Evaluation of PD-L1 expression in PBRM1-altered clear cell renal cell carcinoma.

PURPOSE: Clear cell renal cell carcinoma (ccRCC) often harbors Polybromo 1 (PBRM1) alterations. These alterations are associated with immune checkpoint blockade response in ccRCC, particularly antiprogrammed cell death 1 (PD1)/programmed cell death ligand 1 (PD-L1)-targeted therapy. However, the association between PBRM1 alterations and PD-L1 expression in ccRCC remains unclear. MATERIALS AND METHODS: We analyzed alterations in PBRM1 and PD-L1 expression using immunohistochemistry (IHC) targeting PBRM1 and PD-L1 (22C3) in tissues collected from patients with localized ccRCC (Cohort 1) and advanced ccRCC (Cohort 2). Additionally, next-generation sequencing (NGS) was conducted on Cohort 2 patients to analyze PBRM1 alterations. RESULTS: Cohort 1 comprised 526 patients, of whom 139 (26.4%) exhibited PD-L1 positivity and 205 (38.9%) exhibited loss of PBRM1 expression in IHC. PD-L1 expression was positively associated with the loss of PBRM1 expression (P < 0.001) in localized ccRCC. Kaplan-Meier analysis indicated that PBRM1 expression loss and PD-L1 expression positively correlated with tumor recurrence (P < 0.001 and P = 0.003, respectively). Cohort 2 comprised 59 patients with advanced ccRCC, of whom 33 (56.9%) exhibited PBRM1 genetic alterations. PBRM1 IHC exhibited a sensitivity of 84.48% and specificity of 87.5% compared to NGS results. We did not find a significant association between PBRM1 mutation and PD-L1 expression, in contrast to the findings in Cohort 1. However, we frequently observed that PBRM1 mutation and PD-L1 expression occur concurrently, with 60% of PBRM1-altered ccRCC cases being PD-L1 positive. CONCLUSION: Although our study did not establish a correlation between PBRM1 mutations and PD-L1 expression, it demonstrated that the occurrence of PBRM1-altered ccRCC with PD-L1 expression is not uncommon. Therefore, the presence of PBRM1 alterations may challenge the use of PD-L1 IHC as a predictive marker for PD-L1 blockade in ccRCC.

Clinicopathological implications of the expression of vascular endothelial growth factor and programmed death ligand 1 in clear-cell renal cell carcinoma.

Combined anti-VEGF/anti-programmed death ligand 1 (PD-L1) therapy synergistically improves treatment outcomes in advanced renal cell carcinoma (RCC) compared with anti-PD-L1 or anti-vascular endothelial growth factor (VEGF) monotherapy. Here, we analyzed the expression of VEGF and PD-L1 (SP142) in a retrospective cohort of 513 patients with clear-cell (cc) RCC. PD-L1 expression on tumor cells (TCs) and immune cells (ICs) was evaluated by immunohistochemistry (IHC) with a positive threshold value of ≥1%. Positive staining for PD-L1 on ICs and TCs was found in 115 (22.4%) and 7 (1.4%) cases, respectively. Moderate or strong staining for VEGF on TCs was found in 217 (42.3%) patients. PD-L1 expression on ICs and TCs was positively associated with VEGF expression on TCs. Both VEGF and PD-L1 (IC) positivity (VEGF/PD-L1 [IC]: +/+) was observed in 65 (12.7%) cases. Patients in this subgroup exhibited more aggressive clinicopathologic features, including older age, higher World Health Organization/International Society of Urological Pathology (ISUP) grade, angiolymphatic invasion, tumor necrosis, and sarcomatoid differentiation (P < 0.05). Kaplan-Meier analysis indicated that expression of VEGF and PD-L1 on ICs was positively correlated with tumor recurrence (P < 0.001), whereas expression of PD-L1 on TCs was not (P = 0.554). Tumors with positivity for both antibodies (VEGF/PD-L1 [IC]: +/+) exhibited the worst recurrence-free survival (P < 0.001), and double positivity independently predicted tumor recurrence in ccRCC. The present study provides comprehensive and basic information about VEGF and PD-L1 expression for new combined therapy in primary ccRCC.

Comparative analysis of programmed cell death ligand 1 assays in renal cell carcinoma.

