Consensus statement from the international consensus meeting on post-traumatic cranioplasty.

BACKGROUND: Due to the lack of high-quality evidence which has hindered the development of evidence-based guidelines, there is a need to provide general guidance on cranioplasty (CP) following traumatic brain injury (TBI), as well as identify areas of ongoing uncertainty via a consensus-based approach. METHODS: The international consensus meeting on post-traumatic CP was held during the International Conference on Recent Advances in Neurotraumatology (ICRAN), in Naples, Italy, in June 2018. This meeting was endorsed by the Neurotrauma Committee of the World Federation of Neurosurgical Societies (WFNS), the NIHR Global Health Research Group on Neurotrauma, and several other neurotrauma organizations. Discussions and voting were organized around 5 pre-specified themes: (1) indications and technique, (2) materials, (3) timing, (4) hydrocephalus, and (5) paediatric CP. RESULTS: The participants discussed published evidence on each topic and proposed consensus statements, which were subject to ratification using anonymous real-time voting. Statements required an agreement threshold of more than 70% for inclusion in the final recommendations. CONCLUSIONS: This document is the first set of practical consensus-based clinical recommendations on post-traumatic CP, focusing on timing, materials, complications, and surgical procedures. Future research directions are also presented.

Phase 2 trial of sunitinib and gemcitabine in patients with sarcomatoid and/or poor-risk metastatic renal cell carcinoma. Michaelson MD, McKay RR, Werner L, Atkins MB, Van Allen EM, Olivier KM, Song J, Signoretti S, McDermott DF, Choueiri TK.Cancer. 2015 Oct 1;121(19):3435-43. [Epub 2015 Jun 8]. doi: 10.1002/cncr.29503.

BACKGROUND: Sarcomatoid renal cell carcinoma (RCC) is associated with an aggressive biology and a poor prognosis. Poor-risk RCC is defined by clinical prognostic factors and demonstrates similarly aggressive behavior. No standard treatment exists for patients with sarcomatoid RCC, and treatment options for patients with poor-risk disease are of limited benefit. The objective of this study was to investigate the efficacy of antiangiogenic therapy in combination with cytotoxic chemotherapy in clinically aggressive RCC. METHODS: This was a phase 2, single-arm trial of sunitinib and gemcitabine in patients with sarcomatoid or poor-risk RCC. The primary end point was the objective response rate (ORR). Secondary end points included the time to progression (TTP), overall survival (OS), safety, and biomarker correlatives. RESULTS: Overall, 39 patients had sarcomatoid RCC, and 33 had poor-risk RCC. The ORR was 26% for patients with sarcomatoid RCC and 24% for patients with poor-risk RCC. The median TTP and OS for patients with sarcomatoid RCC were 5 and 10 months, respectively. For patients with poor-risk disease, the median TTP and OS were 5.5 and 15 months, respectively. Patients whose tumors had>10% sarcomatoid histology had a higher clinical benefit rate (ORR plus stable disease) than those with≤10% sarcomatoid histology (P = 0.04). The most common grade 3 or higher treatment-related adverse events included neutropenia (n = 20), anemia (n = 10), and fatigue (n = 7). CONCLUSIONS: These results suggest that antiangiogenic therapy and cytotoxic chemotherapy are an active and well-tolerated combination for patients with aggressive RCC. The combination may be more efficacious than either therapy alone and is currently under further investigation.

Transforming the Perioperative Treatment Paradigm in Non-Metastatic RCC-A Possible Path Forward.

