MicroRNA-509-3p inhibits cancer cell proliferation and migration by targeting the mitogen-activated protein kinase kinase kinase 8 oncogene in renal cell carcinoma.

microRNAs (miRNAs; miR) are a class of small non-coding RNA molecules, which are involved in the pathogenesis of human diseases through the negative regulation of gene expression. Previous studies have demonstrated that miR-509-3p is a novel miRNA associated with cell proliferation and migration in 786-O renal cell carcinoma (RCC) cells. However, the mechanism of action of miR-509-3p in RCC remains to be elucidated. The present study aimed to examine the functional role and mechanism of miR-509-3p in the development of RCC. The results demonstrated that the expression levels of miR-509-3p were downregulated in the 786-O and ACHN RCC cell lines compared with the normal tissues of 10 patients with RCC, as determined by reverse transcription-quantitative polymerase chain reaction. The mRNA expression levels of mitogen-activated protein kinase kinase kinase 8 (MAP3K8) were upregulated in the RCC cell lines. Functional investigations demonstrated that the overexpression of miR-509-3p inhibited the migration and proliferation of the RCC cells, as determined by wound scratch and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Luciferase reporter assays revealed that the overexpression of miR-509-3p reduced the transcriptional activity of MAP3K8. Furthermore, the present study demonstrated that the ectopic transfection of miR-509-3p led to a significant reduction in the mRNA and protein expression levels of MAP3K8 in the RCC cells. Finally, knockdown of MAP3K8 inhibited the migration and proliferation of the RCC cells. Therefore, the results of the present study demonstrated that the miR-509-3p RCC suppressor was a significant regulator of the MAP3K8 oncogene, suggesting that it may have a potential therapeutic role in the treatment of RCC.

microRNA-184 functions as tumor suppressor in renal cell carcinoma.

microRNAs (miRNAs) are evolutionarily conserved, endogenous, small, noncoding RNA molecules of approximately 22 nucleotides in length that function as post-transcriptional gene regulators. Their aberrant expression may be involved in human diseases, including cancer. Although miRNA-184 (miR-184) has been reported in other tumors, its function in renal cell carcinoma (RCC) is still unknown. The aim of the present study was to investigate the role of miR-184 in RCC. The impacts of miR-184 on cell migration, proliferation and apoptosis were evaluated using migration scratch, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assay. Our studies revealed that miR-184 mimic significantly inhibits cell migration, suppresses cell proliferation and induces renal cancer cell apoptosis in vitro when compared with the negative control (P<0.05). In this study, it was observed that miR-184 played a significant role as a tumor suppressor in RCC. Therefore, miR-184 may be a promising therapeutic target for renal cancer treatment in the future.

MicroRNA-451a is associated with cell proliferation, migration and apoptosis in renal cell carcinoma.

MicroRNAs (miRNAs) are an important class of small, non­coding RNA molecules that regulate gene expression at the transcriptional or post­transcriptional level. They are involved in apoptosis, proliferation and migration and are known to have an important role in many types of cancer. Aberrant expression of miRNA­451a (miR­451a) has previously been reported in tumors, however its role in renal cell carcinoma (RCC) is currently unknown. The aim of the present study was to investigate the role of miR­451a in RCC. The expression of miR­451a was analyzed in 50 paired RCC and normal tissues by quantitative polymerase chain reaction. Furthermore, the effects of miR­451a on cell migration, proliferation and apoptosis were evaluated, using migration scratch, MTT and flow cytometric assays. The present study demonstrated that miR­451a was upregulated in RCC, as compared with paired normal tissues (P<0.05). Downregulation of miR­451a using a synthesized inhibitor, significantly suppressed cell migration and proliferation, and induced apoptosis of renal cancer cells in vitro, as compared with a negative control (P<0.05). In the present study, it was determined that miR­451a may have an important role as a tumor enhancer in RCC. These results imply that miR­451a may be a promising therapeutic target for the treatment of RCC.

Bizarre leiomyoma of the scrotum: A case report and review of the literature.

Bizarre leiomyomas of the scrotum are rare benign tumors that are often misdiagnosed. In this study, we present a case of bizarre leiomyoma of the scrotum in a 53-year-old male. The patient presented with a painless scrotal mass that was insidious in the right side of the scrotum with no sudden increase in size. Definitive preoperative diagnosis could not be established; however, following surgical resection of the tumor, a diagnosis of bizarre leiomyoma of the scrotum was determined by pathological examination. The patient was followed up six months following resection and no problems were reported. This is the first reported case of bizarre leiomyoma of the scrotum in China. A supplementary review of previously published cases and literature is also presented.