AIMS: The importance of programmed cell death ligand 1 (PD-L1) expression has emerged in clinical trials of PD-L1 target therapy in renal cell carcinoma (RCC). This study compares PD-L1 assays in RCC. METHODS AND RESULTS: Two US Food and Drug Administration-approved PD-L1 assays (22C3 and SP142) and one research-use only antibody (E1L3N) were used in a retrospective cohort of 591 patients with RCC. PD-L1 positivity on tumour cells (TCs) and immune cells (ICs) and combined positive score (CPS) were evaluated. With the 22C3, SP142 and E1L3N assays, positive PD-L1 expression on TCs ≥1% was observed in 24 (4.1%), 12 (2.0%) and 16 (2.7%) cases and on ICs ≥1% was observed in 132 (22.3%), 120 (20.3%) and 65 (11.0%) cases, respectively. PD-L1 expression scores among the three assays showed moderate-high positive correlation (ρ = 0.599-0.835, P < 0.001). Assays appeared similar, although staining in ICs was comparatively less frequent with E1L3N. 22C3 showed frequent positivity in TCs. PD-L1 expression on TCs was associated with papillary type 2 RCC (P < 0.001). IC infiltration and PD-L1 expression on ICs were predominantly found in clear cell and papillary type 1 RCC (P < 0.05). CONCLUSIONS: Programmed death 1 (PD-1)/PD-L1 target therapy may be beneficial for patients with papillary type 2 RCC, even if they are categorised as a heterogeneous group. PD-L1 assays should be carefully selected, and accurate histological subtyping of RCC is needed prior to decisions on PD-L1 testing, because of the different PD-L1 expression observed among varying RCC subtypes.

Clinicopathological and prognostic significance of programmed death ligand 1 expression in Korean melanoma patients.

Programmed death ligand 1 (PD-L1) expression provides significant value to predict prognosis and response following immunotherapy in several types of cancers. However, its clinicopathological and prognostic significance in melanoma remains unclear. PD-L1 and the number of tumor infiltrating lymphocytes (TILs) were investigated in 63 Korean patients with melanoma based on the melanoma scoring system. We also compared the results using the PD-L1 antibodies-22C3 and E1L3N clones. In addition, BRAF gene mutation was detected using anti-BRAF antibody and real-time polymerase chain reaction. Overall, 29 (46.0%), 16 (25.4%), and 18 (28.6%) patients exhibited the acral lentiginous type, nodular type, and other histological subtypes of melanoma, respectively. PD-L1 expression was detected in 37 (58.7%) cases and was closely associated with a CD8+TILhigh phenotype (P < 0.001). Combined survival analysis depending on PD-L1 and CD8+TILs status showed that the PD-L1-/CD8+TILhigh group demonstrated the best survival outcome, whereas patients with PD-L1+/CD8+ TILlow showed the worst prognosis (P = 0.039). However, PD-L1+/CD8+ TILlow was not an independent prognostic factor. The 22C3 and E1L3N clones showed a high concordance rate (kappa value, 0.799). BRAF mutation status was not correlated with PD-L1 expression. We suggest that evaluation of the combined status of PD-L1 and TIL might be useful to predict the survival of patients with melanoma.

Prognostic relevance of programmed cell death ligand 1 expression in glioblastoma.

The aim of this study was to determine the clinicopathological significance of programmed cell death ligand 1 (PD-L1) expression in glioblastoma (GBM). In a retrospective cohort of 115 consecutive patients with GBM, PD-L1 expression was determined using immunohistochemistry (IHC). Membranous and fibrillary PD-L1 staining of any intensity in > 5% neoplastic cells and tumour infiltrating immune cells (TIIs) was considered positive staining. In addition, isocitrate dehydrogenase-1 (IDH-1) (R132H) expression and cluster of differentiation 3 (CD3)-positive T-cell infiltration were investigated using IHC. O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation assay and fluorescence in situ hybridization (FISH) for the assessment of 1p/19q deletion were performed. Expression of PD-L1 in tumour cells and TIIs was found in 37 (32.2%) and 6 (5.2%) patients, respectively. Kaplan-Meier analysis indicated that PD-L1 expression in tumour cells was significantly associated with poor overall survival (OS) (P = 0.017), though multivariate Cox analysis did not confirm this association (hazard ratio 1.204; P = 0.615). PD-L1 expression in TIIs did not correlate with the patient prognosis (P = 0.545). In addition, MGMT methylation and IDH-1 (R132H) expression were associated with a better prognosis (P < 0.001 and P = 0.024, respectively). The expression of PD-L1 was associated with CD3-positive T-cell infiltration (P < 0.001), and IDH-1 wild type status (P = 0.008). A deeper insight into PD-L1 expression could help to ensure the success of future immunotherapy in GBM. Our study suggested that PD-L1 target therapy might be beneficial for PD-L1-expressing GBM patients with a poor prognosis.

