Ezh2 promotes mammary tumor initiation through epigenetic regulation of the Wnt and mTORC1 signaling pathways.

The regulation of gene expression through histone posttranslational modifications plays a crucial role in breast cancer progression. However, the molecular mechanisms underlying the contribution of histone modification to tumor initiation remain unclear. To gain a deeper understanding of the role of the histone modifier Enhancer of Zeste homology 2 (Ezh2) in the early stages of mammary tumor progression, we employed an inducible mammary organoid system bearing conditional Ezh2 alleles that faithfully recapitulates key events of luminal B breast cancer initiation. We showed that the loss of Ezh2 severely impairs oncogene-induced organoid growth, with Ezh2-deficient organoids maintaining a polarized epithelial phenotype. Transcriptomic profiling showed that Ezh2-deficient mammary epithelial cells up-regulated the expression of negative regulators of Wnt signaling and down-regulated genes involved in mTORC1 (mechanistic target of rapamycin complex 1) signaling. We identified Sfrp1, a Wnt signaling suppressor, as an Ezh2 target gene that is derepressed and expressed in Ezh2-deficient epithelium. Furthermore, an analysis of breast cancer data revealed that Sfrp1 expression was associated with favorable clinical outcomes in luminal B breast cancer patients. Finally, we confirmed that targeting Ezh2 impairs mTORC1 activity through an indirect mechanism that up-regulates the expression of the tumor suppressor Pten. These findings indicate that Ezh2 integrates the mTORC1 and Wnt signaling pathways during early mammary tumor progression, arguing that inhibiting Ezh2 or therapeutically targeting Ezh2-dependent programs could be beneficial for the treatment of early-stage luminal B breast cancer.

Sentinel lymph node biopsy is unreliable in predicting melanoma mortality for both younger and older patients.

BACKGROUND: Melanoma disease patterns vary with patient age. AIM: To evaluate sentinel lymph node biopsy (SLNB) in managing melanoma at differing patient ages. METHODS: Online prediction tools were applied to compare SLNB positivity (SLNB+) and survival risk at patient ages 20-80. Tübingen melanoma data were used to determine variations in the hazard ratio of SLNB+ for mortality at different patient ages. RESULTS: Regardless of tumour thickness, predicted SLNB+ rates were markedly higher than mortality rates for 20-year-old patients. For 80-year-old patients, it is the opposite. DISCUSSION: If 1000 20-year-olds with a 0.4 mm thickness non-ulcerated melanoma underwent SLNB, 100 would likely be positive. If all 100 were to be offered adjuvant drug therapy (ADT), fewer than three more melanoma deaths in those 1000 patients would be avoided. In total, 97 patients would have received medication they may never have needed. If 1000 80-year-olds with a 3 mm thickness non-ulcerated melanoma underwent SLNB, only 40 would likely be positive. In total, 274 patients would be predicted to die of melanoma, 245 being SLNB negative and 29 SLNB+. ADT linked to SLNB+ could deny treatment to 89% of these high-risk patients. LIMITATIONS: The authors relied on published risk data. CONCLUSION: SLNB has poor specificity at predicting mortality in young melanoma patients and poor sensitivity in older patients. SLNB is not indicated in managing cutaneous melanoma for patients under 40 or over 60 years of age. Many such patients could be managed with wide local excision alone in their clinician's office-based practice. For all cutaneous melanoma patients at all ages, linking ADT to BAUSSS biomarker, (an algorithm of Breslow thickness, age, ulceration, subtype, sex and Site) rather than SLNB+ is likely more appropriate. BAUSSS provides a more accurate melanoma-specific mortality risk assessment for patients without burdening them with added surgery, hospitalization, costs or morbidity risk.

A Tunable Calcium Phosphate Coating to Drive in vivo Osseointegration of Composite Engineered Tissues.

Varying degrees of hydroxyapatite (HA) surface functionalization have been implicated as the primary driver of differential osteogenesis observed in infiltrating cells. The ability to reliably create spatially controlled areas of mineralization in composite engineered tissues is of growing interest in the field, and the use of HA-functionalized biomaterials may provide a robust solution to this challenge. In this study, we successfully fabricated polycaprolactone salt-leached scaffolds with two levels of a biomimetic calcium phosphate coating to examine their effects on MSC osteogenesis. Longer duration coating in simulated body fluid (SBF) led to increased HA crystal nucleation within scaffold interiors as well as more robust HA crystal formation on scaffold surfaces. Ultimately, the increased surface stiffness of scaffolds coated in SBF for 7 days in comparison to scaffolds coated in SBF for 1 day led to more robust osteogenesis of MSCs in vitro without the assistance of osteogenic signaling molecules. This study also demonstrated that the use of SBF-based HA coatings can promote higher levels of osteogenesis in vivo. Finally, when incorporated as the endplate region of a larger tissue-engineered intervertebral disc replacement, HA coating did not induce mineralization in or promote cell migration out of neighboring biomaterials. Overall, these results verified tunable biomimetic HA coatings as a promising biomaterial modification to promote discrete regions of mineralization within composite engineered tissues.

