Real-World Impact of Comprehensive Genomic Profiling on Biomarker Detection, Receipt of Therapy, and Clinical Outcomes in Advanced Non-Small Cell Lung Cancer.

PURPOSE: Therapeutic decision making for patients with advanced non-small cell lung cancer (aNSCLC) includes a growing number of options for genomic, biomarker-guided, targeted therapies. We compared actionable biomarker detection, targeted therapy receipt, and real-world overall survival (rwOS) in patients with aNSCLC tested with comprehensive genomic profiling (CGP) versus small panel testing (SP) in real-world community health systems. METHODS: Patients older than 18 years diagnosed with aNSCLC between January 1, 2015, and December 31, 2020, who received biomarker testing were followed until death or study end (September 30, 2021), and categorized by most comprehensive testing during follow-up: SP (≤52 genes) or CGP (>52 genes). RESULTS: Among 3,884 patients (median age, 68 years; 50% female; 73% non-Hispanic White), 20% received CGP and 80% SP. The proportion of patients with ≥one actionable biomarker (actionability) was significantly higher in CGP than in SP (32% v 14%; P < .001). Of patients with actionability, 43% (CGP) and 38% (SP) received matched therapies (P = .20). Among treated patients, CGP before first-line treatment was associated with higher likelihood of matched therapy in any line (odds ratio, 3.2 [95% CI, 1.84 to 5.53]). CGP testing (hazard ratio [HR], 0.80 [95% CI, 0.72 to 0.89]) and actionability (HR, 0.84 [95% CI, 0.77 to 0.91]) were associated with reduced risk of mortality. Among treated patients with actionability, matched therapy receipt showed improved median rwOS in months in CGP (34 [95% CI, 21 to 49] matched v 14 [95% CI, 10 to 18] unmatched) and SP (27 [95% CI, 21 to 43] matched v 10 [95% CI, 8 to 14] unmatched). CONCLUSION: Patients who received CGP had improved detection of actionable biomarkers and greater use of matched therapies, both of which were associated with significant increases in survival.

Assessment of BRCA1 and BRCA2 Germline Variant Data From Patients With Breast Cancer in a Real-World Data Registry.

PURPOSE: The emergence of large real-world clinical databases and tools to mine electronic medical records has allowed for an unprecedented look at large data sets with clinical and epidemiologic correlates. In clinical cancer genetics, real-world databases allow for the investigation of prevalence and effectiveness of prevention strategies and targeted treatments and for the identification of barriers to better outcomes. However, real-world data sets have inherent biases and problems (eg, selection bias, incomplete data, measurement error) that may hamper adequate analysis and affect statistical power. METHODS: Here, we leverage a real-world clinical data set from a large health network for patients with breast cancer tested for variants in BRCA1 and BRCA2 (N = 12,423). We conducted data cleaning and harmonization, cross-referenced with publicly available databases, performed variant reassessment and functional assays, and used functional data to inform a variant's clinical significance applying American College of Medical Geneticists and the Association of Molecular Pathology guidelines. RESULTS: In the cohort, White and Black patients were over-represented, whereas non-White Hispanic and Asian patients were under-represented. Incorrect or missing variant designations were the most significant contributor to data loss. While manual curation corrected many incorrect designations, a sizable fraction of patient carriers remained with incorrect or missing variant designations. Despite the large number of patients with clinical significance not reported, original reported clinical significance assessments were accurate. Reassessment of variants in which clinical significance was not reported led to a marked improvement in data quality. CONCLUSION: We identify the most common issues with BRCA1 and BRCA2 testing data entry and suggest approaches to minimize data loss and keep interpretation of clinical significance of variants up to date.

Multi-omic profiling of simultaneous ductal carcinoma in situ and invasive breast cancer.