Three-dimensional finite element analysis of platform switched implant.

PURPOSE: The purpose of this study was to analyze the influence of the platform switching concept on an implant system and peri-implant bone using three-dimensional finite element analysis. MATERIALS AND METHODS: Two three-dimensional finite element models for wide platform and platform switching were created. In the wide platform model, a wide platform abutment was connected to a wide platform implant. In the platform switching model, the wide platform abutment of the wide platform model was replaced by a regular platform abutment. A contact condition was set between the implant components. A vertical load of 300 N was applied to the crown. The maximum von Mises stress values and displacements of the two models were compared to analyze the biomechanical behavior of the models. RESULTS: In the two models, the stress was mainly concentrated at the bottom of the abutment and the top surface of the implant in both models. However, the von Mises stress values were much higher in the platform switching model in most of the components, except for the bone. The highest von Mises values and stress distribution pattern of the bone were similar in the two models. The components of the platform switching model showed greater displacement than those of the wide platform model. CONCLUSION: Due to the stress concentration generated in the implant and the prosthodontic components of the platform switched implant, the mechanical complications might occur when platform switching concept is used.

Effect of coupled graphene oxide on the sensitivity of surface plasmon resonance detection.

We investigated graphene-oxide-(GO-) coupled surface plasmon resonance (SPR) detection sensitivity for sandwiched antigen-antibody interaction between human and antihuman immunoglobulin G molecules. GO was prepared in a Langmuir-Blodgett solution on gold and dielectric surfaces. Theoretical and experimental data suggest that an increased dielectric spacer thickness reduces resonance shifts for GO-coupled SPR detection as dielectric properties of GO appear to prevail. In general, a metal-enhanced structure was shown to provide a larger resonance shift by plasmonic field enhancement. The far-field properties were described in terms of near-field overlap. The peak resonance shift that was obtained with GO-coupled SPR detection was enhanced to 113% of the resonance shift obtained by conventional thin-film-based SPR detection and may further be improved by GO stacking.

Configuration-controlled Au nanocluster arrays on inverse micelle nano-patterns: versatile platforms for SERS and SPR sensors.

Nanopatterned 2-dimensional Au nanocluster arrays with controlled configuration are fabricated onto reconstructed nanoporous poly(styrene-block-vinylpyridine) inverse micelle monolayer films. Near-field coupling of localized surface plasmons is studied and compared for disordered and ordered core-centered Au NC arrays. Differences in evolution of the absorption band and field enhancement upon Au nanoparticle adsorption are shown. The experimental results are found to be in good agreement with theoretical studies based on the finite-difference time-domain method and rigorous coupled-wave analysis. The realized Au nanopatterns are exploited as substrates for surface-enhanced Raman scattering and integrated into Kretschmann-type SPR sensors, based on which unprecedented SPR-coupling-type sensors are demonstrated.

Grating-based surface plasmon resonance detection of core-shell nanoparticle mediated DNA hybridization.

In this report, we have investigated enhanced surface plasmon resonance (SPR) detection of DNA hybridization using gold core - silica shell nanoparticles in localized plasmonic fields. The plasmonic fields were localized by periodic linear gratings. Experimental results measured for hybridization of 24-mer single-stranded DNA oligomers suggest that core-shell nanoparticles (CSNPs) on gratings of 400 nm period provide enhanced optical signatures by 36 times over conventional thin film-based SPR detection. CSNP-mediated DNA hybridization produced 3 times larger angular shift compared to gold nanoparticles of the same core size. We have also analyzed the effect of structural variation. The enhancement using CSNPs was associated with increased surface area and index contrast that is combined by improved plasmon coupling with localized fields on gratings. The combined approach for conjugated measurement of a biomolecular interaction on grating structures is expected to lower the limit of detection to the order of a few tens of fg/mm(2).

Temozolomide during and after radiation therapy for WHO grade III gliomas: preliminary report of a prospective multicenter study.