An ErbB2 splice variant lacking exon 16 drives lung carcinoma.

Lung cancer causes more deaths annually than any other malignancy. A subset of non-small cell lung cancer (NSCLC) is driven by amplification and overexpression or activating mutation of the receptor tyrosine kinase (RTK) ERBB2 In some contexts, notably breast cancer, alternative splicing of ERBB2 causes skipping of exon 16, leading to the expression of an oncogenic ERBB2 isoform (ERBB2ΔEx16) that forms constitutively active homodimers. However, the broader implications of ERBB2 alternative splicing in human cancers have not been explored. Here, we have used genomic and transcriptomic analysis to identify elevated ERBB2ΔEx16 expression in a subset of NSCLC cases, as well as splicing site mutations facilitating exon 16 skipping and deletions of exon 16 in a subset of these lung tumors and in a number of other carcinomas. Supporting the potential of ERBB2ΔEx16 as a lung cancer driver, its expression transformed immortalized lung epithelial cells while a transgenic model featuring inducible ERBB2ΔEx16 specifically in the lung epithelium rapidly developed lung adenocarcinomas following transgene induction. Collectively, these observations indicate that ERBB2ΔEx16 is a lung cancer oncogene with potential clinical importance for a proportion of patients.

Regulation of cell signalling by uPAR.

Urokinase-type plasminogen activator receptor (uPAR) expression is elevated during inflammation and tissue remodelling and in many human cancers, in which it frequently indicates poor prognosis. uPAR regulates proteolysis by binding the extracellular protease urokinase-type plasminogen activator (uPA; also known as urokinase) and also activates many intracellular signalling pathways. Coordination of extracellular matrix (ECM) proteolysis and cell signalling by uPAR underlies its important function in cell migration, proliferation and survival and makes it an attractive therapeutic target in cancer and inflammatory diseases. uPAR lacks transmembrane and intracellular domains and so requires transmembrane co-receptors for signalling. Integrins are essential uPAR signalling co-receptors and a second uPAR ligand, the ECM protein vitronectin, is also crucial for this process.

Degeneration alters structure-function relationships at multiple length-scales and across interfaces in human intervertebral discs.

Intervertebral disc (IVD) degeneration and associated back pain place a significant burden on the population. IVD degeneration is a progressive cascade of cellular, compositional, and structural changes, which results in a loss of disc height, disorganization of extracellular matrix architecture, tears in the annulus fibrosus which may involve herniation of the nucleus pulposus, and remodeling of the bony and cartilaginous endplates (CEP). These changes to the IVD often occur concomitantly, across the entire motion segment from the disc subcomponents to the CEP and vertebral bone, making it difficult to determine the causal initiating factor of degeneration. Furthermore, assessments of the subcomponents of the IVD have been largely qualitative, with most studies focusing on a single attribute, rather than multiple adjacent IVD substructures. The objective of this study was to perform a multiscale and multimodal analysis of human lumbar motion segments across various length scales and degrees of degeneration. We performed multiple assays on every sample and identified several correlations between structural and functional measurements of disc subcomponents. Our results demonstrate that with increasing Pfirrmann grade there is a reduction in disc height and nucleus pulposus T2 relaxation time, in addition to alterations in motion segment macromechanical function, disc matrix composition and cellular morphology. At the cartilage endplate-vertebral bone interface, substantial remodeling was observed coinciding with alterations in micromechanical properties. Finally, we report significant relationships between vertebral bone and nucleus pulposus metrics, as well as between micromechanical properties of the endplate and whole motion segment biomechanical parameters, indicating the importance of studying IVD degeneration as a whole organ.

Platelet-Rich Plasma, Bone Morphogenetic Protein, and Stem Cell Therapies.

The frequency of use of "biologics," including platelet-rich plasma (PRP), bone morphogenetic protein (BMP), and stem cell therapies in the treatment of orthopaedic conditions has significantly increased over the past few decades. The use of PRP and stem cells has been proposed for a wide variety of conditions including knee and hip osteoarthritis (OA), tendon strains and tendinopathies, muscle strains, and acute and chronic soft-tissue injuries. It has also been proposed for use in the enhancement of healing during surgical treatments. BMP has seen use in promoting fracture union and spinal fusion and has been researched as an adjunct in other procedures as well. The current state of the literature in the use and support of these biologics is outlined here.

