A Cell-free DNA Blood-Based Test for Colorectal Cancer Screening.

BACKGROUND: Colorectal cancer is the third most diagnosed cancer in adults in the United States. Early detection could prevent more than 90% of colorectal cancer-related deaths, yet more than one third of the screening-eligible population is not up to date with screening despite multiple available tests. A blood-based test has the potential to improve screening adherence, detect colorectal cancer earlier, and reduce colorectal cancer-related mortality. METHODS: We assessed the performance characteristics of a cell-free DNA (cfDNA) blood-based test in a population eligible for colorectal cancer screening. The coprimary outcomes were sensitivity for colorectal cancer and specificity for advanced neoplasia (colorectal cancer or advanced precancerous lesions) relative to screening colonoscopy. The secondary outcome was sensitivity to detect advanced precancerous lesions. RESULTS: The clinical validation cohort included 10,258 persons, 7861 of whom met eligibility criteria and were evaluable. A total of 83.1% of the participants with colorectal cancer detected by colonoscopy had a positive cfDNA test and 16.9% had a negative test, which indicates a sensitivity of the cfDNA test for detection of colorectal cancer of 83.1% (95% confidence interval [CI], 72.2 to 90.3). Sensitivity for stage I, II, or III colorectal cancer was 87.5% (95% CI, 75.3 to 94.1), and sensitivity for advanced precancerous lesions was 13.2% (95% CI, 11.3 to 15.3). A total of 89.6% of the participants without any advanced colorectal neoplasia (colorectal cancer or advanced precancerous lesions) identified on colonoscopy had a negative cfDNA blood-based test, whereas 10.4% had a positive cfDNA blood-based test, which indicates a specificity for any advanced neoplasia of 89.6% (95% CI, 88.8 to 90.3). Specificity for negative colonoscopy (no colorectal cancer, advanced precancerous lesions, or nonadvanced precancerous lesions) was 89.9% (95% CI, 89.0 to 90.7). CONCLUSIONS: In an average-risk screening population, this cfDNA blood-based test had 83% sensitivity for colorectal cancer, 90% specificity for advanced neoplasia, and 13% sensitivity for advanced precancerous lesions. (Funded by Guardant Health; ECLIPSE ClinicalTrials.gov number, NCT04136002.).

Structure-based classification predicts drug response in EGFR-mutant NSCLC.

Epidermal growth factor receptor (EGFR) mutations typically occur in exons 18-21 and are established driver mutations in non-small cell lung cancer (NSCLC)1-3. Targeted therapies are approved for patients with 'classical' mutations and a small number of other mutations4-6. However, effective therapies have not been identified for additional EGFR mutations. Furthermore, the frequency and effects of atypical EGFR mutations on drug sensitivity are unknown1,3,7-10. Here we characterize the mutational landscape in 16,715 patients with EGFR-mutant NSCLC, and establish the structure-function relationship of EGFR mutations on drug sensitivity. We found that EGFR mutations can be separated into four distinct subgroups on the basis of sensitivity and structural changes that retrospectively predict patient outcomes following treatment with EGFR inhibitors better than traditional exon-based groups. Together, these data delineate a structure-based approach for defining functional groups of EGFR mutations that can effectively guide treatment and clinical trial choices for patients with EGFR-mutant NSCLC and suggest that a structure-function-based approach may improve the prediction of drug sensitivity to targeted therapies in oncogenes with diverse mutations.

Prospective Study of Perioperative Circulating Tumor DNA Dynamics in Patients Undergoing Hepatectomy for Colorectal Liver Metastases.

OBJECTIVE: To evaluate the association of perioperative ctDNA dynamics on outcomes after hepatectomy for CLM. SUMMARY BACKGROUND DATA: Prognostication is imprecise for patients undergoing hepatectomy for CLM, and ctDNA is a promising biomarker. However, clinical implications of perioperative ctDNA dynamics are not well established. METHODS: Patients underwent curative-intent hepatectomy after preoperative chemotherapy for CLM (2013-2017) with paired prehepatectomy/postoperative ctDNA analyses via plasma-only assay. Positivity was determined using a proprietary variant classifier. Primary endpoint was recurrence-free survival (RFS). Median follow-up was 55 months. RESULTS: Forty-eight patients were included. ctDNA was detected before and after surgery (ctDNA+/+) in 14 (29%), before but not after surgery (ctDNA+/-) in 19 (40%), and not at all (ctDNA-/-) in 11 (23%). Adverse tissue somatic mutations were detected in TP53 (n = 26; 54%), RAS (n = 23; 48%), SMAD4 (n = 5; 10%), FBXW7 (n = 3; 6%), and BRAF (n = 2; 4%). ctDNA+/+ was associated with worse RFS (median: ctDNA+/+, 6.0 months; ctDNA+/-, not reached; ctDNA-/-, 33.0 months; P = 0.001). Compared to ctDNA+/+, ctDNA+/- was associated with improved RFS [hazard ratio (HR) 0.24 (95% confidence interval (CI) 0.1-0.58)] and overall survival [HR 0.24 (95% CI 0.08-0.74)]. Adverse somatic mutations were not associated with survival. After adjustment for prehepatectomy chemotherapy, synchronous disease, and ≥2 CLM, ctDNA+/- and ctDNA-/- were independently associated with improved RFS compared to ctDNA+/+ (ctDNA+/-: HR 0.21, 95% CI 0.08-0.53; ctDNA-/-: HR 0.21, 95% CI 0.08-0.56). CONCLUSIONS: Perioperative ctDNA dynamics are associated with survival, identify patients with high recurrence risk, and may be used to guide treatment decisions and surveillance after hepatectomy for patients with CLM.

