Mathew Knowles Urged Daughters Beyoncé and Solange to Get the BRCA Gene Test After Breast Cancer Battle

Mathew Knowles knows firsthand the power of early detection, which is why he urged his daughters, superstar singers Beyoncé and Solange, to undergo BRCA genetic testing after he was diagnosed with breast cancer in July.

The BRCA gene test is a blood test that identifies harmful and potentially cancer-causing mutations in either one of the two breast cancer susceptibility genes — BRCA1 and BRCA2. Knowles, 67, a music executive who teaches at Prairie View A&M University in Texas, tested positive for the BRCA2 gene mutation while doctors were diagnosing his condition over the summer.

Since mutations in the BRCA2 gene can be inherited, Knowles tells PEOPLE in an interview for this week’s issue that “Beyoncé and Solange have an increased risk” of having his same mutation.

But, he notes, “They have an exceptional team, and they’ve gone through precautionary measures,” including the BRCA gene test.

“They have taken care of that, it’s simple testing,” he says. “And they’re moving on.”

Knowles’ first sign of breast cancer was finding a small speck of blood on his white T-shirt back in July. But in the beginning, he didn’t think anything of it.

“My initial reaction was maybe I worked out too hard,” he says. “Then I thought, maybe it’s some kind of reaction to my medication.”

As the bleeding persisted on and off over the next couple of days, he says, “That’s when I knew I should go to the doctor.”

Bleeding from the nipple is a symptom of breast cancer, and a mammogram and biopsy showed that Knowles had stage 1A breast cancer.

“I had no pain whatsoever,” he says. “It wasn’t like I had discoloration — nothing. Thankfully I had this dot of blood coming out and thankfully I wore white T-shirts. If I didn’t wear white T-shirts, then I might not have noticed.”

Knowles, who was accompanied by his wife Gena Charmaine Avery in the doctor’s office while being diagnosed, says the first call he made once he found out he had breast cancer was to his ex-wife, Beyoncé and Solange’s mother Tina Knowles-Lawson. He says he “never imagined” receiving a diagnosis of breast cancer, a cancer that affects roughly 1 in 800 men, despite an extensive family history of the disease.

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According to Dr. Dorraya El-Ashry, the Chief Scientific Officer at the Breast Cancer Research Foundation, “male breast cancer [occurs] at a much lower incidence rate than female breast cancer.”

“It is at .1% the rate of female breast cancer,” she tells PEOPLE. “Having said that, there are some known genetic causes of breast cancer, BRCA genes. So if a man has a BRCA2 gene mutation, then that elevates the risk from .1% to 6%. BRCA1 and BRCA2 are both involved in causing a number of cancers in both men and women, including breast, prostate, ovarian and pancreatic.”

Knowles is now cancer-free after having a mastectomy to remove his right breast in July, and he plans to have his left breast removed in January as a preventive measure to reduce his risk of recurrence.

“There’s always a risk it will come back,” he says. “But today I am cancer-free. It just requires me, on a six-month basis, to go to a get an early detection [screening] for my prostate, pancreas, melanoma and breast cancer. If that’s the only price I have to pay — every six months spend a day in my life to be inconvenienced to take exams — then I’m very grateful for that.”

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Now, Knowles is hoping to spread awareness not just to his family — but to the world — about the importance of early detection.

“It’s all about early detection,” he says. “The earlier you detect, the better your outcome will be.”

Additionally, he wants to help erase the stigma surrounding breast cancer in men.

“I wanted to take away the stigma of shame — the stigma that men have to be tough,” he says. “And then I hope I have the opportunity to talk to the heads of the American Cancer Society at some point to voice my feedback, because what I’m hearing is that men actually prefer — regardless if it’s the medically correct term — [to call this] ‘chest cancer.’ That’s the word men often use for that area of our body, our chest. I think if we did that, we would have a lot more men go and get exams.”

And he’s looking ahead to 2020 being “the year of Destiny’s Child” as he gears up to release his book, Destiny’s Child: The Untold Story, in December and works on a musical about the iconic ’90s girl group comprised of his daughter Beyoncé, Kelly Rowland and Michelle Williams.

Whether Destiny’s Child fans can expect a reunion tour from the trio in the future, Knowles says it’s still up in the air.

“It would take two to three years just from the day the artist said ‘Yes’ to the day we actually saw the first show,” he says. “The girls haven’t even decided to do it yet. So it will be some time even if they said, ‘Yes.’ For the next two or three years, the closest you’re going to get to a tour is the musical.”

For much more on Mathew Knowles’ battle with breast cancer, pick up the latest issue of PEOPLE, on newsstands Friday.