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Alzheimer’s disease (AD), the most common form of dementia, remains challenging to understand and treat despite decades of research and clinical investigation. This might be partly due to a lack of widely available and cost-effective modalities for diagnosis and prognosis. Recently, the blood-based AD biomarker field has seen significant progress driven by technological advances, mainly improved analytical sensitivity and precision of the assays and measurement platforms. Several blood-based biomarkers have shown high potential for accurately detecting AD pathophysiology. As a result, there has been considerable interest in applying these biomarkers for diagnosis and prognosis, as surrogate metrics to investigate the impact of various covariates on AD pathophysiology and to accelerate AD therapeutic trials and monitor treatment effects. However, the lack of standardization of how blood samples and collected, processed, stored analyzed and reported can affect the reproducibility of these biomarker measurements, potentially hindering progress toward their widespread use in clinical and research settings. To help address these issues, we provide fundamental guidelines developed according to recent research findings on the impact of sample handling on blood biomarker measurements. These guidelines cover important considerations including study design, blood collection, blood processing, biobanking, biomarker measurement, and result reporting. Furthermore, the proposed guidelines include best practices for appropriate blood handling procedures for genetic and ribonucleic acid analyses. While we focus on the key blood-based AD biomarkers for the AT(N) criteria (e.g., amyloid-beta [Aβ]40, Aβ42, Aβ42/40 ratio, total-tau, phosphorylated-tau, neurofilament light chain, brain-derived tau and glial fibrillary acidic protein), we anticipate that these guidelines will generally be applicable to other types of blood biomarkers. We also anticipate that these guidelines will assist investigators in planning and executing biomarker research, enabling harmonization of sample handling to improve comparability across studies.

Amyloid-β (Aβ) deposits are detectable in the brain in vivo using positron emission tomography (PET) and [C-11]-labeled Pittsburgh Compound B ([C-11]PiB); however, the sensitivity of this technique is not well understood. In this study, we examined Aβ pathology in an individual who had clinical diagnoses of probable dementia with Lewy bodies and possible Alzheimer’s disease (AD) but with no detectable [C-11]PiB PET retention ([C-11]PiB(−)) when imaged 17 months prior to death. Brain samples were processed in parallel with region-matched samples from an individual with a clinical diagnosis of probable AD and a positive [C-11]PiB PET scan ([C-11]PiB(+)) when imaged 10 months prior to death. In the [C-11]PiB(−) case, Aβ plaques were sparse, occupying less than 2% cortical area, and were weakly labeled with 6-CN-PiB, a highly fluorescent derivative of PiB. In contrast, Aβ plaques occupied up to 12% cortical area in the [C-11]PiB(+) case, and were intensely labeled with 6-CN-PIB. The [C-11]PiB(−) case had low levels of [H-3]PiB binding (<100 pmol/g) and Aβ1–42 (<500 pmol/g) concentration except in the frontal cortex where Aβ1–42 values (788 pmol/g) approached cortical values in the [C-11]PiB(+) case (800–1,700 pmol/g). In several cortical regions of the [C-11]PiB(−) case, Aβ1–40 levels were within the range of cortical Aβ1–40 values in the [C-11]PiB(+) case. Antemortem [C-11]PiB DVR values correlated well with region-matched postmortem measures of Aβ1–42 and Aβ1–40 in the [C-11]PiB(+), and with Aβ1–42 only in the [C-11]PiB(−) case. The low ratios of [H-3]PiB binding levels to Aβ concentrations and 6-CN-PiB to Aβ plaque loads in the [C-11]PiB(−) case indicate that Aβ pathology in the brain may be associated with low or undetectable levels of [C-11]PiB retention. Studies in greater numbers of [C-11]PiB PET autopsy cases are needed to define the Aβ concentration and [H-3]PiB binding levels required to produce a positive [C-11]PiB PET signal.

INTRODUCTION Detection of Alzheimer's disease (AD) pathophysiology among individuals with mild cognitive changes and those experiencing subjective cognitive decline (SCD) remains challenging. Plasma phosphorylated tau 217 (p‐tau217) is one of the most promising of the emerging biomarkers for AD. However, accessible methods are limited. METHODS We employed a novel p‐tau217 immunoassay (University of Gothenburg [UGOT] p‐tau217) in four independent cohorts (n = 308) including a cerebrospinal fluid (CSF) biomarker‐classified cohort (Discovery), two cohorts consisting mostly of cognitively unimpaired (CU) and mild cognitively impaired (MCI) participants (MYHAT and Pittsburgh), and a population‐based cohort of individuals with SCD (Barcelonaβeta Brain Research Center's Alzheimer's At‐Risk Cohort [β‐AARC]). RESULTS UGOT p‐tau217 showed high accuracy (area under the curve [AUC] = 0.80–0.91) identifying amyloid beta (Aβ) pathology, determined either by Aβ positron emission tomography or CSF Aβ42/40 ratio. In individuals experiencing SCD, UGOT p‐tau217 showed high accuracy identifying those with a positive CSF Aβ42/40 ratio (AUC = 0.91). DISCUSSION UGOT p‐tau217 can be an easily accessible and efficient way to screen and monitor patients with suspected AD pathophysiology, even in the early stages of the continuum.

