Transcriptome analysis of human Leydig cell tumours reveals potential mechanisms underlying its development.

Leydig cell tumours are the most common sex cord-stromal tumours. In the last years, apparent increased incidence is noted while aetiology of the tumour is still unknown. Therefore, here, we focused on the genetics of Leydig cell tumours using the next-generation sequencing. Leydig cell micronodules were revealed in patients with azoospermia who were qualified for testicular biopsy. Complete gene set of Leydig cell tumours was compared with transcriptome of healthy Leydig cells obtained from donors. Bioinformatic analysis of the obtained sequencing data revealed alterations in expression of 219 transcripts. We showed, for the first time, that a significant proportion of differentially expressed genes is directly involved in regulation of apoptotic process, which downregulation might be important to Leydig cell tumour development. Additionally, we found a significant upregulation of heat shock protein genes that might be a unique feature of Leydig cell tumours when compared to other tumour types. Our study offers fundamental transcriptomic data for future studies on human Leydig cell tumour that are crucial to determine its causes. Moreover, presented here the in-depth analysis and discussion of alterations observed in tumour transcriptome may be important for the diagnosis and therapy of this pathology.