In 2017, there is no adjuvant systemic therapy proven to increase overall survival in non-metastatic renal cell carcinoma (RCC). The anti-PD-1 antibody nivolumab improves overall survival in metastatic treatment refractory RCC and is generally tolerable. Mouse solid tumor models have revealed a benefit with a short course of neoadjuvant PD-1 blockade compared to adjuvant therapy. Two ongoing phase 2 studies of perioperative nivolumab in RCC patients have shown preliminary feasibility and safety with no surgical delays or complications. The recently opened PROSPER RCC trial (A Phase 3 RandOmized Study Comparing PERioperative Nivolumab vs. Observation in Patients with Localized Renal Cell Carcinoma Undergoing Nephrectomy; EA8143) will examine if the addition of perioperative nivolumab to radical or partial nephrectomy can improve clinical outcomes in patients with high risk localized and locally advanced RCC. With the goal of increasing cure and recurrence-free survival (RFS) rates in non-metastatic RCC, we are executing a three-pronged, multidisciplinary approach of presurgical priming with nivolumab followed by resection and adjuvant PD-1 blockade. We plan to enroll 766 patients with clinical stage ≥T2 or node positive M0 RCC of any histology in this global, randomized, unblinded, phase 3 National Clinical Trials Network study. The investigational arm will receive two doses of nivolumab 240 mg IV prior to surgery followed by adjuvant nivolumab for 9 months. The control arm will undergo the current standard of care: surgical resection followed by observation. Patients are stratified by clinical T stage, node positivity, and histology. The trial is powered to detect a 14.4% absolute benefit in the primary endpoint of RFS from the ASSURE historical control of 55.8% to 70.2% at 5 years (HR = 0.70). The study is also powered to detect a significant overall survival benefit (HR 0.67). Key safety, feasibility, and quality of life endpoints are incorporated. PROSPER RCC exemplifies team science with a host of planned correlative work to investigate the impact of the baseline immune milieu and changes after neoadjuvant priming on clinical outcomes.

Association of PD-L1 expression on tumor-infiltrating mononuclear cells and overall survival in patients with urothelial carcinoma.

BACKGROUND: Programmed death-1 (PD-1) receptor/PD-1 ligand (PD-L1) pathway negatively regulates T-cell-mediated responses. The prognostic impact of PD-L1 expression needs to be defined in urothelial carcinoma (UC). PATIENTS AND METHODS: Formalin-fixed paraffin-embedded tumor samples from 160 patients with UC were retrieved. PD-L1 expression was evaluated by immunohistochemistry using a mouse monoclonal anti-PD-L1 antibody (405.9A11). PD-L1 positivity on tumor cell membrane was defined as ≥5% of tumor cell membrane staining. The extent of tumor-infiltrating mononuclear cells (TIMCs) as well as PD-L1 expression on TIMCs was scored from 0 to 4. A score of 2, 3, or 4 was considered PD-L1-positive. Clinico-pathological variables were documented. The Cox regression model was used to assess the association of PD-L1 expression with overall survival (OS) in patients who developed metastases. RESULTS: TIMCs were present in 143 of the 160 patient samples. Out of 160 samples, 32 (20%) had positive PD-L1 expression in tumor cell membrane. Out of 143 samples with TIMCs, 58 (40%) had positive PD-L1 expression in TIMCs. Smoking history, prior BCG use and chromosome 9 loss did not correlate with PD-L1 expression in either tumor cell membrane or TIMCs. PD-L1 positivity was not different between non-invasive or invasive UC. In patients who developed metastases (M1) and were treated with systemic therapy (n = 100), PD-L1 positivity on tumor cell membrane was seen in 14% of patients and did not correlate with OS (P = 0.45). Out of 89 M1 patients who had evaluable PD-L1 on TIMCs, PD-L1 expression was seen in 33% of patients and was significantly associated with longer OS on multivariate analysis (P = 0.0007). CONCLUSION: PD-L1 is widely expressed in tumor cell membrane and TIMCs in UC. PD-L1 in tumor cells was not predictive of OS. However, positive PD-L1 expression in TIMCs was significantly associated with longer survival in those patients who developed metastases.

PD-L1 expression in nonclear-cell renal cell carcinoma.

