Non-neoplastic soft tissue masses that mimic sarcoma

Non-neoplastic soft tissue masses may mimic soft tissue sarcoma in a wide variety of clinical settings. Systematic and thorough review of patient history, physical examination, imaging, laboratory results, and biopsy will allow the clinician to differentiate between the two in most cases. We describe several common non-neoplastic entities that may mimic soft tissue sarcoma in case presentation format along with the characteristics that help distinguish them.

Bone cancer

Primary bone cancers are extremely rare neoplasms, accounting for fewer than 0.2% of all cancers. The evaluation and treatment of patients with bone cancers requires a multidisciplinary team of physicians, including musculoskeletal, medical, and radiation oncologists, and surgeons and radiologists with demonstrated expertise in the management of these tumors. Long-term surveillance and follow-up are necessary for the management of treatment late effects related to surgery, radiation therapy, and chemotherapy. These guidelines discuss the management of chordoma, giant cell tumor of the bone, and osteosarcoma.

Epithelioid hemangioma of the spine: a case series of six patients and review of the literature

BACKGROUND CONTEXT

Epithelioid hemangioma (EH) of bone is a benign vascular tumor that can be locally aggressive. It rarely arises in the spine, and the optimum management of EH of the vertebrae is not well delineated.

PURPOSE

The report describes our experience treating six patients with EH of the spine in an effort to document the treatment of the rare spinal presentation.

STUDY DESIGN

This study is designed as a retrospective cohort study.

PATIENT SAMPLE

A continuous series of patients with the diagnosis of EH of the spine who presented at our institution.

OUTCOME MEASURES

The clinical and radiographic follow-up of the patient population is documented.

METHODS

The Bone Sarcoma Registry at our institution was used to obtain a list of all patients diagnosed with EH of the spine. Medical records, radiographs, and pathology reports were retrospectively reviewed in all cases. Only biopsy-proven cases were included.

RESULTS

The six patients included five men and one woman who ranged in age from 20 to 58 years (with an average age of 40 years). The follow-up available for all six patients ranged from 6 to 115 (average 46.8) months. All patients presented with lytic vertebral body lesions. Five patients presented with pain secondary to their tumor, and the tumor in the sixth patient was found incidentally during the workup for a herniated disc. Three patients required surgical management for instability secondary to the destructive nature of their tumors, and two other patients required emergent decompression secondary to spinal cord compression by the tumor. The sixth patient was treated expectantly after biopsy confirmation. Three patients received postoperative radiation therapy as gross tumor remained after surgery. Three patients had gross total resections and did not receive postoperative radiation. Preoperative embolization was used in four patients. One patient continued to have back pain after surgery and radiation and another continued to have ataxia after surgery and radiation. No tumor locally recurred or progressed.

CONCLUSIONS

Our data suggest that EH of the spine can be locally aggressive and lead to instability and cord compression. Surgery is required in such instances; however, observation should be considered in patients without instability or cord compression.

Tissue microarray immunohistochemical detection of brachyury is not a prognostic indicator in chordoma

Brachyury is a marker for notochord-derived tissues and neoplasms, such as chordoma. However, the prognostic relevance of brachyury expression in chordoma is still unknown. The improvement of tissue microarray technology has provided the opportunity to perform analyses of tumor tissues on a large scale in a uniform and consistent manner. This study was designed with the use of tissue microarray to determine the expression of brachyury. Brachyury expression in chordoma tissues from 78 chordoma patients was analyzed by immunohistochemical staining of tissue microarray. The clinicopathologic parameters, including gender, age, location of tumor and metastatic status were evaluated. Fifty-nine of 78 (75.64%) tumors showed nuclear staining for brachyury, and among them, 29 tumors (49.15%) showed 1+ (<30% positive cells) staining, 15 tumors (25.42%) had 2+ (31% to 60% positive cells) staining, and 15 tumors (25.42%) demonstrated 3+ (61% to 100% positive cells) staining. Brachyury nuclear staining was detected more frequently in sacral chordomas than in chordomas of the mobile spine. However, there was no significant relationship between brachyury expression and other clinical variables. By Kaplan-Meier analysis, brachyury expression failed to produce any significant relationship with the overall survival rate. In conclusion, brachyury expression is not a prognostic indicator in chordoma.

