Journal of Experimental & Clinical Cancer Research 2009, 28:120 http://www.jeccr.com/content/28/1/120 Table 4: Association of type of germ cell tumor with hCG levels and vascular density Variable Seminoma Non-seminoma hCG median (mIU/mL) ± SD 792.73 ± 2962.1 26954 ± 96511.2 p 0.069 Vascular density ± SD 20.64 ± 20.14 34.56 ± 33.70 p 0.016 hCG = human chorionic gonadotropin; SD = standard deviation are present in pregnancy; thus, similarities between tumor invasion and its vascularization and blastocyst implanta- tion and placental development have been described [25,26]. In addition, it has been proposed that hCG could induce VEGF production in tissues such as placenta [17] and granulosa cells [18,19]. hCG administration to women undergoing in vitro fertilization increases urinary [27], serum, and follicular-fluid VEGF concentrations [28]. Furthermore, hCG exerts a direct angiogenic effect on hCG/LH receptor-expressing uterine endothelial cells, which respond with increased capillary formation in vitro [16,29]. hCG receptors have been detected in breast carci- noma tissue, which indicates a probable link to a worse breast-cancer prognosis during pregnancy, which we pre- viously hypothesized [30]. We found that predominantly in patients with hCG serum levels ≥ 25 mIU/mL there was increased tumoral vascular neoformation, suggesting that hCG could be involved in angiogenic processes during tumor development. Intrin- sic hCG activity is clinically relevant when serum concen- trations are high, for instance, during pregnancy or under certain pathological conditions that might be associated to the carcinogenesis of testicular germ cells [6,7]. In this study, a prominent VD (median, 19.0 ± 28.9) was observed in all tumors, especially non-seminomas, which would be expected as hCG is elevated in this subtype of germ tumors. Angiogenesis is essential for malignant neo- plasm progression and is correlated with poor prognosis Table 5: Multivariate analysis of factors associated with vascular density Variable Histology (S vs. NS) Metastatic disease hCG AFP LDH Regression co-efficient 0.2 1.2 14 13.4 0.73 p 0.907 0.165 0.04 0.08 0.92 in numerous solid tumors [31], including germ cell testic- ular cancer [32,33]. Particularly in normal testis, the endothelial cell proliferation rate is considerably higher than in other stationary organs. It has been shown that this rate can be increased via hCG stimulation of Leydig cells [34]. In addition, a correlation between hCG and VEGF has been confirmed in rat models and transformed mouse Leydig cell lines (MA-10 cells) [35,36]. In our results, VEGF expression was limited to 56% of the tumors studied, showing no clinical or histopathological association; nevertheless, tissue availability comprised a factor that could render the data less significant. VEGF expression in germ cell testicular tumors was previously found to be significantly higher than in normal testis and was correlated with microvessel density [11,37]; it was also described as an indicator of metastatic disease [12]. However, another study reported no prognostic signifi- cance in relation to metastatic potential, sustaining the possibility of the existence of additional factors affecting metastatic capacity. It has also been suggested that there might be other angiogenic factors, different from VEGF, which are important in testis tumor biology [37]. No significant association was found between VD and VEGF expression or prognosis according to disease-free S = seminoma; NS = non-seminoma; hCG = human chorionic gonadotropin; AFP = alpha-fetoprotein; LDH = lactate dehydrogenase rRFieioglnauitcrioegno1snhaipdobtertowpeinen(htCisGsu)esvearsucmulalervdeelsnsity and human cho- Relationship between tissue vascular density and human chorionic gonadotropin (hCG) serum levels. Page 5 of 7 (page number not for citation purposes)