LOSS OF HETEROZYGOSITY AND DECREASED EXPRESSION OF NME GENES CORRELATE WITH TERATOMATOUS DIFFERENTIATION IN HUMAN MALE GERM-CELL TUMORS

Embryonal carcinoma in the human male is a pluripotential germ cell tu mor (GCT), which is suggested to further differentiate to teratoma whi ch displays somatic differentiation representing all three germinal la yers. In a panel of 37 GCTs we determined frequency of loss of heteroz ygosity (LOH) and the level of expression of nucleoside diphosphate ki nase (NDPK) genes NME 1 and NME 2. The frequency of LOH in teratomas ( 86%) was found to be highly significant (P<0.01) compared to embryonal carcinomas (17%). We also found that the NME encoded proteins are exp ressed at a 4-5 fold lower level in teratomas compared to embryonal ca rcinomas. These findungs lead us to hypothesize that a critical level of NDPK may be necessary for suppression of aberrant somatic different iation. (C) 1994 Academic Press, Inc.