BACKGROUND: Programmed death ligand-1 (PD-L1) expression in nonclear-cell RCC (non-ccRCC) and its association with clinical outcomes are unknown. METHODS: Formalin-fixed paraffin-embedded (FFPE) specimens were obtained from 101 patients with non-ccRCC. PD-L1 expression was evaluated by immunohistochemistry in both tumor cell membrane and tumor-infiltrating mononuclear cells (TIMC). PD-L1 tumor positivity was defined as ≥5% tumor cell membrane staining. For PD-L1 expression in TIMC, a combined score based on the extent of infiltrate and percentage of positive cells was used. Baseline clinico-pathological characteristics and outcome data [time to recurrence (TTR) and overall survival (OS)] were correlated with PD-L1 staining. RESULTS: Among 101 patients, 11 (10.9%) were considered PD-L1+ in tumor cells: 2/36 (5.6%) of chromophobe RCC, 5/50 (10%) of papillary RCC, 3/10 (30%) of Xp11.2 translocation RCC and 1/5 (20%) of collecting duct carcinoma. PD-L1 positivity (PD-L1+) in tumor cells was significantly associated with higher stage (P = 0.01) and grade (P = 0.03), as well as shorter OS (P < 0.001). On the other hand, PD-L1 positivity by TIMC was observed in 57 (56.4%) patients: 13/36 (36.1%) of chromophobe RCC, 30/50 (60%) of papillary RCC, 9/10 (90%) of Xp11.2 translocation RCC and 5/5 (100%) of collecting duct carcinoma. A trend toward shorter OS was observed in patients with PD-L1+ in TIMC (P = 0.08). PD-L1+ in both tumor cell membrane and TIMC cells were associated with shorter TTR (P = 0.02 and P = 0.03, respectively). CONCLUSION: In non-ccRCC, patients with PD-L1+ tumors appear to have worse clinical outcomes, although only PD-L1 positivity in tumor cells is associated with higher tumor stage and grade.

Cox-2 inhibition enhances the activity of sunitinib in human renal cell carcinoma xenografts.

BACKGROUND: Sunitinib (Su), a tyrosine kinase inhibitor of VEGFR, is effective at producing tumour response in clear cell renal cell carcinoma (cRCC), but resistance to therapy is inevitable. As COX-2 is a known mediator of tumour growth, we explored the potential benefit of COX-2 inhibition in combination with VEGFR inhibition in attempts at delaying tumour progression on Su. METHODS: COX-2 expression was compared with areas of hypoxia in tumours that progressed on Su vs untreated tumours. Mice bearing human cRCC xenografts were treated with Su and the COX-2 inhibitor, celecoxib, and the effects on tumour growth were assessed. Sequential vs concurrent regimens were compared. RESULTS: COX-2 expression was increased in cRCC xenografts in areas of tumour hypoxia. The combination of Su and celecoxib achieved longer times to tumour progression compared to treatment with either agent alone or to untreated control animals in four models. This effect was seen with concurrent but not with sequential therapy. CONCLUSION: COX-2 inhibition can extend the effectiveness of VEGFR inhibition. This effect is dependent on the timing of therapy. Clinical trials combining Su and COX-2 inhibitors should be considered as a means delaying time to progression on sunitinib in patients with metastatic cRCC.

Traumatic brain edema in diffuse and focal injury: cellular or vasogenic?

The objective of this study was to confirm the nature of the edema, cellular or vasogenic, in traumatic brain injury in head-injured patients using magnetic resonance imaging techniques. Diffusion-weighted imaging methods were quantified by calculating the apparent diffusion coefficients (ADC). Brain water and cerebral blood flow (CBF) were also measured using magnetic resonance and stable Xenon CT techniques. After obtaining informed consent, 45 severely injured patients rated 8 or less on Glasgow Coma Scale (32 diffuse injury, 13 focal injury) and 8 normal volunteers were entered into the study. We observed that in regions of edema, the ADC was reduced, signifying a predominantly cellular edema. The ADC values in diffuse injured patients without swelling were close to normal and averaged 0.89 +/- 0.08. This was not surprising, as ICP values for these patients were low. In contrast, in patients with significant brain swelling ADC values were reduced and averaged 0.74 +/- 0.05 (p < 0.0001), consistent with a predominantly cellular edema. We also found that the CBF in these regions was well above ischemic threshold at time of study. Taking these findings in concert, it is concluded that the predominant form of edema responsible for brain swelling and raised ICP is cellular in nature.

Mitochondrial injury measured by proton magnetic resonance spectroscopy in severe head trauma patients.

