Struggling! After dating for a year and a half, I found out that my boyfriend has a family history of cancer. Is it hereditary? Should I break up?

Some time ago, I was bored and browsing posts in a community, and I accidentally read a post that was full of "melon feeling".

Initially, a "young lady" asked for help: At that time, she had been with her boyfriend for about a year and a half. By chance, she learned that several close family members of her boyfriend had cancer. Her boyfriend's mother, grandfather, grandmother, and even the son of her grandfather's sister were all like this. The son of her grandfather's sister died of cancer in his thirties.

She couldn't help but worry: She had a good relationship with her boyfriend, but would he have inherited some cancer gene? Should she continue this relationship?

To be honest, I didn’t see the original post. I only saw a screenshot of the original post posted by a netizen and various comments:

Some people calmly analyzed that there are different types of cancer and there is no need to worry; some people comforted Douban users by saying that current problems may not be problems in the future; and some people advised Douban users to cherish the happiness of the moment and not miss a good marriage. But there are also many unfriendly comments such as:

The netizens who took the screenshots clearly also had a mocking attitude:

I can’t sit still anymore!

Let's analyze this calmly. So many of my boyfriend's maternal relatives have suffered from cancer, including young patients. Isn't it normal for netizens who are not familiar with medical knowledge to have genetic concerns?

If it were someone else, or even the boyfriend himself, wouldn't they have suspected genetics? Besides, how can these netizens who are sarcastic and unthinking be sure that it's not their fault?

01

Genetics and tumors

With the development of medicine, scholars have long regarded tumors as more than rapidly growing abnormal tissues, but rather complex diseases involving multiple occurrence and development mechanisms.

Based on different mechanisms, oncology research has also formed huge branch fields in the areas of tumor cell immune escape, unlimited replication potential, infiltration and metastasis mechanisms, abnormal energy metabolism, local microenvironment differences, genomic instability and mutation.

Tumor genetics has become an independent discipline.

With the advancement of genetic testing technology and the development of bioinformatics, more and more studies are revealing the molecular mechanisms of tumor inheritance and the regulatory role of epigenetics in tumor occurrence and development.

The screening and clinical application of tumor susceptibility genes are also rapidly enriched and developed.

Common physical and chemical carcinogens in life, such as alcohol, aflatoxin, formaldehyde, and ultraviolet rays, may be more well-known to the public, but genetic factors are actually also an important cause of tumor occurrence.

Copyright image, no permission to reprint

A study of 9,512 pairs of twins showed that genetic factors accounted for 42% of the risk of prostate cancer, 35% of colorectal cancer, 27% of breast cancer, and 22% of ovarian cancer[1].

It can be seen that genetic factors play a very important role, at least in some specific tumors.

02

Tumor susceptibility genes

In the human genome, some special genes are closely related to the occurrence of tumors and are called "tumor susceptibility genes."

Different tumor susceptibility genes have different pathogenic abilities, so scholars divide tumor susceptibility genes into three levels: high risk, medium risk, and low risk.

Among them, mutations in high-risk and medium-risk tumor susceptibility genes are more likely to cause tumors and are called pathogenic mutations (as opposed to benign mutations).

If a pathogenic mutation occurs in somatic cells, it will only increase the risk of tumor development in the owner of the somatic cells themselves. However, if it occurs in the germ cells that form the fertilized egg, it becomes a heritable mutation and is passed on to future generations from generation to generation.

This is also the case for diseases that show familial clustering characteristics.

At present, a variety of tumor susceptibility genes have been confirmed clinically, such as the BRCA1, BRCA2, PALB2, RAD51C, and RAD51D genes that are closely related to breast cancer and ovarian cancer; the MMR gene that is related to colorectal cancer, endometrial cancer, gastric cancer, small intestine cancer, hepatobiliary cancer, brain cancer and other cancers; and the TP53 gene that is related to leukemia, lymphoma, and childhood tumors.

03

Screening and significance of tumor susceptibility genes

In the past, due to the medical community's insufficient understanding of tumor genetics and the immaturity of genetic testing technology, the screening of subjects for tumor susceptibility gene testing often relied on family history.

Medical staff need to know in detail the tumor type, age of onset, age of death, tumor histology data of the tumor patients in the patient's three generations of paternal and maternal blood relatives, as well as any genetic tests done by any of them;

The person’s risk of carrying a pathogenic mutation is then assessed based on a specific risk assessment model, and genetic testing is performed if the risk exceeds the threshold [2].

This method is actually a compromise when genetic testing technology is not popular, because it is highly dependent on the accuracy of family history information, and many people cannot fully grasp or remember the specific circumstances of each relative in the family, which will result in a considerable degree of misdiagnosis rate.