β-Catenin mutation status and outcomes in sporadic desmoid tumors

BACKGROUND

Mutations in the gene-encoding β-catenin, CTNNB1, are highly prevalent in sporadic desmoid tumors and may predict the risk for recurrence. We sought to determine the prevalence of CTNNB1 mutations in a large cohort of sporadic desmoid tumors and to determine whether CTNNB1 mutation status correlates with disease outcome.

METHODS

Single-base extension genotyping of the CTNNB1 gene was performed on 145 sporadic, paraffin-embedded desmoid tumor specimens. Correlation of mutation status with outcome was performed on a subset of 115 patients who underwent macroscopically complete surgical resection.

RESULTS

CTNNB1 mutations were detected in 106 of 145 (73%) tumor specimens and in 86 of 115 (75%) specimens from patients who underwent curative-intent surgical resection, including discrete mutations in the following codons of CTNNB1 exon 3: T41A (46%), S45F (25%), S45P (1.7%), and S45C (0.9%). Desmoid tumors of the superficial trunk were significantly less likely to harbor CTNNB1 mutations than tumors located elsewhere, but none of the other examined clinicopathologic factors were found to be associated with CTNNB1 mutation status. At a median follow-up of 31 months, 5-year recurrence-free survival was slightly, although not statistically significantly, worse for patients with β-catenin-mutated tumors than for those with wild-type tumors (58% vs. 74%, respectively). The specific CTNNB1 codon mutation did not correlate with the risk for recurrence.

CONCLUSION

CTNNB1 mutations are indeed common in sporadic desmoid tumors. However, our study did not detect a statistically significant difference in recurrence risk according to either the CTNNB1 mutation status or the specific CTNNB1 mutation.

Targeting hedgehog-GLI-2 pathway in osteosarcoma

Osteosarcoma is the most common primary malignant tumor of bone. Patients with localized osteosarcoma are routinely treated with chemotherapy and surgery. However, many of these patients eventually relapse after these treatments. In such cases, there are limited treatment options for these patients and most will eventually die with metastatic disease. Therefore, it is imperative to identify better therapeutic strategies. Hedgehog-GLI is responsible for the development of vertebrate embryonic and tumorigenesis. Specifically, the transcription factor, GLI-2, plays a key role in development of normal prostate. Aberrant activation of GLI-2 is correlated with various malignancies. We observe that GLI-2 is highly expressed in osteosarcoma cell lines, and this correlates with poor clinical outcomes in patients. Knockdown of GLI-2 by siRNA decreases osteosarcoma cell proliferation and viability, which eventually induces cell death as revealed in both in 2D and 3D cultures. In addition, we notice that administration of GLI-2 siRNA can increase the sensitivity of osteosarcoma cells to chemotherapeutic drugs. These findings suggest GLI-2 is required for osteosarcoma cell proliferation and survival. GLI-2 may be exploited as a therapeutic target for the treatment of osteosarcoma patients.

Lipid-functionalized dextran nanosystems to overcome multidrug resistance in cancer: a pilot study

BACKGROUND

The toxicity of anticancer agents and the difficulty in delivering drugs selectively to tumor cells pose a challenge in overcoming multidrug resistance (MDR). Recently, nanotechnology has emerged as a powerful tool in addressing some of the barriers to drug delivery, including MDR in cancer, by utilizing alternate routes of cellular entry and targeted delivery of drugs and genes. However, it is unclear whether doxorubicin (Dox) can be delivered by nanotechnologic approaches.

QUESTIONS/PURPOSES

We asked whether (1) Dox-loaded lipid-functionalized dextran-based biocompatible nanoparticles (Dox/NP) can reverse MDR, (2) Dox/NP has more potent cytotoxic effect on MDR tumors than poly(ethylene glycol)-modified liposomal Dox (PLD), and (3) multidrug resistance protein 1 (MDR1) small interfering RNA loaded in these nanoparticles (siMDR1/NP) can modulate MDR.

METHODS

To create stable Dox/NP and siMDR1/NP, we used two different lipid-modified dextran derivatives. The effect of Dox or Dox/NP was tested on drug-sensitive osteosarcoma (KHOS) and ovarian cancer (SKOV-3) cell cultures in triplicate and their respective MDR counterparts KHOS(R2) and SKOV-3(TR) in triplicate. We determined the effects on drug retention, transfection efficacy of siMDR1/NP, and P-glycoprotein expression and the antiproliferative effect between Dox/NP and PLD in MDR tumor cells.

