Plasma miR371 detects MRD and early relapse of germ cell tumours

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Published: 19 Feb 2023
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Dr Lucia Nappi - University of British Columbia, Vancouver, Canada

Dr Lucia Nappi speaks to ecancer about plasma miR371 detecting minimal residual disease and early relapse of germ cell tumours at the 2023 American Society of Clinical Oncology Genitourinary Cancers Symposium, in San Francisco, California.

She explains how relapse-free survival was correlated to post-orchiectomy miR371 (positive or negative) status and miR371 sensitivity correlated with tumour burden, the time between tumour relapse and miRNA testing and histology.

Dr Nappi concludes by discussing the further studies taking place, including the SWOG S1823 clinical trial.

My research mainly focuses on biomarker discovery and validation in genitourinary tumours with a special interest in prostate cancer and testicular cancer. The study I’m going to present at this ASCO GU is focussed mainly in microRNA which is a very small fragment of RNA that is secreted in the bloodstream specifically by germ cell tumours. We evaluated this microRNA prospectively in very early stage disease of testicular cancer essentially to assess whether or not we can use this microRNA to predict relapse.

What was the methodology?

In order to assess this microRNA expression we used peripheral plasma. The microRNA was extracted and measured by real-time PCR. We had qualitative and quantitative analyses performed.

What were the key findings?

We essentially analysed 101 patients with clinical stage 1 testicular cancer after the orchidectomy prospectively and longitudinally with a long follow-up that exceeded the median time of relapse so that we could be sure that there were no false negatives in our analysis. What we found was that our microRNA 371 detected in peripheral blood was able to detect with a very high positive predictive value and specificity the presence of viable germ cell tumours in both seminoma and non-seminoma clinical stage 1.

As I mentioned, this is a very important but still limited in terms of numbers of patients evaluated study so we need a bigger number to validate prospectively this data on microRNA 371. The SWOG trial S1823, it’s open through SWOG and CCTG, will answer the question of whether or not microRNA 371 could be used to detect minimal residual disease after orchidectomy and predict tumour relapse in these patients and will be extremely important also to understand the timing of the switch eventually if we will get low sensitivity immediately after the orchidectomy.

What could be the impact of this research?

The impact of this research if our data will be validated in larger clinical trials that are currently ongoing, including the S1823 study that is sponsored in Canada and in the US through SWOG and CCTG, it could be very relevant for patients with clinical stage 1 testicular cancer because we could propose a very simple blood test after the orchidectomy for monitoring of tumour relapse, reducing or completely eliminating in some patients, especially in seminoma patients, the use of CT scan. We could use, again if this data will be validated in a larger cohort, we could use the microRNA for assessment of presence of viable germ cell tumours in early stage disease, for example in stage 2a seminoma and non-seminoma with negative tumour markers where our CT scan and serum tumour markers are suboptimal. So we still do not have very good diagnostic tools for these patients and this leads to undertreatment or overtreatment and could lead to long-term side effects. So having a very precise and accurate biomarker will definitely decrease the unnecessary treatment for these patients.