Exploring the microRNA profiles as potential diagnostic probes for oligo- and polymetastatic prognosis of lung metastasis(es) patients

Presuming the stage of metastatic lung cancer is divided by its location, an intermediate state of ≤5 cumulative metastasis is defined as oligometastases (OM) and a widespread state of >5 cumulative metastasis as polymetastases (PM). According to the phenotypes, the different metastatic cancer patients can be treated with different methods: the OM patients can be treated by a metastasis-directed local therapy method, whereas the PM patients are not recommended to take such a treatment. It is also believed that the patients at the initial OM stage may progress to the PM stage. Currently, the OM- and PM-metastatic cancer patients can be identified by traditional imaging methods. However, the current methods are found to be insufficient for the discrimination. It hence is meaningful and important to develop new diagnostic methods for a better prediction to the patients following by selecting a correct metastasis-directed treatment. MicroRNAs (miRNAs) can be used as the genetic probes for the new diagnostic methods. In this study, a bioinformatics strategy was employed to screen the microRNAs as potential diagnostic probes for distinguishing the OM and PM lung metastases patients. The expression profiles of microarray data of GSE38698 were downloaded from Gene Expression Omnibus (http://www.ncbi.nlm.nih.gov/geo/) including the information from 63 patients: 24 PM and 39 OM patients. The microRNA expression patterns of tumor samples were identified for the OM and PM patients who were treated with the high-dose radiotherapy. Followed by analyzing the functional enrichment pathways, an early diagnosis model of OM and PM groups was identified with different expression genes (DEGs). The ratios of PM/OM were calculated by setting a high significance in the expressions of 377 mature miRNAs in the profile [log2 (PM/OM) >1 and P < .05]. Through a high combination power [area under the curve (AUC) ≥ 0.875] with the superior sensitivity and specificity, a panel of 10 miRNAs including 7 upregulation and 3 downregulation expressions were identified as potential probes for discriminating the PM and OM patients from the receiving operation characteristic (ROC). Considering the possible involvements of cancer progress, the interconnected axon guidance, cancer metastasis pathways, proteoglycans, and Mitogen-activated protein kinases signaling pathway and endocytosis were suggested for the subsequent miRNA target analysis. The results may reveal a biological significance that a profile of miRNAs can be used as the potential probes to identify the patients at the OM or PM stages and figure out the metastasis-directed treatment methods for the patients at the different metastasis stages.