Randomized Controlled Trial of Preoperative Topical Decolonization to Reduce Surgical Site Infection for Staphylococcus aureus Nasal Swab-Negative Mohs Micrographic Surgery Patients.

BACKGROUND: Surgical site infection (SSI) is mainly due to endogenous bacteria. Topical decolonization is a preoperative intervention currently advised for proven nasal carriers of Staphylococcus aureus (S. aureus). OBJECTIVE: The authors assessed whether topical decolonization could be of benefit for patients who are not nasal carriers of S. aureus. METHODS AND MATERIALS: The authors performed a randomized controlled trial of S. aureus nasal swab-negative patients. Five days before Mohs surgery topical decolonization with nasal mupirocin and chlorhexidine, body wash was started. The control group had no intervention. RESULTS: In the week after Mohs surgery, the infection rate in the intervention group was 2% (n = 661, 14) and that of the control group was 4% (n = 689, 29). CONCLUSION: Topical decolonization reduces SSI in nasal swab-negative Mohs surgery patients.

Volume outlier benchmark proposal for Australian Mohs surgery.

Peer-derived Australian Mohs data were used to define volume outliers and a benchmark for quality improvement. Higher volume practice was linked to less complex anatomical locations for surgery. Reflection on individual practice compared to peers may reduce the number of volume outliers in Mohs surgery.

Avoiding and Managing Complications in Routine Lumbar Spine Surgery.

Elective lumbar surgery for common degenerative lumbar spine pathology has been consistently demonstrated to have excellent outcomes by multiple validated measures and improves patient quality of life. The rate of complication is low but not unavoidable; there is an increasing recognition of risk factors that can be mitigated to decrease complication rates. When complications occur, prompt recognition and management may minimize deleterious effects on patient outcome. There are considerations for identifying risk factors and, when possible, minimizing them and general strategies for identifying and managing common complications in lumbar spine surgery.

Bupivacaine as an Adjunct to Lidocaine in Mohs Micrographic Surgery: A Prospective Randomized Controlled Trial.

BACKGROUND: In Mohs micrographic surgery (MMS), the standard local anesthetic agent used is lignocaine with adrenaline. However, MMS can be prolonged; thus reinjections of local anesthetics are often required. OBJECTIVE: Is 0.5% bupivacaine with 1:200,000 epinephrine a useful adjunctive treatment when compared with the use of 1% lidocaine with 1:100,000 epinephrine in MMS for the nose? METHODS: Participants undergoing MMS received 2.5 mL of 1% lidocaine with 1:100,000 epinephrine before commencement of Stage 1. At the end of Stage 1, participants were randomized sequentially to either 2.5 mL 0.5% bupivacaine with 1:200,000 epinephrine (Group A) or 2.5 mL of 1% lidocaine with 1:100,000 epinephrine (Group B). Effectiveness of anesthesia was assessed using 30 G needle to 5 points of the wound before further stage or repair. RESULTS: Fifty-one patients were randomized, 26 to Group A, and 25 to Group B. No differences between the 2 groups in size of defect and time lapse between time of injection and time of testing were observed. Seven of 25 were tested positive in Group B. Zero of 26 tested positive in Group A (p = .003, 95% confidence interval: 10%-46%). CONCLUSION: Adjunctive use of 0.5% bupivacaine with 1:200,000 epinephrine is effective in prolonging anesthesia in MMS.

Intraosseous pseudomeningocele of the mobile spine: a case report and review of the literature.

BACKGROUND: Pseudomeningoceles most commonly occur due to prior trauma or surgery and are often located in the posterior paraspinous tissues. Here, we report a case of an intraosseous pseudomeningocele that mimicked an intra-osseous T2 hyperintense lesion in the L1 vertebral body. CASE DESCRIPTION: A 64-year-old male presented with back, left lateral thigh and left knee pain lasting several months. He had no prior history of trauma or surgery. Radiographs of the lumbar spine showed mild levoscoliotic curvature of the lumbar spine, Baastrup's changes between the spinous processes, multilevel degenerative disc disease and facet arthropathy. Magnetic resonance imaging (MRI) of the lumbar spine performed without intravenous contrast showed severe spinal canal stenosis from L1-L2 to L3-L4 and moderate spinal canal stenosis at L4-L5. MRI also showed a 2.5-cm T2 hyperintense lesion involving the posterior aspect of the L1 vertebral body, with questionable contiguity with cerebrospinal fluid. Computed tomography (CT) myelogram was performed instead of biopsy. CT myelogram showed contiguity of the lesion with the intrathecal contrast and a rent in the posterior longitudinal ligament and anterior dura consistent with an intraosseous pseudomeningocele. The patient opted for non-operative management of the pseudomeningocele and his lumbar stenosis due to medical comorbidities. CONCLUSIONS: This case illustrates a rare case of an intra-osseous pseudomeningocele and highlights the importance of CT myelogram for diagnosis.

