Determinants of anti-PD-1 response and resistance in clear cell renal cell carcinoma.

ADAPTeR is a prospective, phase II study of nivolumab (anti-PD-1) in 15 treatment-naive patients (115 multiregion tumor samples) with metastatic clear cell renal cell carcinoma (ccRCC) aiming to understand the mechanism underpinning therapeutic response. Genomic analyses show no correlation between tumor molecular features and response, whereas ccRCC-specific human endogenous retrovirus expression indirectly correlates with clinical response. T cell receptor (TCR) analysis reveals a significantly higher number of expanded TCR clones pre-treatment in responders suggesting pre-existing immunity. Maintenance of highly similar clusters of TCRs post-treatment predict response, suggesting ongoing antigen engagement and survival of families of T cells likely recognizing the same antigens. In responders, nivolumab-bound CD8+ T cells are expanded and express GZMK/B. Our data suggest nivolumab drives both maintenance and replacement of previously expanded T cell clones, but only maintenance correlates with response. We hypothesize that maintenance and boosting of a pre-existing response is a key element of anti-PD-1 mode of action.

The Discovery of a Novel Antimetastatic Bcl3 Inhibitor.

The development of antimetastatic drugs is an urgent healthcare priority for patients with cancer, because metastasis is thought to account for around 90% of cancer deaths. Current antimetastatic treatment options are limited and often associated with poor long-term survival and systemic toxicities. Bcl3, a facilitator protein of the NF-κB family, is associated with poor prognosis in a range of tumor types. Bcl3 has been directly implicated in the metastasis of tumor cells, yet is well tolerated when constitutively deleted in murine models, making it a promising therapeutic target. Here, we describe the identification and characterization of the first small-molecule Bcl3 inhibitor, by using a virtual drug design and screening approach against a computational model of the Bcl3-NF-kB1(p50) protein-protein interaction. From selected virtual screening hits, one compound (JS6) showed potent intracellular Bcl3-inhibitory activity. JS6 treatment led to reductions in Bcl3-NF-kB1 binding, tumor colony formation, and cancer cell migration in vitro; and tumor stasis and antimetastatic activity in vivo, while being devoid of overt systemic toxicity. These results represent a successful application of in silico screening in the identification of protein-protein inhibitors for novel intracellular targets, and confirm Bcl3 as a potential antimetastatic target.

Does Femoral Component Cementation Affect Costs or Clinical Outcomes After Hip Arthroplasty in Medicare Patients?

BACKGROUND: Bundled payment initiatives were introduced to reduce costs and improve quality of care. Cemented vs cementless femoral fixation is a modifiable variable that may influence the cost and quality of care. New bundled payment data from the Centers for Medicare and Medicaid Services allowed us to study the influence of femoral fixation strategy on (1) 90-day costs; (2) readmission rates; (3) reoperation rates; (4) length of stay (LOS); and (5) discharge disposition for Medicare patients undergoing total hip arthroplasty. METHODS: We retrospectively studied 1671 primary total hip arthroplasty Medicare cases, comparing 359 patients who received cemented femoral fixation to 1312 patients who received cementless fixation. Centers for Medicare and Medicaid Services cost data as well as clinical data were reviewed. Demographic differences were present between the 2 cohorts. Statistical analyses were performed, including multiple regression models to adjust for baseline differences. RESULTS: Controlling for cohort differences, cemented patients were significantly more likely to be discharged home compared to cementless patients. Cemented patients also demonstrated trends toward lower costs, lower readmission rates, and shorter LOS compared to cementless patients. All reoperations within the early postoperative period occurred in patients managed with cementless femoral fixation. CONCLUSION: Among Medicare patients, cemented femoral fixation outperformed cementless fixation with respect to discharge disposition and also trended toward superiority with regards to LOS, readmission, cost of care, and reoperation. Cemented femoral fixation remains relevant and useful despite the rising popularity of cementless fixation.

Bcl-3 promotes multi-modal tumour cell migration via NF-κB1 mediated regulation of Cdc42.

