Since there is a correlation of Cx43 and disturbed spermatogenesis, seminoma and the GC neoplasia in situ [2–5], and next-generation sequencing of murine SCCx43KO-/--SC has detected an upregulation of the Krt 18 gene in prepubertal KO mice [39], a re-expression of keratins in our mutant mice was conceivable. Here, GJA1 is linked to seminoma.