determined by flow cytometry. Briefly, whole mouse lungs were digested with collagenase followed by mechanical separation. Lung cells were then stained with fluorescent conjugated antibodies to the surface markers CD4, CD8, cdTCR, and CD49b. Statistics Data were analyzed ” by unpaired two-tailed t-test or by one-way ANOVA where appropriate. For multiple comparisons, following ANOVA, data were compared by Tukey test. Analyses with a resultant p,0.05 were determined significant, additionally p,0.10 is also reported as a trend. Data are presented as mean 6 standard error of the mean. All studies were repeated at a minimum of two times with the resultant combined data presented, except for MTEC gene expression data where representative data is shown. All analyses were conducted with the Microsoft Excel software package. Mouse Tracheal Epithelial Cell Culture MTEC were prepared and propagated as previously described. Cells were isolated from WT and JNK1 2/2 mice and were maintained in submerged culture for studies with IL-17A. IL-17A was added to MTEC cultures at a concentration of 10 ng/ml for 24 hours or as indicated. Testicular germ cell cancer is the most frequent cancer occurring in young men and originates from transformed gonocytes or undifferentiated spermatogonia, which respectively derived from foetal germ cells and adult germ stem cells. Seminomas are the most frequent testicular germ cell tumours. Clinical and experimental studies suggested that oestrogens, the archetype of female hormones, participate in the physiological and pathological 
control of male germ cell proliferation. However, the physiological role of oestrogens during spermatogenesis and the molecular mechanisms by which they regulate germ cell proliferation remain to be elucidated. Identifying these mechanisms is important because foetal exposure to environmental oestrogens 17433371is held responsible for the increasing incidence of male infertility and testicular cancer, which stem from impaired and excessive germ cell proliferation, respectively. Since several years, we have been investigating the role of oestrogens during germ cell proliferation using a human seminoma cell line, JKT-1 which express germ stem cell markers. Using JKT-1 cells, we showed that 17b-estradiol inhibits in vitro cell proliferation through an oestrogen receptor DMXB-A b-dependent mechanism. In contrast, under the above mentioned conditions, we also showed that E2 coupled to BSA, an impermeable E2 conjugate, stimulates in vitro JKT-1 cell proliferation by activating ERK1/2 and protein kinase A through a membrane GPCR unrelated to classical ERs. 1 ” Overexpression of GPR30 in Human Seminoma GPR30, an orphan GPCR, mediates the E2-induced proliferative effects in an ER-negative SKBr3 breast cancer cell line. It has recently been renamed as G protein-coupled oestrogen receptor . GPER is widely expressed in various cell types and cancer cell lines and is overexpressed in endometrial cancers, aggressive breast cancers and ovarian cancers. Although the actual physiological ligand of GPER remains unknown, we considered that it could be a good candidate for mediating the proliferative effect of E2-BSA and of some xeno-oestrogens such as bisphenol A, which are able in vitro to stimulate seminoma cell proliferation. We aimed to investigate GPER expression in normal and malignant human testicular germ cells and its ability to trigger in vitro seminoma cell proliferation. Materials and Methods Cell culture The JKT-1 ce
