DIFFERENTIAL EXPRESSION OF P53, C-KIT, AND CD34 IN PREPUBERTAL AND POSTPUBERTAL TESTICULAR GERM-CELL TUMORS

Background. The origin of testicular germ cell tumors (TGCTs) in child ren is poorly understood. There are clear differences between tumors i n young children and those in adolescents and adults, which may sugges t that they follow different pathways of tumorigenesis. METHODS. Tissu e sections from 25 TGCTs (15 from patients age 4 years or younger and 10 from adolescents or adults) were stained immunohistochemically with anti-p53 (DO-1), CD34, and c-kit proto-oncogene protein product. RESU LTS. CD34 expression was noted only in 5 prepubertal tumors. Expressio n of c-kit was observed in 9 of the 15 prepubertal tumors versus 2 of the 10 postpubertal cases. The intensity of expression was equal to th at of the adjacent normal tubules in the prepubertal tumors, whereas t he intensity was less in the postpubertal tumors. Expression of p53 wa s strong in 8 of the 10 tumors in adolescents or adults, with a 40-70% positivity, whereas only 6 of 15 prepubertal tumors expressed p53, wi th <10% positivity. CONCLUSIONS. CD34 expression in tumors in the grou p of young children suggests a possible link to teratomas and further provides insight into the fundamental differences between this group a nd the adolescent/adult group. The expression of c-kit and p53 provide s further evidence that c-kit/SCF signaling and p53 play potentially d ifferent roles in the initiation and progression of these tumors. Futu re studies will be required to clarify this issue. (C) 1997 American C ancer Society.