A survey covering 16,696,608 people in Greater London, UK, showed that despite 25 years of testing by the UK National Health Service (NHS), more than 97% of BRCA carriers remain undetected. Even Angelina Jolie’s celebrity status has failed to increase the detection rate of BRCA genes[3].

Technological advances have popularized large-scale, high-throughput genetic testing. The significant improvement in testing efficiency and the reduction in costs have given more people the opportunity to undergo genetic testing.

In clinical practice today, genetic testing of tumor tissue from cancer patients has become a common method that no longer relies on family history.

Tumor genes affect the classification and characteristics of tumors. Specific genes can make tumors insensitive or more sensitive to specific methods, which will affect doctors' treatment decisions and allow patients to receive more precise treatment.

Copyright image, no permission to reprint

Doctors can also compare the tumor susceptibility genes in tumor tissue and normal tissue to determine whether the patient's pathogenic mutation comes from his own body cells or is inherited from the family.

This means that doctors can more keenly and accurately assess the disease risk of the patient's blood relatives, help carriers who are not yet sick with preventive treatment, and screen embryos through reproductive medicine to prevent hereditary mutant genes from being passed on to the next generation.

If a person is found to be carrying a pathogenic mutation but no malignant lesions have yet developed in the body, corresponding preventive measures such as imaging screening, histological screening, drug prevention, and preventive surgical resection can be taken according to the risk level of the pathogenic mutation.

Angelina Jolie, mentioned in the previous study, underwent preventive surgery because she was a carrier of the BRCA1 gene, which caused heated discussions at home and abroad at the time.

Now it seems that Jolie's decision was not rash . The National Comprehensive Cancer Network currently recommends that carriers of BRCA1 or BRCA2 genes undergo preventive bilateral mastectomy to reduce the risk of future breast cancer. However, considering that carrying BRCA1/2 genes does not necessarily mean breast cancer will occur, and breast cancer screening methods are becoming more and more mature, whether to take preventive surgery also needs to comprehensively consider the patient's own wishes and the doctor's risk assessment results.

04

Tumor gene detection and ordinary people's life

Technological progress is a good thing overall, but it may not always bring benefits when broken down into individual cases.

The results of genetic testing, including tumor genes and some mutations of unknown significance, may cause worry, anxiety, and psychological burdens such as guilt for passing on the genes to children to the tester, and may also affect the harmony and marital relationships of some families.

From a group perspective, carriers of certain genes may face discrimination or stigmatization in terms of mate selection, employment, and social evaluation.

The United Kingdom and the United States have established relevant anti-discrimination laws (the Genetic Information Anti-Discrimination Act in the United States and the Genetic Testing and Insurance Act in the United Kingdom). In order to prevent commercial insurance companies from setting different insurance amounts based on genetic issues, they are prohibited from obtaining citizens' genetic testing information from the Ministry of Health [4].

For individuals, current clinical practice advocates genetic testing for patients with specific types of cancer. If the test results indicate that relatives are at risk, further testing will be conducted on the relatives to take targeted preventive measures.

Therefore, most people do not need tumor susceptibility gene testing for the time being, and there is no need to feel too heavy psychologically burdened.

Back to the "melon" at the beginning of the article, there may really be certain tumor susceptibility genes in the "boyfriend's" maternal family, or it may just be that the family members are just unlucky.

It is very normal for netizens to have concerns, just like some people hope their partner has single eyelids and some people hope their partner has thick hair - it is a very personal matter.

Everyone values ​​different things. Netizens can have different opinions, but they should not be overly critical.

Of course, even if the "boyfriend" really carries a tumor susceptibility gene, there are already many coping plans. In the future, with the advancement of science and medicine, there will be more and more methods, and they will get better and better.

If the "young lady" who originally posted for help can see this article, I hope the information in this article can provide reference for your doubts.

References:

[1] Lichtenstein P, Holm NV, Verkasalo PK, et al. Environmental and heritable factors in the cause of cancer--analyses of cohorts of twins from Sweden, Denmark, and Finland. N Engl J Med. 2000;343(2):78-85. doi:10.1056/NEJM200007133430201

[2] Evans DG, Harkness EF, Plaskocinska I, et al. Pathology update to the Manchester Scoring System based on testing in over 4000 families. J Med Genet. 2017;54(10):674-681. doi:10.1136/jmedgenet-2017-104584

[3] Manchanda R, Blyuss O, Gaba F, et al. Current detection rates and time-to-detection of all identifiable BRCA carriers in the Greater London population. J Med Genet. 2018;55(8):538-545. doi:10.1136/jmedgenet-2017-105195

[4]https://www.abi.org.uk/data-and-resources/tools-and-resources/genetics/code-on-genetic-testing-and-insurance/

Author: Fei Dao Duan Yu (Doctor)

Review｜Sun Yifei, Medical Education History Research Office, Hebei Medical University

The cover image and the images in this article are from the copyright library

Reproduction of image content is not authorized