Gene Test Can Predict Breast Cancer Risk For Women Diagnosed With Abnormal Cells

Key TakeawaysA genetic blood test can predict a woman’s risk for breast cancer after abnormal cells are found in her breastWomen were two times more likely to develop breast cancer if they scored high on the genetic testTaking family history of breast cancer into account further increased the test’s accuracy.THURSDAY, Oct. 2, 2025 (HealthDay News) — A genetic risk score can help predict which women will develop invasive breast cancer after abnormal cells have been found in their breast tissue, researchers said.Women who scored high on the genetic blood test were twice as likely to develop breast cancer after doctors found abnormal cells, researchers report in Cancer Epidemiology, Biomarkers & Prevention.These women had been diagnosed with in-situ carcinoma, a term for abnormal cells found in the breast ducts and breast lobules, the milk-producing glands in breasts.Women with ductal carcinoma in situ (DCIS) were twice as likely to develop cancer in their other breast if they scored high on the genetic blood test, results showed.Likewise, women with lobular carcinoma in situ (LCIS) were two times more likely to develop breast cancer in the same breast where the abnormal cells were found, researchers said.The test could help guide treatment of women with abnormal cells who have not developed full-blown breast cancer, researchers said.“LCIS is not always surgically removed or treated with hormone therapies, as it is considered lower risk than DCIS,” said lead researcher Jasmine Timbres, a clinical information analyst at King’s College London.“However, these results indicate that those with a family history may benefit from such additional treatments, which could reduce their risk of further cancer,” she said in a news release.For the new study, researchers analyzed data from nearly 2,200 women with DCIS and almost 200 women with LCIS, using a blood test that estimates a patient’s breast cancer risk using 313 different genetic abnormalities linked to the cancer.Taking family history of breast cancer into account further empowered the gene test, researchers found.Women with a family history on top of a high genetic test score were more than three times as likely to develop breast cancer after diagnosis for LCIS, researchers found. The risk increased to fourfold when women who had received mastectomy or radiation therapy for their breast cancer were excluded."In my clinical practice, I see many women diagnosed with DCIS or LCIS,” senior researcher Elinor Sawyer, a consultant clinical oncologist at King’s College London, said in a news release. “Until now, treatment decisions have mostly been based on how the cells look under a microscope. Our research shows that a genetic risk score can also help predict which women are more likely to develop invasive breast cancer.”A fuller profile could enhance risk-assessment, she said. “This means we shouldn't just focus on the cells themselves, but also take into account a woman’s genetic risk and lifestyle factors,” Sawyer said. “By looking at the full picture, we can give women more accurate information about their personal risk of recurrence. This helps them make more informed choices about their treatment options and what’s right for them.”More informationThe American Cancer Society has more on in situ carcinoma.SOURCES: American Association for Cancer Research, news release, Oct. 1, 2025; King’s College London, news release, Oct. 1, 2025 .What This Means For YouWomen diagnosed with in situ carcinoma should ask their doctor about genetic testing for breast cancer risk..Sign up for our weekly HealthDay newsletter