The Role of microRNAs in the Gonocyte Theory as Target of Malignancy: Looking for Potential Diagnostic Biomarkers.

Some pediatric patients with cryptorchidism preserve cells with gonocyte characteristics beyond their differentiation period, which could support the theory of the gonocyte as a target for malignancy in the development of testicular neoplasia. One of the key molecules in gonocyte malignancy is represented by microRNAs (miRNAs). The goal of this review is to give an overview of miRNAs, a class of small non-coding RNAs that participate in the regulation of gene expression. We also aim to review the crucial role of several miRNAs that have been further described in the regulation of gonocyte differentiation to spermatogonia, which, when transformed, could give rise to germ cell neoplasia in situ, a precursor lesion to testicular germ cell tumors. Finally, the potential use of miRNAs as diagnostic and prognostic biomarkers in testicular neoplasia is addressed, due to their specificity and sensitivity compared to conventional markers, as well as their applications in therapeutics.

Neonatal exposure to monosodium glutamate induces morphological alterations in suprachiasmatic nucleus of adult rat.

Neonatal exposure to monosodium glutamate (MSG) induces circadian disorders in several physiological and behavioural processes regulated by the suprachiasmatic nucleus (SCN). The objective of this study was to evaluate the effects of neonatal exposure to MSG on locomotor activity, and on morphology, cellular density and expression of proteins, as evaluated by optical density (OD), of vasopressin (VP)-, vasoactive intestinal polypeptide (VIP)- and glial fibrillary acidic protein (GFAP)-immunoreactive cells in the SCN. Male Wistar rats were used: the MSG group was subcutaneously treated from 3 to 10 days of age with 3.5 mg/g/day. Locomotor activity was evaluated at 90 days of age using 'open-field' test, and the brains were processed for immunohistochemical studies. MSG exposure induced a significant decrease in locomotor activity. VP- and VIP-immunoreactive neuronal densities showed a significant decrease, while the somatic OD showed an increase. Major axes and somatic area were significantly increased in VIP neurons. The cellular and optical densities of GFAP-immunoreactive sections of SCN were significantly increased. These results demonstrated that newborn exposure to MSG induced morphological alterations in SCN cells, an alteration that could be the basis for behavioural disorders observed in the animals.

[Genotype-phenotype correlation in a sample of Mexican patients with cystic fibrosis]. / Correlación genotipo-fenotipo en una muestra de pacientes mexicanos con fibrosis quística.

INTRODUCTION: Cystic fibrosis is a lethal autosomal recessive disease, commonly seen in Caucasian population. The World Health Organization (WHO) estimated that in Mexico, the incidence is approximately 1 per 8,500 live births. Defects in CFTR (cystic fibrosis transmembrane conductance regulator) protein are responsible for alterations in the transport of chloride in the apical membrane of exocrine epithelial cells. This results to a lot of variability in the clinical manifestations, which range from a very serious disease that compromises the life of the patient, to only primary infertility due to absence of CBAVD. The study of the CFTR gene, responsible for this entity, has led to understand the correlation between the molecular defects in this gene and the clinical expression of the patients. Most reports show that only pancreatic function in CF patients directly correlated with genotype and not with other clinical features such as lung disease. OBJECTIVE: In this work we analyzed the genotype-phenotype correlation in a cohort of Mexican patients with CF. MATERIAL AND METHODS: We included 230 patients with CF, stratified based on the genotype and pancreatic disease. Both ratings were correlated with clinical parameters as in sweat chloride levels, lung disease, pancreatic insufficiency or sufficiency (IP and SP) and colonization by Pseudomonas aeruginosa (P. aeruginosa). RESULTS AND DISCUSSION: Our data suggest a strong correlation between the severity of mutations and pancreatic function. Related to this, significant differences were observed in sweat chloride levels, lung disease, colonization by P. aeruginosa, and the age of onset of symptoms, and diagnosis among patients with IP and SP (p < 0.001). The close correlation between IP, both with mutations that eliminate the function of CFTR gene, as with the presence of more serious clinical picture, suggests that IP could be used as an indicator of the severity of CF patients especially in those without characterized mutations yet.

Molecular Characterization of Patients with Cryptorchidism: Preliminary Search for an Expression Profile Related to That of Testicular Germ-Cell Tumors.