RESULTS

Fluorescence microscopy revealed efficient uptake of the Dox/NP and fluorescently tagged siMDR1/NP. Dox/NP showed five- to 10-fold higher antiproliferative activity at the 50% inhibitory concentration than free Dox in tumor cells. Dox/NP showed twofold higher activity than PLD in MDR tumor cells. siMDR1/NP (100 nM) suppressed P-glycoprotein expression in KHOS(R2).

CONCLUSIONS

Dextran-lipid nanoparticles are a promising platform for delivering Dox and siRNAs.

CLINICAL RELEVANCE

Biocompatible dextran-based nanoparticles that are directly translatable to clinical medicine may lead to new potential therapeutics for reversing MDR in patients with cancer.

Pleomorphic spindle cell sarcoma (PSCS) formerly known as malignant fibrous histiocytoma (MFH): a complex malignant soft-tissue tumor

A presentation defining the nature, characteristics, causation, treatment and outcome of patients with lesions formerly known as malignant fibrous histiocytoma and now as pleomorphic spindle cell sarcoma is clearly a very difficult subject. Many authors do not believe that the tumor exists and instead describe them as forms of fibrosarcomas, fibromyxoid lesions, dedifferentiated chondrosarcomas or even leiomyosarcomas. The reasons for this confusion are presumably related to the fact that the malignant pleomorphic spindle cell sarcoma does not seem to be a distinct type of lesion with specific histologic and genetic characteristics. Instead, the tumor has at least four separate histologic variations and no specific gene signature and in fact does not seem to be either familial or ethnic in presentation. In view of the fact that the tumor was traditionally the most frequently encountered malignant soft-tissue neoplasm, the world of orthopedic oncology is clearly distressed by the problems that these patients have and is joined by the radiation oncologists and chemotherapists in seeking new solutions.

Role of resection of malignant peripheral nerve sheath tumors in patients with neurofibromatosis type 1

OBJECT

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas that often arise from major peripheral nerves. Approximately half of MPNSTs arise in patients with neurofibromatosis Type 1 (NF1) who, in comparison with patients without NF1, present at younger ages and with larger tumors that are commonly associated with extensive plexiform neurofibromas. These tumors therefore pose a particularly difficult treatment challenge because of the morbidity often associated with attempted gross-total resection (GTR). Here, the authors aim to examine what role the extent of resection and other covariates play in the long-term survival of patients with NF1 in the setting of MPNST.

METHODS

The authors retrospectively reviewed the records of 23 adult patients with NF1 who underwent surgery for MPNSTs at their institution between 1991 and 2008. The primary end points of the study were mortality, local recurrence, and metastasis. Kaplan-Meier survival curves were evaluated for all patients. Differences for each of the primary end points were evaluated based on cause-specific covariates, which included tiered tumor size, tumor location, grade, resection margin status, postoperative weakness, and use of chemotherapy and radiation therapy. Multivariate analysis was performed using Cox proportional hazards models.

RESULTS

Gross-total resection (p = 0.01) and surgical margin status (p = 0.034) had a statistically important role in prolonging overall survival in patients with NF1 by univariate analysis. When tumor size, location, grade, postoperative weakness, and radiation therapy were also taken into account using multivariate analysis, GTR continued to be a significant prognostic factor (p = 0.035).

CONCLUSIONS

These findings suggest that GTR offers significant long-term benefit on survival in patients with NF1. Benefit on survival occurred independently of all other covariates, suggesting that complete resection should be the principal goal of treatment in this patient population.

Establishment and characterization of a novel chordoma cell line: CH22

Chordoma is a rare primary malignant bone tumor and there exist only a few established human chordoma cell lines. The scarcity of robust chordoma cell lines has limited the ability to study this tumor. In this report, we describe the establishment of a novel chordoma cell line and characterize its in vitro and in vivo behaviors. The tumor tissue was isolated from a patient with recurrent chordoma of the sacrum. After 6 months in culture, the chordoma cell line, referred here as CH22, was established. Microscopic analysis of two-dimensional culture confirmed that the CH22 cells exhibited a typical vacuolated cytoplasm similar to the well-established chordoma cell line U-CH1. Electron microscopy showed cohesive cells with numerous surface filopodia, pockets of glycogen and aggregates of intermediate tonofilaments in cytoplasm. Three-dimensional culture revealed that the CH22 cells could grow and form clusters by day 8. The MTT assays demonstrated that, compared with sensitive osteosarcoma cell lines, CH22 cells were relatively resistant to conventional chemotherapeutic drugs. Western blotting and immunofluorescence analysis confirmed that the CH22 cells expressed brachyury, vimentin, and cytokeratin. Finally, histological analysis of CH22 xenograft tumor tissues demonstrated the appearance of physaliphorous cells and positive staining of brachyury, cytokeratin, and S100. By CT and MRI, imaging xenografts showed the typical appearances seen in human chordomas. These findings suggest that the established novel human chordoma cell line CH22 and its tumorigenecity in SCID nude mice may serve as an important model for studying chordoma cell biology and the development of new therapeutic modalities.

