[Show abstract][Hide abstract] ABSTRACT: Tumor-propagating cells (TPCs) are believed to drive cancer initiation, progression and recurrence. These cells are characterized by enhanced tumorigenicity and self-renewal. The ability to identify such cells in primary human sarcomas relies on the dye exclusion ability of tumor side population (SP) cells. Here, we performed a high-throughput cell surface antigen screen and found that CD146 is enriched in the SP population. In vivo serial transplantation assays showed that CD146+ cells are highly tumorigenic, capable of self-renewal and thus enriches for the TPC population. In addition, depletion of SP cells from the CD146+ population show that CD146+ cells and SP cells are a distinct and overlapping TPC populations. Gene expression profiling of CD146+ and SP cells revealed multiple pathways commonly upregulated in both of these populations. Inhibition of one of these upregulated pathways, Notch signaling, significantly reduced tumor growth and self-renewal. Our data demonstrate that CD146 is an effective cell surface marker for enriching TPCs in primary human sarcomas. Targeting differentially activated pathways in TPCs may provide new therapeutic strategies for treating sarcoma.
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND: Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites. METHODS: Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers. RESULTS: GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, hl (2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (rho = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (rho = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (rho = 0.51, SE =0.18), and bladder and lung (rho = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures. CONCLUSION: Our results provide important insights into the genetic architecture of cancers and suggest new avenues for investigation.
JNCI Journal of the National Cancer Institute 10/2015; 107(12). DOI:10.1093/jnci/djv279 · 12.58 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We carried out whole genome and transcriptome sequencing on four tumor/normal pairs of epithelioid sarcoma. These index cases were supplemented with whole transcriptome sequencing of three additional tumors and three cell lines. Unlike rhabdoid tumor (the other major group of SMARCB1-negative cancers), epithelioid sarcoma shows a complex genome with a higher mutational rate, comparable to that of ovarian carcinoma. Despite this mutational burden, SMARCB1 mutations remain the most frequently recurring event and are probably critical drivers of tumor formation. Several cases show heterozygous SMARCB1 mutations without inactivation of the second allele, and we explore this further in vitro. Finding CDKN2A deletions in our discovery cohort, we evaluated CDKN2A protein expression in a tissue microarray. Six out of sixteen cases had lost CDKN2A in greater than or equal to 90% of cells, while the remaining cases had retained the protein. Expression analysis of epithelioid sarcoma cell lines by transcriptome sequencing shows a unique profile that does not cluster with any particular tissue type nor with other SWI/SNF-aberrant lines. Evaluation of the levels of members of the SWI/SNF complex other than SMARCB1 revealed that these proteins are expressed as part of a residual complex, similarly to previously studied rhabdoid tumor lines. This residual SWI/SNF is susceptible to synthetic lethality and may therefore indicate a therapeutic opportunity.
The Journal of Pathology 09/2015; DOI:10.1002/path.4636 · 7.43 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Computer-assisted surgery is a rapidly expanding field that enables improved intra-operative accuracy compared to the freehand surgical techniques currently utilized. It has been researched and developed for a wide array of surgical fields including Orthopaedic Surgery, Otolaryngology, Craniomaxillofacial Surgery, Spinal Surgery, Neurosurgery and Urology. Its use in Orthopaedic Oncology dates back to 2004, with rapid developments that have led to the ability to accurately and reliably plan resection planes with safe oncologic margins around malignant bone tumors. The purpose of this article is to provide an introduction to the topic of computer-assisted surgery, and to give a perspective on the current state and the future developments of this technology in the subspecialty of Orthopaedic Oncology. Further, the article provides a brief overview of the local work that has been done in this field in Toronto as part of the Guided Therapeutics (GTx) group at University Health Network (UHN) and Mount Sinai Hospital.
University of Toronto medical journal 07/2015; 92(3):78-83.
[Show abstract][Hide abstract] ABSTRACT: The etiologic contribution of germline genetic variation to sporadic osteosarcoma is not well understood. Osteosarcoma is a sentinel cancer of Li-Fraumeni syndrome (LFS), in which approximately 70% of families meeting the classic criteria have germline TP53 mutations. We sequenced TP53 exons in 765 osteosarcoma cases. Data were analyzed with χ(2) tests, logistic regression, and Cox proportional hazards regression models. We observed a high frequency of young osteosarcoma cases (age <30 years) carrying a known LFS- or likely LFS-associated mutation (3.8%) or rare exonic variant (5.7%) with an overall frequency of 9.5%, compared with none in case patients age 30 years and older (P < .001). This high TP53 mutation prevalence in young osteosarcoma cases is statistically significantly greater than the previously reported prevalence of 3% (P = .0024). We identified a novel association between a TP53 rare variant and metastasis at diagnosis of osteosarcoma (rs1800372, odds ratio = 4.27, 95% confidence interval = 1.2 to 15.5, P = .026). Genetic susceptibility to young onset osteosarcoma is distinct from older adult onset osteosarcoma, with a high frequency of LFS-associated and rare exonic TP53 variants.