Cryptorchidism (CO) is a risk factor for the development of testicular germ-cell tumors (TGCT). This is supported by reports showing the persistence of gonocytes in CO patients. These cells are proposed to be related to the development of germ-cell neoplasia in situ (GCNIS), which is considered the precursor stage/lesion of TGCT. Therefore, it is proposed that some patients with CO could express some molecular markers related to TGCT. In this study, we analyzed testicular tissue samples from CO, TGCT, and controls. We determined the expression of POU5F1, PLAP, and KIT by immunohistochemistry and that of the hsa-miR-371-373 cluster, hsa-miR-367, and LATS2, PTEN, and IGFR1 genes by RT-qPCR. We then carried out a bioinformatic analysis to identify other possible candidate genes as tumor biomarkers. We found that 16.7% (2/12) of the CO patients presented increased expression of POU5F1, KIT, PLAP, hsa-miR-371-373, and hsa-miR-367 and decreased expression of LATS2 and IGF1R. Finally, the genes ARID4B, GALNT3, and KPNA6 were identified as other possible candidate tumor biomarkers. This is the first report describing the expression of the hsa-miR-371-373 cluster, hsa-miR-367, LATS2, and IGF1R in the testicular tissues of two CO patients with cells immune-positive to POU5F1, PLAP, and KIT, which is similar to what is observed in TGCT.

Alterations induced by chronic lead exposure on the cells of circadian pacemaker of developing rats.

Lead (Pb) exposure alters the temporal organization of several physiological and behavioural processes in which the suprachiasmatic nucleus (SCN) of the hypothalamus plays a fundamental role. In this study, we evaluated the effects of chronic early Pb exposure (CePbe) on the morphology, cellular density and relative optical density (OD) in the cells of the SCN of male rats. Female Wistar rats were exposed during gestation and lactation to a Pb solution containing 320 ppm of Pb acetate through drinking water. After weaning, the pups were maintained with the same drinking water until sacrificed at 90 days of age. Pb levels in the blood, hypothalamus, hippocampus and prefrontal cortex were significantly increased in the experimental group. Chronic early Pb exposure induced a significant increase in the minor and major axes and somatic area of vasoactive intestinal polypeptide (VIP)- and vasopressin (VP)-immunoreactive neurons. The density of VIP-, VP- and glial fibrillary acidic protein (GFAP)-immunoreactive cells showed a significant decrease in the experimental group. OD analysis showed a significant increase in VIP neurons of the experimental group. The results showed that CePbe induced alterations in the cells of the SCN, as evidenced by modifications in soma morphology, cellular density and OD in circadian pacemaker cells. These findings provide a morphological and cellular basis for deficits in circadian rhythms documented in Pb-exposed animals.

Protective effect of α-tocopherol on damage to rat testes by experimental cryptorchidism.

It is thought that the degeneration of germ cells associated with an increase in the temperature due to cryptorchidism involves oxidative stress. α-Tocopherol is a powerful antioxidant that prevents oxidation of polyunsaturated fats found in membranes and stabilizes peroxyl radicals. For this reason we were interested in determining the role of α-Tocopherol using experimental cryptorchidism, followed by orchidopexia in neonatal rats. Eighty-four, 10-day-postpartum (dpp) male rats (Wistar strain) were used and divided into 7 groups: healthy control, sham with α-Tocopherol treated with 30 or 100 mg/kg doses, sham vehicle, cryptorchidism treated with α-Tocopherol at 30 or 100 mg/kg doses and cryptorchidism vehicle. Cryptorchidism was surgically induced at 10 dpp. At 25 dpp the animals were treated with α-Tocopherol and the vitamin vehicle. Lipoperoxidation and testicular morphology was determined in half of the animals at 40 dpp (short term). The remaining animals underwent orchidopexia and fertility was determined at 90 dpp. Testicular morphology was determined at 120 dpp (long term) in these animals. A significant reduction of lipoperoxidation was observed in the cryptorchid group treated with α-Tocopherol compared to the untreated cryptorchid group, in addition to short-term histological alterations. At long term, we observed an increase in the area and maturation of the seminiferous epithelium, a decrease in apoptosis and histological alterations and an increase in fertility from α-Tocopherol treatment. α-Tocopherol treatment decreased lipoperoxidation, possibly stabilizing free radicals produced during cryptorchidism, reducing morphological testicular alterations and favoring fertility.

