MicroRNA profiling of peripheral nerve sheath tumours identifies miR-29c as a tumour suppressor gene involved in tumour progression.

BACKGROUND: Neurofibromatosis type 1 is one of the most common familial diseases, the hallmark of which is the development of multiple neurofibromas. These are benign nerve sheath tumours, which can transform into malignant peripheral nerve sheath tumours (MPNST). METHODS: The aim of this study was to identify differentially expressed microRNA (miRNA) in neurofibromas and MPNST obtained from patients with neurofibromatosis type 1 using microarray analysis. Differential expression was validated by reverse transcription quantitative-PCR, and functional studies were performed after transfection of miRNA oligonucleotide mimics into MPNST cells. RESULTS: Sixteen miRNA were significantly differentially expressed in MPNST compared with NF, and of these fourteen were downregulated in MPNST: these included miR-30e*, miR-29c*, miR-29c, miR-340*, miR-30c, miR-139-5p, miR-195, miR-151-5p, miR-342-5p, miR-146a, miR-150, miR-223, let-7 a and let-7 g with a false discovery rate of q=8.48E-03 for the least significant miRNA. In contrast, miR-210 and miR-339-5p were upregulated in MPNST compared with neurofibromas. Prediction softwares/algorithms identified a list of genes targeted by miR-29c including extracellular matrix genes and matrix metalloproteinase (MMP)-2, all of which are reported to be involved in cell migration and invasion. Functional studies in a MPNST cell line, sNF96.2, using a mimic of the mature miR-29c showed reduced invasion, whereas there was no change in proliferation. Zymography of the manipulated cells showed that MMP2 activity was also reduced when miR-29c expression was forced in sNF96.2. CONCLUSION: We provide evidence that reduction of miR-29c has a pivotal role in the progression of nerve sheath tumours and results by increasing the invasive/migratory properties of nerve sheath tumours.

The outcome of extra-abdominal fibromatosis treated at a tertiary referral centre.

PURPOSE: To review the outcomes of patients with extra-abdominal fibromatosis treated at a tertiary referral centre. METHODS: A retrospective review of a series of 72 patients with fibromatosis treated at the Royal National Orthopaedic Hospital (RNOH) between 1980 and 2009, with a median follow up of 4 years (1-17 years). RESULTS: Forty patients were primary referrals, and 32 more had operations at the referring hospital. Five were treated non-operatively; 48 patients were treated by operation alone and 19 patients underwent surgery supplemented by adjuvant therapy. Recurrence was seen in 24 of the operation alone group and 10 in the operation and adjuvant therapy group. The rate of recurrence was lower with complete excision. However, complete excision was impossible in some cases because of extension into the chest or spinal canal, or involvement with the axial vessels and lumbosacral or brachial plexus. CONCLUSION: We suggest that operative excision should seek to preserve function and that supplementary adjuvant therapy may reduce the risk of recurrence, although excision margin appears to be the most important factor. The aggressive, infiltrative behaviour of deep fibromatoses and the associated genetic mutations identified, clearly distinguish them from the superficial fibromatoses and makes their treatment more difficult and dangerous, especially where vital structures are involved.

Potential therapeutic targets for chordoma: PI3K/AKT/TSC1/TSC2/mTOR pathway.

Chordomas are radio- and chemo-resistant tumours and metastasise in as many as 40% of patients. The aim of this study was to identify potential molecular targets for the treatment of chordoma. In view of the reported association of chordoma and tuberous sclerosis complex syndrome, and the available therapeutic agents against molecules in the PI3K/AKT/TSC1/TSC2/mTOR pathway, a tissue microarray of 50 chordoma cases was analysed for expression of active molecules involved in this signalling pathway by immunohistochemistry and a selected number by western blot analysis. Chordomas were positive for p-AKT (92%), p-TSC2 (96%), p-mTOR (27%), total mTOR (75%), p-p70S6K (62%), p-RPS6 (22%), p-4E-BP1 (96%) and eIF-4E (98%). Phosphatase and tensin homologue deleted on chromosome 10 expression was lost in 16% of cases. Mutations failed to be identified in PI3KCA and RHEB1 in the 23 cases for which genomic DNA was available. Fluorescence in situ hybridisation analysis for mTOR and RPS6 loci showed that 11 of 33 and 21 of 44 tumours had loss of one copy of the respective genes, results which correlated with the loss of the relevant total proteins. Fluorescence in situ hybridisation analysis for loci containing TSC1 and TSC2 revealed that all cases analysed harboured two copies of the respective genes. On the basis of p-mTOR and or p-p70S6K expression there is evidence indicating that 65% of the chordomas studied may be responsive to mTOR inhibitors, rapamycin or its analogues, and that patients may benefit from combined therapy including drugs that inhibit AKT.

Dedifferentiated chordoma: a report of four cases arising 'de novo'.

Dedifferentiated chordoma is a rare and aggressive variant of the conventional tumour in which an area undergoes transformation to a high-grade lesion, typically fibrous histiocytoma, fibrosarcoma, and rarely, osteosarcoma or rhabdomyosarcoma. The dedifferentiated component dictates overall survival, with smaller areas of dedifferentiation carrying a more favourable prognosis. Although it is more commonly diagnosed in recurrences and following radiotherapy, there have been a few reports of spontaneous development. We describe four such cases, which were diagnosed de novo following primary excision, and discuss the associated clinical and radiological features.

Cyclical sciatica: endometriosis of the sciatic nerve.

We describe a case of sciatic endometriosis in a 25-year-old woman diagnosed by MRI and histology with no evidence of intrapelvic disease. The presentation, diagnosis and management of this rare condition are described. Early diagnosis and treatment are important to prevent irreversible damage to the sciatic nerve.

