How Does Lynch Syndrome Increase Cancer Risk

Some people get cancer at a young age for no apparent reason. For me, there was an underlying condition: Lynch syndrome.

Lynch syndrome is a hereditary cancer syndrome. It is one of the most common inherited conditions, with estimates suggesting 1 in 300 people may have it. Lynch syndrome carriers have an alteration in a gene which puts them at a higher risk of developing certain cancers. Families with the syndrome may have a history of colorectal or endometrial cancers or a history of cancer diagnosis at a younger age. In my case, there were no clues.

I (and my sister) inherited the gene from our mum who will have inherited it from one of her parents. Since her parents have passed away, there is no way of finding out which one. My mum has never developed a cancer of any type (thank God), although she had her womb removed in her forties. I’m sure she wouldn’t mind me telling you that. Both of her parents lived into their nineties, and neither of them died of cancer. This knowledge prompted me to make some serious lifestyle changes, more of which in future posts.

Genetics of Lynch Syndrome

Lynch Syndrome is caused by a genetic mutation
Lynch Syndrome is caused by a genetic mutation. Photo by National Cancer Institute on Unsplash

When the oncologists examined my tumour, they found it showed a genetic mutation. They shared the immunohistochemistry (try saying that after a few drinks) report with me. IHC, according to BiteSizeBio is used to help diagnose a range of diseases by identifying abnormal cells. This report showed there was a loss of MSH2 and MSH6 genes, which might indicate Lynch Syndrome. Clear as mud, right? No? It wasn’t for me either.

I met the oncologist from the genetics team and she explained that these two genes provide instructions to make protein. This protein helps to repair DNA by identifying errors when DNA is copied to prepare for cell division. So in people with a lack of MSH2 and MSH6 genes, the protein to identify errors is missing, thus allowing the erroneous DNA to continue dividing.

Bit clearer? I hope so. Should you have any questions about this, pop your questions in the comments or use the contact form and I will do my best to answer them.

Increased Cancer Risk

My oncologist at the Royal Marsden was also keen to refer me to the genetics team because the type of cancer I had. Lynch syndrome increases a person’s chances of developing womb cancer at a younger age, and at 42 I was younger than average to get it. However, womb cancer can develop at any age, so women should never dismiss their concerns because of their young age. 

Carriers of Lynch syndrome have a higher risk of developing certain others cancers, too, the main one being colorectal cancer. Other cancers with an increased risk are ovarian, gastric, brain and skin cancers. Having the gene doesn’t automatically mean you will get cancer, for example, the risk for colorectal cancers is 35-50% higher and womb cancer is 30-40% higher. The other cancers come with a lot lower risk factors. You can read more in the Royal Marsden’s guide to Lynch Syndrome.

Family History

History of certain cancers in a family may indicate Lynch syndrome
History of certain cancers in a family may indicate Lynch syndrome. Photo by Annie Spratt on Unsplash

A fact: not everyone with Lynch syndrome has a family history of cancer. I am a case in point. That is why the diagnosis was totally unexpected. When I met the genetics team’s oncologist and we looked at my family history, there were nothing that stood out as indicating Lynch syndrome. Yes, there were some cancer-related deaths, but nothing that pointed to an inherited mutated gene.

According to MacMillan (they have a brilliant, easy-to-understand guide to Lynch syndrome) you are more likely to have a mutation linked to Lynch syndrome if there are patterns of cancer in the family. These may include a cancer diagnosis before the age of 50 or several close family members over generations having a diagnosis of cancers linked to the genetic mutation.

Anyone worried about cancer patterns in their family should talk to their GP. They may refer you to a genetics specialist if there is cause for concern.

What Happens After Lynch Syndrome Diagnosis

The important thing to remember is that not everyone with Lynch syndrome will develop cancer. Knowing that I have it makes me more aware of possible symptoms and to see a doctor if I have any concerns. It also means that I will have regular colonoscopies (lucky me) to detect any signs of colorectal cancers early. I am taking aspirin, as studies have indicated that this may reduce the risk of cancer in Lynch syndrome carriers.

Since my diagnosis, my sister and my mum have found out that they are carriers, too. Since it comes from my mum’s side, her sister and brother will have the test next. Then, if necessary, their children. When it comes to Lynch syndrome knowledge is definitely power as it can support early diagnosis and therefore add years to a carrier’s life.

I will write in more detail about life as a Lynch syndrome carrier in a later post. You can sign up here for email notices on new posts so you won’t miss it or any other new posts.

Until next time.

To help us spread awareness of Lynch syndrome and womb cancer and to raise money for The Royal Marsden Cancer Charity, you can: 

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12 thoughts on “How Does Lynch Syndrome Increase Cancer Risk

  1. There are so much we still don’t know about genetics of cancer. It’s great you are sharing this.

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