A key challenge in the implementation of anti-metastatics as cancer therapies is the multi-modal nature of cell migration, which allows tumour cells to evade the targeted inhibition of specific cell motility pathways. The nuclear factor-kappaB (NF-κB) co-factor B-cell lymphoma 3 (Bcl-3) has been implicated in breast cancer cell migration and metastasis, yet it remains to be determined exactly which cell motility pathways are controlled by Bcl-3 and whether migrating tumour cells are able to evade Bcl-3 intervention. Addressing these questions and the mechanism underpinning Bcl-3's role in this process would help determine its potential as a therapeutic target. Here we identify Bcl-3 as an upstream regulator of the two principal forms of breast cancer cell motility, involving collective and single-cell migration. This was found to be mediated by the master regulator Cdc42 through binding of the NF-κB transcription factor p50 to the Cdc42 promoter. Notably, Bcl-3 depletion inhibited both stable and transitory motility phenotypes in breast cancer cells with no evidence of migratory adaptation. Overexpression of Bcl-3 enhanced migration and increased metastatic tumour burden of breast cancer cells in vivo, whereas overexpression of a mutant Bcl-3 protein, which is unable to bind p50, suppressed cell migration and metastatic tumour burden suggesting that disruption of Bcl-3/NF-κB complexes is sufficient to inhibit metastasis. These findings identify a novel role for Bcl-3 in intrinsic and adaptive multi-modal cell migration mediated by its direct regulation of the Rho GTPase Cdc42 and identify the upstream Bcl-3:p50 transcription complex as a potential therapeutic target for metastatic disease.

Patient Blood Management Program Improves Blood Use and Clinical Outcomes in Orthopedic Surgery.

WHAT WE ALREADY KNOW ABOUT THIS TOPIC: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Although randomized trials show that patients do well when given less blood, there remains a persistent impression that orthopedic surgery patients require a higher hemoglobin transfusion threshold than other patient populations (8 g/dl vs. 7 g/dl). The authors tested the hypothesis in orthopedic patients that implementation of a patient blood management program encouraging a hemoglobin threshold less than 7 g/dl results in decreased blood use with no change in clinical outcomes. METHODS: After launching a multifaceted patient blood management program, the authors retrospectively evaluated all adult orthopedic patients, comparing transfusion practices and clinical outcomes in the pre- and post-blood management cohorts. Risk adjustment accounted for age, sex, surgical procedure, and case mix index. RESULTS: After patient blood management implementation, the mean hemoglobin threshold decreased from 7.8 ± 1.0 g/dl to 6.8 ± 1.0 g/dl (P < 0.0001). Erythrocyte use decreased by 32.5% (from 338 to 228 erythrocyte units per 1,000 patients; P = 0.0007). Clinical outcomes improved, with decreased morbidity (from 1.3% to 0.54%; P = 0.01), composite morbidity or mortality (from 1.5% to 0.75%; P = 0.035), and 30-day readmissions (from 9.0% to 5.8%; P = 0.0002). Improved outcomes were primarily recognized in patients 65 yr of age and older. After risk adjustment, patient blood management was independently associated with decreased composite morbidity or mortality (odds ratio, 0.44; 95% CI, 0.22 to 0.86; P = 0.016). CONCLUSIONS: In a retrospective study, patient blood management was associated with reduced blood use with similar or improved clinical outcomes in orthopedic surgery. A hemoglobin threshold of 7 g/dl appears to be safe for many orthopedic patients.

Hospital Charges and Length of Stay Following Radical Cystectomy in the Enhanced Recovery After Surgery Era.

OBJECTIVE: To report our center's experience with enhanced recovery after surgery (ERAS) pathway for radical cystectomy (RC), specifically evaluating complications, LOS, 30- and 90-day readmissions, and hospital charges. Pathways of this type have been shown to decrease the length of stay (LOS) and postoperative ileus. However, concerns persist that ERAS is costly and increases readmissions. To date, limited studies have evaluated these concerns. MATERIALS AND METHODS: Our ERAS protocol was implemented for RC in December 2015. Outcomes in ERAS patients were compared with those in RC patients from the time period before ERAS. Patients were excluded if they underwent concomitant nephroureterectomy. RESULTS: Fifty-six consecutive ERAS patients were compared with 54 pre-ERAS patients. The median charge for index hospitalization was $31,090 in the ERAS group and $35,489 in the pre-ERAS group (P = .036). The median LOS was 5.0 days in the ERAS group and 8.5 days in the pre-ERAS group (P = < .001). The pre-ERAS group had a significantly increased use of nasogastric tube (13.8% vs 30.0%) and parenteral nutrition (6.9% vs 20.4%). The overall complication rate (including infectious, renal, deep vein thrombosis and pulmonary embolism, myocardial infarction and stroke, and respiratory and gastrointestinal-related complications) was similar between the 2 groups (51.7% in the ERAS group and 62.0% in the pre-ERAS group, P = .28). Thirty- and 90-day readmissions also remained similar (19.0% vs 14.8%, P = .55, and 31.0% vs 27.7%, P = .64). The most common readmission reason was infection, specifically urinary tract infection. CONCLUSION: Implementation of the ERAS pathway at our center resulted in significantly reduced LOS and total hospital charge, with comparable rates of complication and readmission, highlighting the need for ERAS pathways in patients undergoing RC.

Blood utilization in revision versus first-time cardiac surgery: an update in the era of patient blood management.