Identification of Ube2b as a novel target of androgen receptor in mouse sertoli cells.

Many genes are regulated by androgen and its receptor (AR), but the direct target genes of AR, especially those involved in spermatogenesis and male infertility, remain unclear. Here, we identified ubiquitin-conjugating enzyme E2B (Ube2b) as a critical target gene of AR. The expression of UBE2B was decreased in the testes of Sertoli cell AR knockout (S-AR(-/y)) mice analyzed by quantitative RT-PCR (qRT-PCR) and immunofluorescence. The upregulation of Ube2b gene by testosterone was further demonstrated by Western blot and qRT-PCR in TM4 cells, a mouse Sertoli cell line. Moreover, luciferase assay, electrophoretic mobility shift assay, and chromatin immunoprecipitation assay validated that the ligand-bound AR activated Ube2b transcription via direct binding to the androgen-responsive element of the Ube2b promoter. In vitro analyses showed that testosterone increased UBE2B expression and activated H2A ubiquitylation, while downregulation of UBE2B blocked the testosterone-induced H2A ubiquitylation. The ubiquitylation of H2A was markedly decreased in the testes of S-AR(-/y) mice by immunohistochemistry. Digital gene expression analysis showed that 113 genes were significantly downregulated and 71 were upregulated by UBE2B in TM4 cells. These results suggest that Ube2b, as a direct AR transcriptional target in Sertoli cells, mediates the function of AR in spermatogenesis by promoting H2A ubiquitylation.

Identification of miR-7 as an oncogene in renal cell carcinoma.

MicroRNA-7 (miR-7) has been described as a tumor suppressor in several human cancers, but the results of a study to identify miRNAs associated with metastatic capability in breast cancer suggested that miR-7 may be characterized as an oncogene. The present study was to determine the expression and function of miR-7 in renal cell carcinoma. Quantitative real-time polymerase chain reaction was used to validate the expressions of miR-7 in 48 paired renal cell carcinomas (RCC) and normal tissues, based on the preliminary sequencing results of miRNAs. Furthermore, the impacts of miR-7 on cell migration, proliferation and apoptosis were analyzed using wound scratch assay, MTT and flow cytometry, respectively. The results demonstrated that miR-7 was up-regulated in RCC compared with normal tissues (p = 0.001). Down-regulation of miR-7 with synthesized inhibitor inhibited cell migration in vitro, suppressed cell proliferation and induced renal cancer cell apoptosis, prompting that miR-7 could be characterized as an oncogene in RCC. The present study was the first to reveal that miR-7 was up-regulated in RCC and it played an important role in RCC by affecting cellular migration, proliferation and apoptosis. Further researches should be conducted to explore the roles and target genes of miR-7 in RCC and other cancers.

TGF-ß-activated kinase-1: a potential prognostic marker for clear cell renal cell carcinoma.

BACKGROUND: TGF-ß-activated kinase-1 (TAK1) has been found to be over-expressed in a variety of solid malignancies and related to tumor growth. The aim of this study was to evaluate the expression level of TAK1 in clear cell renal cell carcinoma (ccRCC) and assess its value as a novel prognostic marker. METHODS: TAK1 mRNA was assessed in 51 paired ccRCC tissues and adjacent normal tissues (ADTs) by real-time PCR. Tissue TAK1 protein was also assessed in 91 ADTs and 177 samples of ccRCC immunohistochemically for evaluation of relationships with clinical characteristics. RESULTS: RT-PCR showed that TAK1 RNA level was significantly higher in ccRCC tissues than in the paired ADTs and immunohistochemistry confirmed higher expression of TAK1 protein in ccRCC samples compared with ADTs. TAK1 protein expression in 177 ccRCC samples was significantly correlated with T stage, N classification, metastasis, recurrence and Fuhrman grade, but not age and gender. Patients with low TAK1 levels had a better survival outcome. TAK1 expression and N stage were independent prognosis factors for the overall survival of ccRCC patients. CONCLUSIONS: Overexpression of TAK1 predicts a poor prognosis in patients with ccRCC, so that TAK1 may serve as a novel prognostic marker.

