ST6GAL1 is associated with poor response to chemoradiation in rectal cancer.

INTRODUCTION: Colorectal cancer is the third most common cause of cancer death. Rectal cancer makes up a third of all colorectal cases. Treatment for locally advanced rectal cancer includes chemoradiation followed by surgery. We have previously identified ST6GAL1 as a cause of resistance to chemoradiation in vitro and hypothesized that it would be correlated with poor response in human derived models and human tissues. METHODS: Five organoid models were created from primary human rectal cancers and ST6GAL1 was knocked down via lentivirus transduction in one model. ST6GAL1 and Cleaved Caspase-3 (CC3) were assessed after chemoradiation via immunostaining. A tissue microarray (TMA) was created from twenty-six patients who underwent chemoradiation and had pre- and post-treatment specimens of rectal adenocarcinoma available at our institution. Immunohistochemistry was performed for ST6GAL1 and percent positive cancer cell staining was assessed and correlation with pathological grade of response was measured. RESULTS: Organoid models were treated with chemoradiation and both ST6GAL1 mRNA and protein significantly increased after treatment. The organoid model targeted with ST6GAL1 knockdown was found to have increased CC3 after treatment. In the tissue microarray, 42 percent of patient samples had an increase in percent tumor cell staining for ST6GAL1 after treatment. Post-treatment percent staining was associated with a worse grade of treatment response (p = 0.01) and increased staining post-treatment compared to pre-treatment was also associated with a worse response (p = 0.01). CONCLUSION: ST6GAL1 is associated with resistance to treatment in human rectal cancer and knockdown in an organoid model abrogated resistance to apoptosis caused by chemoradiation.

Cephalomedullary Nailing of Unstable Geriatric Intertrochanteric Fractures on a Traction Table Combined With Percutaneous Reduction Techniques Is Safe and Results in a Low Rate of Cutout.

OBJECTIVES: To describe a reproducible technique for reduction assessment and percutaneous reduction of unstable intertrochanteric fractures treated with a cephalomedullary nail on a traction table. DESIGN: Retrospective cohort study. SETTING: Level-1 trauma center. PATIENTS: Two-hundred 20 consecutive patients with intertrochanteric fractures. INTERVENTION: Initial closed reduction performed on a traction table. Accessory incisions were used to facilitate a reduction in 77 patients (35%). All fractures were stabilized with a cephalomedullary nail. MAIN OUTCOME MEASUREMENTS: Radiographic outcome including union, cutout, and fracture collapse (FC). Surgical outcomes including infection and hematoma were also reported. RESULTS: Mechanical complications (nonunion, cutout, and varus collapse) occurred in 8.8% of patients at 1 year. Eleven of 13 patients who developed these complications had either suboptimal implant placement (tip-to-apex distance >25 mm) or a varus reduction. There was no difference in the incidence of reoperation, nonunion, lag screw cutout, or posttraumatic arthritis based on the use of an accessory incision for fracture reduction. There was a significant increase in FC in patients who received an accessory incision (6.8 mm vs. 5.4 mm, P = 0.04). One patient (1%) developed a hematoma in the accessory incision cohort, and 1 patient (0.7%) who did not have an accessory incision developed a postoperative infection. CONCLUSIONS: The current study suggests utilization of accessory incisions assist in reduction is safe and is associated with a low rate of complications. The surgeon should prioritize fracture reduction and optimal implant placement and not hesitate to use an accessory incision to assist with fracture reduction. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A Comparison of Outcomes following Plate versus Pin Fixation of Metacarpal Shaft and Neck Fractures.

The aim of this study is to compare clinical and radiographic outcomes of open reduction and internal fixation versus closed reduction and percutaneous pinning of metacarpal fractures in relation to anatomic and surgical variables. Methods: Electronic medical records at two institutions were reviewed for patients who underwent surgical intervention for metacarpal fractures. Data were collected from those who underwent reduction and internal fixation with either plates or Kirschner wires (K-wires). Inclusion criteria included minimum postoperative follow-up of 60 days and age 18 years or older. Exclusion criteria included insufficient radiographic data, previously attempted closed reduction with immobilization, pathologic fracture mechanism, history of previous trauma or surgery to the affected bone, and fixation technique other than plate or K-wire. Results: We reviewed data for patients treated over a 22-year time period. Ultimately, 81 metacarpal shaft and neck fractures in 60 patients met inclusion criteria. Among all metacarpal fractures, complications were present in 39 (48.1%) cases. There were no significant associations between complication prevalence and hardware type. Revision surgery was required in 11 (13.6%) patients; there were no significant associations between revision procedures and hardware type. Postoperatively, all patients with imaging data had radiograph follow-up to assess union status. There was no significant association between time to union and hardware type. Conclusions: Outcomes showed no significant difference between plate and pin fixation for metacarpal shaft and neck fractures. These findings suggest that surgeons may have flexibility to decide on the type of operative intervention while considering patient-specific factors, such as the need for early mobilization.

Outcomes of Intramedullary Nail Fixation for Metastatic Disease: Impending and Pathologic Fractures.