PURPOSE: The progression of ductal carcinoma in situ (DCIS) to invasive breast carcinoma (IBC) in humans is highly variable. To better understand the relationship between them, we performed a multi-omic characterization of co-occurring DCIS and IBC lesions in a cohort of individuals. METHODS: Formalin-fixed paraffin-embedded tissue samples from 50 patients with co-occurring DCIS and IBC lesions were subjected to DNA-seq and whole transcriptome RNA-seq. Paired DCIS and IBC multi-omics profiles were then interrogated for DNA mutations, gene expression profiles and pathway analysis. RESULTS: Most small variants and copy number variations were shared between co-occurring DCIS and IBC lesions, with IBC exhibiting on average a higher degree of additional mutations. However, 36% of co-occurring lesions shared no common mutations and 49% shared no common copy number variations. The most frequent genomic variants in both DCIS and IBC were PIK3CA, TP53, KMT2C, MAP3K1, GATA3 and SF3B1, with KMT2C being more frequent in DCIS and TP53 and MAP3K1 more frequent in IBC, though the numbers are too small for definitive conclusions. The most frequent copy number variations were seen in MCL1, CKSB1 and ERBB2. ERBB2 changes were not seen in IBC unless present in the corresponding DCIS. Transcriptional profiles were highly distinct between DCIS and IBC, with DCIS exhibiting upregulation of immune-related signatures, while IBC showed significant overexpression in genes and pathways associated with cell division and proliferation. Interestingly, DCIS and IBC exhibited significant differential expression of different components of extracellular matrix (ECM) formation and regulation, with DCIS showing overexpression of ECM-membrane interaction components while IBC showed upregulation of genes associated with fibronectin and invadopodia. CONCLUSION: While most co-occurring DCIS and IBC were mutationally similar and suggestive of a common clonal progenitor, transcriptionally the lesions are highly distinct, with IBC expressing key pathways that facilitate invasion and proliferation. These results are suggestive of additional levels of regulation, epigenetic or other, that facilitate the acquisition of invasive properties during tumor evolution.

Race-Associated Genomic Correlates of Therapeutic Response in African American Patients With Non-Small-Cell Lung Cancer.

PURPOSE: African American individuals are disproportionately affected by lung cancer in terms of incidence and mortality. In oncogene-driven non-small-cell lung cancer (NSCLC), emerging evidence indicates that underlying molecular heterogeneity, which can be affected by ancestry, contributes to variable drug sensitivity and therapeutic responses. The purpose of this study was to evaluate race-associated differences in reported treatment decisions, therapeutic outcomes, and molecular features in KRAS- and EGFR-mutant NSCLC. MATERIALS AND METHODS: This is a retrospective study using real-world clinical-genomic data from health systems in the United States to evaluate race-associated outcomes in advanced-stage KRAS- or EGFR-driven NSCLC. Our overall objectives were to evaluate race-associated therapeutic outcomes and to describe molecular features in non-Hispanic Black (NHB) and non-Hispanic White (NHW) patients with NSCLC. RESULTS: A total of 723 NSCLC patients with KRAS and 315 patients with EGFR oncogenic mutations were evaluated. In KRAS-mutant patients, variable outcomes were observed in NHB and NHW patients on the basis of receiving chemotherapy alone or in combination with immune checkpoint inhibitors. NHB patients received treatment at significantly lower rates compared with NHW patients. In the EGFR-mutant cohort, NHB and NHW patients received EGFR-targeted agents at similar rates, and overall survival was not significantly different. Race-associated differences in molecular features included a higher frequency of TP53 comutation in KRAS-mutant NHB patients and higher prevalence of EGFR G719S subtype in NHB patients. CONCLUSION: In a real-world cohort of patients with NSCLC, we identified race-associated differences in therapeutic outcomes and described molecular characteristics in NHB and NHW patients with NSCLC. To proactively identify patients most likely to respond to systemic therapies, a more comprehensive approach is needed to help guide therapy selection in individualized patient populations.

Proteogenomic analysis of chemo-refractory high-grade serous ovarian cancer.

To improve the understanding of chemo-refractory high-grade serous ovarian cancers (HGSOCs), we characterized the proteogenomic landscape of 242 (refractory and sensitive) HGSOCs, representing one discovery and two validation cohorts across two biospecimen types (formalin-fixed paraffin-embedded and frozen). We identified a 64-protein signature that predicts with high specificity a subset of HGSOCs refractory to initial platinum-based therapy and is validated in two independent patient cohorts. We detected significant association between lack of Ch17 loss of heterozygosity (LOH) and chemo-refractoriness. Based on pathway protein expression, we identified 5 clusters of HGSOC, which validated across two independent patient cohorts and patient-derived xenograft (PDX) models. These clusters may represent different mechanisms of refractoriness and implicate putative therapeutic vulnerabilities.

Rethinking status 1A criteria in pediatric cardiac transplantation: A case for the prioritization of patients with single ventricle anatomy supported by ventricular assist devices.

