Alexander L. Lazarides

A mouse-human phase 1 co-clinical trial of a protease-activated fluorescent probe for imaging cancer

A first-in-human phase 1 clinical trial of the PEGylated protease-activated fluorescent probe, LUM015, enables tumor imaging at a safe and tolerable dose in humans. Protease probe tested in humans Cancer cells secrete more of the protease cathepsin than healthy cells, partly as a way to enzymatically remodel their surroundings for tumor growth and metastasis. Whitley et al. developed an imaging probe that could be activated in the presence of these cathepsins, thus allowing surgeons to distinguish tumor margins intraoperatively. Their probe, called LUM015, was able to signal the presence of cancer in vivo in a mouse sarcoma model, and in a so-called “co-clinical trial” in 15 patients, it was safe and cleaved as expected in different types of tumor tissues. With favorable biodistribution and pharmacokinetics also demonstrated, protease-activated probes are now poised for further adaptation to tumor resections, signaling the presence of residual cancer. Local recurrence is a common cause of treatment failure for patients with solid tumors. Intraoperative detection of microscopic residual cancer in the tumor bed could be used to decrease the risk of a positive surgical margin, reduce rates of reexcision, and tailor adjuvant therapy. We used a protease-activated fluorescent imaging probe, LUM015, to detect cancer in vivo in a mouse model of soft tissue sarcoma (STS) and ex vivo in a first-in-human phase 1 clinical trial. In mice, intravenous injection of LUM015 labeled tumor cells, and residual fluorescence within the tumor bed predicted local recurrence. In 15 patients with STS or breast cancer, intravenous injection of LUM015 before surgery was well tolerated. Imaging of resected human tissues showed that fluorescence from tumor was significantly higher than fluorescence from normal tissues. LUM015 biodistribution, pharmacokinetic profiles, and metabolism were similar in mouse and human subjects. Tissue concentrations of LUM015 and its metabolites, including fluorescently labeled lysine, demonstrated that LUM015 is selectively distributed to tumors where it is activated by proteases. Experiments in mice with a constitutively active PEGylated fluorescent imaging probe support a model where tumor-selective probe distribution is a determinant of increased fluorescence in cancer. These co-clinical studies suggest that the tumor specificity of protease-activated imaging probes, such as LUM015, is dependent on both biodistribution and enzyme activity. Our first-in-human data support future clinical trials of LUM015 and other protease-sensitive probes.

Rotator cuff tears in young patients: a different disease than rotator cuff tears in elderly patients

BACKGROUND The purpose of this study was to conduct a systematic review of the literature to evaluate the characteristics of injury and treatment outcomes of rotator cuff tears in young patients. METHODS A systematic electronic search was performed for clinical studies evaluating rotator cuff tears in patients younger than 40 years with special emphasis on reporting of injury characteristics and treatment outcomes with a minimum 1-year follow-up. RESULTS Twelve studies (involving 336 patients) met inclusion criteria. The mean age of the patients was 28 years (range, 16-40 years), with a mean follow-up of 39 months. There were 2 distinct subgroups. The majority of studies (7 of 10) showed that patients typically had a full-thickness tear with an acute traumatic etiology. However, within the subgroup of elite throwers, 5 of 6 studies demonstrated a majority of tears that were partial thickness stemming from chronic overuse. Rotator cuff repair improved pain and strength in almost all studies reporting on these parameters. Eighty-seven percent of patients reported they were satisfied. However, all studies examining elite throwers showed significant difficulty in returning to play (25%-97%). CONCLUSIONS In young patients with rotator cuff tears, there are 2 primary groups. (1) A majority group with rotator cuff tears of traumatic origin responded well to both arthroscopic and open rotator cuff repair in terms of pain relief and self-reported outcomes postoperatively. These patients reported high levels of satisfaction and return to preinjury level of play. (2) A unique subpopulation composed of elite throwers had improved outcomes but suboptimal return to play.

A Novel Imaging System Distinguishes Neoplastic from Normal Tissue During Resection of Soft Tissue Sarcomas and Mast Cell Tumors in Dogs.

