Wilma Stewart (55) is taking the lead with her sister Karen Hamilton (51) to launch Cancer Research UK's Walk All Over Cancer campaign which runs throughout March.
The charity is inviting people to walk 10,000 steps every day this month to raise funds for research.
The brave Ballymena sisters survived horrific breast cancer journeys only to be shattered by news that they and their two daughters carried the BRCA 1 gene.
BRCA 1 increases the chances of breast and ovarian cancer by 87% in people who carry it. The sisters discovered they had inherited it from their father who was an only child.
Wilma and Karen and their two girls, aged just 29 and 31 at the time and who are both single, had to make the agonising decision of whether or not to have their breasts removed.
All four faced the surgery and both Wilma and Karen also went through hysterectomies to prevent ovarian cancer. Their daughters now have to make that difficult decision when they reach 35.
The sisters share their stories today in the hope of highlighting the need for support for the latest campaign by Cancer Research UK.
Karen and Wilma are hoping new breakthroughs in research could prevent their two girls from having to take the painful step of having their ovaries removed when they turn 35.
Wilma, who is a bank official, has a long-term partner Mervyn Robinson (63) who is a retired financial advisor.
She had been urged by a friend to go to breast screening with Action Cancer when she turned 40.
She recalls: "You go every two years and it was on my second mammogram at the age of 42 that it was picked up in 2007.
"I was lucky because it was only 4mm and my lymph nodes were not affected.
"For me it was just disbelief. I felt healthy, so for someone to tell me I had cancer was such a shock. When you have cancer you deal with it every day, wondering if it is going to come back or spread."
Wilma came through a lumpectomy and six weeks of radiotherapy. As her breast cancer was hormonal driven she was also given medication for five years.
It was because of her experience that Wilma urged her younger sister Karen to go for the free mammogram with Action Cancer when she turned 40.
Karen had found a lump in her breast which was not picked up by a mammogram she booked with the charity in December 2014.
Still concerned, she went to her GP and was red flagged to the breast clinic where she was told she had cancer.
She said: "It was January 6, 2015 and because the mammogram in December was clear, to be told I had cancer was just devastating.
"I had a different type of cancer to my sister. Mine was triple negative and I was then told I would need surgery and chemotherapy as well as radiotherapy. When the doctor said I needed chemotherapy, the blood left me and I nearly passed out."
Little did Karen know it was only the beginning of a nightmare journey which would drag on for the next three years.
She came through a lumpectomy but faced a second operation as doctors weren't satisfied they had a clear margin of tissue.
It was while undergoing treatment that she was tested to see if there was a genetic link to explain why both sisters had developed the disease.
Discovering that she was carrying BRCA1 was the start of a ripple effect which spread through all the females in the family.
Wilma recalls: "We were completely shocked as there had been no incidences of cancer in our family and the only thing I knew about BRCA1 was that Angelina Jolie had it.
"It turned out my father is a carrier and he is an only child.
"It was bad enough for me and Karen to have a double mastectomy but for the girls to have to make that decision being so young was just terrible.
"They were horrified that they had to get their breasts off and felt it was so unfair. They did get counselling which helped a bit.
"Both girls are single parents and in the end they decided they had to do it for their children but it wasn't easy."
The surgery which involved reconstruction was not without its complications with three of the four women developing infections.
Wilma explains: "My sister went first and took a bad infection which lasted for months and in the end she lost her left breast.
"Her daughter had her surgery and also took an infection and had to be isolated in hospital for eight days and nobody could go and see her.
"I then had mine and I was okay for five months. Then I took an infection and had three more operations to try and save the implant but I lost my left breast too.
"My daughter went last and thankfully it went well for her. I'm delighted that it worked for the two girls but my sister and I have been left with one breast. "
For Karen who had already been through two surgeries and almost a year of treatments, the prospect of more operations was particularly tough.
She says: "I felt I had been through so much. I had the hysterectomy first and after it I was told they found something nasty and needed to go in for more surgery and for me that was really traumatic, I really was close to breaking point.
"I felt I had been so brave to get through the cancer only to be told I needed more surgery. That second operation was nail biting but thankfully they were satisfied I had no cancerous cells."
However Karen's tough journey was not over yet. She still had to undergo her double mastectomy and reconstructive surgery.
Three days after that operation she was sent home to recover but was soon back in hospital with an infection.
She was given antibiotics and again sent home only to find herself back in hospital a few days later.
Eventually she had to have her left reconstructed breast removed.
The emotional and physical scars of her ordeal run deep.
Karen is single and had not given up hope on meeting someone special to share her life with. Now she fears she will never have the courage to take that step.
She admits: "I have been left with such a horrendous scar. It is awful as a middle-aged woman to look at myself every day and see that.
"When people look at you they think you look well but they have no idea how you are feeling inside. I am on my own and would like to meet someone but I can't see it happening now. I have missed opportunities because I couldn't bring myself to go there.
"It has been worse for my daughter and niece who are so young. My daughter is a very beautiful young woman but she lacks a bit of self-confidence and it has knocked her for six.
"It feels surreal what we all have been through; it has been pretty horrific for all of us.
"Six years on I feel very lucky I am still here but not so lucky that I was dealt such an awful card."
Equally her sister feels gratitude that she has survived.
Wilma adds: "One day at a time is my mantra. The NHS has been fantastic and I just feel lucky to still be here.
"We are both happy to be able to support this new appeal by Cancer Research UK and hope local people will get behind the charity to walk all over cancer."
Cancer Research UK is challenging people to sign up and pledge to walk 10,000 steps a day in March as part of its Walk All Over Cancer campaign.
Ten thousand steps are roughly five miles and, based on the average person's strides, by the end of March participants will have clocked up more than 150 miles.
Walk All Over Cancer has linked in with Fitbit, so that those taking part can automatically publish their step count on their fundraising page throughout the month.
Jean Walsh, Cancer Research UK's spokesperson for Northern Ireland said: "We're really grateful for Wilma and Karen's support and we hope lots of people will be inspired to follow in their footsteps.
"By raising vital funds, people could help to get life-saving research back on track after the impact of Covid-19."
To sign up and receive a free fundraising pack, with tips and ideas to help with the challenge visit cruk.org/walkallover. Participants are being encouraged to use #WalkAllOverCancer and tag @CR_UK when sharing their challenge on social media