Published by Oxford University Press 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.
Journal of the National Cancer Institute 07/2015; 107(7). DOI:10.1093/jnci/djv101 · 12.58 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Surgical resection with curative intent for giant cell tumor of bone (GCTB) may be associated with severe morbidity. This interim analysis evaluated reduction in surgical invasiveness after denosumab treatment in patients with resectable GCTB.
Patients with primary or recurrent GCTB, for whom the initially planned surgery was associated with functional compromise or morbidity, received denosumab 120 mg subcutaneously every 4 weeks (additional doses on days 8 and 15 of the first cycle). Planned and actual GCTB-related surgical procedures before and after denosumab treatment were reported. Patients were followed for surgical outcome, adverse events, and recurrence following resection.
Overall, 222 patients were evaluable for surgical downstaging (54 % were women; median age 34 years). Lesions (67 % primary and 33 % recurrent) were located in the axial (15 %) and appendicular skeleton (85 %). At the data cutoff date, most patients had not yet undergone surgery (n = 106; 48 %) or had a less morbid procedure (n = 84; 38 %) than originally planned. Median (interquartile range) time on denosumab was 19.5 (12.4-28.6) months for the 106 patients who had not undergone surgery and were continuing on monthly denosumab. Native joint preservation was 96 % (n = 24/25) for patients with planned joint/prosthesis replacement and 86 % (n = 30/35) for patients with planned joint resection/fusion. Of the 116 patients who had surgery (median postsurgical follow-up 13.0 [8.5-17.9] months), local recurrence occurred in 17 (15 %) patients.
For patients with resectable GCTB, neoadjuvant denosumab therapy resulted in beneficial surgical downstaging, including either no surgery or a less morbid surgical procedure.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to determine the relationship of the time interval between completion of preoperative radiation therapy (RT) and surgical resection on wound complications (WCs) in extremity soft tissue sarcoma (STS).
Overall, 798 extremity STS patients were managed with preoperative RT and surgery from 1989 to 2013. WCs were defined as requiring secondary operations/invasive procedures for wound care, use of vacuum-assisted closure, prolonged dressing changes, or infection within 120 days of surgery.
Mean tumor size was 8.8 cm. A total of 743 (93 %) tumors were primary presentations, 565 (71 %) patients had lower extremity tumors, and 238 patients (30 %) had a prior unplanned excision. Of 242 patients (30 %) who developed a WC, 206 (37 %) had lower extremity tumors and 36 (15 %) had upper extremity tumors. Mean time from RT completion to surgery was 41.3 (range 4-470) days; 42.0 (range 4-470) days for upper extremity cases, and 41.1 (range 4-109) days for lower extremity cases. Similarly, mean time interval for patients who developed a WC was 40.9 (range 4-100) days, and 41.5 (range 4-470) days for those who did not develop a WC (p = 0.69). Thirty-nine cases (5 %) had surgery within 3 weeks of RT; 15 (38 %) patients developed WCs versus 227 (30 %) patients who had their tumors excised after 3 weeks (p = 0.28). One hundred and twenty-nine (16 %) patients had surgery within 4 weeks, and 39 (30 %) patients developed WCs versus 203 (30 %) patients who had their tumors excised after 4 weeks (p = 1.0). A trend towards a higher rate of WCs was seen for those patients who had surgery after 6 weeks (28 % prior vs. 34 % after; p = 0.08). There was no difference in WCs with intensity-modulated RT (IMRT) versus non-IMRT cases (p = 0.6).
The time interval between preoperative RT and surgical excision in extremity STS had minimal influence on the development of WCs. Four- or 5-week intervals showed equivalent complication rates between the two groups, suggesting an optimal interval to reduce potential WCs.
[Show abstract][Hide abstract] ABSTRACT: A common and aggressive subtype of soft-tissue sarcoma, undifferentiated pleomorphic sarcoma (UPS) was examined to determine the role of micro-RNAs (miRNAs) in modulating distant metastasis. Following histopathologic review, 110 fresh frozen clinically annotated UPS samples were divided into two independent cohorts for Training (42 patients), and Validation (68 patients) analyses. Global miRNA profiling on the Training Set and functional analysis in vitro suggested that miRNA-138 and its downstream RHO-ROCK cell adhesion pathway was a convergent target of miRNAs associated with the development of metastasis. A six-miRNA signature set prognostic of distant metastasis-free survival (DMFS) was developed from Training Set miRNA expression values. Using the six-miRNA signature, patients were successfully categorized into high- and low-risk groups for DMFS in an independent Validation Set, with a hazard ratio (HR) of 2.25 (p = 0.048). After adjusting for other known prognostic variables such as age, gender, tumor grade, size, depth, and treatment with radiotherapy, the six-miRNA signature retained prognostic value with a HR of 3.46 (p < 0.001). A prognostic miRNA biomarker for clinical validation was thus identified along with a functional pathway that modulates UPS metastatic phenotype.