Alzheimer's disease (AD), the most common form of dementia, remains challenging to understand and treat despite decades of research and clinical investigation. This might be partly due to a lack of widely available and cost-effective modalities for diagnosis and prognosis. Recently, the blood-based AD biomarker field has seen significant progress driven by technological advances, mainly improved analytical sensitivity and precision of the assays and measurement platforms. Several blood-based biomarkers have shown high potential for accurately detecting AD pathophysiology. As a result, there has been considerable interest in applying these biomarkers for diagnosis and prognosis, as surrogate metrics to investigate the impact of various covariates on AD pathophysiology and to accelerate AD therapeutic trials and monitor treatment effects. However, the lack of standardization of how blood samples and collected, processed, stored analyzed and reported can affect the reproducibility of these biomarker measurements, potentially hindering progress toward their widespread use in clinical and research settings. To help address these issues, we provide fundamental guidelines developed according to recent research findings on the impact of sample handling on blood biomarker measurements. These guidelines cover important considerations including study design, blood collection, blood processing, biobanking, biomarker measurement, and result reporting. Furthermore, the proposed guidelines include best practices for appropriate blood handling procedures for genetic and ribonucleic acid analyses. While we focus on the key blood-based AD biomarkers for the AT(N) criteria (e.g., amyloid-beta [A[beta]]40, A[beta]42, A[beta]42/40 ratio, total-tau, phosphorylated-tau, neurofilament light chain, brain-derived tau and glial fibrillary acidic protein), we anticipate that these guidelines will generally be applicable to other types of blood biomarkers. We also anticipate that these guidelines will assist investigators in planning and executing biomarker research, enabling harmonization of sample handling to improve comparability across studies.

Amyloid-β (Aβ) deposits are detectable in the brain in vivo using positron emission tomography (PET) and [C-11]-labeled Pittsburgh Compound B ([C-11]PiB); however, the sensitivity of this technique is not well understood. In this study, we examined Aβ pathology in an individual who had clinical diagnoses of probable dementia with Lewy bodies and possible Alzheimer's disease (AD) but with no detectable [C-11]PiB PET retention ([C-11]PiB(-)) when imaged 17 months prior to death. Brain samples were processed in parallel with region-matched samples from an individual with a clinical diagnosis of probable AD and a positive [C-11]PiB PET scan ([C-11]PiB(+)) when imaged 10 months prior to death. In the [C-11]PiB(-) case, Aβ plaques were sparse, occupying less than 2% cortical area, and were weakly labeled with 6-CN-PiB, a highly fluorescent derivative of PiB. In contrast, Aβ plaques occupied up to 12% cortical area in the [C-11]PiB(+) case, and were intensely labeled with 6-CN-PIB. The [C-11]PiB(-) case had low levels of [H-3]PiB binding (< 100 pmol/g) and Aβ1-42 (< 500 pmol/g) concentration except in the frontal cortex where Aβ1-42 values (788 pmol/g) approached cortical values in the [C-11]PiB(+) case (800-1, 700 pmol/g). In several cortical regions of the [C-11]PiB(-) case, Aβ1-40 levels were within the range of cortical Aβ1-40 values in the [C-11]PiB(+) case. Antemortem [C-11]PiB DVR values correlated well with region-matched postmortem measures of Aβ1-42 and Aβ1-40 in the [C-11]PiB(+), and with Aβ1-42 only in the [C-11]PiB(-) case. The low ratios of [H-3]PiB binding levels to Aβ concentrations and 6-CN-PiB to Aβ plaque loads in the [C-11]PiB(-) case indicate that Aβ pathology in the brain may be associated with low or undetectable levels of [C-11]PiB retention. Studies in greater numbers of [C-11]PiB PET autopsy cases are needed to define the Aβ concentration and [H-3]PiB binding levels required to produce a positive [C-11]PiB PET signal.Amyloid-β (Aβ) deposits are detectable in the brain in vivo using positron emission tomography (PET) and [C-11]-labeled Pittsburgh Compound B ([C-11]PiB); however, the sensitivity of this technique is not well understood. In this study, we examined Aβ pathology in an individual who had clinical diagnoses of probable dementia with Lewy bodies and possible Alzheimer's disease (AD) but with no detectable [C-11]PiB PET retention ([C-11]PiB(-)) when imaged 17 months prior to death. Brain samples were processed in parallel with region-matched samples from an individual with a clinical diagnosis of probable AD and a positive [C-11]PiB PET scan ([C-11]PiB(+)) when imaged 10 months prior to death. In the [C-11]PiB(-) case, Aβ plaques were sparse, occupying less than 2% cortical area, and were weakly labeled with 6-CN-PiB, a highly fluorescent derivative of PiB. In contrast, Aβ plaques occupied up to 12% cortical area in the [C-11]PiB(+) case, and were intensely labeled with 6-CN-PIB. The [C-11]PiB(-) case had low levels of [H-3]PiB binding (< 100 pmol/g) and Aβ1-42 (< 500 pmol/g) concentration except in the frontal cortex where Aβ1-42 values (788 pmol/g) approached cortical values in the [C-11]PiB(+) case (800-1, 700 pmol/g). In several cortical regions of the [C-11]PiB(-) case, Aβ1-40 levels were within the range of cortical Aβ1-40 values in the [C-11]PiB(+) case. Antemortem [C-11]PiB DVR values correlated well with region-matched postmortem measures of Aβ1-42 and Aβ1-40 in the [C-11]PiB(+), and with Aβ1-42 only in the [C-11]PiB(-) case. The low ratios of [H-3]PiB binding levels to Aβ concentrations and 6-CN-PiB to Aβ plaque loads in the [C-11]PiB(-) case indicate that Aβ pathology in the brain may be associated with low or undetectable levels of [C-11]PiB retention. Studies in greater numbers of [C-11]PiB PET autopsy cases are needed to define the Aβ concentration and [H-3]PiB binding levels required to produce a positive [C-11]PiB PET signal.