Over the past 2 years advancements in the techniques and technology of pediatric heart transplantation have exponentially increased. However, even as the number of pediatric donor hearts has grown, demand for this limited resource continues to far outpace supply. Thus, lifesaving support in the form of ventricular assist devices (VAD) has become increasingly utilized in bridging pediatric patients to cardiac transplant. In the current pediatric heart transplant listing criteria, adopted by the United Network for Organ Sharing (UNOS) in 2016, all pediatric patients with a VAD are granted 1A status and assigned top transplant priority regardless of their underlying pathology. However, should this be the case? We suggest that the presence of a VAD alone may not be sufficient for status 1A listing. In doing so, we specifically highlight the heightened acuity, resource utilization, risk profile, and diminished outcomes in patients with single ventricle physiology supported with VAD as compared to patients with structurally normal hearts who would both be listed under 1A status. Given this, from a distributive justice perspective, we further suggest that the lack of granularity in current pediatric cardiac transplant listing categories may inadvertently lead to an inequitable distribution of donor organs and hospital resources especially as it pertains to those with single ventricle anatomy on VAD support. We propose revisiting the current listing priorities in light of improved techniques, technology, and recent data to mitigate this phenomenon. By doing this, pediatric patients with single ventricle disease might be more equitably stratified while awaiting heart transplant.

Inferring Negative Molecular Biomarker Data at Scale.

PURPOSE: Patients who represent the negative biomarker population, those tested for a biomarker but found to be negative, are a critical component of the growing molecular data repository. Many next-generation sequencing (NGS)-based tumor sequencing panels test hundreds of genes, but most laboratories do not provide explicit negative results on test reports nor in their structured data. However, the need for a complete picture of the testing landscape is significant. Syapse has created an internal ingestion and data transformation pipeline that uses the power of natural language processing (NLP), terminology management, and internal rulesets to semantically align data and infer negative results not explicitly stated. PATIENTS AND METHODS: Patients within the learning health network with a cancer diagnosis and at least one NGS-based molecular report were included. To obtain this critical negative result data, laboratory gene panel information was extracted and transformed using NLP techniques into a semistructured format for analysis. A normalization ontology was created in tandem. With this approach, we were able to successfully leverage positive biomarker data to derive negative data and create a comprehensive data set for molecular testing paradigms. RESULTS: The application of this process resulted in a drastic improvement in data completeness and clarity, especially when compared with other similar data sets. CONCLUSION: The ability to accurately determine positivity and testing rates among patient populations is imperative. With only positive results, it is impossible to draw conclusions about the entire tested population or the characteristics of the subgroup who are negative for the biomarker in question. We leverage these values to perform quality checks on ingested data, and end users can easily monitor their adherence to testing recommendations.

Psychological Flexibility Mediates Wellbeing for People with Adverse Childhood Experiences during COVID-19.

BACKGROUND: The psychological impact of COVID-19 is multifaceted, both acute and chronic, and has not affected everyone equally. METHOD: This longitudinal study compared those with and without Adverse Childhood Experiences (ACEs) on measures of psychological distress and wellbeing over time. RESULTS: All groups (No ACE, Low ACE, and High ACE) had similar levels of distress at Time 1, with significant increases in psychological distress for those with ACEs over time, but not for those without. Psychological Flexibility was strongly and significantly associated with decreases in psychological distress and improved wellbeing. It significantly mediated the relationship between ACE and wellbeing. CONCLUSIONS: Those with ACEs report significantly increased psychological distress over time, compared to those without ACE during the COVID-19 pandemic. Evidence-based interventions using Psychological Flexibility may improve mental health and wellbeing to help further mediate its effects.

Laboratory and Clinical Implications of Incidental and Secondary Germline Findings During Tumor Testing.

CONTEXT.­: Next-generation sequencing is a powerful clinical tool for cancer management but can produce incidental/secondary findings that require special consideration. OBJECTIVE.­: To discuss clinical and laboratory issues related to incidental or secondary germline findings in the clinical setting of tumor testing and inform future guidelines in this area. DESIGN.­: A College of American Pathologists workgroup including representation from the American Society of Clinical Oncology, the Association for Molecular Pathology, and the American College of Medical Genetics and Genomics created a review of items that should be considered when developing guidelines for incidental or secondary findings when performing clinical tumor testing. RESULTS.­: Testing recommendations should be cognizant of the differences among anticipated incidental, unanticipated incidental, and secondary findings, and whether normal tissue is also tested. In addition to defining which variants will be reported, robust recommendations must also take into account test design and validation, reimbursement, cost, infrastructure, impact on reflex testing, and maintenance of proficiency. Care providers need to consider the potential of a test to uncover incidental or secondary findings, the recommendation of upfront counseling, the need for consent, the timing of testing and counseling, and that the exact significance of a finding may not be clear. CONCLUSIONS.­: As clinical oncology testing panels have become a mainstay of clinical cancer care, guidelines addressing the unique aspects of incidental and secondary findings in oncology testing are needed. This paper highlights clinical and laboratory considerations with regard to incidental/secondary findings and is a clarion call to create recommendations.