Prenatal diagnosis in a cystic fibrosis family: a combined molecular strategy for a precise diagnosis.

INTRODUCTION: The high genetic heterogeneity in populations with a wide spectrum of mutations in the CF transmembrane conductance regulator gene (CFTR), makes the detection of mutations a very hard and difficult task, thereby limiting the accurate diagnosis of the disease, mainly in patients with uncharacterized mutations. MATERIAL AND METHODS: Molecular strategies, like targeted identification of the most frequent CFTR mutations in Mexican population combined with linkage analysis using markers, is very useful for carrier detection and for prenatal diagnosis in affected families with CF. In this paper we show that the combination of methodologies was a crucial alternative to reach a precise prenatal CF diagnosis. We documented CF diagnosis in a 14th-week fetus combining the screening of the most common mutations in Mexican population with linkage analysis of two extragenic polymorphisms (XV2C/TaqI and KM19/PstI). RESULTS: We determined that the fetus inherited the PG542X mutation from its mother and an unknown mutation from its father through the chromosomal phases analysis.

Analysis of the CAG tract length in the Androgen Receptor gene in Mexican patients with nonsyndromic cryptorchidism.

OBJECTIVES: Cryptorchidism is the most common genitourinary birth defect in live newborn males and is considered as an important risk factor for testicular germ cell tumors and infertility. The Androgen Receptor gene is important in this pathology due to its participation, mainly, in the inguinoscrotal phase of testicular descent. We determine the length of the CAG tract in the Androgen Receptor (AR) gene in Mexican patients with nonsyndromic cryptorchidism. METHODS: One hundred and 15 males were included; of these, 62 had nonsyndromic cryptorchidism and 53 were healthy volunteers. DNA was extracted from a peripheral blood samples, subsequently, the CAG tract in exon 1 of AR gene was amplified by PCR and sequenced. RESULTS: Mexican patients with nonsyndromic cryptorchidism presented 25.03 ± 2.58 repeats of CAG tract in the AR gene compared to 22.72 ± 3.17 repeats of CAG tract in Mexican healthy individuals (p≤0.0001; t value of 4.3). Furthermore, the deletion of codon 57 that corresponds to the deletion of a leucine residue at position 57 (Del L57) in the AR gene was found for the first time in a nonsyndromic cryptorchidism patient. This molecular alteration has been related previously to testicular germ cell tumor (TGCT). CONCLUSIONS: The CAG tract in the AR gene is longer in patients with nonsyndromic cryptorchidism than in healthy individuals, supporting the association between this polymorphism of the AR gene and nonsyndromic cryptorchidism in the Mexican population.

Deciphering the epigenetic network in cancer radioresistance.

Radiotherapy, in addition to surgery and systemic chemotherapy, remains the core of the current clinical management of cancer. Radioresistance is one of the major causes of disease progression and mortality in cancer; therefore, it is a significant challenge in the treatment of locally advanced, recurrent and metastatic cancer. Epigenetic mechanisms that control hallmarks of cancer have a key role in the development of radiation resistance of cancer cells. Recent advances in DNA methylation, histone modification, chromatin remodeling and non-coding RNAs identified in the control of signal transduction pathways in cancer and cancer stem cells have provided even greater promise in the improvement of understanding cancer radioresistance. Many epigenetic drugs that target epigenetic enzymes revert the radioresistant phenotypes decreasing the possibility that resistant cancer cells will develop refractory tumors to radiotherapy. Epigenetic profiles identified as regulators of DNA damage repair, hypoxia, cell survival, apoptosis and invasion are determinants in the development of tumor radioresistance; hence, they also are promising in personalized medicine to develop novel targeted therapies or biomarkers to follow-up the effectiveness of radiotherapy. Now, it is clear that radiotherapy can influence a complex epigenetic network for transcriptional reprogramming, enabling the cells to adapt and avoid the effect of radiotherapy. This review aims to highlight the epigenetic modifications identified in cancer radioresistance and to discuss approaches to disable epigenetic networks to increase the sensitivity and specificity of radiotherapy.

Chronic lead exposure alters photic entrainment of locomotor activity rhythm and neuronal photoactivation in the suprachiasmatic nucleus of the adult rat.