The role of adjuvant chemotherapy in stage II colon cancer continues to be debated. The presence of circulating tumor DNA (ctDNA) after surgery predicts very poor recurrence-free survival, whereas its absence predicts a low risk of recurrence. The benefit of adjuvant chemotherapy for ctDNA-positive patients is not well understood. We conducted a trial to assess whether a ctDNA-guided approach could reduce the use of adjuvant chemotherapy without compromising recurrence risk. Patients with stage II colon cancer were randomly assigned in a 2:1 ratio to have treatment decisions guided by either ctDNA results or standard clinicopathological features. For ctDNA-guided management, a ctDNA-positive result at 4 or 7 weeks after surgery prompted oxaliplatin-based or fluoropyrimidine chemotherapy. Patients who were ctDNA-negative were not treated. The primary efficacy end point was recurrence-free survival at 2 years. A key secondary end point was adjuvant chemotherapy use. Of the 455 patients who underwent randomization, 302 were assigned to ctDNA-guided management and 153 to standard management. The median follow-up was 37 months. A lower percentage of patients in the ctDNA-guided group than in the standard-management group received adjuvant chemotherapy (15% vs. 28%; relative risk, 1.82; 95% confidence interval [CI], 1.25 to 2.65). In the evaluation of 2-year recurrence-free survival, ctDNA-guided management was noninferior to standard management (93.5% and 92.4%, respectively; absolute difference, 1.1 percentage points; 95% CI, -4.1 to 6.2 [noninferiority margin, -8.5 percentage points]). Three-year recurrence-free survival was 86.4% among ctDNA-positive patients who received adjuvant chemotherapy and 92.5% among ctDNA-negative patients who did not. A ctDNA-guided approach to the treatment of stage II colon cancer reduced adjuvant chemotherapy use without compromising recurrence-free survival. (Supported by the Australian National Health and Medical Research Council and others; DYNAMIC Australian New Zealand Clinical Trials Registry number, ACTRN12615000381583.).

Systematic reviews of diagnostic test accuracy (DTA) studies are fundamental to the decision making process in evidence based medicine. Although such studies are regarded as high level evidence, these reviews are not always reported completely and transparently. Suboptimal reporting of DTA systematic reviews compromises their validity and generalisability, and subsequently their value to key stakeholders. An extension of the PRISMA (preferred reporting items for systematic review and meta-analysis) statement was recently developed to improve the reporting quality of DTA systematic reviews. The PRISMA-DTA statement has 27 items, of which eight are unmodified from the original PRISMA statement. This article provides an explanation for the 19 new and modified items, along with their meaning and rationale. Examples of complete reporting are used for each item to illustrate best practices.