The impact of the first wave of the Covid-19 pandemic on parents of children with externalising difficulties in ireland: A longitudinal cohort study.

BACKGROUND: This longitudinal cohort study aimed to examine the impact of the first wave of the COVID-19 pandemic in Ireland on parents of children with externalising difficulties, in comparison to parents of children without such difficulties. METHOD: Parents of 159 children completed online self-report measures at three time points during the first wave of the COVID-19 pandemic; (a) Delay and Mitigation Phase (March 2020 to May 2020), (b) Reopening of Society Phase (June 2020 to July 2020) and (c) Wave 2 Case Acceleration Phase (September 2020 to October 2020). Participants were allocated to the clinical group if they met the clinical cut off point on the Conduct or Hyperactivity/Inattention subscales of the Strengths and Difficulties Questionnaire at Time 1. RESULTS: Parents of children with externalising difficulties experienced significantly higher levels of stress, lower levels of wellbeing and engaged in higher levels of avoidant-focused coping strategies longitudinally. There was a significant difference between outcomes at the different phases of the COVID-19 pandemic, for stress related to parenting, personal/family stress related to the impact of the COVID-19 and type of coping strategies employed. Children with externalising difficulties, in comparison to children without externalising difficulties, showed significantly greater adjustment over time for behavioural and emotional difficulties, as reported by their parents. CONCLUSIONS: Results provide important information regarding the trajectory of psychological outcomes in parents of children with externalising difficulties over the first wave of the COVID-19 pandemic, highlighting the need for increased parental supports during, and after, the COVID-19 pandemic.

Customizable Natural Language Processing Biomarker Extraction Tool.

PURPOSE: Natural language processing (NLP) in pathology reports to extract biomarker information is an ongoing area of research. MetaMap is a natural language processing tool developed and funded by the National Library of Medicine to map biomedical text to the Unified Medical Language System Metathesaurus by applying specific tags to clinically relevant terms. Although results are useful without additional postprocessing, these tags lack important contextual information. METHODS: Our novel method takes terminology-driven semantic tags and incorporates those into a semantic frame that is task-specific to add necessary context to MetaMap. We use important contextual information to capture biomarker results to support Community Health System's use of Precision Medicine treatments for patients with cancer. For each biomarker, the name, type, numeric quantifiers, non-numeric qualifiers, and the time frame are extracted. These fields then associate biomarkers with their context in the pathology report such as test type, probe intensity, copy-number changes, and even failed results. A selection of 6,713 relevant reports contained the following standard-of-care biomarkers for metastatic breast cancer: breast cancer gene 1 and 2, estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, and programmed death-ligand 1. RESULTS: The method was tested on pathology reports from the internal pathology laboratory at Henry Ford Health System. A certified tumor registrar reviewed 400 tests, which showed > 95% accuracy for all extracted biomarker types. CONCLUSION: Using this new method, it is possible to extract high-quality, contextual biomarker information, and this represents a significant advance in biomarker extraction.

A Curriculum for Genomic Education of Molecular Genetic Pathology Fellows: A Report of the Association for Molecular Pathology Training and Education Committee.

Molecular genetic pathology (MGP) is a subspecialty of pathology and medical genetics and genomics. Genomic testing, which is defined as that which generates large data sets and interrogates large segments of the genome in a single assay, is increasingly recognized as essential for optimal patient care through precision medicine. The most common genomic testing technologies in clinical laboratories are next-generation sequencing and microarray. It is essential to train in these methods and to consider the data generated in the context of the diagnosis, medical history, and other clinical findings of individual patients. Accordingly, updating the MGP fellowship curriculum to include genomics is timely, important, and challenging. At the completion of training, an MGP fellow should be capable of independently interpreting and signing out results of a wide range of genomic assays and, given the appropriate context and institutional support, of developing and validating new assays in compliance with applicable regulations. The Genomics Task Force of the MGP Program Directors, a working group of the Association for Molecular Pathology Training and Education Committee, has developed a genomics curriculum framework and recommendations specific to the MGP fellowship. These recommendations are presented for consideration and implementation by MGP fellowship programs with the understanding that MGP programs exist in a diversity of clinical practice environments with a spectrum of available resources.