Chronic lead (Pb) exposure affects the circadian physiological processes regulated by suprachiasmatic nucleus (SCN), which is synchronized (entrainment) by light. Disorders in the entrainment capacity of an organism alter its performance to interact with the environment, thus affecting its health status. The objectives of the present study were to evaluate whether chronic early Pb exposure affects the entrainment of the circadian rhythm of locomotor activity by light and to explore the possible mechanisms involved. Adult male Wistar rats, control and chronically exposed to Pb (320 ppm) in drinking water from gestation to adult age, were used. Assessment of the metal level showed a significant increase of Pb in the blood, hypothalamus and prefrontal cortex of the experimental rats. Continuous registrations of locomotor activity (12 h:12 h light-dark cycle) depicted that Pb induces important delay of this activity when the light was turned off. The Pb exposed animals entrained faster with a photoperiod delay of 6 h, (lights on at 13:00 h), and maintained the significant delay in the onset of activity at lights out. In continuous darkness, the animals were exposed to a light pulse at circadian time 23. This resulted in a significant decrease of photo-stimulated neurons (immunoreactivity to c-Fos) in the SCN of the metal-exposed animals. These results show that chronic early Pb exposure alters the photic entrainment of the rhythm of locomotor activity, which is evidenced by a significant decrease in both the number of photo-stimulated neurons and neuronal population (Nissl stain) of the SCN.

Disorders in the function of Sertoli cells and arrest in the differentiation of gonocytes in patients with cryptochidism and microlithiasis.

PURPOSE: This study aimed to correlate the presence of microlithiasis (ML) in cryptorchidism (CO) patients with the functionality of Sertoli cells and the arrest of gonocyte differentiation. METHODS: Testicular biopsies were obtained from 21 inguinal CO pediatric patients and were classified in two groups as follows: patients with ML and those without ML. In both groups, the number of Sertoli cells/seminiferous cords and their functionality were determined, considering the concentrations of inhibin B. In addition, the area and the histological alterations of seminiferous epithelium were evaluated. The arrest of gonocyte differentiation was determined by immunoreactivity to SALL4, AP2É£, PLAP and POU5F1. RESULTS: We found a statistical correlation between the presence of ML with the alterations in the functionality of Sertoli cells without reflecting in the differentiation of the gonocytes. CONCLUSION: The study of this population suggests that the association between CO and ML shows a malfunction of the Sertoli cells without necessarily causing arrest in the differentiation of gonocytes in these patients.

CFTR allelic heterogeneity in Mexican patients with cystic fibrosis: implications for molecular screening.

INTRODUCTION: Cystic fibrosis, the most common autosomal recessive disorder, is caused by defects in the CF transmembrane conductance regulator gene (CFTR) that encodes a chloride channel. To date, over 1,800 mutations have been described related to the causative gene of CF, showing a variable frequency among populations. In a previous extensive analysis of the CFTR locus in 97 Mexican patients, 34 different mutations (75% of CF alleles) were found using several strategies for mutation screening; however, 63% had at least an uncharacterized allele. Despite the combined technologies used, there are still a great number of unknown mutations in the Mexican population. OBJECTIVE: Screening of the CFTR gene to provide additional evidence of the mutational wide spectrum responsible for CF in Mexican patients. MATERIAL AND METHODS: In this study, the number of unrelated CF patients was increased to 230, 133 new cases and the 97 previously reported to include 63% with at least an uncharacterized allele. Additional tools were used to improve the detection rate of CF mutations, such as a commercial kit for 36 mutations plus a single chain conformational polymorphism method and DNA sequencing. RESULTS: By using a combination of these strategies we characterized 77.7% of all the CF alleles, resulting in a total of 46 different mutations detected, including the identification of 12 additional mutations (p.R334W, p.A455E, c.3120+1G > A, c.3272-26A > G, c.711+1G > T, p.Q552X, p.W1282X, c.IVS8-5T, p.R1162X and p.R347P, p.D1152H and p.T1036N). Although these 12 mutations have been reported in other populations, they have not yet been reported in Mexican patients. This report shows that Mexico has one of the widest spectra of CFTR mutations worldwide. The knowledge of the ethnic and geographic distribution of CFTR mutations in this population will allow the development of more effective methods for diagnosis and treatment.

Indolaminergic System in Adult Rat Testes: Evidence for a Local Serotonin System.

