A new study has reported that Nigerian breast cancer patients have a surprisingly high rate of harmful BRCA mutations, including many never previously reported. Inherited BRCA1 and BRCA2 mutations, which result in familial breast/ovarian cancer syndrome, are the strongest genetic predictors of breast cancer. Little data concerning the frequency and type of BRCA1/BRCA2 mutations is available for populations of African ancestry, who suffer a disproportionate burden of early onset breast cancer. The study included 434 breast cancer patients treated at the University College Hospital in Ibadan, Nigeria. The women were not specifically selected for a family history of breast cancer. The authors performed complete BRCA1 and BRCA2 sequence analyses for the women.
In contrast to previous reports that BRCA1/BRCA2 mutations are relatively rare or undetectable in African-American populations, the study participants were found to have an exceptionally high rate of BRCA1 (7.1%) and BRCA2 (3.9%) mutations. Almost half of the mutations have never previously been reported. A total of 16 different BRCA1 mutations were found, seven of which have not previously been described. Thirteen different BRCA2 mutations were detected, six of which were also previously unreported. The authors suggest that family-based models of risk assessment and genetic counseling should be broadly disseminated in Nigeria and other underserved and understudied populations, coupled with interventions to reduce breast cancer risk.