Variables Prevalent Among Early Unplanned Readmissions in Infants Following Congenital Heart Surgery.

Medically complex children including infants undergoing cardiac surgery are at increased risk for hospital readmissions. Investigation of this population may reveal opportunities to optimize systems and coordination of care. A retrospective study of all infants undergoing cardiac surgery from 2015 through 2016 at a large tertiary institution who were readmitted within 1 year of discharge from cardiac surgical hospitalization was performed. Data specific to patient characteristics, surgical hospitalization, and readmission hospitalization are described. Unplanned readmissions within 1 year of hospital discharge were analyzed with Cox proportional hazard regression to identify factors associated with increased hazard for earlier unplanned readmission. Comparable to previous reports, 12% (78/658) of all surgical hospitalizations were associated with unplanned readmission within 30 days. Infectious etiology, followed by cardiac and gastrointestinal problems, was the most common reasons for unplanned 30-day readmission. Unplanned readmissions within 2 weeks of discharge were multifactorial and less commonly related to cardiac or surgical care. Primary nasogastric tube feeding at the time of discharge was the only significant risk factor for earlier unplanned readmission (p = 0.032) on multivariable analysis. Increased care coordination with particular attention to feeding and comorbidity management may be future targets to effectively mitigate readmissions and improve quality of care in this population.

Comorbidity and COVID-19: investigating the relationship between medical and psychological well-being.

OBJECTIVE: The unprecedented occurrence of a global pandemic is accompanied by both physical and psychological burdens that may impair quality of life. Research relating to COVID-19 aims to determine the effects of the pandemic on vulnerable populations who are at high risk of developing negative health or psychosocial outcomes. Having an ongoing medical condition during a pandemic may lead to greater psychological distress. Increased psychological distress may be due to preventative public health measures (e.g. lockdown), having an ongoing medical condition, or a combination of these factors. METHODS: This study analyses data from an online cross-sectional national survey of adults in Ireland and investigates the relationship between comorbidity and psychological distress. Those with a medical condition (n = 128) were compared to a control group without a medical condition (n = 128) and matched according to age, gender, annual income, education, and work status during COVID-19. Participants and data were obtained during the first public lockdown in Ireland (27 March 2020-8 June 2020). RESULTS: Individuals with existing medical conditions reported significantly higher levels of anxiety (p < .01) and felt less gratitude (p ≤ .001). Exploratory analysis indicated that anxiety levels were significantly associated with illness perceptions specific to COVID-19. Post hoc analysis revealed that psychological well-being was not significantly related to condition type (e.g. respiratory disorders). CONCLUSION: This research supports individualised supports for people with ongoing medical conditions during the COVID-19 pandemic, and has implications for the consideration of follow-up care specifically for mental health. Findings may also inform future public health policies and post-vaccine support strategies for vulnerable populations.

YouTube as a Source of Patient Information for Prenatal Repair of Myelomeningocele.

OBJECTIVE: With the increasing interest in fetal repair of myelomeningoceles (MMCs) over the last decade, it is reasonable to anticipate the need for high quality and accessible educational materials for patients. Patients often look to the internet for details regarding medical topics and specifically to YouTube for informative health-related videos. This study aims to analyze the content and shortcomings of currently available videos on YouTube regarding prenatal repair of MMCs. STUDY DESIGN: A YouTube search was performed on December 15, 2018, using the terms "fetoscopic surgery for neural tube defect" and "fetal surgery for neural tube defect." The first 50 videos from each search were sorted by relevance and evaluated for video source (i.e., professional, personal, or other), target audience (medical professionals or general public), general descriptive statistics (i.e., video length, number of views, number of comments), and for five areas of content determined by the authors to constitute basic patient information regarding a surgical procedure: (1) procedure details, (2) eligibility criteria, (3) alternatives to surgery, (4) surgical risks, and (5) success rate. Accuracy of videos was not assessed. RESULTS: Of the 16 videos that met inclusion criteria, only 1 discussed fetoscopic surgery. The majority (62.5%) of videos were produced by a professional source and 81.3% were targeted toward the general public rather than medical professionals. Of the 16 videos, 10 (62.5%) included details regarding the surgery, 3 (18.8%) discussed eligibility criteria, and 8 (50.0%) mentioned alternatives to surgery. Additionally, seven videos (43.8%) discussed risks of the procedure and six (37.5%) included surgical success rate. CONCLUSION: Only 2 of the 16 videos included all five areas of content that were evaluated, and both were in regard to open fetal repair. This study not only calls attention to the initial shortcomings of YouTube videos regarding fetal surgery for neural tube defects but also demonstrates the need for further investigation and more comprehensive analysis.