Serotonin (5-HT) is member of a family of indolamine molecules that participate in a wide variety of biological processes. Despite its important role in the regulation of local blood systems, little is known about the physiological function of 5-HT in reproductive organs, its functional implications, and its role in the reproduction of mammals. In the present work, we evaluated the localization and distribution of 5-HT (using histochemical analysis of indolamines) and different components of the serotoninergic system in rat testes. We detected local synthesis and degradation through immunofluorescence and western blot analyses against the TPH1, MAOA, 5-HTT, and VMAT1 serotonin transporters. We also identified the localization and distribution of the 5-HT1B, 5-HT2A, and 5-HT3A receptors. RT-PCR results showed the presence of the Tph1, Maoa, Slc6a4, and Htr3a genes in testes and in the brain stem (Tph1 was used as a negative control). High-performance liquid chromatography was used to determine the presence of 5-HT and the activity of tryptophan hydroxylase in testes homogenates in vitro. Our observations suggest that TPH1 activity and local 5-HT synthesis befall in rat testes. We propose that 5-HT could participate in the regulation of testosterone synthesis and in the spermatogenesis process via local serotoninergic system. However, more studies are needed before concluding that rat testes, or those of other mammals, contain an active form of tryptophan hydroxylase and produce 5-HT.

Cryptorchidism and Testicular Tumor: Comprehensive Analysis of Common Clinical Features and Search of SNVs in the KIT and AR Genes.

Allelic variants in genes implicated in the development of testicular germ cell tumor (TGCT) could be present in patients with cryptorchidism (CO). Currently; the mechanisms explaining this relationship are still unknown. In this study the common clinical features in patients with CO and TGCT and 6 variants of KIT and AR genes associated to TGCT were analyzed. Population analyzed included 328 individuals: 91 patients with CO; 79 with TGCT, 13 of them with previous CO diagnosis, and 158 healthy males. Of the 13 patients with TGCT and history of CO, one patient (7.7%) presented the heterozygous form of the variant rs121913507 and two patients (15.4%) presented homozygote genotype for the variant rs121913506 in KIT gene. Interestingly, the heterozygous form for the variant rs121913506 of KIT gene was identifying in all of 13 patients. The rs201934623, rs774171864, and rs12014709 variants of the AR gene did not show any clinical association. Our results strongly support that genetic component in CO could be conditioning for the development of TGCT. Notably, KIT gene variants might be determinants in the pathological association between TGCT and CO.

New insights into radioresistance in breast cancer identify a dual function of miR-122 as a tumor suppressor and oncomiR.

Radioresistance of tumor cells gives rise to local recurrence and disease progression in many patients. MicroRNAs (miRNAs) are master regulators of gene expression that control oncogenic pathways to modulate the radiotherapy response of cells. In the present study, differential expression profiling assays identified 16 deregulated miRNAs in acquired radioresistant breast cancer cells, of which miR-122 was observed to be up-regulated. Functional analysis revealed that miR-122 has a role as a tumor suppressor in parental cells by decreasing survival and promoting radiosensitivity. However, in radioresistant cells, miR-122 functions as an oncomiR by promoting survival. The transcriptomic landscape resulting from knockdown of miR-122 in radioresistant cells showed modulation of the ZNF611, ZNF304, RIPK1, HRAS, DUSP8 and TNFRSF21 genes. Moreover, miR-122 and the set of affected genes were prognostic factors in breast cancer patients treated with radiotherapy. Our data indicate that up-regulation of miR-122 promotes cell survival in acquired radioresistant breast cancer and also suggest that miR-122 differentially controls the response to radiotherapy by a dual function as a tumor suppressor an and oncomiR dependent on cell phenotype.

Epigallocatechin-3-gallate protects the testis from damage generated by experimental cryptorchidism in rabbits.

