Serum miR371 in testicular germ cell cancer before and after orchiectomy, assessed by digital-droplet PCR in a prospective study.

MicroRNA-371a-3p (miR371) has been suggested as a sensitive biomarker in testicular germ cell cancer (TGCC). We aimed to compare miR371 with the classical biomarkers α-fetoprotein (AFP) and ß-human chorionic gonadotropin (hCGß). Overall, 180 patients were prospectively enrolled in the study, with serum samples collected before and after orchiectomy. We compared the use of digital droplet PCR (RT-ddPCR) with the quantitative PCR used by others for detection of miR371. The novel RT-ddPCR protocol showed high performance in detection of miR371 in serum samples. In the study cohort, miR371 was measured using RT-ddPCR. MiR371 detected CS1 of the seminoma and the non-seminoma sub-types with a sensitivity of 87% and 89%, respectively. The total sensitivity was 89%. After orchiectomy, miR371 levels declined in 154 of 159 TGCC cases. The ratio of miR371 pre- and post-orchiectomy was 20.5 in CS1 compared to 6.5 in systemic disease. AFP and hCGß had sensitivities of 52% and 51% in the non-seminomas. MiR371 is a sensitive marker that performs better than the classical markers in all sub-types and clinical stages. Especially for the seminomas CS1, the high sensitivity of miR371 in detecting TGCC cells may have clinical implications.

Investigation of six testicular germ cell tumor susceptibility genes suggests a parent-of-origin effect in SPRY4.

Recent genome-wide association studies have identified single-nucleotide polymorphisms (SNPs) associated with testicular germ cell tumor (TGCT) risk in the genes ATF7IP, BAK1, DMRT1, KITLG, SPRY4 and TERT. In the present study, we validate these associations in a Scandinavian population, and explore effect modification by parental sex and differences in associations between the major histological subtypes seminoma and non-seminoma. A total of 118 SNPs in the six genes were genotyped in a population-based Swedish-Norwegian sample comprising 831 TGCT case-parent triads, 474 dyads, 712 singletons and 3919 population controls. Seven hundred and thirty-four additional SNPs were imputed using reference haplotypes from the 1000 genomes project. SNP-TGCT association was investigated using a likelihood-based association test for nuclear families and unrelated subjects implemented in the software package UNPHASED. Forward stepwise regression within each gene was applied to determine independent association signals. Effect modifications by parent-of-origin and effect differences between histological subtypes were explored. We observed strong association between SNPs in all six genes and TGCT (lowest P-value per gene: ATF7IP 6.2 × 10(-6); BAK1 2.1 × 10(-10); DMRT1 6.7 × 10(-25); KITLG 2.1 × 10(-48); SPRY4 1.4 × 10(-29); TERT 1.8 × 10(-18)). Stepwise regression indicated three independent signals for BAK1 and TERT, two for SPRY4 and one each for DMRT1, ATF7IP and KITLG. A significant parent-of-origin effect was observed for rs10463352 in SPRY4 (maternal odds ratio = 1.72, paternal odds ratio = 0.99, interaction P = 0.0013). No significant effect differences between seminomas and non-seminomas were found. In summary, we validated previously reported genetic associations with TGCT in a Scandinavian population, and observed suggestive evidence of a parent-of-origin effect in SPRY4.

Risk of metachronous contralateral testicular germ cell tumors: a population-based study of 7,102 Norwegian patients (1953-2007).

The purpose of the study was to identify overall incidence and risk of developing a metachronous contralateral testicular germ cell tumor (TGCT) and compare the risk for patients treated before and after 1980 (cisplatin became available for patients with metastatic TGCT). Our hypothesis was that the risk of metachronous TCGT would be reduced for patients with metastatic disease diagnosed after 1980. We included 7,102 men with unilateral TGCT, recorded in the Cancer Registry of Norway. Allowing for competing risk, cumulative incidence and adjusted hazard ratio (HR) were estimated for different subgroups, and the diagnostic periods 1953-1979 (I) and 1980-2007 (II). Relative risks were assessed by standardized incidence ratio (SIR). In Period I and Period II, 38 and 137 males, respectively, were diagnosed with metachronous contralateral TGCT. Corresponding 20-year cumulative incidences were 1.9% and 3.9%. In Period II, risk of a second TGCT was halved [HR = 0.5, 95% confidence interval (95% CI) = 0.33-0.77] for patients with metastatic compared to localized disease. For patients presenting with localized and metastatic disease, the SIRs for Period I were 14.6 (95% CI = 9.6-21.2) and 25.3 (95% CI = 12.1-46.5), respectively. In Period II, the corresponding numbers were 19.0 (95% CI = 15.6-22.9) and 9.8 (95% CI = 6.4-14.5). In conclusion, the risk of metachronous contralateral TGCT was halved for patients with metastatic compared to localized disease in Period II, whereas this protective effect of extent of disease lacked significance for Period I. These findings support our hypothesis that cisplatin-based chemotherapy reduced the risk of a second TGCT for patients with metastatic TGCT diagnosed after 1980.