BACKGROUND/AIM: Intramedullary nail (IMN) fixation has become a treatment mean for impending and pathologic femur fractures. Currently there continues to be a lack of data examining functional outcomes, complications, and survivorship of patients treated with IMNs for metastatic disease of the femur. PATIENTS AND METHODS: We retrospectively identified 183 IMNs placed for impending (n=145) or pathologic (n=38) metastatic fractures from 2010 to 2018. Functional outcomes and complications including blood transfusions, venous thromboembolisms (VTEs) and reoperations were studied. RESULTS: Patients with impending lesions were more likely to be ambulatory at final follow-up (pathologic: 82%, impending: 99%, p<0.0001) and reported greater musculoskeletal tumor society scores (p<0.0001). Likewise, pathologic fractures were associated with greater discharge to non-home locations (p<0.0001) and were more likely to require a postoperative transfusion (pathologic: 66%, impending: 22%, p=0.0001). However, there was no difference in the incidence of VTEs (p=1.00) or reoperations (p=0.69) between cohorts. Patients treated for impending fractures had improved overall survival at 1 year (54% vs. 26%, p<0.0001). CONCLUSION: IMN fixation was durable in impending and pathologic femoral fractures. Early identification of metastases remains critical as patients treated for impending lesions had greater functional outcomes, fewer complications and improved survivorship compared to patients treated for pathologic fractures.

Replication timing alterations in leukemia affect clinically relevant chromosome domains.

Human B-cell precursor acute lymphoid leukemias (BCP-ALLs) comprise a group of genetically and clinically distinct disease entities with features of differentiation arrest at known stages of normal B-lineage differentiation. We previously showed that BCP-ALL cells display unique and clonally heritable, stable DNA replication timing (RT) programs (ie, programs describing the variable order of replication and subnuclear 3D architecture of megabase-scale chromosomal units of DNA in different cell types). To determine the extent to which BCP-ALL RT programs mirror or deviate from specific stages of normal human B-cell differentiation, we transplanted immunodeficient mice with quiescent normal human CD34+ cord blood cells and obtained RT signatures of the regenerating B-lineage populations. We then compared these with RT signatures for leukemic cells from a large cohort of BCP-ALL patients with varied genetic subtypes and outcomes. The results identify BCP-ALL subtype-specific features that resemble specific stages of B-cell differentiation and features that seem to be associated with relapse. These results suggest that the genesis of BCP-ALL involves alterations in RT that reflect biologically significant and potentially clinically relevant leukemia-specific epigenetic changes.

Incorporating Pericytes into an Endothelial Cell Bead Sprouting Assay.

Angiogenesis is the growth of new vessels from pre-existing vasculature and is an important component of many biological processes, including embryogenesis and development, wound healing, tumor growth and metastasis, and ocular and cardiovascular diseases. Effective in vitro models that recapitulate the biology of angiogenesis are needed to appropriately study this process and identify mechanisms of regulation that can be ultimately targeted for novel therapeutic strategies. The bead angiogenesis assay has been previously demonstrated to recapitulate the multiple stages of endothelial sprouting in vitro. However, a limitation of this assay is a lack of endothelial - mural cell interactions, which are key to the molecular and phenotypic regulation of endothelial cell function in vivo. The protocol given here presents a methodology for the incorporation of mural cells into the bead angiogenesis assay and demonstrates a tight association of endothelial cells and pericytes during sprouting in vitro. The protocol also details a methodology for effective silencing of target genes using siRNA in endothelial cells for mechanistic studies. Altogether, this protocol provides an in vitro assay that more appropriately models the diverse cell types involved in sprouting angiogenesis, and provides a more physiologically-relevant platform for therapeutic assessment and novel discovery of mechanisms of angiogenesis regulation.

Estimating the excess lifetime risk of radiation induced secondary malignancy (SMN) in pediatric patients treated with craniospinal irradiation (CSI): Conventional radiation therapy versus helical intensity modulated radiation therapy.

PURPOSE: To quantify the risk of radiation-induced second malignancies (SMN) in pediatric patients receiving craniospinal irradiation (CSI) either with 3-dimensional conformal radiation therapy (Conv CSI) or tomotherapy helical intensity modulated radiation therapy (Tomo CSI). METHODS AND MATERIALS: A novel predictive model that accounts for short- and long-term carcinogenesis was incorporated into our institutional treatment planning system to quantify the lifetime risk of SMN in incidentally irradiated organs. Five pediatric patients previously treated with CSI were studied. For each case, Conv CSI and Tomo CSI plans were computed. The excess absolute number of SMN was computed for each plan for each patient. For female patients, age was varied to assess its impact. RESULTS: Tomo CSI has a much higher risk than Conv CSI for breast cancer. Tomo has a slightly increased risk for the lung, and conventional has a slightly higher risk for the thyroid. Both techniques have intermediate risks to the pancreas and stomach, and lesser risks to the bladder and rectum. For the breast, the magnitude of the absolute risks varied with age: 14.2% versus 7.4% (Tomo vs Conv) age 5; 16.9% versus 7.6% age 10, and 18.6% versus 8.0% age 15. CONCLUSIONS: Tomo has a higher risk for inducing breast and lung second cancers, and when using Tomo-based intensity modulated radiation therapy, care should be taken to avoid incidental radiation to the breast. When planning CSI, one needs to balance these cancer risks against other normal tissue effects.