High expression of FER tyrosine kinase predicts poor prognosis in clear cell renal cell carcinoma.

FER tyrosine kinase (FER) has been demonstrated to play a critical role in tumorigenesis and metastasis; however, its potential value as a novel prognostic marker for clear cell renal cell carcinoma (ccRCC) remains unclear. In 48 paired samples of ccRCCs and normal adjacent tissues (ADTs), real-time PCR was used to evaluate the expression of FER mRNA. The expression of FER protein was assessed in 87 ADTs and 206 samples of ccRCC using immunohistochemical methods. Statistical analysis was used to examine the correlations between the expression levels of FER and the clinical characteristics of ccRCC patients. A significant difference was identified between ccRCC tissues and ADTs in the mRNA levels of FER. Immunohistochemistry analyses revealed higher expression of FER protein in 87 ccRCC samples compared to the paired ADTs. In addition, FER protein expression in 206 ccRCC samples was significantly correlated with tumor size, T stage, N classification, metastasis, recurrence and Fuhrman grade, while associations with age and gender were not identifed. The Kaplan-Meier survival analysis showed that patients with high FER levels had a poorer survival outcome compared with those with lower levels. The log-rank test demonstrated that the cumulative survival rates were significantly different between the two groups. The Cox regression analysis indicated that FER expression, N stage and distant metastasis were independent prognostic factors for overall survival of ccRCC patients. Our results indicate that overexpression of FER in tumor tissues predicts a poor prognosis of patients with ccRCC, and FER may serve as a novel prognostic marker for ccRCC.

Identification of PCAG1 as a novel prostate cancer-associated gene.

The aim of the present study was to identify a new prostate cancer­associated gene and analyze its expression pattern. Comprehensive expression analysis of expressed sequence tags (ESTs) and microarray data and serial analysis of gene expression (SAGE) were conducted to screen in silico for candidate prostate cancer­associated genes. Reverse transcription (RT)-PCR was performed to validate prostate cancer specificity. Prostate cancer­associated gene 1 (PCAG1) was identified. The expression of PCAG1 mRNA and protein was evaluated in common human normal tissues, common malignant tumors, prostate adenocarcinoma and paired adjacent normal prostate tissues. An immunofluorescence assay was conducted to determine the subcellular location of PCAG1. PCAG1 mRNA was absent in the 15 pooled normal tissues (including normal prostate tissue) but registered at low levels in the spleen tissue (+). By contrast, PCAG1 mRNA was significantly higher than in the adjacent normal tissues in each of the 14 cases of prostate cancer, with ~50% scoring a high degree of expression (+++). Of the 32 types of normal tissues, 29 (including normal prostate tissue) demonstrated negative PCAG1 protein staining while the remaining tissues of the adrenal gland, parathyroid gland and liver expressed low levels. While 18/20 cases of prostate adenocarcinoma showed positive expression results, PCAG1 protein expression in the remaining types of cancer was scarce when present at all; only 41/380 other cancer cases demonstrated positive results at a low level. The most substantial PCAG1-positive expression results were identified by cytoplasmic staining in 36/38 prostate adenocarcinoma cases, with 10 cases showing high expression levels, 20 showing medium levels and 6 showing low levels. In the paired adjacent normal prostate tissues, only 3/38 cases showed low level positive staining, while 35/38 cases were negative. Immunofluorescent staining of the human prostate cancer PC3 cell line showed positive PCAG1 expression results in the mitochondria. The present study demonstrated that while PCAG1 mRNA was highly expressed in prostate cancer tissues, it was almost absent in all common normal tissues and paired adjacent normal prostate tissues. Furthermore, PCAG1 protein was also highly expressed in prostate cancer tissues, while few common normal tissues, other common malignant tumors and paired adjacent normal prostate tissues had even low levels of expression. Clarification of the function and transcriptional mechanism of PCAG1 may aid the elucidation of the mechanisms of carcinogenesis and progression of prostate cancer. The unique expression pattern of PCAG1 suggests its potential in certain clinical applications.

Sporadic renal haemangioblastoma: Case report and review of the literature.

Haemangioblastoma is a benign tumour which generally occurs in a relatively restricted area of the central nervous system. Renal haemangioblastoma are extremely rare. We report a rare case of renal haemangioblastoma occurring in a 61-year-old male with a solid mass, which was detected during a routine examination. The patient was asymptomatic and abdominal computed tomography (CT) revealed a solid mass in the right kidney. No definitive preoperative diagnosis could be established. Surgical resection of the tumour revealed sporadic renal haemangioblastoma by pathological examination. The patient was followed up at 1 year without any problems. We also present a supplementary review of previously published cases and literature.