This prospective study was performed to determine the efficacy, safety, and tolerability of concurrent chemoradiotherapy (CCRT) followed by adjuvant chemotherapy with temozolomide (TMZ) in the treatment of patients with WHO grade III gliomas. Thirty-three adult patients with WHO grade III glioma and aged >17 years were enrolled from three institutions between 2003 and 2008. The median age was 41 years (range, 17-60 years). The pathological diagnoses were anaplastic astrocytomas in 21 patients and anaplastic oligodendrogliomas in 12 patients. The preoperative Karnofsky performance scale score was >60 for all patients. The patients received fractionated focal irradiation in daily fractions of 2 Gy administered five days per week for six weeks, for a total of 60 Gy, in combination with continuous daily TMZ, followed by six cycles of adjuvant TMZ. The median dose of radiotherapy was 59.4 Gy (range, 28.8-61.2 Gy) and the duration of CCRT was 7.0 weeks (range, 3.1-8.3 weeks). A median of 6.2 cycles (range, 2-12 cycles) of TMZ chemotherapy were performed during the period of adjuvant chemotherapy. The response rate was 61% and the tumor-control rate was 82%. Mean progression-free survival (PFS) was 48.7 months (95% CI, 36.0-61.4) and the 12, 24, and 36-month PFS was 74%, 60%, and 50%, respectively. Mean overall survival (OS) was 66.4 months (95% CI, 56.4-76.4) and the 12 and 24-month OS was 97% and 77%, respectively. The extent of surgical resection was a significant prognostic factor for PFS and OS (hazard ratio, 0.24; 95% CI, 0.02-0.73; and hazard ratio, 0.12; 95% CI, 0.01-0.88, respectively; P < 0.001). However, there was no significant difference in the PFS and OS of patients regarding loss of heterozygosity in chromosomes 1p and 19q and methylation of O (6)-methylguanine-DNA methyltransferase promoter, because of the small number of patients available. Only five cases (15%) receiving CCRT with TMZ and three cases (9%) receiving adjuvant chemotherapy had hematological toxicity greater than grade 3. All these patients, however, tolerated the therapy well enough to continue treatment. No opportunistic infections were noted. This protocol for WHO grade III gliomas was relatively safe and tolerable. It showed the possibility of achieving favorable results compared with those of historical controls. A randomized controlled study with a long-term follow-up may be mandatory to evaluate its efficacy.

Surface-enhanced plasmon resonance detection of nanoparticle-conjugated DNA hybridization.

We have investigated surface-enhanced plasmon resonance detection of DNA hybridization. Surface enhancement was based on the excitation of localized surface plasmon using subwavelength nanogratings, at a 300 nm period, coated with 24-mer ssDNA oligonucleotide, while optical signatures of DNA were amplified at the same time by gold nanoparticles conjugated with complementary ssDNA strands. When using nanoparticles of different sizes, maximum sensitivity enhancement, of more than 18 times, was obtained with nanoparticles of 20 nm diameter. This enhancement is mainly due to nanoparticle-associated signal amplification. Additional surface enhancement boosted the detection sensitivity by 57%. We have also confirmed the sensitivity enhancement to be linearly related to nanoparticle volume.

Localized surface plasmon resonance detection of layered biointeractions on metallic subwavelength nanogratings.

Enhanced detection of multiple targets such as self-assembled monolayer (SAM) formation, DNA hybridization, and ethanol ambient changes was explored using localized surface plasmon resonance (LSPR) excited by metallic surface nanogratings. The sensitivity enhancement depends on the target as well as the nanostructure with a maximum at 242% over a conventional structure when detecting an 11-mercaptoundecanoic acid SAM with an LSPR structure of 200 nm period. The measured enhancement shows smaller target-dependent variance when detecting various layered biointeractions, while structure-dependent variance was much larger. The result suggests the feasibility of the efficient detection of multiple biointeractions at enhanced sensitivity and extends the applicability of a nanostructured LSPR biosensor for diverse biomolecular events.

Monte Carlo study of coherent diffuse photon transport in a homogeneous turbid medium: a degree-of-coherence based approach.

We employ a Monte Carlo (MC) algorithm to investigate the decoherence of diffuse photons in turbid media. For the MC simulation of coherent photons, the degree of coherence, defined as a random variable for a photon packet, is associated with a decoherence function that depends on the scattering angle and is updated as a photon interacts with a medium via scattering. Using a slab model, the effects of medium scattering properties were studied, which reveals that a linear random variable model for the degree of coherence is in better agreement with experimental results than a sinusoidal model and that decoherence is quick for the initial few scattering events followed by a slow and gradual decrease of coherence.

Fitting-based determination of an effective medium of a metallic periodic structure and application to photonic crystals.

Effective permittivities of a metallic periodic structure for which the second-order effective-medium theory does not yield correct results were obtained by numerically fitting to rigorous-coupled-wave analysis (RCWA). The calculated effective medium showed good agreement with RCWA and minimal deviation in the long-wavelength limit with variation in angle of incidence, grating depth, superstrate, and fill factor. In terms of the standard deviation, the effective medium was least affected by the change in grating depths. The calculated effective permittivities were applied to a three-dimensional metallic photonic-crystal structure and produced a photonic bandgap that is consistent with published experimental data.