BACKGROUND: Relative to first-time (primary) cardiac surgery, revision cardiac surgery is associated with increased transfusion requirements, but studies comparing these cohorts were performed before patient blood management (PBM) and blood conservation measures were commonplace. The current study was performed as an update to determine if this finding is still evident in the PBM era. STUDY DESIGN AND METHODS: Primary and revision cardiac surgery cases were compared in a retrospective database analysis at a single tertiary care referral center. Two groups of patients were assessed: 1) those having isolated coronary artery bypass (CAB) or valve surgery and 2) all other cardiac surgeries. Intraoperative and whole hospital transfusion requirements were assessed for the four major blood components. RESULTS: Compared to the primary cardiac surgery patients, the revision surgery patients required approximately twofold more transfused units intraoperatively (p < 0.0001) and approximately two- to threefold more transfused units for the whole hospital stay (p < 0.0001). Intraoperative massive transfusion (>10 red blood cell [RBC] units) was substantially more frequent with revision versus primary cardiac surgery (2.6% vs. 0.1% [p < 0.0001] for isolated CAB or valve and 6.1% vs. 1.9% [p < 0.0001] for all other cardiac surgeries). Revision surgery was an independent risk factor for both moderate (6-10 RBC units) and massive intraoperative transfusion. CONCLUSIONS: In the era of PBM, with restrictive transfusion strategies and a variety of methods for blood conservation, revision cardiac surgery patients continue to have substantially greater transfusion requirements relative to primary cardiac surgery patients. This difference in transfusion requirement was greater than what has been previously reported in the pre-PBM era.

A comprehensive Choosing Wisely quality improvement initiative reduces unnecessary transfusions in an Academic Department of Surgery.

BACKGROUND: We implemented a comprehensive Choosing Wisely initiative to reduce unnecessary transfusions in an Academic Department of Surgery. METHODS: We conducted a survey- and lecture-based educational intervention to increase awareness about published transfusion guidelines. Monthly transfusion reports were subsequently distributed to all faculty, fellows, residents, and mid-level practitioners. Blood utilization measures were compared pre- vs. post-intervention to assess effectiveness. RESULTS: 7994 blood product orders (5388 pre-intervention, 2606 post-intervention) were placed (07/2014-06/2016). Red blood cell (RBC) (45% vs. 55%; P < 0.001) and plasma (68% vs. 75%; P = 0.02) compliance improved post-intervention, with a corresponding 15% decrease in RBC utilization (0.47 ± 0.02 vs. 0.40 ± 0.02 units/patient; P = 0.01), and 24% decrease in plasma (0.25 ± 0.02 vs. 0.19 ± 0.02 units/patient; P = 0.06). These reductions translate into $125,558 in blood product acquisition cost avoidance (RBC = $114,386, plasma = $11,172). CONCLUSIONS: Implementation of a comprehensive Choosing Wisely campaign targeting individual providers at all levels significantly improved transfusion practices and decreased costs within the Department of Surgery.

Physiologic correlates of intraoperative blood transfusion among patients undergoing major gastrointestinal operations.

BACKGROUND: Guidelines for transfusion focus on nadir levels of hemoglobin. Hemoglobin triggers may not be helpful, however, in defining appropriate intraoperative use of packed red blood cells. We sought to define the use of intraoperative packed red blood cells relative to quantitative physiologic factors at the time of operation. METHODS: Prospective intraoperative data on patients undergoing a major gastrointestinal operation between 2010 and 2014 were analyzed. Risk of intraoperative transfusion was assessed with multivariable extended Cox models using baseline clinical covariates and time-varying intraoperative covariates. RESULTS: Among 2,316 patients, the mean preoperative hemoglobin was 12.6 g/dL (standard deviation = 2.0 g/dL), while the median estimated blood loss was 200 mL (interquartile range: 100-55 mL). Overall, 357 (15.4%) patients received a transfusion intraoperatively. A greater hazard of transfusion was associated with a greater American Society of Anesthesiologists class (ref: American Society of Anesthesiologists class I-II; American Society of Anesthesiologists class III-IV; hazard ratio = 1.44, 95% confidence interval, 1.18-1.77, P < .001), and a lesser preoperative hemoglobin level (per 1 g/dL increase; hazard ratio = 0.70, 95% confidence interval, 0.65-0.74, P < .001). In addition, an increase in heart rate of 10 beats/min above the cumulative average at any measurement was associated with up to a 30% increased probability of transfusion (hazard ratio = 1.30, 95% confidence interval, 1.15-1.47, P < .001); similarly, an increase in mean arterial pressure of 10 mm Hg was associated with an 8% decreased likelihood of transfusion (hazard ratio = 0.92, 95% confidence interval, 87-0.99, P = .017). In contrast, nadir hemoglobin was not associated with the risk of receiving a transfusion (hazard ratio = 1.10, 95% confidence interval, 0.97-1.23, P = .129). Among patients who received an intraoperative transfusion, 9.2% (n = 33) never had a hemoglobin nadir below 10 g/dL, nor an average mean arterial pressure less than 65 mm Hg or a heart rate greater than 100 beats/min around the time of transfusion. CONCLUSION: Among the intraoperative factors, heart rate, and mean arterial pressure were strongly associated with the likelihood of receiving a transfusion, despite the observation that 9.2% of patients never had a physiologic indicator for transfusion or a nadir hemoglobin below 10 g/dL, suggesting a subset of patients could benefit from a decrease in intraoperative rate of transfusion.