Cryptorchidism (CO) is a risk factor for infertility in men. It is associated with an increase in oxidative stress which alters the differentiation of the gonocytes to spermatogonia. Epigallocatechin-3-gallate (EGCG) is an antioxidant that acts as a free radical scavenger and activates the antioxidant enzymes. The aim of this work was to investigate if EGCG plays a role in the protection of the testicle from alterations generated by CO and its possible mechanism. Male rabbits 7 days old were divided into four groups and distributed as follows: 1) control (C) treated with EGCG vehicle (V) (C/V); 2) C with administration of EGCG from 65 to 120 days postpartum (dpp) (C/EGCG); 3) CO induced by administration of 17ß-estradiol plus EGCG vehicle (CO/V) and 4) CO plus EGCG administration (CO/EGCG). The animals were euthanized at 120 dpp and their testes were processed to evaluate lipid peroxidation, activities of superoxide dismutase (SOD) and catalase (CAT) enzymes as well as serum testosterone (T) concentrations. In addition, the rates of apoptosis, cell proliferation and histological alterations were determined. The CO/EGCG group showed a significant reduction in lipid peroxidation, a significant increase in the anti-oxidant enzyme activities and concentrations of T. Also, there was a significant decrease in the histological alterations, absence of gonocytes and active spermatogenesis when compared with CO/V group. These results show that EGCG reduces lipid peroxidation and increases the activity of the endogenous anti-oxidant system which protects the testes from alterations produced by oxidative stress generated during experimental CO.

Influence of SNPs in Genes that Modulate Lung Disease Severity in a Group of Mexican Patients with Cystic Fibrosis.

BACKGROUND: The variation in cystic fibrosis (CF) lung disease not always is explained by the CFTR genotype, so it has become apparent that modifier genes must play a considerable role in the phenotypic heterogeneity of CF, so we investigated the association of allelic variants in modifier genes that modulate the severity of lung function in a group of Mexican patients diagnosed with CF. METHODS: We included 140 CF patients classified according to lung phenotype and analyzed 17 single nucleotide polymorphisms (SNPs) by TaqMan® allelic discrimination. RESULTS: We demonstrated that patients with GG or GC genotype of the allelic variant rs11003125 (MBL2-550) of the MBL2 gene exhibit most of the lung manifestations at an earlier age; and the rs1042713 allelic variant of ADRB2 gene, showed statistical difference only with the age of first spirometry. When we used the dominant model, the MBL2 allele rs11003125 (MBL2-550; p = 0.022, Odds Ratio (OR) 2.87, 95% CI 1.14-7.27) was significantly associated with CF patients as risk factor, and the ADRB2 allele rs1042713 (p.Arg16Gly; p = 0.005, Odds Ratio (OR) 0.37, 95% CI 0.19-0.75) was significantly associated with CF patients as protect factor. CONCLUSIONS: Our findings suggest that the MBL2 and ADRB2 genes exerts an important genetic influence on the lung disease in our patients. Taking into account our results, we insist on not leaving aside this type of studies, since having techniques such as GWAS or WES will be able to advance in achieving a better quality of life for CF patients with severe lung disease.

Epigenetic and risk factors of testicular germ cell tumors: a brief review.

Testicular germ cell cancer (TGCT) is the most common malignancy among young adult males, which has become important due to its increased incidence and mortality in the population worldwide. The etiology is multifactorial. Recent studies have shown some associations between the development of isolated TGCT and certain risk factors, such as exposure to endocrine disruptors, cryptorchidism, and family history of cancer, in order to identify the key pieces in carcinogenesis. Some of the most important findings in recent years is the association of different genes, such as c-KIT/KITLG, expression of the miR-371-373 cluster and protein expression as c-KIT and POU5F1 in the development of this neoplasia, and the identification of new molecular markers as TGFBR3 gene, identifying aberrant methylation patterns in promoter regions of several genes, expression of miR-1297 which regulates PTEN and protein expression as DMTR1. In the future, a multidisciplinary research strategy could provide valuable new insights into the etiology of TGCTs, which support clinical diagnosis of TGCT in the next years to increase survival in this kind of patients.

Development of germ cell neoplasia in situ in chinchilla rabbits.

The present study was designed to describe the development of germ cell neoplasia in situ in Chinchilla rabbit by administration of estradiol. The study was performed in rabbits distributed into two groups: control and 17 ß-estradiol. The determination of histological alterations and POU5F1 and c-kit proteins employed as biomarkers for the diagnosis of this neoplasia was carried out. Testicular descent and complete spermatogenesis were observed in the control group. The protein biomarkers were negative. However, in the rabbits treated with estradiol, the testes remained undescended with the gonocytes undifferentiated to spermatogonia. There were histological lesions owing to germ cell neoplasia in situ and positive to POU5F1 and c-kit proteins. These findings indicate that the chinchilla rabbit is an ideal model to study this neoplasia in which the histological characteristics and biomarkers of the disease could be clearly observed. Using this model we suggested that the persisting gonocytes could be responsible for the development of germ cell neoplasia in situ.