
A multinational research team of scientists have identified the genes responsible for inherited Bosom cancer in Nigerian women, according to the study published in the 21 August issue of the Journal for Clinical Oncology.
“This is the first study to use high-throughput genomic analysis of African women,” said study author Olufunmilayo Olopade, MD, Walter L. Palmer Distinguished Service Professor of Medicine and Human Genetics, director of the Center for Clinical Cancer Genetics and associate dean for Global Health at the University of Chicago.
“Based on state-of-the-art genomic technologies, two things were clear,” added co-author Mary-Claire King, PhD, American Cancer Society Professor of Medicine and Genome Sciences at the University of Washington in Seattle. “Risks to Nigerian women who carry mutations in Bosom cancer genes are higher than risks to women in the U.S. with mutations in the same genes. And inherited Bosom cancer plays a bigger role in the total occurrence of Bosom cancer in Nigeria compared to the U.S.”
According to a report by www.news-medical.net, the study enrolled 1,136 women with invasive Bosom cancer and 997 controls; women of similar ages and heritage who did not have Bosom cancer. Disease was far more advanced at diagnosis than in the U.S., with 86 percent of the patients who were fully evaluated diagnosed at either stage 3 or stage 4.
Almost half (46 percent) of the patients were diagnosed with triple-negative Bosom cancer (tumors that lack estrogen receptors, progesterone receptors and human epidermal growth factor receptors). This is an aggressive Bosom cancer subtype, likely to have with a poor prognosis, even in wealthy countries.
For their study of “Inherited Bosom Cancer in Nigerian Women,” the authors sequenced 25 genes associated with increased risk of Bosom cancer and identified all damaging mutations in each of those genes.
They found that one out of eight Bosom cancers in the study was caused by an inherited mutation in one of four of these genes. Mutations in BRCA1 (7 percent of patients) and BRCA2 (4 percent) were the most common, followed by PALB2 (1 percent) and TP53 (0.4 percent).
Patients with BRCA1 or TP53 mutations were diagnosed at younger ages than women with other mutations. The mean age at diagnosis for all cases in the study was 47.5 years, but the BRCA1 carriers were diagnosed at an average age of 42.6 years. Patients with TP53 mutations were diagnosed even earlier, at an average age of 32.8 years.
“Genomic sequencing to identify women at extremely high risk of Bosom cancer could be a highly innovative approach to tailored risk management and life-saving interventions,” the authors wrote. Given the limited treatment resources available in this setting, “prevention and early detection services should target these highest-risk women.”
Following up on the study, the Chicago-Ibadan team has already developed a risk-prediction model for Bosom cancer in Nigerian and other Sub-Saharan African women, who are, on average, more than 10 years younger when diagnosed than American women. This predictive model can identify individuals at high risk of Bosom cancer, tailor surveillance and suggest risk-reduction strategies.
There is an urgent need to address “widening global disparities in Bosom cancer mortality that disproportionately impact women of African ancestry,” the authors wrote. Bosom cancer among both African American and Nigerian women is more frequently triple-negative than in other populations for complex reasons that remain poorly understood. Given the young ages at diagnosis in Nigeria, focusing on genetically high-risk women could, the authors suggest, “substantially reduce premature mortality from Bosom cancer.”
“It may seem paradoxical to apply the most recent technology in severely resource-limited settings,” the authors add, “but in fact the solution fits the problem… Women with extremely high risk of Bosom cancer due to mutations in these genes can be identified inexpensively and unambiguously, and offered interventions to reduce cancer risk.”
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