Exosomal non-coding RNAs for monitoring breast cancer patients

Exosomal non-coding RNAs were explored as a basis for monitoring breast cancer patients. Specifically, exosomal microRNAs (miRNAs), and especially miR-21, were the focus of this project. Consistent with our hypothesis, we found that miR-21 was highly expressed in exosomes of cancer patients compared to ‘healthy' individuals. However, circulating miR-21 levels, when compared in post- versus presurgery serum, did not decline for all five experimental patients. This unexpected observation could be the result of small sample size and lack of both endogenous and exogenous miRNA controls. All five patients had early stage breast cancer. We found that our methods were possibly not sensitive enough to detect very small differences between pre- and post-surgery serum. Future experiments might involve samples at a later stage of cancer. High miR-21 levels in post-tumor resection serum raised an issue concerning how long cancerous exosomes can stay in the blood after tumor removal. As well, recovery time from surgery might vary from patient to patient. Consequently, additional serum samples from patients might be obtained at a later time after surgery. This research signals an advance over current modes of cancer detection and involves a more patient-centric approach. Customized-miRNA panels might someday be the standard for each breast-cancer patient. The release of breast-tumor exosomes and their miRNA cargo iv into the blood stream allow for disease detection by way of non-invasive methods achieved at lower application costs. This technology, with all its advantages, might result in more frequent screenings of patients and thus an earlier detection of cancer and more efficient patient care.