A dominant-negative mutation of HSF2 associated with idiopathic azoospermia.

Idiopathic azoospermia (IA) is a severe form of male infertility due to unknown causes. The HSF2 gene, encoding the heat shock transcription factor 2, had been suggested to play a significant role in the spermatogenesis process since the Hsf2-knockout male mice showed spermatogenesis defects. To examine whether HSF2 is involved in the pathogenesis of IA in human, we sequenced all the exons of HSF2 in 766 patients diagnosed with IA and 521 proven fertile men. A number of coding mutations private to the patient group, which include three synonymous mutations and five missense mutations, were identified. Of the missense mutations, our functional assay demonstrated that one heterozygous mutation, R502H, caused a complete loss of HSF2 function and that the mutant suppressed the normal function of the wild-type (WT) allele through a dominant-negative effect, thus leading to the dominant penetrance of the mutant allele. These results support a role for HSF2 in the pathogenesis of IA and further implicate this transcription factor as a potential therapeutic target.

Ketamine-associated urinary tract dysfunction: an underrecognized clinical entity.

INTRODUCTION: The use of ketamine as a recreational drug is on the increase among young adults attending clubs and parties. Recreational ketamine users have anecdotally reported increased lower urinary tract symptoms while using the substance. METHODS: We describe the severe lower urinary tract symptoms experienced in 6 patients with chronic recreational ketamine use. We obtained a detailed history and physical examination along with further investigation to identify a relationship between recreational ketamine use and these symptoms. RESULTS: The urine cultures were sterile in all cases. Intravenous urography was performed in 3 patients and demonstrated bilateral upper ureteric narrow, mild bilateral hydronephrosis and contracted bladder urodynamic studies showed detrusor instability with urinary leakage when the bladder was filled to a capacity of 30- 50 ml. Cystoscopy revealed a small capacity bladder with erythematous lesions throughout the bladder. Bladder biopsies were performed in 3 patients and showed up as chronic cystitis. Ketamine cessation along with intravesical sodium hyaluronate solution appeared to provide some symptomatic relief. CONCLUSION: Ketamine-associated urinary tract dysfunction appears to be a relatively new clinical phenomenon. The pathological mechanism of ketamine-associated urinary tract dysfunction is unknown and current management strategies are ketamine cessation along with intravesical sodium hyaluronate solution.

Frequent mutations of chromatin remodeling genes in transitional cell carcinoma of the bladder.

Transitional cell carcinoma (TCC) is the most common type of bladder cancer. Here we sequenced the exomes of nine individuals with TCC and screened all the somatically mutated genes in a prevalence set of 88 additional individuals with TCC with different tumor stages and grades. In our study, we discovered a variety of genes previously unknown to be mutated in TCC. Notably, we identified genetic aberrations of the chromatin remodeling genes (UTX, MLL-MLL3, CREBBP-EP300, NCOR1, ARID1A and CHD6) in 59% of our 97 subjects with TCC. Of these genes, we showed UTX to be altered substantially more frequently in tumors of low stages and grades, highlighting its potential role in the classification and diagnosis of bladder cancer. Our results provide an overview of the genetic basis of TCC and suggest that aberration of chromatin regulation might be a hallmark of bladder cancer.

MicroRNA expression signatures of bladder cancer revealed by deep sequencing.