Desmoid tumor: analysis of prognostic factors and outcomes in a surgical series

BACKGROUND

Desmoid tumors are rare and exhibit a highly unpredictable natural history. We sought to analyze prognostic factors associated with recurrence in a large single-institution study of patients with desmoid tumors.

METHODS

We performed a retrospective review of 177 patients with desmoid tumor who underwent macroscopically complete surgical resection, with or without the addition of radiotherapy (RT) or systemic therapy, from 1970 to 2009. We examined patterns of presentation, all known risk factors for recurrence, and their association with recurrence-free survival (RFS).

RESULTS

Twenty-two patients (12 %) had intra-abdominal desmoid tumors, and 155 (88 %) had extra-abdominal tumors. Patterns of presentation included primary (n = 133, 75 %) and locally recurrent (n = 44, 25 %) disease. Treatment was surgery alone in 125 patients (71 %), surgery and RT in 36 (20 %), and surgery and systemic therapy with or without RT in 20 (11 %). Median follow-up was 40 months. Overall, the local relapse rate was 29 %, and 10-year RFS was 60 %. R0 resection status was the only predictor of freedom from local recurrence on multivariate analysis (odds ratio 0.32; 95 % confidence interval 0.15-0.66; P = 0.002). The selective use of adjuvant RT appeared to improve local control in patients with positive margins.

CONCLUSIONS

For patients with desmoid tumors undergoing surgery, wide excision with negative margins should be the goal, but not at the expense of function, as fewer than half of patients with positive margins will experience recurrence.

Prognostic factors and outcomes of patients with myxofibrosarcoma

BACKGROUND

Myxofibrosarcomas (MFS) are a historically heterogeneous group of tumors that exhibit a propensity for local recurrence. The objectives of this study were to analyze the prognostic factors and outcomes of patients with MFS treated at a single institution.

METHODS

We retrospectively reviewed the records of 69 consecutive patients with pathologically confirmed MFS of the extremities or superficial trunk who underwent surgery from August 1995 to November 2010. Clinicopathologic features, treatments, and patient outcomes were reviewed.

RESULTS

Sixty-nine patients were identified, of whom 38 were men (55%). The median age was 62 years. Sixty-four patients (93%) presented with primary tumors, and 5 patients (7%) presented with locally recurrent tumors. Median tumor size was 6.0 cm, and 44 patients (64%) had grade 3 tumors (FNCLCC [Fédération Nationale des Centres de Lutte Contre le Cancer] classification). Margins were microscopically positive in 14 patients (20%) and negative in 55 patients (80%), including close margins (<1 mm) in 14 patients (20%). Fifty-three patients (77%) received radiotherapy. At a median follow-up of 41 months, there were 11 local (16%) and 11 distant (16%) recurrences. The local and distant 5-year recurrence-free survival rates were 72% and 82%, and the 5-year overall survival was 61%. Increased age (scaled by 0.1; hazard ratio [HR] 1.80, P=0.002) and tumor size (HR 1.12, P=0.004) were negatively correlated with overall survival. Positive/close (<1 mm) margin status (HR 4.34, P=0.030) predicted worsened local recurrence-free survival.

CONCLUSIONS

MFS exhibit a propensity for local recurrence, which is predicted by resection with positive or close margins. Aggressive surgery combined with radiotherapy may contribute to more effective local control.

Systematic kinome shRNA screening identifies CDK11 (PITSLRE) kinase expression is critical for osteosarcoma cell growth and proliferation

PURPOSE

Identification of new targeted therapies is critical to improving the survival rate of patients with osteosarcoma. The goal of this study is to identify kinase based potential therapeutic target in osteosarcomas.

