Decoding Breast Cancer: New Insights into Treatment Response and Relapse
"Unlocking the potential of miR-155 and miR-24 in predicting early breast cancer relapse for personalized medicine."
Breast cancer remains a significant health challenge for women worldwide, with diverse outcomes and a constant need for more refined prognostic tools. Traditional methods often fall short in accurately predicting which patients will relapse, leading to a push for innovative approaches that can personalize treatment strategies and improve patient survival rates.
MicroRNAs (miRs) have emerged as promising biomarkers in cancer research. These small molecules play a crucial role in regulating gene expression and are highly stable in serum, making them ideal candidates for monitoring disease progression and treatment response. Several miRs have been identified as oncogenic, functioning to suppress tumor suppressors and promote metastasis.
A recent study delved into the potential of using miR-155 and miR-24 as predictors for early breast cancer relapse. By collecting and analyzing serum samples from 133 early breast cancer (EBC) patients at three critical time points—before surgery, after surgery, and after adjuvant therapy—researchers aimed to uncover expression patterns that could differentiate between high- and low-risk patient groups and ultimately predict relapse.
Serum microRNAs and relapse prediction
A study of early breast cancer (EBC) reported that most patients had elevated serum levels of four oncomiRs—miR-155, miR-19a, miR-181b, and miR-24—at diagnosis pmc.ncbi.nlm.nih.gov. In a longitudinal analysis, 133 EBC patients were followed for four years after diagnosis, and serum miR-155 and miR-24 were identified as predictive of relapse mdpi.com. The reported p-values for relapse prediction were 0.025 for miR-155 and 0.041 for miR-24 mdpi.com.
Circulating miR-155 as a biomarker
Elevated miR-155 in primary breast tumor tissue has been frequently reported, but the pattern of circulating miR-155 and its clinical biomarker application have not been fully established pmc.ncbi.nlm.nih.gov. A 2026 review reports that elevated plasma miR-155 has been associated with more advanced disease and poorer survival, and cites a meta-analysis with a pooled diagnostic AUC of about 0.92 mdpi.com. These findings support diagnostic potential while underscoring that circulating miR-155’s clinical use remains incompletely resolved.
How Can Monitoring miR-155 and miR-24 Levels Improve Breast Cancer Treatment?
The study's findings revealed that EBC patients exhibited significantly elevated levels of specific miRs at the time of diagnosis compared to healthy controls. Notably, miR-155, miR-181b, and miR-24 levels decreased significantly after surgery, indicating a potential response to initial treatment. Furthermore, miR-19a levels decreased after adjuvant therapy, suggesting an ongoing impact of treatment on miR expression.
- Predictive Power of miR-155 and miR-24: Multivariate analysis confirmed that miR-155 and miR-24 were predictive of EBC relapse. This means that by monitoring the levels of these miRs, clinicians can better assess a patient's risk of relapse.
- Influence of Ki-67: The predictive accuracy of miR-155 and miR-24 was enhanced when combined with Ki-67 expression levels, a well-known marker of cell proliferation. This suggests a synergistic effect, where combining these biomarkers provides a more precise risk assessment.
- Limited Impact of Other Factors: Interestingly, traditional risk factors like triple-negativity, HER2 status, grade, and lymph node involvement did not significantly affect relapse prediction when oncomiRs were considered. This highlights the potential of miRs to provide independent prognostic information.
Diagnostic findings vary across studies
The 2024 systematic review and meta-analysis notes that the diagnostic value of circulating miR-155 for breast cancer differs across studies pmc.ncbi.nlm.nih.gov. That variation is a reason to assess its potential through pooled evidence rather than assume consistent performance in every study or setting. Separately, an early breast cancer study examined four oncomiRs—miR-155, miR-19a, miR-181b, and miR-24—and the tumor-suppressor microRNA let-7a for distinguishing high- and low-risk disease and reflecting surgical tumor removal mdpi.com.
PXDNL biomarker research and an antibody deal
One breast cancer study tested PXDNL mRNA expression using The Cancer Genome Atlas (TCGA) database and reported that PXDNL may be an independent prognostic biomarker doi.org. In a separate development, Genentech agreed to pay Affimed $96 million up front, with up to $5 billion more in potential payments doi.org. The supplied information describes these as distinct research and business developments and does not establish a direct comparison of their clinical value.
The Future of Breast Cancer Treatment: Personalized and Precise
The study's conclusion emphasizes the significance of oncomiRs, particularly miR-155 and miR-24, as key players in the diagnosis and monitoring of breast cancer. These molecules are more abundant in EBC patients compared to healthy controls and decline after therapy, reflecting treatment response.
MicroRNAs in precision medicine
A 2025 review discusses research limitations and the outlook for applying microRNAs in breast cancer precision medicine frontiersin.org. It identifies early diagnosis, individualized treatment, and prognosis assessment as areas where future research may offer new strategies frontiersin.org. A separate 2022 study suggests that breast cancer cell-expressed miR-155 can enhance antitumor immune responses and that boosting its expression in breast tumors could be a therapeutic strategy jci.org. The study also proposes serum miR-155 as a predictive biomarker for prognosis and response to immune therapy jci.org.
Monitoring treatment and recurrence
Research on circulating miR-155 describes its clinical biomarker application as not yet fully established ncbi.nlm.nih.gov. A study published February 4, 2026, proposes miRNA-155 as a potential biomarker for early breast cancer detection and for monitoring treatment efficacy sciencedirect.com. These are potential applications reported by the studies, rather than established routine clinical uses.
Differences in oncomiR levels accurately reflect EBC risk groups, enabling clinicians to identify patients at higher risk of relapse. The data strongly suggest that miR-155 and miR-24 can independently predict relapse, regardless of traditional clinical and pathological risk factors. The combination of oncomiR levels with Ki-67 expression further refines the accuracy of relapse prediction.
The integration of oncomiR monitoring into routine clinical practice represents a significant step towards personalized breast cancer treatment. By tailoring therapies based on individual risk profiles, clinicians can optimize treatment effectiveness, minimize unnecessary interventions for low-risk patients, and ultimately improve the quality of life and survival rates for all individuals affected by breast cancer.