RNA for urooncologists
There is a possibility of using microRNAs for early diagnosis of prostate cancer
Chinese experts have identified 5 specific microRNAs that can help in detecting prostate cancer at an early stage, according to the journal BioMed Research International (Lyu et al., Discovery and Validation of Serum microRNAs as Early Diagnostic Biomarkers for Prostate Cancer in Chinese Population). Their study showed that in combination with PSA analysis and prostate volume determination, this microRNA panel has a high diagnostic value.
Prostate-specific antigen (PSA) is considered the main biomarker of prostate cancer (prostate cancer) worldwide. It has a relatively good sensitivity, but low specificity, since an increase in its concentration in the blood serum can also be observed in many benign conditions.
In recent years, experts have increasingly said that controlling the level of PSA can lead to overdiagnosis, overtreatment and an increase in the cost of medical care without significantly reducing mortality from prostate cancer. Therefore, it is necessary to look for more specific markers for patients with elevated levels of antigen.
microRNAs (miRNAs) are small RNAs 19-23 nucleotides long that are not translated into protein, but regulate the expression of up to 30% of protein-coding genes. It has been established that these molecules play a key role in many biological processes, including differentiation, proliferation and apoptosis of cells. Abnormal expression of some microRNAs is often found in tumor cells. Different microRNAs can function either as tumor suppressors or as oncogenes. At the same time, they are easily detected in plasma and blood serum. Therefore, microRNAs are currently being considered as potential diagnostic markers of prostate cancer and other cancers.
Chinese experts compared the microRNA profiles in the blood of patients with prostate cancer and benign prostatic hyperplasia (BPH), who have elevated PSA levels and underwent transrectal prostate biopsy under ultrasound control to identify possible markers of malignant tumors and improve the accuracy of cancer diagnosis.
Using a microchip study and the qRT-PCR method, 5 microRNAs with potential diagnostic value were detected: miR-365a-3p, miR-4286, miR-424-5p, miR-27a-3p and miR-29b-3p. Sensitivity and specificity of these differentially expressed microRNAs were determined by ROC analysis in combination with 4 more variables: age of patients, PSA level, ratio of free to total PSA (f/tPSA) and prostate volume. The area index under the AUC ROC curve was 0.892 (sensitivity 78.95%, specificity 92.21%).
The diagnostic efficacy of the microRNA panel was confirmed in a validation study involving 100 patients (57 patients diagnosed with prostate cancer and 43 with BPH). The prognosticality of a positive result was 69%, the prognosticality of a negative result was 66%.
The authors emphasized that all the patients included in the study were Asian. Therefore, the data obtained may be unreliable in relation to patients of other races. Moreover, it has already been reported about racial differences in microRNA expression in diseases such as hypertension, colon cancer, triple negative breast cancer, endometrial cancer and others.
Repeated examination in a larger population and among patients of other races will clarify the prognostic value of the identified biomarkers.
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