EXPERIMENTAL DESIGN

We used a lentiviral-based shRNA kinase library to screen for kinases which play a role in osteosarcoma cell survival. The cell proliferation assay was used to evaluate cell growth and survival. siRNA assays were applied to confirm the observed phenotypic changes resulting from the loss of kinase gene expression. CDK11 (PITSLRE) was identified as essential for the survival of osteosarcoma cells, and its expression was confirmed by Western blot analysis and immunohistochemistry. Overall patient survival was correlated with the CDK11 expression and its prognosis. The role of CDK11 expression in sustaining osteosarcoma growth was further evaluated in an osteosarcoma xenograft model in vivo.

RESULTS

Osteosarcoma cells display high levels of CDK11 expression. CDK11 expression knocked down by either lentiviral shRNA or siRNA inhibit cell growth and induce apoptosis in osteosarcoma cells. Immunohistochemical analysis showed that patients with osteosarcoma with high CDK11 tumor expression levels were associated with significantly shorter survival than patients with osteosarcoma with low level of tumor CDK11 expression. Systemic in vivo administration of in vivo ready siRNA of CDK11 reduced the tumor growth in an osteosarcoma subcutaneous xenograft model.

CONCLUSIONS

We show that CDK11 signaling is essential in osteosarcoma cell growth and survival, further elucidating the regulatory mechanisms controlling the expression of CDK11 and ultimately develop a CDK11 inhibitor that may provide therapeutic benefit against osteosarcoma.

Neoadjuvant chemoradiotherapy for patients with high-risk extremity and truncal sarcomas: A 10-year follow-up study

10058

Background: Patients with high-risk extremity and truncal soft tissue sarcomas (STS) are at considerable risk for recurrence. A regimen of preoperative mesna, doxorubucin hydrochloride (Adriamycin), ifosfamide, and dacarbazine (MAID), interdigitated with radiotherapy (RT), followed by resection and postoperative chemotherapy with or without RT, has demonstrated high rates of local and distant control. The goal of this series is to study outcomes of our most recent cohort of patients treated on this regimen. Methods: We retrospectively reviewed records of 55 consecutive patients with STS of the extremity or superficial trunk who completed all phases of treatment at our institution from January 2000–July 2011. Clinicopathologic characteristics and patient outcomes were analyzed. Results: Fifty-five patients were analyzed and had a median age of 53 years (range 18-73). The median tumor size was 10.1cm (range 2.5-35.5 cm). Twenty-seven (49%) and 28 (51%) patients had grade 2 and 3 tumors, respectively. Margins were negative in 49 (89%) patients, and positive in 6 (11%) patients. At a median follow-up of 43 months, there were 7 (13%) locoregional, and 17 (31%) distant recurrences. The local and distant 5-year recurrence-free survival (RFS) rates were 92% and 64%, respectively. The 5-year overall (OS) and disease-specific survival rates were 86% and 89%, respectively. There were no treatment-related deaths or secondary myelodysplasias. There were no significant predictors of OS or RFS. Conclusions: Outcomes of a contemporary cohort of patients with extremity and truncal STS treated with an intense regimen of neoadjuvant chemoradiotherapy and surgery are consistent with previous reports from our institution and better than reports of chemotherapy alone. [Table: see text]

Long-term follow-up of patients treated with neoadjuvant chemotherapy and radiotherapy for large, extremity soft tissue sarcomas

BACKGROUND

Patients with large, high-grade, extremity soft tissue sarcomas (STS) are at significant risk for distant recurrence and death. A regimen of preoperative chemotherapy consisting of mesna, Adriamycin (doxorubicin), ifosfamide, and dacarbazine (MAID), interdigitated with radiotherapy (RT) and followed by resection and postoperative chemotherapy with or without RT, has demonstrated high rates of local and distant control. We report the long-term follow-up data on 48 patients treated with this regimen compared to an historical matched-control patient population.

METHODS

Adult patients with high-grade extremity STS ≥ 8 cm were treated with 3 cycles of preoperative chemotherapy combined with 44 Gy of RT followed by surgery. Three cycles of postoperative MAID were planned. For patients with positive surgical margins, 16 Gy of RT was delivered postoperatively.

RESULTS

Patients received the MAID/RT regimen from 1989 through 1999. After a median follow-up of 9.3 years in surviving patients in the MAID group and 13.2 years in surviving patients in the control group, the 7-year disease-specific and overall survival rates were 81% and 50% (P = .004) and 79% and 45% (P = .003) for the MAID and control patients, respectively. Five of 11 patients in the MAID group and 7 of 25 control patients died of sarcoma ≥5 years after treatment. One patient in the MAID group developed a fatal myelodysplasia at 53 months.