Increased Psychological Distress during COVID-19 and Quarantine in Ireland: A National Survey.

BACKGROUND: The emergence of the coronavirus pneumonia (COVID-19) resulted in a global pandemic. The psychological impact of an epidemic is multifaceted and acute, with long-term consequences. METHODS: A cross-sectional online survey-based design was employed, assessing the psychological impact of COVID-19 on members of the Irish public during the quarantine period of COVID-19 in Ireland. Participants were invited to complete the Depression, Anxiety, and Stress Scale-21 (DASS-21) retrospectively (prior to quarantine) and during the quarantine period, as well as measures of illness perceptions, well-being, and a bespoke measure (the Effects of COVID Questionnaire, ECQ), which assessed perceptions of COVID-related stresses associated with personal concerns, caring for children, caring for aging parents, as well as gratitude. RESULTS: A total of n = 1620 entered the survey platform, with a total of n = 847 surveys completed by members of the Irish public. Entry into COVID-19 quarantine was associated with significant increases in clinically significant symptoms of depression, stress, and anxiety. The ECQ reliably assessed a range of COVID-19-related stresses and had large and significant correlations with the DASS-21. CONCLUSIONS: The COVID-19 quarantine was associated with stresses and significant increases in symptoms of depression, anxiety, and stress in a national Irish cohort. The public require increased access to mental health services to meet this increase in COVID-19-related psychological distress.

Making Lemonade Together -- How Program Directors, Applicants, and Medical Schools Can Thrive During the Upcoming Interview Season.

This article was migrated. The article was marked as recommended. The virtual residency interview process ushers in a new era of medical education. Many stakeholders are increasingly concerned as validated recommendations regarding Match success appear less reliable, fossilized rules have become increasingly fluid, and traditional streams of communication have become inadequate. Program directors will look to sell their program using unvalidated methods. Applicants will make life-altering decisions using fewer data points than historically available. Medical schools will endeavor to advise their students as they gear up for breaking new ground. In this piece, we introduce considerations and recommendations for the main players involved in the virtual interview process. If each party prioritizes teamwork and communication, we can collectively tackle the challenges of the upcoming cycle and turn lemons into lemonade.

The Cancer Immunotherapy Biomarker Testing Landscape.

CONTEXT.­: Cancer immunotherapy provides unprecedented rates of durable clinical benefit to late-stage cancer patients across many tumor types, but there remains a critical need for biomarkers to accurately predict clinical response. Although some cancer immunotherapy tests are associated with approved therapies and considered validated, other biomarkers are still emerging and at various states of clinical and translational exploration. OBJECTIVE.­: To provide pathologists with a current and practical update on the evolving field of cancer immunotherapy testing. The scientific background, clinical data, and testing methodology for the following cancer immunotherapy biomarkers are reviewed: programmed death ligand-1 (PD-L1), mismatch repair, microsatellite instability, tumor mutational burden, polymerase δ and ε mutations, cancer neoantigens, tumor-infiltrating lymphocytes, transcriptional signatures of immune responsiveness, cancer immunotherapy resistance biomarkers, and the microbiome. DATA SOURCES.­: Selected scientific publications and clinical trial data representing the current field of cancer immunotherapy. CONCLUSIONS.­: The cancer immunotherapy field, including the use of biomarker testing to predict patient response, is still in evolution. PD-L1, mismatch repair, and microsatellite instability testing are helping to guide the use of US Food and Drug Administration-approved therapies, but there remains a need for better predictors of response and resistance. Several categories of tumor and patient characteristics underlying immune responsiveness are emerging and may represent the next generation of cancer immunotherapy predictive biomarkers. Pathologists have important roles and responsibilities as the field of cancer immunotherapy continues to develop, including leadership of translational studies, exploration of novel biomarkers, and the accurate and timely implementation of newly approved and validated companion diagnostics.