OBJECTIVE To assess the ability of a novel imaging system designed for intraoperative detection of residual cancer in tumor beds to distinguish neoplastic from normal tissue in dogs undergoing resection of soft tissue sarcoma (STS) and mast cell tumor (MCT). STUDY DESIGN Non-randomized prospective clinical trial. ANIMALS 12 dogs with STS and 7 dogs with MCT. METHODS A fluorescent imaging agent that is activated by proteases in vivo was administered to the dogs 4-6 or 24-26 hours before tumor resection. During surgery, a handheld imaging device was used to measure fluorescence intensity within the cancerous portion of the resected specimen and determine an intensity threshold for subsequent identification of cancer. Selected areas within the resected specimen and tumor bed were then imaged, and biopsies (n=101) were obtained from areas that did or did not have a fluorescence intensity exceeding the threshold. Results of intraoperative fluorescence and histology were compared. RESULTS The imaging system correctly distinguished cancer from normal tissue in 93/101 biopsies (92%). Using histology as the reference, the sensitivity and specificity of the imaging system for identification of cancer in biopsies were 92% and 92%, respectively. There were 10/19 (53%) dogs which exhibited transient facial erythema soon after injection of the imaging agent which responded to but was not consistently prevented by intravenous diphenhydramine. CONCLUSION A fluorescence-based imaging system designed for intraoperative use can distinguish canine soft tissue sarcoma (STS) and mast cell tumor (MCT) tissue from normal tissue with a high degree of accuracy. The system has potential to assist surgeons in assessing the adequacy of tumor resections during surgery, potentially reducing the risk of local tumor recurrence. Although responsive to antihistamines, the risk of hypersensitivity needs to be considered in light of the potential benefits of this imaging system in dogs.

A Fluorescence-Guided Laser Ablation System for Removal of Residual Cancer in a Mouse Model of Soft Tissue Sarcoma

The treatment of soft tissue sarcoma (STS) generally involves tumor excision with a wide margin. Although advances in fluorescence imaging make real-time detection of cancer possible, removal is limited by the precision of the human eye and hand. Here, we describe a novel pulsed Nd:YAG laser ablation system that, when used in conjunction with a previously described molecular imaging system, can identify and ablate cancer in vivo. Mice with primary STS were injected with the protease-activatable probe LUM015 to label tumors. Resected tissues from the mice were then imaged and treated with the laser using the paired fluorescence-imaging/ laser ablation device, generating ablation clefts with sub-millimeter precision and minimal underlying tissue damage. Laser ablation was guided by fluorescence to target tumor tissues, avoiding normal structures. The selective ablation of tumor implants in vivo improved recurrence-free survival after tumor resection in a cohort of 14 mice compared to 12 mice that received no ablative therapy. This prototype system has the potential to be modified so that it can be used during surgery to improve recurrence-free survival in patients with cancer.

The Use of Radiation Therapy in Well-Differentiated Soft Tissue Sarcoma of the Extremities: An NCDB Review.

Objective. This study investigated patterns of utilization of radiation therapy (RT) and correlated this with overall survival by assessing patients with well-differentiated soft tissue sarcoma of the extremity (STS-E) in the National Cancer Database (NCDB). Methods. All patients diagnosed with well-differentiated STS-E between 1998 and 2006 were identified in the NCDB. Patients were stratified by use of surgery alone versus use of adjuvant RT after surgery and analyzed using multivariate analysis, Kaplan-Meier analysis, and propensity matching. Results. 2113 patients with well-differentiated STS-E were identified in the NCDB for inclusion with a mean follow-up time of 74 months. 69% of patients were treated with surgery alone, while 26% were treated with surgery followed by adjuvant RT. Patients undergoing amputation were less likely to receive adjuvant RT. There was no difference in overall survival between patients with well-differentiated STS treated with surgery alone and those patients who received adjuvant RT. Conclusions. In the United States, adjuvant RT is being utilized in a quarter of patients being treated for well-differentiated STS-E. While the use of adjuvant RT may be viewed as a means to facilitate limb salvage, this large national database review confirms no survival benefit, regardless of tumor size or margin status.

Histological Evaluation of Tendon-Bone Healing of an Anterior Cruciate Ligament Hamstring Graft in a 14-Year-Old Boy

Anterior cruciate ligament (ACL) injuries are one of the most common knee injuries, with over 100,000 ACL reconstructions performed in the United States every year. There are a number of graft options available for use in ACL repair. Hamstring tendon autografts are commonly used for ACL reconstruction. The advantages cited for autografts versus allografts are as follows: lower cost, no risk of immunological reactions, and better integration and remodeling. The healing response depends on the interplay between the bone and tendon in which collagen fiber continuity is re-established. This process is achieved by bony ingrowth of immature trabecular bone into immature, disorganized collagen fibers. Gradually, the collagen fibers reorganize into a parallel array until the tendoosseous junction is re-established. Studies of the healing response involved in ACL autograft reconstruction have been well documented in animal studies, but most studies of the graft healing response in human patients have been limited to biopsy specimens. To our knowledge, there are no examples in the literature of the ACL graft healing response in the tibial and femoral tunnels of human whole knee specimens. Beynnon et al, in a previous study, performed biomechanical testing on a recovered human ACL graft but did not specifically examine the healing response. We report the case of a young male patient who subsequently required resection of his knee for osteosarcoma of the tibia 4 months after ACL reconstruction with a hamstring tendon autograft. The patient and his parents provided written informed consent for print and electronic publication of this case report.

