PD-1 Blockade in Solid Tumors with Defects in Polymerase Epsilon.

Missense mutations in the polymerase epsilon (POLE) gene have been reported to generate proofreading defects resulting in an ultramutated genome and to sensitize tumors to checkpoint blockade immunotherapy. However, many POLE-mutated tumors do not respond to such treatment. To better understand the link between POLE mutation variants and response to immunotherapy, we prospectively assessed the efficacy of nivolumab in a multicenter clinical trial in patients bearing advanced mismatch repair-proficient POLE-mutated solid tumors. We found that only tumors harboring selective POLE pathogenic mutations in the DNA binding or catalytic site of the exonuclease domain presented high mutational burden with a specific single-base substitution signature, high T-cell infiltrates, and a high response rate to anti-PD-1 monotherapy. This study illustrates how specific DNA repair defects sensitize to immunotherapy. POLE proofreading deficiency represents a novel agnostic biomarker for response to PD-1 checkpoint blockade therapy. SIGNIFICANCE: POLE proofreading deficiency leads to high tumor mutational burden with high tumor-infiltrating lymphocytes and predicts anti-PD-1 efficacy in mismatch repair-proficient tumors. Conversely, tumors harboring POLE mutations not affecting proofreading derived no benefit from PD-1 blockade. POLE proofreading deficiency is a new tissue-agnostic biomarker for cancer immunotherapy. This article is highlighted in the In This Issue feature, p. 1397.

A Comprehensive Comparison of Early-Onset and Average-Onset Colorectal Cancers.

BACKGROUND: The causative factors for the recent increase in early-onset colorectal cancer (EO-CRC) incidence are unknown. We sought to determine if early-onset disease is clinically or genomically distinct from average-onset colorectal cancer (AO-CRC). METHODS: Clinical, histopathologic, and genomic characteristics of EO-CRC patients (2014-2019), divided into age 35 years and younger and 36-49 years at diagnosis, were compared with AO-CRC (50 years and older). Patients with mismatch repair deficient tumors, CRC-related hereditary syndromes, and inflammatory bowel disease were excluded from all but the germline analysis. All statistical tests were 2-sided. RESULTS: In total, 759 patients with EO-CRC (35 years, n = 151; 36-49 years, n = 608) and AO-CRC (n = 687) were included. Left-sided tumors (35 years and younger = 80.8%; 36-49 years = 83.7%; AO = 63.9%; P < .001 for both comparisons), rectal bleeding (35 years and younger = 41.1%; 36-49 years = 41.0%; AO = 25.9%; P = .001 and P < .001, respectively), and abdominal pain (35 years and younger = 37.1%; 36-49 years = 34.0%; AO = 26.8%; P = .01 and P = .005, respectively) were more common in EO-CRC. Among microsatellite stable tumors, we found no differences in histopathologic tumor characteristics. Initially, differences in TP53 and Receptor Tyrosine Kinase signaling pathway (RTK-RAS)alterations were noted by age. However, on multivariate analysis including somatic gene analysis and tumor sidedness, no statistically significant differences at the gene or pathway level were demonstrated. Among advanced microsatellite stable CRCs, chemotherapy response and survival were equivalent by age cohorts. Pathogenic germline variants were identified in 23.3% of patients 35 years and younger vs 14.1% of AO-CRC (P = .01). CONCLUSIONS: EO-CRCs are more commonly left-sided and present with rectal bleeding and abdominal pain but are otherwise clinically and genomically indistinguishable from AO-CRCs. Aggressive treatment regimens based solely on the age at CRC diagnosis are not warranted.

Mismatch Repair-Deficient Rectal Cancer and Resistance to Neoadjuvant Chemotherapy.

PURPOSE: Evaluate response of mismatch repair-deficient (dMMR) rectal cancer to neoadjuvant chemotherapy. EXPERIMENTAL DESIGN: dMMR rectal tumors at Memorial Sloan Kettering Cancer Center (New York, NY) were retrospectively reviewed for characteristics, treatment, and outcomes. Fifty patients with dMMR rectal cancer were identified by IHC and/or microsatellite instability analysis, with initial treatment response compared with a matched MMR-proficient (pMMR) rectal cancer cohort. Germline and somatic mutation analyses were evaluated. Patient-derived dMMR rectal tumoroids were assessed for chemotherapy sensitivity. RESULTS: Of 21 patients receiving neoadjuvant chemotherapy (fluorouracil/oxaliplatin), six (29%) had progression of disease. In comparison, no progression was noted in 63 pMMR rectal tumors (P = 0.0001). Rectal cancer dMMR tumoroids reflected this resistance to chemotherapy. No genomic predictors of chemotherapy response were identified. Of 16 patients receiving chemoradiation, 13 (93%) experienced tumor downstaging; one patient had stable disease, comparable with 48 pMMR rectal cancers. Of 13 patients undergoing surgery, 12 (92%) had early-stage disease. Forty-two (84%) of the 50 patients tested positive for Lynch syndrome with enrichment of germline MSH2 and MSH6 mutations when compared with 193 patients with Lynch syndrome-associated colon cancer (MSH2, 57% vs 36%; MSH6, 17% vs 9%; P < 0.003). CONCLUSIONS: Over one-fourth of dMMR rectal tumors treated with neoadjuvant chemotherapy exhibited disease progression. Conversely, dMMR rectal tumors were sensitive to chemoradiation. MMR status should be performed upfront in all locally advanced rectal tumors with careful monitoring for response on neoadjuvant chemotherapy and genetic testing for Lynch syndrome in patients with dMMR rectal cancer.

Encorafenib, Binimetinib, and Cetuximab in BRAF V600E-Mutated Colorectal Cancer.

BACKGROUND: Patients with metastatic colorectal cancer with the BRAF V600E mutation have a poor prognosis, with a median overall survival of 4 to 6 months after failure of initial therapy. Inhibition of BRAF alone has limited activity because of pathway reactivation through epidermal growth factor receptor signaling. METHODS: In this open-label, phase 3 trial, we enrolled 665 patients with BRAF V600E-mutated metastatic colorectal cancer who had had disease progression after one or two previous regimens. Patients were randomly assigned in a 1:1:1 ratio to receive encorafenib, binimetinib, and cetuximab (triplet-therapy group); encorafenib and cetuximab (doublet-therapy group); or the investigators' choice of either cetuximab and irinotecan or cetuximab and FOLFIRI (folinic acid, fluorouracil, and irinotecan) (control group). The primary end points were overall survival and objective response rate in the triplet-therapy group as compared with the control group. A secondary end point was overall survival in the doublet-therapy group as compared with the control group. We report here the results of a prespecified interim analysis. RESULTS: The median overall survival was 9.0 months in the triplet-therapy group and 5.4 months in the control group (hazard ratio for death, 0.52; 95% confidence interval [CI], 0.39 to 0.70; P<0.001). The confirmed response rate was 26% (95% CI, 18 to 35) in the triplet-therapy group and 2% (95% CI, 0 to 7) in the control group (P<0.001). The median overall survival in the doublet-therapy group was 8.4 months (hazard ratio for death vs. control, 0.60; 95% CI, 0.45 to 0.79; P<0.001). Adverse events of grade 3 or higher occurred in 58% of patients in the triplet-therapy group, in 50% in the doublet-therapy group, and in 61% in the control group. CONCLUSIONS: A combination of encorafenib, cetuximab, and binimetinib resulted in significantly longer overall survival and a higher response rate than standard therapy in patients with metastatic colorectal cancer with the BRAF V600E mutation. (Funded by Array BioPharma and others; BEACON CRC ClinicalTrials.gov number, NCT02928224; EudraCT number, 2015-005805-35.).

Sources of mu activity and their functional connectivity in perceiving complexities in reciprocal social interactive motion: An exploratory study using the 'Namaste' task.

Cognitive processes underlying reciprocal social interactions are understood by the mechanism of embodiment, which is closely related to the mirror neuron system. Electroencephalographic (EEG) mu activity is a neural marker of the mirror neuron system. This study investigated the mu activity, localization of its sources and functional connectivity, which was induced while watching reciprocal social interactive motion across various degrees of complexity. Eighteen healthy participants underwent high-resolution EEG recording using 256-channels while they watched a specifically designed, culture specific, video task that showed two persons interacting socially using body gestures. Task complexity was determined by (1) whether there was an identical gestural response or a non-identical one; (2) whether the participant watched two persons interacting or was virtually involved in the interaction. Source localization and functional connectivity analysis was conducted for mu activity across various tasks. We also correlated mu activity and functional connectivity measures with serum BDNF. We found that spectral densities in various brain sources of mu activity and their increased functional connectivity distinguished identical and non-identical reciprocal expression observations, while mu suppression alone did not discriminate various degrees of complexities. These findings might have important implications in the understanding of mechanisms underlying mirror neuron dysfunction in various psychiatric disorders.

Shape-selective oriented cerium oxide nanocrystals permit assessment of the effect of the exposed facets on catalytic activity and oxygen storage capacity.

The catalytic performance of a range of nanocrystalline CeO2 samples, prepared to have different morphologies, was measured using two accepted indicators; oxygen storage and diesel soot combustion. The same powders were characterized in detail by HR-TEM, XRD, XPS, and Raman methods. The study demonstrates that activity is determined by the relative fraction of the active crystallographic planes, not by the specific surface area of the powders. The physical study is a step toward quantitative evaluation of the relative contribution to activity of the different facets. The synthetic protocol permits fabrication of CeO2 nanostructures with preferentially grown active planes, and therefore has potential in developing catalytic applications and in nanocompositing.

Assessing the likelihood of new-onset inflammatory bowel disease following tumor necrosis factor-alpha inhibitor therapy for rheumatoid arthritis and juvenile rheumatoid arthritis.

The association between inhibition of tumor necrosis factor-alpha (TNF-α) in patients with rheumatoid arthritis (RA) and juvenile rheumatoid arthritis (JRA) and the onset of inflammatory bowel disease (IBD) is unclear. We sought to evaluate this association by analyzing adverse events (AEs) reported to the Food and Drug Administration Adverse Event Reporting System (FAERS) with a standardized scoring tool for drug-induced AEs. A search of the FAERS for RA or JRA (January 2003-December 2011) reported with adalimumab, certolizumab pegol, etanercept, golimumab, or infliximab was performed. This dataset was then queried for cases indicating IBD. Full-length reports were accessed using the Freedom of Information Act and organized by age, sex, concomitant medications, co-morbidities, type of TNF-α inhibitor used, and diagnosis/treatment details. The Naranjo score was used to determine whether the drug-induced AEs were definite, probable, possible, or doubtful. There were 158 cases of IBD after TNF-α inhibitor exposure in RA or JRA patients. Use of the Naranjo score revealed that, in a majority of the cases (71.5 %), TNF-α inhibitor exposure was considered a 'possible' cause. A majority of the 'probable cases' in JRA were reported with etanercept (40 patients, 90.91 %). There were no 'definite' cases of anti-TNF-induced IBD. After applying the Naranjo scale, a weak association between new-onset IBD and TNF-α inhibitor therapy in RA patients and a moderately strong association especially with etanercept exposure in JRA patients was observed. However, causality cannot be determined due to limitations of the FAERS and the Naranjo score.

One-pot synthesis of ultra-small cerium oxide nanodots exhibiting multi-colored fluorescence.

CeO(2) nanodots of diameter 2nm have been synthesized by the thermolysis of cerium acetate in diphenylether in the presence of an oleic acid surfactant. The surfactant coating enabled them to be easily dispersible in nonpolar solvents. The CeO(2) dots exhibited size dependant optical properties such as a red shift in absorption and band gap. As a result, the surfactant coated CeO(2) nanocrystals emit photons in the visible region with broad photoluminescence spectra resulting in multi-colored fluorescence, which originates from defects associated with CeO(2) nanocrystals approaching molecular dimensions.