Refining the serum miR-371a-3p test for viable germ cell tumor detection

Abstract

Circulating miR-371a-3p has excellent performance in the detection of viable (non-teratoma) germ cell tumor (GCT) pre-orchiectomy; however, its ability to detect occult disease is understudied. To refine the serum miR-371a-3p assay in the minimal residual disease setting we compared performance of raw (Cq) and normalized (∆Cq, RQ) values from prior assays, and validated interlaboratory concordance by aliquot swapping. Revised assay performance was determined in a cohort of 32 patients suspected of occult retroperitoneal disease. Assay superiority was determined by comparing resulting receiver-operator characteristic (ROC) curves using the Delong method. Pairwise t-tests were used to test for interlaboratory concordance. Performance was comparable when thresholding based on raw Cq vs. normalized values. Interlaboratory concordance of miR-371a-3p was high, but reference genes miR-30b-5p and cel-miR-39-3p were discordant. Introduction of an indeterminate range of Cq 28–35 with a repeat run for any indeterminate improved assay accuracy from 0.84 to 0.92 in a group of patients suspected of occult GCT. We recommend that serum miR-371a-3p test protocols are updated to (a) utilize threshold-based approaches using raw Cq values, (b) continue to include an endogenous (e.g., miR-30b-5p) and exogenous non-human spike-in (e.g., cel-miR-39-3p) microRNA for quality control, and (c) to re-run any sample with an indeterminate result.

Advancing GCT Management: A Review of miR-371a-3p and Other miRNAs in Comparison to Traditional Serum Tumor Markers

“…Understanding the immense possibilities for use of circulating microRNAs is underway; however, a major hindrance could result from the current lack of standardized conventions used to collect, store, analyze, and interpret data. The development of an accepted protocol may limit obstacles, such as interlaboratory heterogeneity, allowing for widespread clinical use of circulating miRNA levels [34,35]. Current studies are gaining traction on this issue [28].…”

“…Current studies are gaining traction on this issue [28]. Lafin et al suggested the use of raw Cq values from serum qPCR-based methods with pre-amplification after discovering the normalization process of assays increased the likelihood of variation and therefore heterogeneity [34]. The use of raw miR-371a-3p Cq data, in this context, is associated with lower cost, which can be useful for incorporation of miRNA analysis into routine clinical testing.…”