MicroRNAs are important regulators of cellular function and are associated with aging and cancer, but not much is known about chemotherapy’s effect on them. Recently, a group of European researchers found that adjuvant chemotherapy does not significantly boost aging progression in older adults with breast cancer. They presented on Friday, December 9, during the San Antonio Breast Cancer Symposium about the predictive role of microRNAs in determining the decline in functionality and quality of life, toxicity, and unexpected hospitalization during or after chemotherapy.

To determine whether chemotherapy accelerates the aging process, the group evaluated 46 patients with breast cancer at least 70 years old who were receiving adjuvant chemotherapy and compared outcomes with those of 43 patients with breast cancer at least 70 years old who were not receiving chemotherapy. (The group published on the topic earlier in 2016.) 

All patients underwent geriatric assessment at study initiation, after three months, and after one year. At each evaluation, the serum expression of nine age-related microRNAs were analyzed. With the exception of one, all microRNAs underwent moderate fluctuations over the course of the study with no significant differences between both groups. Only miR-106b appeared to behave slightly different in the chemotherapy group, the researchers said.

Additionally, five of the microRNAs were significantly correlated with clinical aging and frailty and with other biomarkers of aging. In particular, miR-106b, miR-374a, and miR-378a were associated with interleukin-6 (IL-6); miR-301a and miR-378a showed a relevant correlation with monocyte chemoattractant protein (MCP)-1.

Using the patients’ aging microRNA profiles allowed the researchers to cluster patients into two groups, each of which exhibited significantly different results for several biologic and clinical aging parameters. In the first cluster of 43 patients, five microRNAs were underexpressed whereas one (miR-378a) was overexpressed. This cluster was characterized by older age, a higher geriatric risk profile, and elevated IL-6, tumor necrosis factor (TNF)-α, and MCP-1 levels compared to the second cluster of 45 patients. A substantially higher percentage of patients in the first cluster (31.9%) than in the second cluster (7.4%) experienced decline in quality of life after chemotherapy.

“Our data endorsed specific age-related microRNAs as promising aging or frailty biomarkers in oncogeriatric populations,” the researchers concluded.