Chemotherapy-associated cognitive impairment is a side-effect of chemotherapy in which people experience difficulties with concentration, decision making, and memory. Findings from a 2015 study suggest that women with a BDNF gene variation experience fewer cognitive problems during chemotherapy compared to those without this variation.
BDNF is a growth factor that is involved in the growth and repair of neurons. BDNF is expressed in the prefrontal cortex and hippocampus regions of the brain, which are involved in executive function, learning, and memory. A common variation in the BDNF gene called a single nucleotide polymorphism, or SNP, can alter how the BDNF protein functions. The SNP, known as Val66Met, results in the amino acid valine being replaced with methionine in the BDNF protein. Researchers have studied how the Val66Met SNP affects various aspects of cognition.
Previous research has demonstrated that women with breast cancer who were treated with chemotherapy experienced varying levels of cognitive decline. The current study investigated whether genetics, particularly variations in the BDNF gene, might make a person more susceptible to experiencing these effects.
The prospective cohort study involved 145 women (average age, 51 years) with early-stage breast cancer who were scheduled to receive chemotherapy. The authors of the study evaluated the participants' cognitive function using neuropsychological tools before, during, and at the end of chemotherapy treatment. Also, the researchers determined which version of the BDNF gene each participant possessed. If a patient’s test score during or at the end of treatment was 15 percent lower than baseline, they were considered to have cognitive impairment.
The authors observed that 54 women experienced cognitive impairment after treatment; however, those with the Met allele had fewer problems with verbal fluency and multitasking compared to those with the Val allele, particularly in older participants. This information may allow for early interventions in preventing cognitive impairment during chemotherapy.
These findings suggest that women may differ in their susceptibility to chemotherapy-associated cognitive impairment depending on which version of the BDNF gene they carry. Further research is required to confirm these findings, and brain imaging studies are needed to determine if these findings are the result of changes in brain anatomy.
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