E-cadherin represses anoikis resistance in sarcomas through both signaling and mechanical mechanisms

E-cadherin, an epithelial-specific cell-cell adhesion molecule, plays multiple roles in maintaining adherens junctions, regulating migration and invasion, and mediating intracellular signaling. Downregulation of E-cadherin is a hallmark of epithelial-mesenchymal transition (EMT) and correlates with poor prognosis in multiple carcinomas. Conversely, upregulation of E-cadherin is prognostic for improved survival in sarcomas. Yet, despite the prognostic benefit of E-cadherin expression in sarcoma, the mechanistic significance of E-cadherin in sarcomas remains poorly understood. Here, by combining mathematical models with wet-bench experiments, we identify the core regulatory networks mediated by E-cadherin in sarcomas, and decipher their functional consequences. Unlike in carcinomas, E-cadherin overexpression in sarcomas does not induce a mesenchymal-epithelial transition (MET). However, E-cadherin acts to reduce both anchorage-independent growth and spheroid formation of sarcoma cells. Ectopic E-cadherin expression acts to downregulate phosphorylated CREB (p-CREB) and the transcription factor, TBX2, to inhibit anoikis resistance. RNAi-mediated knockdown of TBX2 phenocopies the effect of E-cadherin on p-CREB levels and restores anoikis sensitivity to sarcoma cells. Beyond its signaling role, E-cadherin expression in sarcoma cells can also strengthen cell-cell adhesion and restricts spheroid growth through mechanical action. Together, our results demonstrate that E-cadherin inhibits sarcoma aggressiveness by inducing anoikis and restricting colony growth.

Race is an independent predictor of survival in patients with soft tissue sarcoma of the extremities

BackgroundIn the United States, race and socioeconomic status are well known predictors of adverse outcomes in several different cancers. Existing evidence suggests that race and socioeconomic status may impact survival in soft tissue sarcoma (STS). We investigated the National Cancer Database (NCDB), which contains several socioeconomic and medical variables and contains the largest sarcoma patient registry to date. Our goal was to determine the impact of race, ethnicity and socioeconomic status on patient survival in patients with soft tissue sarcoma of the extremities (STS-E).MethodsWe retrospectively analyzed 14,067 STS-E patients in the NCDB from 1998 through 2012. Patients were stratified based on race, ethnicity and socioeconomic status. Univariate and multivariate analyses were used to correlate specific outcomes and survival measures with these factors. Then, long-term survival between groups was evaluated using the Kaplan-Meier (KM) method with comparisons based on the log-rank test. Multiple variables were analyzed between two groups.ResultsOf the 14,067 patients analyzed, 84.9% were white, 11% were black and 4.1% were Asian. Black patients were significantly more likely (7.18% vs 5.65% vs 4.47%) than white or Asian patients to receive amputation (p = 0.027). Black patients were also less likely to have either an above-median education level or an above-median income level (p < 0.001). In addition, black patients were more likely to be uninsured (p < 0.001) and more likely to have a higher Charleson Comorbidity Score than white or Asian patients. Tumors were larger in size upon presentation in black patients than in white or Asian patients (p < 0.001). Black patients had significantly poorer overall survival than did white or Asian patients (p < 0.001) with a KM 5-year survival of 61.4% vs 66.9% and 69.9% respectively, and a 24% higher independent likelihood of dying in a multivariate analysis.ConclusionThis large database review reveals concerning trends in black patients with STS-E. These include larger tumors, poorer resources, a greater likelihood of amputation, and poorer survival than white and Asian patients. Future studies are warranted to help ensure adequate access to effective treatment for all patients.

Custom Facial Reconstruction for Osteosarcoma of the Jaw

Osteosarcoma accounts for most primary bone cancers in children and young adults. High-grade lesions are typically managed with a combination of chemotherapy and wide-margin surgical excision. Although this malignancy typically affects the metaphyseal region of long bones, it also can be seen in the axial skeleton. Of axial locations, tumors in the head and neck can be particularly troubling to treat. Segmental bone loss after resection of malignant mandibular tumors continues to present important challenges to the reconstructive surgeon. Recent advancements in 3-dimensional modeling have facilitated custom templates for patient-specific reconstructions. This report describes the case of a young woman with osteosarcoma of the mandible undergoing customized template composite facial reconstruction using a vascularized osteoseptocutaneous fibula flap.

Correction to: Factors associated with poorer outcomes in the surgical treatment of multiligament knee injuries

The author would like to correct the following errors in the publication of the original article: