New Synthetic Lethality Re-Sensitizing Platinum-Refractory Cancer Cells to Cisplatin In Vitro: The Rationale to Co-Use PARP and ATM Inhibitors.

The pro-apoptotic tumor suppressor BIN1 inhibits the activities of the neoplastic transcription factor MYC, poly (ADP-ribose) polymerase-1 (PARP1), and ATM Ser/Thr kinase (ATM) by separate mechanisms. Although BIN1 deficits increase cancer-cell resistance to DNA-damaging chemotherapeutics, such as cisplatin, it is not fully understood when BIN1 deficiency occurs and how it provokes cisplatin resistance. Here, we report that the coordinated actions of MYC, PARP1, and ATM assist cancer cells in acquiring cisplatin resistance by BIN1 deficits. Forced BIN1 depletion compromised cisplatin sensitivity irrespective of Ser15-phosphorylated, pro-apoptotic TP53 tumor suppressor. The BIN1 deficit facilitated ATM to phosphorylate the DNA-damage-response (DDR) effectors, including MDC1. Consequently, another DDR protein, RNF8, bound to ATM-phosphorylated MDC1 and protected MDC1 from caspase-3-dependent proteolytic cleavage to hinder cisplatin sensitivity. Of note, long-term and repeated exposure to cisplatin naturally recapitulated the BIN1 loss and accompanying RNF8-dependent cisplatin resistance. Simultaneously, endogenous MYC was remarkably activated by PARP1, thereby repressing the BIN1 promoter, whereas PARP inhibition abolished the hyperactivated MYC-dependent BIN1 suppression and restored cisplatin sensitivity. Since the BIN1 gene rarely mutates in human cancers, our results suggest that simultaneous inhibition of PARP1 and ATM provokes a new BRCAness-independent synthetic lethal effect and ultimately re-establishes cisplatin sensitivity even in platinum-refractory cancer cells.

The financial burden of reexcising incompletely excised soft tissue sarcomas: a cost analysis.

BACKGROUND: Although survival outcomes have been evaluated between those undergoing a planned primary excision and those undergoing a reexcision following an unplanned resection, the financial implications associated with a reexcision have yet to be elucidated. METHODS: A query for financial data (professional, technical, indirect charges) for soft tissue sarcoma excisions from 2005 to 2008 was performed. A total of 304 patients (200 primary excisions and 104 reexcisions) were identified. Wilcoxon rank sum tests and χ2 or Fisher's exact tests were used to compare differences in demographics and tumor characteristics. Multivariable linear regression analyses were performed with bootstrapping techniques. RESULTS: The average professional charge for a primary excision was $9,694 and $12,896 for a reexcision (p<.001). After adjusting for tumor size, American Society of Anesthesiologists status, grade, and site, patients undergoing reexcision saw an increase of $3,699 in professional charges more than those with a primary excision (p<.001). Although every 1-cm increase in size of the tumor results in an increase of $148 for a primary excision (p=.006), size was not an independent factor in affecting reexcision charges. The grade of the tumor was positively associated with professional charges of both groups such that higher-grade tumors resulted in higher charges compared to lower-grade tumors (p<.05). CONCLUSIONS: Reexcision of an incompletely excised sarcoma results in significantly higher professional charges when compared to a single, planned complete excision. Additionally, when the cost of the primary unplanned surgery is considered, the financial burden nearly doubles.

Serum levels of methyl methacrylate following inhalational exposure to polymethylmethacrylate bone cement.

UNLABELLED: Teratogenic effects of polymethylmethacrylate cement at levels used during routine orthopaedic procedures have never been reported, however the hypothetical risk remains a major concern among female surgeons. Our aim was to determine if methyl methacrylate is detectible in the serum during routine cement exposure. METHODS: Twenty healthy volunteers were exposed during the mixing of polymethylmethacrylate cement in a simulated operating room environment. Forty serum samples were obtained during the expected peak inhalational exposure and levels of methyl methacrylate were assessed utilizing headspace gas chromatography mass spectrometry. RESULTS: Methyl methacrylate was not detected in any of the forty experimental specimens. CONCLUSIONS: With a detection level of 0.5 ppm, methyl methacrylate is undetectable in the serum during routine mixing of polymethylmethacrylate cement.

Signal transduction pathway analysis in desmoid-type fibromatosis: transforming growth factor-ß, COX2 and sex steroid receptors.

Despite reports of sex steroid receptor and COX2 expression in desmoid-type fibromatosis, responses to single agent therapy with anti-estrogens and non-steroidal anti-inflammatory drugs are unpredictable. Perhaps combination pharmacotherapy might be more effective in desmoid tumors that co-express these targets. Clearly, further understanding of the signaling pathways deregulated in desmoid tumors is essential for the development of targeted molecular therapy. Transforming growth factor-ß (TGFß) and bone morphogenetic proteins (BMP) are important regulators of fibroblast proliferation and matrix deposition, but little is known about the TGFß superfamily in fibromatosis. A tissue microarray representing 27 desmoid tumors was constructed; 14 samples of healing scar and six samples of normal fibrous tissue were included for comparison. Expression of selected receptors and activated downstream transcription factors of TGFß family signaling pathways, ß-catenin, sex steroid hormone receptors and COX2 were assessed using immunohistochemistry; patterns of co-expression were explored via correlational statistical analyses. In addition to ß-catenin, immunoreactivity for phosphorylated SMAD2/3 (indicative of active TGFß signaling) and COX2 was significantly increased in desmoid tumors compared with healing scar and quiescent fibrous tissue. Low levels of phosphorylated SMAD1/5/8 were detected in only a minority of cases. Transforming growth factor-ß receptor type 1 and androgen receptor were expressed in both desmoid tumors and scar, but not in fibrous tissue. Estrogen receptor-ß was present in all cases studied. Transforming growth factor-ß signaling appears to be activated in desmoid-type fibromatosis and phosphorylated SMAD2/3 and COX2 immunoreactivity might be of diagnostic utility in these tumors. Given the frequency of androgen receptor, estrogen receptor-ß and COX2 co-expression in desmoid tumors, further assessment of the efficacy of combination pharmacotherapy using hormonal agonists/antagonists together with COX2 inhibitors should be considered.

Nuclear p63 expression in osteoblastic tumors.

Expression of the p63 tumor suppressor protein has been reported in the mononuclear stromal cells of giant cell tumor of the bone, which may represent osteoblast-precursor cells. Only a limited number of osteoblastic tumors have been studied for p63 expression thus far. We therefore examined whether p63 may serve as a marker for osteoblastic differentiation in osteosarcomas or as a differential diagnostic marker to distinguish osteoblastoma from osteosarcoma. Immunohistochemical stains for p63 were performed on a tissue microarray containing 71 chemotherapy naïve biopsy samples of osteosarcoma, 21 whole sections of osteosarcoma, and 8 osteoblastomas. Nuclear p63 was detected in seven of eight osteoblastomas but was restricted to stromal cells within primitive, immature-appearing areas of osteoid deposition. Although only 7 of 71 (10 %) biopsy samples of osteosarcoma represented on the tissue microarray were positive for p63, 7 of 21 (33 %) osteosarcomas were positive when whole tissue sections were evaluated. Although p63 is detected in most osteoblastomas, it is also observed in a significant subset of osteosarcomas, severely limiting its utility in distinguishing between benign and malignant osteoblastic tumors. The relatively low prevalence of p63 expression in osteosarcoma would also seem to preclude its use as a marker of osteoblastic differentiation in skeletal sarcomas.

Is There Unconscious Bias in the Orthopaedic Residency Interview Selection Process?

OBJECTIVE: Orthopaedic surgery has historically been a white male-dominated field. Given the diverse patient population presenting to providers with musculoskeletal pathology, it is thought that it would be beneficial for the orthopaedic workforce to more closely mirror this patient population. This study aims to elucidate whether unconscious bias may have an effect on the scoring of applications for residency interview selection. DESIGN: Applications for the 2019-2020 residency match cycle were initially reviewed and scored by faculty members. Applications were then redacted of all information suggestive of race or gender and returned to evaluators for rescoring after at least 6 months. The pre and post-redaction data was compared using ANOVA and student's two-tailed t tests. SETTING: Department of Orthopaedic Surgery, Medical College of Georgia at Augusta University. PARTICIPANTS: Thirteen attending surgeons scored 320 2019-2020 Electronic Residency Application System (ERAS) applications, unblinded and blinded of applicant identifying information. RESULTS: Interviewed applicants were similar to the non-interviewed group in all measured variables except for higher pre-redaction scores (8.73-7.81; p = 0.02) which was expected (Table 2). Minority applicants had significant differences in Step 1 scores (243 vs 247; p < 0.01), Step 2 scores (251 vs 254; p = 0.01), articles (5.9 vs 3.8; p < 0.01), posters (5.9 vs 3.5; p < 0.01), and pre-redaction scores (7.44 vs 8.07; p = 0.01) compared to white applicants (Table 4). There was no relationship noted between step score and number or type of research items (Table 5). Pre-redaction and post-redaction scores were significantly different in white applicants who experienced a negative change (8.07-7.88; p = 0.03 (Table 6)). Males had statistically significant differences compared to females in Step 1 score (246 vs 243; p = 0.01) (Table 7). CONCLUSIONS: This study was unable to prove unconscious bias based on a lack of statistically significant change of score when blinded, however the direction in change of scores was unlikely to be accounted for exclusively by objective differences between applicants, suggesting a trend toward unconscious bias. It remains unclear how influential subjective portions of the ERAS application such as personal statements, Letters of Recommendation, hobbies, and activities are on the overall assessment of an applicant and whether or not unconscious bias manifests in these subjective portions. Further investigation is needed in this area. Until then, residency programs should take immediate measures to mitigate potential implicit bias in the residency interview selection process. Actions can include implicit bias training for all faculty members involved in resident selection, standardization of application scoring and possibly redacting all or portions of the ERAS application so that only objective academic markers are presented to evaluators. Gaining a better understanding of these barriers is not only essential for their removal, but also allows for better preparation of applicants for success in the match with the ultimate goal being to correct the persistent disparity in the field of orthopaedic surgery.

Methylthioadenosine phosphorylase and activated insulin-like growth factor-1 receptor/insulin receptor: potential therapeutic targets in chordoma.

Currently there is no effective chemotherapy for chordoma. Recent studies report co-expression of insulin-like growth factor-1 receptor (IGF1R) and its cognate ligand in chordoma, but it is unknown whether this receptor tyrosine kinase is activated in these tumours. Additionally, genetic studies have confirmed frequent deletions of chromosome 9p in chordomas, which encompasses the cyclin-dependent kinase inhibitor 2A (CDKN2A) locus. Another gene in this region, methylthioadenosine phosphorylase (MTAP), is an essential enzyme of the purine salvage pathway and has therapeutic relevance because MTAP-deficient cells are particularly sensitive to inhibitors of de novo purine synthesis. We investigated whether these pathways might be potential therapeutic targets for chordoma. Paraffin-embedded tissue samples from 30 chordomas were analysed by immunohistochemistry for expression of the phosphorylated isoforms of IGF1R or the insulin receptor (pIGF1R/pIR) and selected downstream signalling molecules, including BCL2-associated agonist of cell death protein (BAD). Expression of CDKN2A and MTAP proteins was also assessed. Skeletal chondrosarcomas, benign notochordal cell tumours, and fetal notochord were studied for comparison. Phosphorylated IGF1R/IR was detected in 41% of chordomas, together with activated downstream signalling molecules, and pIGF1R/pIR was absent in benign notochordal cell tumours and fetal notochord. Thirty-nine per cent of chordomas were negative for MTAP immunoreactivity. Patients with pIGF1R/pIR-positive tumours showed significantly decreased median disease-free survival in multivariate survival analysis (p = 0.036), whereas phosphorylation of BAD at serine-99 was found to be associated with a favourable prognosis (p = 0.002). Approximately 40% of chordomas demonstrate evidence of activation of the IGF1R/IR signalling pathway or loss of a key enzyme in the purine salvage pathway. Aberrant signalling cascades and disrupted metabolic pathways such as these may represent opportunities for novel targeted therapeutic approaches for the treatment of chordoma.

Rare Lower Extremity Fibrosarcomatous Variant of Dermatofibrosarcoma With Myxoid Features Treated With Transtibial Amputation.

Dermatofibrosarcoma protuberans (DFSP) is an uncommon soft tissue tumor originating from the dermis, with high rates of local recurrence and invasive growth but low likelihood of distant metastasis. Fibrosarcomatous transformation (FS-DFSP) of DFSP accounts for approximately 5-15% of DFSP tumors, is a higher-grade tumor, with higher chances of metastasis and poorer prognosis. We present a case of a 66-year-old female presented with a large fungating mass on the left dorsal foot. Ultrasound-guided core needle biopsy with immunohistochemistry suggested a spindle cell neoplasm, favoring myxofibrosarcoma with intermediate grade. The patient elected for below-knee amputation over limb salvage with wide resection and free flap reconstruction. Based on clinical presentation, radiologic, histologic features and fluorescence in situ hybridization (FISH) studies confirmed the diagnosis of fibrosarcomatous variant of dermatofibrosarcoma protuberans with myxoid change. FS-DFSP with myxoid change is a rare soft tissue tumor that requires aggressive treatment due to its high rates of recurrence. This case presents a rare tumor in a unique location that was successfully treated with limb amputation, which is not documented in current literature.

Progressive Osteolysis After Use of Synthetic Bone Graft Substitute.

Benign bone tumors are commonly treated with intralesional curettage and bone graft, with autogenous bone graft being the gold standard. However, autogenous bone graft has its limitation, and artificial bone graft substitutes were developed as an alternative. PRO-DENSE™ (Wright Medical Technology, Arlington, Tennessee) is a calcium sulfate and calcium phosphate mixed bone graft substitute that is biodegradable and osteoconductive, which has made them a popular choice among surgeons. However, long-term studies of this treatment method for benign tumors are still limited. In this report, we present a case of progressive femoral neck osteolysis caused by an inflammatory reaction to PRO-DENSE™ two years after intralesional curettage and bone grafting of a benign bone tumor.  A twenty-one-year-old female with fibrous dysplasia underwent intralesional curettage with the use of PRO-DENSE™ bone substitute to fill the cavitary defect. She developed an inflammatory reaction to the bone graft substitute leading to increasing pain and osteolysis requiring a reoperation. Bone graft substitute has many advantages; however, they should be used with discretion due to many unknown regarding their safety and long-term outcomes.

Unusual Presentation of Lipofibromatosis-Like Neural Tumor in an Adult: A Case Report.

Lipofibromatosis-like neural tumor (LPF-NT) is a rare variant of lipofibromatosis. Standard lipofibromatosis tumors show a predilection for the distal extremities of male children or young adults and are typically painless, slow-growing, subcutaneous or deep soft tissue masses. We present a case of a 50-year-old male with a slowly expanding, right foot mass. Physical examination revealed a painful, non-tender firm mass on the right medial foot. Magnetic imaging studies revealed a poorly defined soft tissue mass extending through subcutaneous tissue up to the dermis. Histologic examination revealed a spindle cell neoplasm. Immunohistochemistry showed co-expression of S100 protein, CD34 and TRK. In addition, the lesion was found to be positive for the LMNA-NTRK1 fusion by next-generation sequencing. These findings were supportive of a diagnosis of LPF-NT. At 3-month post-excision, the patient had no pain and repeat imaging indicated no evidence of tumor. The authors recommended including LPF-NT in the differential diagnosis of masses or lesions that are fibro-fatty tumors.

CALAXO osteoconductive interference screw: the value of postmarket surveillance.

The CALAXO osteoconductive interference screw was recalled in August 2007 due to reports of increased numbers of postoperative complications associated with screw swelling and prominence leading to the need for surgical debridement. This study reviews complications associated with CALAXO screw use in a consecutive cohort of patients undergoing anterior cruciate ligament reconstruction surgery by the senior author at the authors' institution. Over a 12-month period, 226 CALAXO interference screws, either of 20 mm length or 25 mm length, were implanted in 112 patients, and postoperative complications were noted. The 25-mm tibial screw was over 5 times (RR 5.2, 95% CI 1.8 to 15.3) more likely to be prominent than the 20-mm screw (p value=.002). Four surgical debridements were required in the 25-mm tibial screw group; none were required in the 20-mm group. The authors hypothesize that the inability to bury the longer screw length into the bone tunnel is associated with postoperative complications associated with the CALAXO screw.

Extreme Postinjection Flare in Response to Intra-Articular Triamcinolone Acetonide (Kenalog).

As intra-articular corticosteroid injections (CSIs) are a common treatment for osteoarthritis, physicians must well understand their potential side effects. Postinjection flares are an acute side effect of intra-articular CSIs, with symptoms ranging from mild joint effusion to disabling pain. The present case involved a severe postinjection flare that occurred after the patient, a 56-year-old woman with moderate osteoarthritis in the left knee, received 2 mL of 1% lidocaine and 2 mL (40 mg) of triamcinolone acetonide (Kenalog). Two hours after injection, she experienced swelling and intense pain in the knee and was unable to ambulate. The knee was aspirated with a return of 25 mL of "butterscotch"-colored fluid. This case is novel in that its acuity of onset, severity of symptoms, and synovial fluid analysis mimicked septic arthritis, which was ultimately ruled out with negative cultures and confirmation of triamcinolone acetonide crystals in the synovial aspirate, viewed by polarized light microscopy. Thus, the patient's reaction represents an acute crystal-induced inflammatory response. Although reactions to an intra-articular CSI of this severity are rare, it is important for treating physicians to inform patients of this potential side effect.

Morphologic and immunophenotypic analysis of desmoid-type fibromatosis after radiation therapy.

The morphologic changes seen in desmoid-type fibromatosis after radiotherapy have not been well studied, and the degree of cytologic atypia, cellularity, mitotic activity, and lesional necrosis found in desmoid-type fibromatosis treated with ionizing radiation has not been thoroughly assessed. Therefore, we evaluated a series of primary and locally recurrent desmoid-type fibromatoses resected at variable intervals after radiation therapy (XRT) and compared their histopathologic and immunophenotypic features with paired pathologic specimens that were obtained before radiotherapy. The morphologic characteristics of desmoid-type fibromatoses resected before and after radiotherapy were not significantly different in 7 of the 8 cases studied. One case resected 191 months after XRT showed morphologic evidence of fibrosarcomatous transformation, with zonal necrosis, hypercellularity, severe nuclear atypia, and increased mitotic activity. No significant differences in the immunophenotype of desmoid-type fibromatosis were observed after XRT. In rare cases of recurrent desmoid-type fibromatosis, the differential diagnosis may include radiation-induced fibrosarcoma. Our data suggest that histomorphologic alterations attributable to the effects of ionizing radiation in desmoid-type fibromatosis are minimal. Therefore, the presence of cytologic features of malignancy in this setting warrants careful examination and consideration of the rare occurrence of postradiation sarcoma. Lesser degrees of nuclear atypia seen in isolation do not necessarily indicate a poor prognosis in irradiated desmoid-type fibromatosis.

Signal transduction pathway analysis in fibromatosis: receptor and nonreceptor tyrosine kinases.

Despite reports of receptor tyrosine kinase activation in desmoid-type fibromatosis, therapeutic benefits of kinase inhibitor therapy are unpredictable. Variability in signal transduction or cellular kinases heretofore unevaluated in desmoid tumors may be responsible for these inconsistent responses. In either case, a better understanding of growth regulatory signaling pathways is necessary to assess the theoretical potential of inhibitor therapy. Immunohistochemical analysis of tyrosine kinases and activated isoforms of downstream signal transduction proteins was performed on a tissue microarray containing 27 cases of desmoid-type fibromatosis and 14 samples of scar; 6 whole sections of normal fibrous tissue were studied for comparison. Platelet-derived growth factor receptor, ß type, and focal adhesion kinase 1 were expressed in all desmoid tumors and healing scars but only 80% and 50% of nonproliferative fibrous tissue samples, respectively. Hepatocyte growth factor receptor was detected in 89% of desmoids and all scars tested, but not in any of the fibrous tissue samples. Epidermal growth factor receptor was detected in only 12% of desmoids and not in scar or fibrous tissue. Mast/stem cell growth factor receptor, receptor tyrosine-protein kinase erbB-2, and phosphorylated insulin-like growth factor 1 receptor/insulin receptor were negative in all study cases. Variable levels of phosphorylated downstream signal transduction molecules RAC-α/ß/γ serine/threonine-protein kinase, mitogen-activated protein kinase, and signal transducer and activator of transcription-3 were observed in desmoids (58%, 62%, and 67%), scar tissues (100%, 86%, and 86%), and fibrous tissue (33%, 17%, and 17%). These results indicate that tyrosine kinase signaling is active in both fibromatosis and healing scar, but not in most nonproliferating fibrous tissues. Although platelet-derived growth factor receptor, ß type, is expressed ubiquitously in desmoids, the kinases driving cell proliferation in desmoids remain unresolved.

Osteoblastoma characterized by a three-way translocation: report of a case and review of the literature.

Osteoblastoma, an uncommon primary bone tumor, produces both osteoid and primitive woven bone in a background of fibrovascular connective tissue. Although most osteoblastomas are considered benign, a controversial aggressive variant has been described, which may cause diagnostic confusion with malignant tumors such as osteosarcoma. To date, no specific diagnostic cytogenetic or molecular marker has been identified for osteoblastoma to aid in its distinction. Conventional cytogenetic analysis of an osteoblastoma arising in the femur of a 23-year-old woman revealed a novel three-way translocation involving chromosomes 1, 2 and 14 [t(1;2;14) (q42;q13;q24)]. Rearrangement of 1q42 has been identified in a previously reported case.