Tumors of the germ cells lineage were found, ranging from well-differentiated seminomas (one 18-mpf ambra1b−/− and one ambra1a−/− at the same age, Fig. 1H) to undifferentiated germ cell tumor with infiltration of adjacent coelomic organs (17-mpf ambra1b−/−, Fig. 1I). The gene discussed is MSLN; the disease is seminoma.