The aim of this study was to evaluate the extent of mitochondrial injury by assessing N-Acetyl-Aspartate by MR spectroscopy in head injured patients and relating the extent of mitochondrial injury to outcome. The study population (n = 15) consisted of head injured patients (GCS < 8) in whom legal consent was obtained for MRS studies. Studies were performed on a 1.5 Tesla Vision/Siemens system. Size of Voxel equaled 8 cm3 with location determined from T1 images. Voxels were positioned adjacent to the lesion and in the contralateral hemisphere for focal and bilateral for diffuse. Mitochondrial impairment was considered as percent reduction in NAA/ Cr ratio compared to matched controls. Mitochondrial impairment gradually increases soon after injury reaching a nadir at 10 days. Subsequently, mitochondria recover in patients with favorable outcome, but remains impaired in patients with poor outcome. The prognostic value of NAA/Cr to assist in management and also to serve as a surrogate endpoint for clinical trials appears promising.

The effect of cyclosporin A on brain edema formation following experimental cortical contusion.

Cyclosporin A (CsA) has been shown by our laboratory and others to be neuroprotective in the experimental animal model of traumatic brain injury. However, we found that the intrathecal administration resulted in a concomitant increase of brain edema. The aim of this study was to assess whether intravascular administration may also influence brain edema formation. This project includes two independent series in which different doses of CsA were intravenously given to Sprague-Dawley rats of each group. In the first series, the animals were exposed to focal brain injury by a controlled cortical impact (CCI, 6 m/sec, 3 mm depth) and randomized into the following two groups: 20 mg/kg CsA and control vehicle. In the second series, animals were also injured by CCI and randomized into 35 mg/kg CsA and control vehicle. The intravenous continuous (1 h) infusion was begun 30 minutes after the insult. All animals were sacrificed at 24 hours post injury to assess the brain water content using the gravimetric method. Intravenously-administrated CsA of either 20 or 35 mg/kg did not significantly change the brain water content. We therefore suggest that an intravascular route may be better for CsA administration because the intrathecal injection may exacerbate brain edema as found in our previous study.

Diffuse brain injury complicated by acute subdural hematoma and secondary insults in the rodents: the effect of surgical evacuation.

Head Trauma associated with acute sudural hematoma (SDH) and complicated by secondary insult is a grave clinical combination with complex pathophysiology. The aim of this study was to develop a clinically relevant injury model, which can be used to study the interaction between injury mechanisms. We present a novel model of SDH combined with diffuse brain injury (DBI) and a hypoxic secondary insult, and investigate the effects of surgical evacuation. Adult Sprague-Dawley rats were given a 300 microliters SDH and 20 minute-hypoxia following Impact Acceleration DBI. Hematoma was evacuated at one hour post-injury. Physiological parameters were measured for 5 hours, together with assessment of brain water content. Secondary insult after traumatic SDH was associated with significant brain swelling and stimulated refractory rise in ICP. In traumatic SDH complicated by secondary insult, brain swelling is exacerbated by surgical evacuation.

Diffuse brain injury complicated by acute subdural hematoma in the rodents: the effect of early or delayed surgical evacuation.

Of all the possible clinical factors affecting the outcome of patients suffering acute subdural hematomas (SDH), timing of surgical evacuation is certainly the most debated. The purpose of this study was to develop an experimental model able to reproduce the clinical behavior of post-traumatic SDH as observed in head injured patients. We present a novel model of SDH combined with diffuse brain injury (DBI), and investigate the effects of early and delayed surgical evacuation. Following Impact Acceleration DBI, adult Sprague-Dawley rats were given a 400 microliters SDH. Hematoma was then evacuated at one (rapid evacuation) or four hours (delayed evacuation) post-injury. Physiological parameters were measured for 5 hours, followed by the assessment of brain water content. In this experimental model, there is strong evidence that trauma acts synergistically with SDH enhancing brain edema formation and increasing ICP. In absence of secondary insult, rapid evacuation of traumatic SDH limits exposure to high ICP, reduces brain edema and is beneficial.

Application of chemical shift imaging for measurement of NAA in head injured patients.

