Stem Cell Origin of Testicular Seminoma

IntroductionA major question concerning cancer is its cells of origin. We hypothesized that distinct cancer subtypes arise from unique cancer-initiating cells. By performing a microarray meta-analysis of seminomas and spermatogonial stem cells, we investigated a putative cell of origin for seminoma.Materials and MethodsWe obtained published microarray data for 6 human adult germ cell lines, 16 embryonic stem cell lines, 3 normal testicular tissue samples, and 40 seminomas from the Gene Expression Omnibus database. By assessing correlations between various tissue microarrays, we determined the number of transitional events and the distance between seminomas and human spermatogonial stem cells.ResultsOur meta-analysis showed that spermatogonial stem cells correlated similarly with seminoma (95% CI of Spearman ρ, 0.33-0.44) and with normal somatic testicular tissue cells (95% CI, 0.39-0.40), which suggests parallel paths of cellular origins.ConclusionAnalysis of our results suggests that a unique cancer subtype, namely seminoma, may have originated from an undifferentiated cell with stemness features rather than from a differentiated cell that acquired stemness features.