DNA polymerase ζ generates tandem mutations in immunoglobulin variable regions.

Low-fidelity DNA polymerases introduce nucleotide substitutions in immunoglobulin variable regions during somatic hypermutation. Although DNA polymerase (pol) η is the major low-fidelity polymerase, other DNA polymerases may also contribute. Existing data are contradictory as to whether pol ζ is involved. We reasoned that the presence of pol η may mask the contribution of pol ζ, and therefore we generated mice deficient for pol η and heterozygous for pol ζ. The frequency and spectra of hypermutation was unaltered between Polζ(+/-) Polη(-/-) and Polζ(+/+) Polη(-/-) clones. However, there was a decrease in tandem double-base substitutions in Polζ(+/-) Polη(-/-) cells compared with Polζ(+/+) Polη(-/-) cells, suggesting that pol ζ generates tandem mutations. Contiguous mutations are consistent with the biochemical property of pol ζ to extend a mismatch with a second mutation. The presence of this unique signature implies that pol ζ contributes to mutational synthesis in vivo. Additionally, data on tandem mutations from wild type, Polζ(+/-), Polζ(-/-), Ung(-/-), Msh2(-/-), Msh6(-/-), and Ung(-/-) Msh2(-/-) clones suggest that pol ζ may function in the MSH2-MSH6 pathway.

A role for Msh6 but not Msh3 in somatic hypermutation and class switch recombination.

Somatic hypermutation is initiated by activation-induced cytidine deaminase (AID), and occurs in several kilobases of DNA around rearranged immunoglobulin variable (V) genes and switch (S) sites before constant genes. AID deaminates cytosine to uracil, which can produce mutations of C:G nucleotide pairs, and the mismatch repair protein Msh2 participates in generating substitutions of downstream A:T pairs. Msh2 is always found as a heterodimer with either Msh3 or Msh6, so it is important to know which one is involved. Therefore, we sequenced V and S regions from Msh3- and Msh6-deficient mice and compared mutations to those from wild-type mice. Msh6-deficient mice had fewer substitutions of A and T bases in both regions and reduced heavy chain class switching, whereas Msh3-deficient mice had normal antibody responses. This establishes a role for the Msh2-Msh6 heterodimer in hypermutation and switch recombination. When the positions of mutation were mapped, several focused peaks were found in Msh6(-/-) clones, whereas mutations were dispersed in Msh3(-/-) and wild-type clones. The peaks occurred at either G or C in WGCW motifs (W = A or T), indicating that C was mutated on both DNA strands. This suggests that AID has limited entry points into V and S regions in vivo, and subsequent mutation requires Msh2-Msh6 and DNA polymerase.

Absence of DNA polymerase eta reveals targeting of C mutations on the nontranscribed strand in immunoglobulin switch regions.

Activation-induced cytosine deaminase preferentially deaminates C in DNA on the nontranscribed strand in vitro, which theoretically should produce a large increase in mutations of C during hypermutation of immunoglobulin genes. However, a bias for C mutations has not been observed among the mutations in variable genes. Therefore, we examined mutations in the mu and gamma switch regions, which can form stable secondary structures, to look for C mutations. To further simplify the pattern, mutations were studied in the absence of DNA polymerase (pol) eta, which may produce substitutions of nucleotides downstream of C. DNA from lymphocytes of patients with xeroderma pigmentosum variant (XP-V) disease, whose polymerase eta is defective, had the same frequency of switching to all four gamma isotypes and hypermutation in mu-gamma switch sites (0.5% mutations per basepair) as control subjects. There were fewer mutations of A and T bases in the XP-V clones, similar to variable gene mutations from these patients, which confirms that polymerase eta produces substitutions opposite A and T. Most importantly, the absence of polymerase eta revealed an increase in C mutations on the nontranscribed strand. This data shows for the first time that C is preferentially mutated in vivo and pol eta generates hypermutation in the mu and gamma switch regions.