Primary tumours of the synovium. A report of four cases of malignant tumour.

Four patients who developed malignant synovial tumours are described; one with chondromatosis developed a synovial chondrosarcoma and three with pigmented villonodular synovitis developed malignant change. The relevant literature is discussed.

An unusual presentation of muscular sarcoidosis.

Sarcoidosis is a noncaseating granulomatous disease that involves multiple organs, most commonly the lungs, lymph nodes, skin, and eyes, but may be clinically evident in any organ system. Symptomatic muscular sarcoidosis is very rare and has been reported in only 1.4% of known sarcoidosis cases, while skeletal involvement has been reported in 1-13%. Different types of muscular and osseous sarcoidosis have been described in the literature. We present a case of muscular sarcoidosis, which is unique in its clinical presentation and imaging findings. The presence of the marked periosteal reaction, which has never been described with muscular sarcoidosis, also makes this case unique.

Brachyury, a crucial regulator of notochordal development, is a novel biomarker for chordomas.

Chordomas are malignant tumours that occur along the spine and are thought to derive from notochordal remnants. There is significant morphological variability between and within chordomas, with some showing prominent areas of chondroid differentiation. Our microarray data from a broad range of connective tissue neoplasms indicate that, at the transcriptional level, chordomas resemble cartilaginous neoplasms. Here we show that chordomas express many genes known to be involved in cartilage development, but they also uniquely express genes distinguishing them from chondroid neoplasms. The brachyury transcription factor, known to be involved in notochordal development, is only expressed by chordomas. Using a polyclonal antibody, we show that brachyury is expressed in the embryonic notochord and in all 53 chordomas analysed, labelling both chondroid and chordoid areas of these tumours. In contrast, the protein was not detected in over 300 neoplasms, including 163 chondroid tumours. Brachyury was not detected in the nucleus pulposus, arguing against the hypothesis that this tissue derives directly from the notochord. These data provide compelling evidence that chordomas derive from notochord and demonstrate that brachyury is a specific marker for the notochord and notochord-derived tumours.

Bellini duct carcinoma. A clinical and in vitro study.

OBJECTIVE: Bellini duct carcinoma (BDC) is a rare and highly aggressive renal tumor whose histogenesis is still a matter of debate although a putative origin from collecting ducts has been proposed. METHODS: A primary tumor cell culture was obtained from a BDC of a 57-year-old man who presented with a mass of the right kidney. The patient died from disease progression 18 months after diagnosis. The light and ultrastructural features were consistent with previous reports on BDC. The expression of low (Ker 18) and high (Ker 5, Ker 8, Ker 10) molecular weight keratins was studied. RESULTS: The BDC tumor cells displayed strong positivity for keratins, 5, 8 and 18 but did not react with the anti-keratin 10 antibody. Northern blot analysis of total mRNA revealed expression of the c-erbB-1 oncogene unlike two conventional clear cell carcinomas of the kidney used as control. Cytogenetic analysis revealed an aneuploid karyotype: 53,XY,del(1)(p34),+iso(1q),+iso(5p),+4,+7,+8,-14,del(16)(q22). No submicroscopic deletion on p14-21 and p26 regions of the short arm of chromosome 3 was detected on Southern blot analysis. CONCLUSIONS: The absence of structural changes in the short arm of chromosome 3 (usually present in hereditary and sporadic renal cell carcinomas) in the presence of chromosomal abnormalities observed in malignant lesions of urothelial origin confers to BDC a unique genetic profile among papillary tumors of the kidney.

Gastrointestinal stromal tumor: evidence for a smooth-muscle origin.

A gastrointestinal stromal tumor, arising from the rectal ampulla of a 63-yr-old man, was investigated using conventional techniques as well as Western blot analysis of its cytoskeleton proteins. The expression of desmin, muscle-specific actins, vimentin, S-100 protein, chromogranin, neuron-specific enolase, and keratins was studied using the avidin-biotin technique. The tumor cells showed a positive reaction only to antivimentin antibody. Ultrastructural analysis failed to provide conclusive evidence for neural or muscular origin of the tumor. Western blot analysis of the tumor whole-protein extract allowed identification of the presence of gamma-smooth-muscle actin, thus suggesting an enteric smooth-muscle origin of the tumor. This result seems partially to support a parenchymal smooth-muscle origin for S-100 protein and desmin-negative gastrointestinal tumors.

Mono- and bi-allelic expression of insulin-like growth factor II gene in human muscle tumors.

Insulin-like growth factor II (IGF-II) is a mitogen for many cell types and an important modulator of muscle growth and differentiation. IGF-II gene is prevalently expressed during prenatal development and its gene activity is regulated by genomic imprinting, in that the allele inherited from the father is active and the allele inherited from the mother is inactive in most normal tissues. IGF-II expression is activated in several types of human neoplasms and an alteration of IGF-II imprinting has been described in Beckwith-Wiedemann syndrome and Wilms' tumor. Here we show that monoallelic expression of IGF-II gene is conserved in normal adult muscle tissue whereas two or more copies of active IGF-II alleles, arising by either relaxation of imprinting or duplication of the active allele, are found in 9 out of 11 (82%) rhabdomyosarcomas retaining heterozygosity at 11p15, regardless of the histological subtype. Since IGF-II has been indicated as an autocrine growth factor for rhabdomyosarcoma cells, these findings strongly suggest that acquisition of a double dosage of active IGF-II gene is an important step for the initiation or progression of rhabdomyosarcoma tumorigenesis. Among different types of muscle tumors, relaxation of imprinting seems to arise prevalently in rhabdomyosarcomas, since we have detected only one case of partial reactivation of the maternal IGF-II allele out of 7 leiomyosarcomas tested.