Characterization of Precancerous and Neoplastic Human Testicular Germ Cells

Abstract

Testicular germ cell tumors are in most cases preceded by an intratubular noninvasive form of neoplasia, known as carcinoma in situ (CIS, Skakkebaek and Berthelsen 1978). These atypical germ cells resemble gonocytes or spermatogonia (Nüesch-Bachmann and Hedinger 1977), but also show nuclear atypia indicative of malignant transformation. Atypical intratubular cells have been known to precede overt tumors for up to 16 years (Bannwart et al. 1988). However, they do not have invasive properties and the attempts to grow them as xenografts in nude mice have been unsuccessful (Walt and Stevens unpublished results). The transition of CIS to invasive carcinoma therefore remains poorly understood. In an effort to understand better the pathobiology of testicular neoplasias and their precancerous precursors, we have studied the expression of certain biochemical tumor markers (Walt et al. 1986) and of alkaline phosphatase isozymes (Hofmann et al. 1989), the activity of nucleolus organizer regions (NORs) (Delozier-Blanchet et al. 1986a), and the presence of a number of specific chromosomal regions by in situ hybridization on paraffin sections (Emmerich et al. 1989). For these investigations we have used xenografts and their related cell lines (DelozierBlanchet et al. 1986b; Emmerich et al. 1989; Hofmann et al. 1989; Walt et al. 1986) as well as primary tumors and primary precancerous and ejaculated germ cells (Jauch et al. 1989; Walt et al. 1989). We hope that this summary of data will allow the development of new strategies for further research in this area.