Immunotherapy targeting the PD-1 axis has activity in several tumour types. We aimed to establish the activity and safety of the PD-1 inhibitor pembrolizumab in patients with untreated brain metastases from melanoma or non-small-cell lung cancer (NSCLC). In this non-randomised, open-label, phase 2 trial, we enrolled patients aged 18 years or older with melanoma or NSCLC with untreated brain metastases from the Yale Cancer Center. Patients had at least one untreated or progressive brain metastasis between 5 and 20 mm in diameter without associated neurological symptoms or the need for corticosteroids. Patients with NSCLC had tumour tissue positive for PD-L1 expression; this was not required for patients with melanoma. Patients were given 10 mg/kg pembrolizumab every 2 weeks until progression. The primary endpoint was brain metastasis response assessed in all treated patients. The trial is ongoing and here we present an early analysis. The study is registered with ClinicalTrials.gov, number NCT02085070. Between March 31, 2014, and May 31, 2015, we screened 52 patients with untreated or progressive brain metastases (18 with melanoma, 34 with NSCLC), and enrolled 36 (18 with melanoma, 18 with NSCLC). A brain metastasis response was achieved in four (22%; 95% CI 7–48) of 18 patients with melanoma and six (33%; 14–59) of 18 patients with NSCLC. Responses were durable, with all but one patient with NSCLC who responded showing an ongoing response at the time of data analysis on June 30, 2015. Treatment-related serious and grade 3–4 adverse events were grade 3 elevated aminotransferases (n=1 [6%]) in the melanoma cohort, and grade 3 colitis (n=1 [6%]), grade 3 pneumonitis (n=1 [6%]), grade 3 fatigue (n=1 [6%]), grade 4 hyperkalemia (n=1 [6%]), and grade 2 acute kidney injury (n=1 [6%]) in the NSCLC cohort. Clinically significant neurological adverse events included transient grade 3 cognitive dysfunction and grade 1–2 seizures (n=3 [17%]) in the melanoma cohort. Pembrolizumab shows activity in brain metastases in patients with melanoma or NSCLC with an acceptable safety profile, which suggests that there might be a role for systemic immunotherapy in patients with untreated or progressive brain metastases. Merck and the Yale Cancer Center.

A positive surgical margin (PSM) following cancer resection oftentimes necessitates adjuvant treatments and carries significant financial and prognostic implications. We sought to compare PSM rates for the ten most common solid cancers in the United States, and to assess trends over time. Over 10 million patients were identified in the National Cancer Data Base from 1998–2012, and 6.5 million had surgical margin data. PSM rates were compared between two time periods, 1998–2002 and 2008–2012. PSM was positively correlated with tumor category and grade. Ovarian and prostate cancers had the highest PSM prevalence in women and men, respectively. The highest PSM rates for cancers affecting both genders were seen for oral cavity tumors. PSM rates for breast cancer and lung and bronchus cancer in both men and women declined over the study period. PSM increases were seen for bladder, colon and rectum, and kidney and renal pelvis cancers. This large-scale analysis appraises the magnitude of PSM in the United States in order to focus future efforts on improving oncologic surgical care with the goal of optimizing value and improving patient outcomes.

Protein phosphorylation is one of the most widespread post-translational modifications in biology 1 , 2 . With advances in mass-spectrometry-based phosphoproteomics, 90,000 sites of serine and threonine phosphorylation have so far been identified, and several thousand have been associated with human diseases and biological processes 3 , 4 . For the vast majority of phosphorylation events, it is not yet known which of the more than 300 protein serine/threonine (Ser/Thr) kinases encoded in the human genome are responsible 3 . Here we used synthetic peptide libraries to profile the substrate sequence specificity of 303 Ser/Thr kinases, comprising more than 84% of those predicted to be active in humans. Viewed in its entirety, the substrate specificity of the kinome was substantially more diverse than expected and was driven extensively by negative selectivity. We used our kinome-wide dataset to computationally annotate and identify the kinases capable of phosphorylating every reported phosphorylation site in the human Ser/Thr phosphoproteome. For the small minority of phosphosites for which the putative protein kinases involved have been previously reported, our predictions were in excellent agreement. When this approach was applied to examine the signalling response of tissues and cell lines to hormones, growth factors, targeted inhibitors and environmental or genetic perturbations, it revealed unexpected insights into pathway complexity and compensation. Overall, these studies reveal the intrinsic substrate specificity of the human Ser/Thr kinome, illuminate cellular signalling responses and provide a resource to link phosphorylation events to biological pathways. Analysis of the kinase activity of 300 protein Ser/Thr kinases reveals that the substrate specificity of the kinome is substantially more diverse than expected and is driven extensively by negative selectivity