Hello strawbplant and welcome to Cancer Chat.

It's completely understandable to be concerned about a possible genetic link to cancer, especially if it affects your family's health. Many people here are navigating similar concerns, and this is a great place to  share experiences.

While browsing, I came across this page from our website that might have information of interest: Causes of Cancer. It covers various factors, including genetic ones, that can contribute to the risk of cancer. I hope this can be useful to you.

Feel free to share more about your situation or ask any questions you might have. There are many knowledgeable and compassionate members here who I'm sure will be happy to chat with you.

Best wishes,

Renata, Cancer Chat Moderator

My Mam had a similar theory, but I pointed out that all of the many members of her family who had died of cancer were heavy smokers and heavy drinkers. 
Those two unhealthy habits cause an awful lot of cancer cases. 

Sadly, smoking tends to run in families as kids copy their parents.