CONCLUSIONS

For patients with high-risk, extremity STS, the significant survival benefits conferred by an intense regimen of neoadjuvant chemoradiotherapy and surgery are sustained even with long-term follow-up.

Phase II study of neoadjuvant bevacizumab and radiotherapy for resectable soft tissue sarcomas

PURPOSE

Numerous preclinical studies have demonstrated that angiogenesis inhibitors can increase the efficacy of radiotherapy (RT). We sought to examine the safety and efficacy of bevacizumab (BV) and RT in soft tissue sarcomas and explore biomarkers to help determine the treatment response.

METHODS AND MATERIALS

Patients with ≥5 cm, intermediate- or high-grade soft tissue sarcomas at significant risk of local recurrence received neoadjuvant BV alone followed by BV plus RT before surgical resection. Correlative science studies included analysis of the serial blood and tumor samples and serial perfusion computed tomography scans.

RESULTS

The 20 patients had a median tumor size of 8.25 cm, with 13 extremity, 1 trunk, and 6 retroperitoneal/pelvis tumors. The neoadjuvant treatment was well tolerated, with only 4 patients having Grade 3 toxicities (hypertension, liver function test elevation). BV plus RT resulted in ≥80% pathologic necrosis in 9 (45%) of 20 tumors, more than double the historical rate seen with RT alone. Three patients had a complete pathologic response. The median microvessel density decreased 53% after BV alone (p <.05). After combination therapy, the median tumor cell proliferation decreased by 73%, apoptosis increased 10.4-fold, and the blood flow, blood volume, and permeability surface area decreased by 62-72% (p <.05). Analysis of gene expression microarrays of untreated tumors identified a 24-gene signature for treatment response. The microvessel density and circulating progenitor cells at baseline and the reduction in microvessel density and plasma soluble c-KIT with BV therapy also correlated with a good pathologic response (p <.05). After a median follow-up of 20 months, only 1 patient had developed local recurrence.

CONCLUSIONS

The results from the present exploratory study indicated that BV increases the efficacy of RT against soft tissue sarcomas and might reduce the incidence of local recurrence. Thus, this regimen warrants additional investigation. Gene expression profiles and other tissue and circulating biomarkers showed promising correlations with treatment response.

Proton-based radiotherapy for unresectable or incompletely resected osteosarcoma

BACKGROUND

A study was undertaken to assess clinical outcome and the role of proton therapy for local control of osteosarcoma (OSA).

METHODS

All patients who received proton therapy or mixed photon-proton radiotherapy from 1983 to 2009 at the Massachusetts General Hospital were reviewed. Criteria for proton therapy were the need for high dose in the context of highly conformal radiotherapy of unresected or partially resected OSA, positive postoperative margins, postoperative imaging studies with macroscopic disease, or incomplete resection as defined by the surgeon. The primary endpoint was local control of the site treated; secondary endpoints were disease-free survival (DFS), overall survival (OS), long-term toxicity, and prognostic factors associated with clinical outcome.

RESULTS

Fifty-five patients with a median age of 29 years (range, 2-76 years) were offered proton therapy. The mean dose was 68.4 gray (Gy; standard deviation, 5.4 Gy). Of the total dose, 58.2% (range, 11%-100%) was delivered with protons. Local control after 3 and 5 years was 82% and 72%, respectively. The distant failure rate was 26% after 3 and 5 years. The 5-year DFS was 65%, and the 5-year OS was 67%. The extent of surgical resection did not correlate with outcome. Risk factors for local failure were ≥ 2 grade disease (P < .0001) and total treatment length (P = .008). Grade 3 to 4 late toxicity was seen in 30.1 % of patients. One patient died from treatment-associated acute lymphocytic leukemia, and 1 from secondary carcinoma of the maxilla.

CONCLUSIONS

Proton therapy to deliver high radiotherapy doses allows locally curative treatment for some patients with unresectable or incompletely resected OSA.

