Researchers also found that one in five breast cancer survivors diagnosed with leukemia also had mutations in the genes that may be responsible for their disease.
The study, which was recently published in the medical journal Cancer, involved 88 women who had been diagnosed with breast cancer, but they later developed leukemia or blood cancer because of chemotherapy.
Breast cancer survivors are the group of cancer patients that has the highest risk of developing leukemia in the wake of cytotoxic medications used to treat their tumors. But the risk is even higher if they have an inherited risk of cancer, study authors noted.
Dr. Jane E. Churpek, lead author of the study and researcher with the University of Chicago, and her team analyzed DNA samples of breast cancer survivors that were later diagnosed with blood cancer to see whether any inherited mutations may be responsible for it.
About one in four breast cancer survivors had an extra primary cancer diagnosis. After therapy, seven participants were diagnosed with acute lymphoblastic leukemia, while 81 survivors developed myeloid neoplasm.
About 80 percent of volunteers were able to provide a detailed family history of cancer. Fifty-seven percent of those participants had at least a family member that had been diagnosed with pancreatic, genital, or breast cancer.
DNA tests revealed that 47 breast cancer survivors (21%) inherited a genetic mutations in the genes that may be responsible for their breast cancer diagnosis – six patients had a BRCA1 gene mutation, two had a BRCA2 mutation, three patients had a mutation in the TP53 gene, while two patients had mutations in the CHEK2, respectively PALB2 genes.
Scientists explained that all these affected genes help the body locate and repair damaged DNA and they play a crucial role in a blood cancer diagnosis.
Yet, critics of the study underlined that the findings may not be accurate since the research team wasn’t able to produce solid evidence that leukemia was a disease generated by breast cancer drugs. Experts explained that the blood cancer diagnosis might as well not be related to breast cancer treatment.
Researchers currently plan to further study the link between breast cancer treatments, family history of breast cancer and risk of leukemia in survivors.
An earlier study conducted by a Johns Hopkins team showed that breast cancer survivors have a 0.5 percent risk of being diagnosed with leukemia within 10 years following treatment.
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