer in the family;

-the appearance of linked cancers in a family (ovarian and breast cancer/colon and endometrial cancer)

Genetic counseling in the case of cancer

The main task in genetic counseling in the case of cancer is risk assessment. This allows the affected person to take preventative measures. Genetic counseling and risk assessment are usually the first thing clients are interested in when it comes to cancer. Risk assessment not only helps the individual, but it is also of great assistance to the family as a whole in taking preventative measures.

Cancer prevention

Cancer is best treated in its earliest stages and as such a precise diagnosis must be established quickly. A late diagnosis will almost certainly be the cause of a fatal outcome. By establishing a precise diagnosis on the genetic and molecular levels and by analyzing the family history we can better understand and help each and every case. The following steps must be taken:

  • Is there a close relative affected by cancer?
  • Is there multiple distant relatives affected by cancer?
  • Did a certain form of cancer appear unusually early in someone’s life?

If one of the conditions above are met, then it is highly likely that you are in a risk group. It is vital that you consult a professional from either the field of medicine or genetics in order to assess your risk. If there is a degree of risk a genetic test should be done in order to remove any doubts. Preventative measures should be taken if the results confirm the initial suspicion.

A brief table with preventative measures and possibilities routes of testing for certain cancers is provided below:

Common approach Brest and ovarian cancerLung cancerColon cancerPancreatic cancerProstate cancer

When a case of cancer appears in a family, the first questions to arise are whether or not other family members at risk are and will the condition reappear.

Cancer can be inherited, but isn’t always such. How do we know this? We can find the answer to this question by following the parameters below:

  1. Number of cases within the family. The higher the number the more probable chance that it is inherited
  2. The time at which cancer appears. If the cancer appears earlier in life than in the average population (breast cancer at 35 as an example) then there is a high chance of it being inherited.
  3. The number of primary tumors. If there is a large amount of primary tumors in a patients, then the chance of the condition being inherited is also high (primary tumor in both breasts as an example)

If based on the parameters above you suspect that you are at risk then you should consult an expert, who will determine your risk and develop a preventative strategy. An early diagnosis is a life saver in the case of cancer.

An inherited form should be taken into consideration if there is lots of cases in the family as well is if the following parameters are met:

  1. Early appearance of cancer, usually before the age of 50
  2. Primary tumors in both breasts/ovaries
  3. Brest cancer in males
  4. Two or more people affected
  5. Ovarian cancer in a close relative

A positive familiar finding suggested that the person most likely carries the mutation needed for the disease to arise and is such is at a high level of risk.

For ovarian/breast cancer there are at least 20 genes which can cause this conditions. BRCA1 and BRCA2 are the two mostly commonly associated with these cancers. Females with a mutated BRCA 1 gene have an 80% higher chance of getting breast cancer than females without this mutation. A mutation of the BRCA 2 genes increases the chance for breast cancer by 45%.

What if the results of genetic tests show that you carry a mutation? Is there a way to prevent this condition from arising?

Regular preventative checkups with medical professionals are needed. Also breast and ovarian removal may be considered in patients with extremely high risk levels.

Genetic research in lungs cancer is still in its infancy. But one thing is for sure and that is that if you have multiple relatives with lungs cancer, appropriate counseling should be a priority. About 20 genes are so far known to be behind lung cancer. The p53 gene is most commonly the one found. Smokers with mutations in the p53 gene have a 50% chance of being diagnosed with lung cancer. What should you do if you are in a risk group? You should firstly quit smoking. Secondly you should consult your physician about possible imaging and preventative diagnostic measures. Caution should be taken with some diagnostic methods due to radiation exposure (chest X-ray, CT and so on).

You may have a higher risk of developing colon cancer if some of the following facts are true:

  1. Two or more relatives from the same side of the family(mother’s or father’s side) are affected
  2. You have a relative who was diagnosed with the condition at a young age, usually before 50
  3. You have a relative with 10 or more benign polyps
  4. A relative of yours is diagnosed with either colon or endometrial cancer

If anyone of the above mentioned facts is true then it is highly likely that you carry a genetic predisposition for colon cancer

The first question to usually arise is: „What is my likelihood of being diagnosed?” Generally speaking when there is a predisposition for colon cancer, you may have a 5-6% of being diagnosed. However this is not always the case and personal characteristics should be taken into consideration. For example, people with a mutation in the MLH1 and MSH2 gene have a 50-60% of being diagnosed with colon cancer.

The second question which is most commonly asked is: “What to do if I carry a dangerous mutation.”

If you happen to be a carrier of a dangerous mutation which predisposes you for this type of cancer, then it should be of up most importance for you to contact your physician and schedule regular colonoscopies in order to prevent a potential metastasis.

You may have an inherited risk of pancreatic cancer if some of the following is true:

  1. In your family there are 2 or more cases of pancreatic cancer, before the age of 50, from one side of the family(mother’s or father’s)
  2. You have a relative who is diagnosed with a highly aggressive form of pancreatic cancer
  3. Cases of pancreatic cancer are usually linked with other cancers such as: breast, colon, ovarian and prostate cancer

There are about 12 genes which are most commonly associated with pancreatic cancer. If one of these mutations is found, then the person carrying them has a 3 to 10 time’s higher chance of getting pancreatic cancer

What to do if the test results for mutations in one of these genes come back positive? Is there any form of prevention?

Unfortunately early diagnosis and prevention of pancreatic cancer is currently difficult. But regular ultrasounds can help discover the tumor early as well as certain tumor markers found in the blood.

You may have an inherited risk of prostate cancer if some of the following is true:

  1. In your family there are 2 or more cases of prostate cancer, before the age of 50, from one side of the family(mother’s or father’s)
  2. You have a relative who is diagnosed with a highly aggressive form of prostate cancer

There are about 7 genes which are most commonly associated with pancreatic cancer.

What to do if the test results for mutations in one of these genes come back positive? Is there any form of prevention?

Likely there is a form of early diagnosis and prevention. The method in question is regular screenings. Screening should be done 10 years before the appearance of earliest case of prostate cancer within the family. What does this mean? If your cousin was diagnosed with prostate cancer at the age of 40, then you should start screening yourself when you turn 30. Also there are tumor markers which can be found in the blood stream and can be used in conjunction with early screening.

Genetic testing for certain types of cancer
  • Certain forms of cancer and tests
  • Ovarian and breast cancer
  • Peutz-Jeghers syndrome
  • Renal carcinoma
  • Lynch syndrome (Inherited nonpolyposis colorectal carcinoma)
  • Familiar adenomatosis polyposis(Gardner syndrome)
  • Follicular thyroid cancer
  • Juvenile polyposis
  • Microsatellite instability
  • KRAS and HRAS status in targeted colorectal cancer therapy
  • BRAF status in papillary thyroid cancer
  • BRAF status in melanomas and colorectal cancer
  • Multiple endocrine neoplasms, Type IIA/Sipple Syndrome/Hirschprung disease
  • Multiple endocrine neoplasms, Type I, MEN1


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