BACKGROUND: MicroRNAs (miRNAs) are a class of small noncoding RNAs that regulate gene expression. They are aberrantly expressed in many types of cancers. In this study, we determined the genome-wide miRNA profiles in bladder urothelial carcinoma by deep sequencing. METHODOLOGY/PRINCIPAL FINDINGS: We detected 656 differentially expressed known human miRNAs and miRNA antisense sequences (miRNA*s) in nine bladder urothelial carcinoma patients by deep sequencing. Many miRNAs and miRNA*s were significantly upregulated or downregulated in bladder urothelial carcinoma compared to matched histologically normal urothelium. hsa-miR-96 was the most significantly upregulated miRNA and hsa-miR-490-5p was the most significantly downregulated one. Upregulated miRNAs were more common than downregulated ones. The hsa-miR-183, hsa-miR-200b ∼ 429, hsa-miR-200c ∼ 141 and hsa-miR-17 ∼ 92 clusters were significantly upregulated. The hsa-miR-143 ∼ 145 cluster was significantly downregulated. hsa-miR-182, hsa-miR-183, hsa-miR-200a, hsa-miR-143 and hsa-miR-195 were evaluated by Real-Time qPCR in a total of fifty-one bladder urothelial carcinoma patients. They were aberrantly expressed in bladder urothelial carcinoma compared to matched histologically normal urothelium (p < 0.001 for each miRNA). CONCLUSIONS/SIGNIFICANCE: To date, this is the first study to determine genome-wide miRNA expression patterns in human bladder urothelial carcinoma by deep sequencing. We found that a collection of miRNAs were aberrantly expressed in bladder urothelial carcinoma compared to matched histologically normal urothelium, suggesting that they might play roles as oncogenes or tumor suppressors in the development and/or progression of this cancer. Our data provide novel insights into cancer biology.

Epigenetic inactivation of PCDH10 in human prostate cancer cell lines.

PCDH10 (protocadherin-10), a novel tumour suppressor gene, is down-regulated in several human cancers due to hypermethylation of promoter CGIs (CpG islands). Here, we investigated the expression of PCDH10 in different normal adult tissues and in a panel of prostate cancer cell lines. PCDH10 was widely expressed in normal tissues with higher levels in the prostate. The expression of PCDH10 was markedly reduced or silenced in prostate cancer cell lines compared with normal adult prostate tissue. Decreased PCDH10 expression was correlated with the methylation status of the PCDH10 promoter. Furthermore, the DNA demethylating agent 5'-azacytidin restored PCDH10 expression by suppressing PCDH10 promoter methylation in prostate cancer cell lines. Treatment with Trichostatin A alone had no significant effect on the expression of PCDH10 but enhanced the effect of 5'-azacytidin. In conclusion, we found that the decreased PCDH10 expression in prostate cancer cells was associated with the aberrant methylation of PCDH10 promoter CGI. Our results may contribute to the understanding of the role of PCDH10 inactivation in the progression of prostate cancers.

Identification and characterization of human PCDH10 gene promoter.

Recent studies have suggested roles for PCDH10 as a novel tumor suppressor gene. In our previous work, we located the core promoter of PCDH10 to a 462-bp segment of 5'-flanking region characterized by a high GC content. Here we further identified and characterized the promoter for PCDH10. Transient transfection of PC3 and LNCaP cells with a series of deleted promoter constructs indicated that the minimal promoter region was between nucleotides -144 and -99. This segment contained a CAAT box, a GT box, and a putative transcription factor binding site for AP-4. Mutational analysis identified that the CAAT box and GT box are necessary for promoter activity. Ectopic expression of NF-Ys increased reporter gene activity, whereas expression of a dominant-negative NF-YA decreased reporter gene activity. Co-transfection of Sp1/Sp3 expression plasmids enhanced reporter gene activity in a dose-dependent manner. Mithramycin A, an inhibitor of Sp-DNA interaction, reduced PCDH10 promoter activity. Electrophoretic mobility shift assays and chromatin immunoprecipitation demonstrated binding of transcription factors Sp1/Sp3 to the promoter region in vitro and in vivo. Our data show that Sp1/Sp3 and CBF/NF-Y transcription factors play a crucial role in the basal expression of the human PCDH10 gene.

UPK3A: a promising novel urinary marker for the detection of bladder cancer.

OBJECTIVES: Current methods for reliable detection of bladder cancer have some limitations. Finding better noninvasive methods for detection of bladder cancer is an important topic in urology. We want to evaluate prospectively the early detection power of human uroplakin 3 A (UPK3A) for bladder cancer. METHODS: Urine samples were obtained from 32 healthy volunteers, 44 patients with benign urological disorders and 122 patients with bladder cancer. The urine UPK3A levels were quantified by enzyme-linked immunosorbent assay. All the samples were also tested with NMP22 test and cytology examination. RESULTS: The urinary UPK3A levels are uniformly elevated in bladder cancer patients than in those of normal volunteers and patients with benign urological disorders, and the differences in the mean urinary UPK3A levels of bladder cancer patients and those of normal individuals or benign urological disorders are statistically significant (P <.01). The receiver operating characteristic (ROC) curve of UPK3A showed an excellent area under the ROC curve of 0.907. In this study, the optimal combination of sensitivity and specificity were determined as 83% and 83%, for a cut-off value of absorbance unit 0.0685, respectively. The sensitivity of urine UPK3A, NMP22, and cytology for detecting bladder cancer were 83%, 58%, and 64%, respectively, whereas specificity was 83%, 75%, and 82%, respectively. CONCLUSIONS: We conclude that individuals with bladder cancer have higher UPK3A values. Our data suggest that urine measurement of UPK3A is a sensitive marker for the detection of bladder cancer. However, it needs further studies in larger cohorts.