[Show abstract][Hide abstract] ABSTRACT: Enchondromas are benign cartilage tumors and precursors to malignant chondrosarcomas. Somatic mutations in the isocitrate dehydrogenase genes (IDH1 and IDH2) are present in the majority of these tumor types. How these mutations cause enchondromas is unclear. Here, we identified the spectrum of IDH mutations in human enchondromas and chondrosarcomas and studied their effects in mice. A broad range of mutations was identified, including the previously unreported IDH1-R132Q mutation. These mutations harbored enzymatic activity to catalyze α-ketoglutarate to d-2-hydroxyglutarate (d-2HG). Mice expressing Idh1-R132Q in one allele in cells expressing type 2 collagen showed a disordered growth plate, with persistence of type X-expressing chondrocytes. Chondrocyte cell cultures from these animals or controls showed that there was an increase in proliferation and expression of genes characteristic of hypertrophic chondrocytes with expression of Idh1-R132Q or 2HG treatment. Col2a1-Cre;Idh1-R132Q mutant knock-in mice (mutant allele expressed in chondrocytes) did not survive after the neonatal stage. Col2a1-Cre/ERT2;Idh1-R132 mutant conditional knock-in mice, in which Cre was induced by tamoxifen after weaning, developed multiple enchondroma-like lesions. Taken together, these data show that mutant IDH or d-2HG causes persistence of chondrocytes, giving rise to rests of growth-plate cells that persist in the bone as enchondromas.
Proceedings of the National Academy of Sciences 02/2015; 112(9):201424400. DOI:10.1073/pnas.1424400112 · 9.67 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Pigmented villonodular synovitis (PVNS) is a rare proliferative process of the synovium which most commonly affects the knee and occurs in either a localised (LPVNS) or a diffuse form (DPVNS). The effect of different methods of surgical synovectomy and adjuvant radiotherapy on the rate of recurrence is unclear. We conducted a systematic review and identified 35 observational studies in English which reported the use of surgical synovectomy to treat PVNS of the knee. A meta-analysis included 630 patients, 137 (21.8%) of whom had a recurrence after synovectomy. For patients with DPVNS, low-quality evidence found that the rate of recurrence was reduced by both open synovectomy (odds ration (OR) = 0.47; 95% CI 0.25 to 0.90; p = 0.024) and combined open and arthroscopic synovectomy (OR = 0.19, 95% CI = 0.06 to 0.58; p = 0.003) compared with arthroscopic surgery. Very low-quality evidence found that the rate of recurrence of DPVNS was reduced by peri-operative radiotherapy (OR = 0.31, 95% CI 0.14 to 0.70; p = 0.01). Very low-quality evidence suggested that the rate of recurrence of LPVNS was not related to the surgical approach. This meta-analysis suggests that open synovectomy or synovectomy combined with peri-operative radiotherapy for DPVNS is associated with a reduced rate of recurrence. Large long-term prospective multicentre observational studies, with a focus on both rate of recurrence and function, are required to confirm these findings. Cite this article: Bone Joint J 2015;97-B:550–7.
The Bone & Joint Journal 01/2015; 97-B:550-557. DOI:10.1302/0301-620X.97B4 · 3.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background
Complex anatomy of the forearm may impact on local control and survivals of soft tissue sarcoma. Little is known about characteristics and oncologic outcomes following surgical treatment. Methods
Demographic and tumor data of 117 patients with forearm soft tissue sarcoma were collected and analyzed. Following limb salvage, survivals, and prognostic factors were studied. ResultsSeventy-three patients were males (62%) and 53 (45%) were referred after unplanned excision. Pleomorphic undifferentiated sarcoma was most frequent (45%). The average tumor size was 5.1cm and grade III histology was mostly identified (53%). With radiotherapy, local recurrence occurs in 8 patients (7%) and 30 patients (24%) developed metastasis. Overall survival, disease free survival, local recurrence free survival, and metastasis free survival were 83%, 74%, 93%, and 74%, respectively. Better survival was found for grade I (80% vs. 60%) and small size (<5cm) (72% vs. 47%). Large size tumor, extra-compartmental site, extramuscular, and virgin tumor were positive predictors of metastasis. Conclusion
Soft tissue sarcomas of the forearm are often referred after unplanned excision. Limb salvage was achieved for most and local recurrence remained low in context of radiotherapy. Metastatic progression remained frequent. Low grade and small size were predictors of survival. J. Surg. Oncol. 2014 110:676-681. (c) 2014 Wiley Periodicals, Inc.