DNA ploidy of testicular germ cell tumors in childhood; difference from adult testicular tumors

Abstract

It is well known that there are various differences in the biological characteristics and clinical behavior between prepubertal testicular germ cell tumors and adult ones. We analyzed the nuclear DNA ploidy of testicular tumors in childhood using DNA flow cytometry for clarifying those biological features and shedding some insights in the pathogenesis of testicular germ cell tumors. Formalin-fixed, paraffin-embedded specimens of primary tumors taken from 9 boys with histological evidence of yolk sac tumors and 8 with prepubertal teratoma treated in our clinic were used for flow cytometry analysis with some modification of the Hedley's technique. The results were compared with those of adult testicular tumors which we previously reported. All specimens in children showed "DNA euploid"; DNA diploid in all teratomas and 6 yolk sac tumors, DNA tetraploid in other 3 yolk sac tumors. Neither distinct DNA aneuploidy nor DNA heterogeneity were detected in children. Our previous study proved that the vast majority of adult testicular tumors contain DNA aneuploid stemlines. Although prepubertal yolk sac tumor and teratoma are histologically identical with those in adults, this study apparently reveal the different DNA stemline ploidy in prepubertal testicular tumors compared with that in adult ones. It has been known that carcinoma in situ (CIS) of the testis is a precursor of adult testicular germ cell tumors and the CIS cells in precancerous state already shows aneuploid DNA histogram patterns. Moreover, CIS has never been observed in children. The current results are in agreement with the hypothesis that the pathogenesis of prepubertal testicular tumor is different from that of adult ones.(ABSTRACT TRUNCATED AT 250 WORDS)