Neurochemical damage following brain injury can be assessed non-invasively by measurement of N-Acetyl-Aspartate (NAA) using Proton Magnetic Resonance Spectroscopy (1HMRS). This report documents results of applying Chemical Shift Imaging (CSI) postprocessing for measuring NAA in traumatically injured brain. Following stabilization, severely head-injured patients (GCS 8 or less) were transported to the MRI suite. Semi-quantitative measurement of NAA, creatine (Cr/PCr) and choline (Cho) were obtained from single voxels (8 cm3) and CSI for acquisition of smaller voxels (2 cm3) throughout areas of the brain. Studies were completed with no complication. In focal injury, SVS positioned at the site of lesion demonstrated reduced NAA, compared to contralateral hemisphere. In diffuse injury, CSI demonstrated uniform reduction of NAA throughout the brain. NAA/Cho showed normal levels within 24 hours of injury averaging 2.4 and decreased over the next 10 days reaching a plateau of 0.75. At 30 days, NAA showed no recovery in poor outcome patients. In patients with good outcome, NAA initially low recovered near baseline levels. CSI provides a comprehensive neurochemical assessment of neuronal damage. NAA decreases and remains low in patients with poor outcome. NAA recovers in patients with favorable outcome, suggesting marginal metabolic impairment and possible re-synthesis of the NAA pool.

N-Acetylaspartate reduction as a measure of injury severity and mitochondrial dysfunction following diffuse traumatic brain injury.

N-Acetylaspartate (NAA) is considered a neuron-specific metabolite and its reduction a marker of neuronal loss. The objective of this study was to evaluate the time course of NAA changes in varying grades of traumatic brain injury (TBI), in concert with the disturbance of energy metabolites (ATP). Since NAA is synthesized by the mitochondria, it was hypothesized that changes in NAA would follow ATP. The impact acceleration model was used to produce three grades of TBI. Sprague-Dawley rats were divided into the following four groups: sham control (n = 12); moderate TBI (n = 36); severe TBI (n = 36); and severe TBI coupled with hypoxia-hypotension (n = 16). Animals were sacrificed at different time points ranging from 1 min to 120 h postinjury, and the brain was processed for high-performance liquid chromatography (HPLC) analysis of NAA and ATP. After moderate TBI, NAA reduced gradually by 35% at 6 h and 46% at 15 h, accompanied by a 57% and 45% reduction in ATP. A spontaneous recovery of NAA to 86% of baseline at 120 h was paralleled by a restoration in ATP. In severe TBI, NAA fell suddenly and did not recover, showing critical reduction (60%) at 48 h. ATP was reduced by 70% and also did not recover. Maximum NAA and ATP decrease occurred with secondary insult (80% and 90%, respectively, at 48 h). These data show that, at 48 h post diffuse TBI, reduction of NAA is graded according to the severity of insult. NAA recovers if the degree of injury is moderate and not accompanied by secondary insult. The highly similar time course and correlation between NAA and ATP supports the notion that NAA reduction is related to energetic impairment.

Transition from in situ to invasive testicular germ cell neoplasia is associated with the loss of p21 and gain of mdm-2 expression.

INTRODUCTION: The tumor suppressor gene p53 has been shown to transcriptionally regulate expression of the cell cycle dependent kinase inhibitor p21. p53 is in turn regulated by the ubiquitin ligase mouse double minute-2 (mdm-2). We have set out to examine p21 expression in testicular germ cell tumors and its relationship with p53 and mdm-2 expression. METHODS: Immunohistochemical analysis was performed on formalin-fixed paraffin-embedded tissue for p53, p21, and mdm-2 in 31 testicular germ cell tumors, which included 17 pure seminomas and 14 mixed germ cell tumors composed predominantly of embryonal carcinoma. Twenty-seven cases contained adjacent areas of intratubular germ cell neoplasia (ITGCN). RESULTS: 17 out of 17 seminomas and 14 out of 14 embryonal carcinomas expressed p53 in both ITGCN and the invasive tumor. In contrast, none of the 17 seminomas and only 2 of 14 embryonal carcinomas revealed positive staining for p21 protein. p21 expression was noted in 18 of 27 cases (67%) of ITGCN, and in 16 of these cases (89%) the corresponding invasive tumor had lost p21 expression. In nine additional cases p21 expression was absent in both the invasive and intratubular tumor. mdm-2 expression was present in 8 out of 17 (47%) seminomas and 13 out of 14 (93%) embryonal carcinomas but was present in only 2 out of 27 (7%) cases of ITGCN. Statistically significant associations for loss of p21 and gain of mdm-2 expression in invasive tumors were present (P < .0001). CONCLUSIONS: The co-expression of p53 and p21 in ITGCN is consistent with preservation of p53-directed induction of p21. The loss of p21 expression in invasive tumors suggests a disruption of the p53 regulatory pathway. The inverse correlation of p21 and mdm-2 expression in both ITGCN and invasive tumors could indicate that loss of the functional p53 regulatory pathway may be correlated with the onset of mdm-2 expression. These results raise the possibility that the loss of p21 expression may be associated with the development of invasive germ cell tumors from ITGCN. Persistent p53 expression in the presence of mdm-2 suggests that in testicular germ cell tumors, while mdm-2 can block the transactivation potential of p53, it can no longer target p53 for degradation.

