Establishment and Genomic Characterization of Mouse Xenografts of Human Primary Prostate Tumors

Serum prostate-specific antigen screening has led to earlier detection and surgical treatment of prostate cancer, favoring an increasing incidence-to-mortality ratio. However, about one third of tumors that are diagnosed when still confined to the prostate can relapse within 10 years from the first treatment. The challenge is therefore to identify prognostic markers of aggressive versus indolent tumors. Although several preclinical models of advanced prostate tumors are available, a model that recapitulates the genetic and growth behavior of primary tumors is still lacking. Here, we report a complete histopathological and genomic characterization of xenografts derived from primary localized low- and high-grade human prostate tumors that were implanted under the renal capsule of immunodeficient mice. We obtained a tumor take of 56% and show that these xenografts maintained the histological as well as most genomic features of the parental tumors. Serum prostate-specific antigen levels were measurable only in tumor xenograft-bearing mice, but not in those implanted with either normal prostate tissue or in tumors that likely regressed. Finally, we show that a high proliferation rate, but not the pathological stage or the Gleason grade of the original tumor, was a fundamental prerequisite for tumor take in mice. This mouse xenograft model represents a useful preclinical model of primary prostate tumors for their biological characterization, biomarker discovery, and drug testing.Screening based on serum prostate-specific antigen (PSA) has led to earlier detection of prostate cancer (PCa) and to the possibility of excision of organ confined tumors by surgical treatment. However, about one third of tumors that are diagnosed when still confined to the prostate relapse within 10 years. The parameters used for risk classification and clinical decision-making include purely clinical and pathological features and are not sufficiently discriminatory. The challenge, therefore, is to identify those patients at risk for relapse after surgery as well as those with indolent tumors not requiring further intervention, especially in patients with intermediate risk of recurrence.^1,2,3 If primary tumors have embedded the indolent or the aggressive signature, molecular profiling should in theory identify these and help guide therapy. Unfortunately, tumors are often too small to perform thorough and comprehensive molecular analyses to arrive at these signatures, begging for a model that will allow expansion of the primary tumor while retaining its genetic characteristics.As a result, considerable efforts have been devoted to generate clinically relevant models of prostate tumors. Although a number of cell lines and in vivo models have been developed, to date, most are based on metastatic disease, and no model exists that is able to recapitulate human primary tumors.^4,5Available mouse models of PCa include both genetically engineered mice (GEM), in which one gene at a time is either overexpressed or knocked-out, and mouse xenografts, where usually human tumor cells are injected into the mouse by different techniques (ie, subcutaneous, orthotopic, intravenous, intracardiac injections).^6,7 Although a substantial number of preclinical studies are available, most of these do not show a good predictivity of drug response. In addition, prostate tumors developed in a genetically conditioned background (GEM) show histopathological features that differ somewhat from that of human cancers. These tumors are driven by single specific alterations, at least in their first phase of development, reflecting the complexity of human tumor biology only to a limited extent.^8,9 GEMs may therefore be ideal to screen compounds that target a particular molecular pathway, which is activated in this case by genetic manipulations. On the other hand, mouse models such as xenografts are able to recapitulate the histopathological and molecular heterogeneity of human cancer. These models are commonly generated by injecting established cell lines, because of the fact that freshly isolated primary cells rarely form tumors in immunodeficient mice.¹⁰ Unfortunately, genetic variability ensues in these established cancer cells over several passages while the risk of contamination from other commonly used cell lines is frequent. Importantly, established prostatic cancer cell lines are derived mostly from metastases, thus not recapitulating human primary prostate tumors.^4,5The ideal alternative would be to generate mouse xenografts of human primary tumor tissues. A debated theme is whether growth efficiency of human prostate tumors in the murine host can be improved. In fact, subcutaneous implantations of human localized prostate tumors in immunodeficient mice have been performed for many years with scarce results in terms of tumor take.^11,12Here we report our experience in generating xenografts by implanting a large cohort of fresh tumor tissue samples from radical prostatectomy specimens in mice with different immunodeficient status. We show that 56% of a cohort of human organ-confined prostate cancers with Gleason score (GS) comprised between 7 and 9 was able to grow in mice in the subrenal capsule site, whereas scarce or no success was achieved by both orthotopic and subcutaneous implantations.To our knowledge, this is the first in-depth characterization of a cohort of human prostate tumors and paired mouse xenografts. These results will be relevant when planning future in vivo studies on the use of human prostate tissues either for biological approaches, drug testing, or biomarker discovery.     

Vertebral artery dissection onset mimics migraine with aura in a graphic designer

Headache is the most common symptom in patients with cervical artery dissection. This symptom, however, rarely occurs in isolation, and more commonly is associated with other neurological symptoms and signs. Visual symptoms associated with vertebral artery dissection (VD) have also been observed, but do not typically mimic the migraine aura. Here, we report a young patient who presented VD, embolic ischemic lesions, and visual symptoms with the features of aura, followed by migraine headache. The suggestion of VD dissection should be kept in mind in those cases complaining of the first attack of headache that mimics migraine with aura. In these cases, an extensive neuroimaging study is advisable.     

β-Catenin is a useful adjunct immunohistochemical marker for the diagnosis of pulmonary lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare multisystem disease leading to cystic destruction of the lung parenchyma and is associated with abnormal smooth muscle proliferation affecting airways, lymphatics, and blood vessels. LAM occurs sporadically or in association with the tuberous sclerosis complex (TSC). Recent evidence demonstrates the role of aberrant β-catenin signaling in TSC. To further understand the pathogenesis of LAM and to examine the diagnostic usefulness of β-catenin, we examined protein expression in 28 pulmonary LAM cases and 10 cases of renal angiomyolipoma resected from patients with sporadic LAM. Immunohistochemical analysis was performed for established markers of LAM cells (HMB45, estrogen receptor [ER]-α, and progesterone receptor [PR]) and β-catenin. All LAM cases were positive for β-catenin and demonstrated high specificity with overall immunoreactivity superior to HMB45, ER-α, and PR. Similar expression was demonstrated in renal angiomyolipoma. Our results indicate that β-catenin is a useful marker of LAM and may be clinically useful in the diagnostic setting.     

Application of neuroendoscopy to intraventricular lesions

We present an overview of the history, development, technological advancements, current application, and future trends of cranial endoscopy. Neuroendoscopy provides a safe and effective management modality for the treatment of a variety of intracranial disorders, either tumoral or non-tumoral, congenital, developmental, and degenerative, and its knowledge, indications, and limits are fundamental for the armamentarium of the modern neurosurgeon.     

Molecular diagnostics and mitochondrial dysfunction: a future perspective

This review deals with the state of the art in knowledge about molecular diagnostics in mitochondrial diseases. A considerable development over the last years of several lines of biological, biochemical and biophysical investigation techniques has enormously enlarged the chance to obtain significant information by their application in the study of mitochondrial diseases in both in vivo and in vitro clinical applied research. The nosography of mitochondrial diseases is, therefore, day by day enriched by reports of new acquisitions that merge with the innovative contribution that novel laboratory and clinical investigative technologies add to the knowledge of the physiopathology and management of these complex diseases. Apart from the molecular genetic characterization of mitochondrial diseases, different experimental laboratory approaches have contributed, from a molecular point of view, to add new insights in this field of medicine. The strategies of these investigations can be targeted to detect and evaluate the significance of molecules that can play a relevant role in the determination of clinical phenotypes, making it possible to better understand several still unexplained mechanisms of cell damage.