ROCK1 as a potential therapeutic target in osteosarcoma

Osteosarcoma is the most common primary malignancy of bone. Patients with localized disease are routinely treated with surgery and chemotherapy. Unfortunately, many of these patients eventually relapse even after high-dose pre- and postoperative chemotherapy. Upon recurrence of the tumor locally or distantly, they have limited treatment options that are usually unsuccessful. Our prior studies screening lentiviral shRNA libraries, searching for kinases involved in osteosarcoma cell growth and proliferation have identified the Rho-associated coiled-coil containing protein kinase 1 (ROCK1) as a possible hit. We show in this study that ROCK1 is highly expressed in various tumor cell lines and tumor tissues from osteosarcoma patients. ROCK1 knockdown by synthetic siRNA decreases cell proliferation, viability and induces apoptosis in osteosarcoma cell lines KHOS and U-2OS. Finally, we established the relationship between expression levels of ROCK1 and clinical prognosis in osteosarcoma patients by using immunohistochemistry. There were significant differences in overall survival between cohorts of patients with ROCK1 levels categorized as high-staining, moderate-staining, and low-staining. High levels of ROCK1 were associated with poor outcomes in clinical osteosarcoma. These findings suggest that knockdown of ROCK1 inhibits proliferation and induces apoptosis in osteosarcoma cell lines. ROCK1 may be a promising therapeutic target for the treatment of osteosarcoma patients.

Inhibition of polo-like kinase 1 leads to the suppression of osteosarcoma cell growth in vitro and in vivo

Osteosarcoma is the most common type of primary bone cancer in children and adolescents. Treatment options for osteosarcoma may include surgery, chemotherapy, and radiotherapy. Unfortunately, many patients eventually relapse, resulting in an unsatisfactory outcome. The serine/threonine-specific polo-like kinase 1 (PLK1) is a kinase that plays an important role in mitosis and the maintenance of genomic stability. PLK1 has been found to be highly expressed in the malignant cells of osteosarcoma. Here, we describe the in-vitro and in-vivo effects of BI 2536, a small-molecule inhibitor of PLK1, which through inhibiting PLK1 enzymatic activity, causes mitotic arrest and eventually induces cancer cell apoptosis. In this study, we show that the PLK1 inhibitor, BI 2536, inhibits proliferation and induces apoptosis in two-dimensional and three-dimensional cultures of osteosarcoma cell lines, KHOS and U-2OS. A proliferation assay performed both in two-dimensional and three-dimensional culture showed that the growth of both cell lines was inhibited by BI 2536. Cell cycle analysis showed that the cells treated with BI 2536 were mainly arrested in the G2/M phase. Immunofluorescence and western blotting analysis confirmed that the administration of BI 2536 led to significant decrease of PLK1 and Mcl-1 protein expression levels in dose-dependent and time-dependent manners. Furthermore, BI 2536-induced apoptosis in the osteosarcoma cell lines was shown by poly (ADP-ribose) polymerase cleavage and caspase assay. Finally, in mouse osteosarcoma xenografts, BI 2536-treated mice had significantly smaller tumors compared with the control mice. These findings offer evidence of the potential role for targeting PLK1 in osteosarcoma therapy.

Recurrent chromosomal copy number alterations in sporadic chordomas

The molecular events in chordoma pathogenesis have not been fully delineated, particularly with respect to copy number changes. Understanding copy number alterations in chordoma may reveal critical disease mechanisms that could be exploited for tumor classification and therapy. We report the copy number analysis of 21 sporadic chordomas using array comparative genomic hybridization (CGH). Recurrent copy changes were further evaluated with immunohistochemistry, methylation specific PCR, and quantitative real-time PCR. Similar to previous findings, large copy number losses, involving chromosomes 1p, 3, 4, 9, 10, 13, 14, and 18, were more common than copy number gains. Loss of CDKN2A with or without loss of CDKN2B on 9p21.3 was observed in 16/20 (80%) unique cases of which six (30%) showed homozygous deletions ranging from 76 kilobases to 4.7 megabases. One copy loss of the 10q23.31 region which encodes PTEN was found in 16/20 (80%) cases. Loss of CDKN2A and PTEN expression in the majority of cases was not attributed to promoter methylation. Our sporadic chordoma cases did not show hotspot point mutations in some common cancer gene targets. Moreover, most of these sporadic tumors are not associated with T (brachyury) duplication or amplification. Deficiency of CDKN2A and PTEN expression, although shared across many other different types of tumors, likely represents a key aspect of chordoma pathogenesis. Sporadic chordomas may rely on mechanisms other than copy number gain if they indeed exploit T/brachyury for proliferation.