Androgen-driven prostate epithelial cell proliferation and differentiation in vivo involve the regulation of p27.

Androgens control both growth and differentiation of the normal prostate gland. However, the mechanisms by which androgens act upon the cell cycle machinery to regulate these two fundamental processes are largely unknown. The cyclin-dependent kinase (cdk) inhibitor p27 is a negative cell cycle regulator involved in differentiation-associated growth arrest. Here, we investigate the role and regulation of p27 in the testosterone proprionate (TP)-stimulated regeneration of the ventral prostate (VP) of castrated rats. Continuous TP administration to castrated rats triggered epithelial cell proliferation, which peaked at 72 h, and then declined despite further treatment. Castration-induced atrophy of the VP was associated with a significant increase in p27 expression as compared with the VP of intact animals. Twelve hours after the initiation of androgen treatment, total p27 levels as well as its fraction bound to cdk2, its main target, significantly dropped in the VP of castrated rats. Thereafter, concomitantly to the induction of epithelial cell proliferation, the glandular morphology of VP was progressively restored at 48-96 h of TP treatment. During this period of the regenerative process, whereas both proliferating basal and secretory epithelial cells did not express p27, the protein was selectively up-regulated in the nonproliferating secretory epithelial compartment. This up-regulation of p27 expression was coincident with an increase in its association with, and presumably inhibition of, cdk2. At each time point of TP treatment, p27 abundance in the VP was inversely correlated with the level of its proteasome-dependent degradation activity measured in vitro in VP lysates, whereas only slight changes in the amount of p27 transcripts were detected. In addition, the antiandrogen flutamide blocked maximal TP-induced p27 degradation completely. Finally, the expression of skp2, the ubiquitin ligase that targets p27 for degradation, was seen to increase with androgen administration, preceding maximal proliferation and concomitantly to augmented p27 degradation activity. Taken together, our data indicate that androgens mediate both proliferation and differentiation signals in normal prostate epithelial cells in vivo, through regulation of p27.

Primary effusion lymphoma in HIV-infected patients with multicentric Castleman's disease.

Multicentric Castleman's disease (MCD) and primary effusion lymphoma (PEL) are two B-cell lymphoproliferative diseases associated with Kaposi's sarcoma-associated herpes virus/human herpesvirus-8 (KSHV/HHV-8). Although MCD is considered a prelymphoma state, it is not known whether a pathogenetic link exists between MCD and PEL. This paper reports the clinico-pathological features of four cases of PEL (two pericardial, one pleural, and one peritoneal) developing in the context of HIV-associated MCD. Effusions, lymph nodes, spleen, and additional tissues from three autopsies were examined for morphology/immunophenotype, search for HHV-8 DNA, and assessment of immunoglobulin heavy chain gene (IgH) configuration using polymerase chain reaction (PCR)-based techniques. MCD and PEL samples contained HHV-8 DNA. Clonal IgH rearrangements were detected only in PEL, whereas MCD tissues were polyclonal. Light-chain immunostaining confirmed B-cell clonality in PEL (two lambda, one kappa, one not tested) and polyclonality in MCD. The autopsies revealed different morphological variants of visceral KS and multi-organ atypical infiltrates exhibiting immunoblastic/plasmablastic features reminiscent of PEL morphology, with a restriction of lambda-positive cells. In two cases, using microdissection and IgH PCR analysis, multiple/discrete bands were found in the infiltrates, compatible with polyclonality/oligoclonality. The case showing an oligoclonal IgH ladder contained a rearrangement of identical junctional size to the PEL clone; however, further analysis with PEL-derived clonotypic primers and sequencing of PCR products showed no amplification and nucleotide diversity, respectively, indicating that the two B-cell populations examined were clonally unrelated. These data show that MCD and PEL may co-exist in HIV-infected patients, suggesting a relevant association between these two HHV-8-related disorders. Although a definite clonal relationship between MCD and PEL was not demonstrated, it is hypothesized that in some MCD cases, within expanded polyclonal B-cell populations secondary to HHV-8 infection, clonal expansions may occur that localize into a body cavity, i.e. PEL.

p63 is a prostate basal cell marker and is required for prostate development.