Integrated profiling of microRNAs and mRNAs: microRNAs located on Xq27.3 associate with clear cell renal cell carcinoma.

BACKGROUND: With the advent of second-generation sequencing, the expression of gene transcripts can be digitally measured with high accuracy. The purpose of this study was to systematically profile the expression of both mRNA and miRNA genes in clear cell renal cell carcinoma (ccRCC) using massively parallel sequencing technology. METHODOLOGY: The expression of mRNAs and miRNAs were analyzed in tumor tissues and matched normal adjacent tissues obtained from 10 ccRCC patients without distant metastases. In a prevalence screen, some of the most interesting results were validated in a large cohort of ccRCC patients. PRINCIPAL FINDINGS: A total of 404 miRNAs and 9,799 mRNAs were detected to be differentially expressed in the 10 ccRCC patients. We also identified 56 novel miRNA candidates in at least two samples. In addition to confirming that canonical cancer genes and miRNAs (including VEGFA, DUSP9 and ERBB4; miR-210, miR-184 and miR-206) play pivotal roles in ccRCC development, promising novel candidates (such as PNCK and miR-122) without previous annotation in ccRCC carcinogenesis were also discovered in this study. Pathways controlling cell fates (e.g., cell cycle and apoptosis pathways) and cell communication (e.g., focal adhesion and ECM-receptor interaction) were found to be significantly more likely to be disrupted in ccRCC. Additionally, the results of the prevalence screen revealed that the expression of a miRNA gene cluster located on Xq27.3 was consistently downregulated in at least 76.7% of ∼50 ccRCC patients. CONCLUSIONS: Our study provided a two-dimensional map of the mRNA and miRNA expression profiles of ccRCC using deep sequencing technology. Our results indicate that the phenotypic status of ccRCC is characterized by a loss of normal renal function, downregulation of metabolic genes, and upregulation of many signal transduction genes in key pathways. Furthermore, it can be concluded that downregulation of miRNA genes clustered on Xq27.3 is associated with ccRCC.

Development of neonatal mouse and fetal human testicular tissue as ectopic grafts in immunodeficient mice.

AIM: To investigate the stepwise development and germ cell gene expression in allografted neonatal mouse testes and the differentiation of immature human testicular cells in xenografted human testes. METHODS: Immunodeficient nude mice were used as hosts for allografting of neonatal mouse testes and xenografting of human fetal testicular tissues. Stepwise development and stage-specific gene expression of germ cells in allografts were systematically evaluated and parallel compared with those in intact mice by periodically monitoring the graft status with measurement of graft weight, histological analysis and determination of five stage-specific genes. Human testicular tissues from 20 and 26 weeks fetuses were used for the xenografting study. Histological analysis of xenografts was performed 116 and 135 d after the grafting procedure. RESULTS: In the allografting study, progressive increase in tissue volume and weight as well as in tubule diameter in grafts was observed; the appearance time of various germ cells in seminiferous tubules, including spermatogonia, spermatocytes, round and elongate spermatids and sperm, was comparable with that in intact donors; the initiation of gene transcription in grafts showed a similar trend as in normal mice. Graft weight ceased to increase after 7-8 weeks and degradation of grafts was observed after 5 weeks with progressive damage to seminiferous epithelium. In the xenografting study using immature human testicular tissues, graft survival and development was indicated by increasing graft weight, Sertoli cells differentiation into advanced stage, germ cells migration and location to the basal lamina and formation of a niche-like structure. CONCLUSION: The developmental course and gene expression pattern of germ cells in allografts were similar to those in intact mice. The best time point for retrieval of mouse sperm from grafts was 5-7 weeks after grafting procedure. An accelerated development of immature human testicular cells could be achieved by ectopic xenografting of human testes.