CYTOGENETIC FINDINGS IN PEDIATRIC GERM-CELL TUMORS

Three pediatric germ cell tumors (GCT) were cytogenetically analyzed. A mediastinal mature teratoma in a 15-year-old girl had a balanced t(8 ;22)(p21;q12) as the sole clonal aberration, an intrathoracic immature teratoma in a 2-year-old girl had the complex karyotype 46,XX,der(6) ;q11q23),de1(8)(q22),-1O,der(12)t(10;12),(q22;q22- 23),der(16)t(1;16)( q12;q11),+mar and a congenital presacral endodermal sinus tumor was ch aracterized by the karyotype dd(11)(p15),der(13)t(1;13)(q21;p13),add(1 4)(p13),d e1(15)(q24),+der(?)t(?;11)(?;q13). The present three tumors had no chromosome aberration in common, nor has any specific change be en detected in the 13 previously reported cytogenetically aberrant ped iatric GCT. The karyotypic picture comes across as far more heterogene ous than that of GCT of adults. Whereas gain of 12p material, in the v ast majority through i(12)(p10) formation, dominates in the adult sett ing, the most common cytogenetic abnormalities in pediatric GCT seem t o be unbalanced recombinations leading to gain of 1q. Other recurrent changes include, in decreasing order of frequency, numerical and struc tural aberrations leading to gain of 8q and 12p, loss of distal 1p, +3 , loss of 7q22-32, -10, -13 and -18.