The p53 homologue p63 encodes for different isotypes able to either transactivate p53 reporter genes (TAp63) or act as p53-dominant-negatives (DeltaNp63). p63 is expressed in the basal cells of many epithelial organs and its germline inactivation in the mouse results in agenesis of organs such as skin appendages and the breast. Here, we show that prostate basal cells, but not secretory or neuroendocrine cells, express p63. In addition, prostate basal cells in culture predominantly express the DeltaNp63alpha isotype. In contrast, p63 protein is not detected in human prostate adenocarcinomas. Finally, and most importantly, p63(-/-) mice do not develop the prostate. These results indicate that p63 is required for prostate development and support the hypothesis that basal cells represent and/or include prostate stem cells. Furthermore, our results show that p63 immunohistochemistry may be a valuable tool in the differential diagnosis of benign versus malignant prostatic lesions.

Her-2-neu expression and progression toward androgen independence in human prostate cancer.

BACKGROUND: Human prostate cancers are initially androgen dependent but ultimately become androgen independent. Overexpression of the Her-2-neu receptor tyrosine kinase has been associated with the progression to androgen independence in prostate cancer cells. We examined the expression of Her-2-neu in normal and cancerous prostate tissues to assess its role in the progression to androgen independence. METHODS: Prostate cancer tissue sections were obtained from 67 patients treated by surgery alone (UNT tumors), 34 patients treated with total androgen ablation therapy before surgery (TAA tumors), and 18 patients in whom total androgen ablation therapy failed and who developed bone metastases (androgen-independent [AI] disease). The sections were immunostained for Her-2-neu, androgen receptor (AR), prostate-specific antigen (PSA), and Ki-67 (a marker of cell proliferation) protein expression. Messenger RNA (mRNA) levels and gene amplification of Her-2-neu were examined by RNA in situ hybridization and fluorescent in situ hybridization(FISH), respectively, in a subset of 27 tumors (nine UNT, 11 TAA, and seven AI). All statistical tests were two-sided. RESULTS: Her-2-neu protein expression was statistically significantly higher in TAA tumors than in UNT tumors with the use of two different scoring methods (P =.008 and P =.002). The proportion of Her-2-neu-positive tumors increased from the UNT group (17 of 67) to the TAA group (20 of 34) to the AI group (14 of 18) (P<.001). When compared with UNT tumors, tumor cell proliferation was higher in AI tumors (P =.014) and lower in TAA tumors (P<.001). All tumors expressed AR and PSA proteins. Although Her-2-neu mRNA expression was high in TAA and AI tumors, no Her-2-neu gene amplification was detected by FISH in any of the tumor types. CONCLUSIONS: Her-2-neu expression appears to increase with progression to androgen independence. Thus, therapeutic targeting of this tyrosine kinase in prostate cancer may be warranted.

Forkhead transcription factors are critical effectors of cell death and cell cycle arrest downstream of PTEN.

PTEN acts as a tumor suppressor, at least in part, by antagonizing phosphoinositide 3-kinase (PI3K)/Akt signaling. Here we show that Forkhead transcription factors FKHRL1 and FKHR, substrates of the Akt kinase, are aberrantly localized to the cytoplasm and cannot activate transcription in PTEN-deficient cells. Restoration of PTEN function restores FKHR to the nucleus and restores transcriptional activation. Expression of a constitutively active form of FKHR that cannot be phosphorylated by Akt produces the same effect as reconstitution of PTEN on PTEN-deficient tumor cells. Specifically, activated FKHR induces apoptosis in cells that undergo PTEN-mediated cell death and induces G(1) arrest in cells that undergo PTEN-mediated cell cycle arrest. Furthermore, both PTEN and constitutively active FKHR induce p27(KIP1) protein but not p21. These data suggest that Forkhead transcription factors are critical effectors of PTEN-mediated tumor suppression.