The low co-expression of c-KIT and PLAP in SEM could result from the different cellular origin of seminomas, because c-KIT is expressed in both spermatogonia and prespermatogonia whereas PLAP is expressed only in prespermatogonia, while in people both cells give rise to CSEM [10],[11],[17],[20],[27],[29],[31]. The gene discussed is KIT; the disease is seminoma.