Intratubular germ cell neoplasia of the human testis: heterogeneous protein expression and relation to invasive potential.

Testicular germ cell cancer develops from premalignant intratubular germ cell neoplasia, unclassified cells that are believed to arise from failure of normal maturation of fetal germ cells from gonocytes (OCT4(+)/MAGEA4(-)) into pre-spermatogonia (OCT4(-)/MAGEA4(+)). Intratubular germ cell neoplasia cell subpopulations based on stage of germ cell differentiation have been described, however the importance of these subpopulations in terms of invasive potential has not been reported. We hypothesized that cells expressing an immature (OCT4(+)/MAGEA4(-)) germ cell profile would exhibit an increased proliferation rate compared with those with a mature profile (OCT4(+)/MAGEA4(+)). Therefore, we performed triple immunofluorescence and stereology to quantify the different intratubular germ cell neoplasia cell subpopulations, based on expression of germ cell (OCT4, PLAP, AP2γ, MAGEA4, VASA) and proliferation (Ki67) markers, in testis sections from patients with preinvasive disease, seminoma, and non-seminoma. We compared these subpopulations with normal human fetal testis and with seminoma cells. Heterogeneity of protein expression was demonstrated in intratubular germ cell neoplasia cells with respect to gonocyte and spermatogonial markers. It included an embryonic/fetal germ cell subpopulation lacking expression of the definitive intratubular germ cell neoplasia marker OCT4, that did not correspond to a physiological (fetal) germ cell subpopulation. OCT4(+)/MAGEA4(-) cells showed a significantly increased rate of proliferation compared with the OCT4(+)/MAGEA4(+) population (12.8 versus 3.4%, P<0.0001) irrespective of histological tumor type, reflected in the predominance of OCT4(+)/MAGEA4(-) cells in the invasive tumor component. Surprisingly, OCT4(+)/MAGEA4(-) cells in patients with preinvasive disease showed significantly higher proliferation compared to those with seminoma or non-seminoma (18.1 versus 10.2 versus 7.2%, P<0.05, respectively). In conclusion, this study has demonstrated that OCT4(+)/MAGEA4(-) cells are the most frequent and most proliferative cell population in tubules containing intratubular germ cell neoplasia, which appears to be an important factor in determining invasive potential of intratubular germ cell neoplasia to seminomas.

A comparison of the pathology of transitional cell carcinoma of the bladder and upper urinary tract.

OBJECTIVE: To clarify the histopathological patterns of upper and lower urinary tract transitional cell carcinomas (TCCs), as previous reports suggest that upper urinary tract TCCs have a greater tendency towards high-grade disease than bladder TCCs, of which most are low-grade and low-stage tumours. PATIENTS AND METHODS: All patients presenting with TCC of bladder or upper urinary tract between February 1991 and December 2001 at one institution were identified. Further patient information was obtained from the hospital database and case-note review. RESULTS: In all, 164 patients with upper urinary tract TCC and 2197 with bladder TCC were identified. There was a correlation between grade and stage of both upper urinary tract and bladder TCCs. 35% of the upper tract TCCs were classified as grade 2 and 44% as grade 3, while for bladder TCCs, 31% of lesions were classified as grade 2 and 35% as grade 3 (P = 0.003). Of the upper urinary tract lesions 33% were stage pT2-T4, compared with only 20% of bladder TCCs (P = 0.001). CONCLUSIONS: Upper urinary tract TCC is a higher grade and stage disease than bladder cancer, a finding that emphasizes the need for aggressive treatment of upper urinary tract TCC. If endourological management of upper urinary tract TCC is considered, histopathological determination of tumour grade before treatment is essential.