Periocular Mohs micrographic surgery in Western Australia 2009-2012: A single centre retrospective review and proposal for practice benchmarks.

BACKGROUND/OBJECTIVES: Periocular skin tumours pose management challenges with literature supporting a multidisciplinary approach. This retrospective review identifies trends in multidisciplinary management, ascertaining potential benchmarks for practice review. METHODS: A retrospective review of 720 patients with periocular tumours, treated with Mohs micrographic surgery (MMS) at a single free standing Day Surgery Facility between 2009 and 2012. RESULTS: In all, 690 patients were included, with mean age 65 and slight male preponderance. Basal cell carcinoma was the most commonly excised tumour (85.4%) and lower eyelid most common tumour site (58%). Of the cases repaired by Mohs surgeons, 2% involved more than one cosmetic subunit, compared with 23% by oculoplastic surgeons. Of the cases repaired by MMS, 1% had eyelid margin involvement, compared with 64% of the cases by oculoplastic surgeons. Mean preoperative lesion size for cases repaired by Mohs and oculoplastic surgeons was 0.5 cm2 . Mean postoperative defect size was smaller for cases repaired by Mohs surgeons compared with oculoplastic surgeons (1.5 and 1.9 cm2 ). Mean number of stages was less for Mohs surgeon repairs (n = 1.5) compared with oculoplastic surgeon repairs (n = 1.9). Cases repaired by oculoplastic surgeons were more often combination repairs. CONCLUSIONS: This study identifies potential benchmarks for Mohs surgeons when reviewing or establishing a periocular Mohs surgery practice and for doctors referring periocular tumours for surgical removal. These include the proportion of periocular cases managed jointly and the location, size of defect and number of stages involved in tumors repaired by Mohs surgeon alone compared to those repaired by oculoplastic surgeons.

Vertebral body fracture after TLIF: a new complication.

BACKGROUND: The transforaminal posterior approach (TLIF) procedure was first described in 1982. Current literature indicates its equality in outcomes for fusion constructs as other anterior-posterior procedures. As a procedure becomes more popular and is more frequently performed the types and number of complications that occur increase. We report on a two case series that underwent TLIF. Both patients had satisfactory postoperative imaging, but presented later with coronal plane vertebral body fractures in the caudal vertebral body of the TLIF construct. We believe the complication may be related to: (a) unrecognized fracture of the endplate during cage impaction; (b) overloading the endplates by maximizing the lordosis achieved by using the reverse jackknife position on a Jackson table; (c) underlying mineral bone disease in patients. As the TLIF procedure increases in popularity, caution should be exercised to avoid the same potential complications. PURPOSE: To describe a potential complication with the TLIF procedure. STUDY DESIGN: Case report. PATIENT SAMPLE: 2. OUTCOME MEASURE: Revision surgery. METHODS: Case series. RESULTS: Caudal vertebral body fracture is a potential complication after TLIF. CONCLUSION: TLIF procedures can result in an unstable vertebral body fracture potentially necessitating revision decompression & stabilization. We recommend extra caution in patients with mineral bone disease, as technical errors can be magnified.

Mammary epithelial-specific disruption of c-Src impairs cell cycle progression and tumorigenesis.

The tyrosine kinase c-Src is activated in a large proportion of breast cancers, in which it is thought to play a key role in promoting the malignant phenotype. c-Src activity is also elevated in transgenic mouse models of breast cancer, including the widely used polyomavirus middle-T antigen (PyVmT) model, which provides an opportunity to study the importance of c-Src in mammary tumorigenesis. However, germline c-Src deletion in mammary epithelial and stromal compartments complicates the interpretation of in vivo tumorigenesis studies as a result of severe defects in mammary gland development. We have therefore engineered a mouse strain in which deletion of c-Src can be targeted to the mammary epithelium. We demonstrate that mammary epithelial disruption of c-Src impairs proliferation and tumor progression driven by PyVmT in vivo. Whereas related kinases substitute for c-Src in PyVmT signaling, c-Src ablation impairs cell cycle progression with decreased cyclin expression and elevated expression of cyclin-dependent kinase inhibitors. Our data indicate that c-Src has essential and unique functions in proliferation and tumor progression in this mouse model that may also be important in certain contexts in some human breast cancers.