Integrative clinical genomics of metastatic cancer.

Metastasis is the primary cause of cancer-related deaths. Although The Cancer Genome Atlas has sequenced primary tumour types obtained from surgical resections, much less comprehensive molecular analysis is available from clinically acquired metastatic cancers. Here we perform whole-exome and -transcriptome sequencing of 500 adult patients with metastatic solid tumours of diverse lineage and biopsy site. The most prevalent genes somatically altered in metastatic cancer included TP53, CDKN2A, PTEN, PIK3CA, and RB1. Putative pathogenic germline variants were present in 12.2% of cases of which 75% were related to defects in DNA repair. RNA sequencing complemented DNA sequencing to identify gene fusions, pathway activation, and immune profiling. Our results show that integrative sequence analysis provides a clinically relevant, multi-dimensional view of the complex molecular landscape and microenvironment of metastatic cancers.

Preoperative Circulating Tumor DNA in Patients with Peritoneal Carcinomatosis is an Independent Predictor of Progression-Free Survival.

BACKGROUND: Next-generation sequencing (NGS) is a useful tool for detecting genomic alterations in circulating tumor DNA (ctDNA). To date, most ctDNA tests have been performed on patients with widely metastatic disease. Patients with peritoneal carcinomatosis (metastases) present unique prognostic and therapeutic challenges. We therefore explored preoperative ctDNA in patients with peritoneal metastases undergoing surgery. METHODS: Patients referred for surgical resection of peritoneal metastases underwent preoperative blood-derived ctDNA analysis (clinical-grade NGS [68-73 genes]). ctDNA was quantified as the percentage of altered circulating cell-free DNA (% cfDNA). RESULTS: Eighty patients had ctDNA testing: 46 (57.5%) women; median age 55.5 years. The following diagnoses were included: 59 patients (73.8%), appendix cancer; 11 (13.8%), colorectal; five (6.3%), peritoneal mesothelioma; two (2.5%), small bowel; one (1.3%) each of cholangiocarcinoma, ovarian, and testicular cancer. Thirty-one patients (38.8%) had detectable preoperative ctDNA alterations, most frequently in the following genes: TP53 (25.8% of all alterations detected) and KRAS (11.3%). Among 15 patients with tissue DNA NGS, 33.3% also had ctDNA alterations (overall concordance = 96.7%). Patients with high ctDNA quantities (≥ 0.25% cfDNA, n = 25) had a shorter progression-free survival (PFS) than those with lower ctDNA quantities (n = 55; 7.8 vs. 15.0 months; hazard ratio 3.23, 95% confidence interval 1.43-7.28, p = 0.005 univariate, p = 0.044 multivariate). CONCLUSIONS: A significant proportion of patients with peritoneal metastases referred for surgical intervention have detectable ctDNA alterations preoperatively. Patients with high levels of ctDNA have a worse prognosis independent of histologic grade.

Physician Experiences and Understanding of Genomic Sequencing in Oncology.

The amount of information produced by genomic sequencing is vast, technically complicated, and can be difficult to interpret. Appropriately tailoring genomic information for non-geneticists is an essential next step in the clinical use of genomic sequencing. To initiate development of a framework for genomic results communication, we conducted eighteen qualitative interviews with oncologists who had referred adult cancer patients to a matched tumor-normal tissue genomic sequencing study. In our qualitative analysis, we found varied levels of clinician knowledge relating to sequencing technology, the scope of the tumor genomic sequencing study, and incidental germline findings. Clinicians expressed a perceived need for more genetics education. Additionally, they had a variety of suggestions for improving results reports and possible resources to aid in results interpretation. Most clinicians felt genetic counselors were needed when incidental germline findings were identified. Our research suggests that more consistent genetics education is imperative in ensuring the proper utilization of genomic sequencing in cancer care. Clinician suggestions for results interpretation resources and results report modifications could be used to improve communication. Clinicians' perceived need to involve genetic counselors when incidental germline findings were found suggests genetic specialists could play a critical role in ensuring patients receive appropriate follow-up.

Development of a Streamlined Work Flow for Handling Patients' Genetic Testing Insurance Authorizations.

Obtaining genetic testing insurance authorizations for patients is a complex, time-involved process often requiring genetic counselor (GC) and physician involvement. In an effort to mitigate this complexity and meet the increasing number of genetic testing insurance authorization requests, GCs formed a novel partnership with an industrial engineer (IE) and a patient services associate (PSA) to develop a streamlined work flow. Eight genetics clinics and five specialty clinics at the University of Michigan were surveyed to obtain benchmarking data. Tasks needed for genetic testing insurance authorization were outlined and time-saving work flow changes were introduced including 1) creation of an Excel password-protected shared database between GCs and PSAs, used for initiating insurance authorization requests, tracking and follow-up 2) instituting the PSAs sending GCs a pre-clinic email noting each patients' genetic testing insurance coverage 3) inclusion of test medical necessity documentation in the clinic visit summary note instead of writing a separate insurance letter and 4) PSAs development of a manual with insurance providers and genetic testing laboratories information. These work flow changes made it more efficient to request and track genetic testing insurance authorizations for patients, enhanced GCs and PSAs communication, and reduced tasks done by clinicians.

Large, Prospective Analysis of the Reasons Patients Do Not Pursue BRCA Genetic Testing Following Genetic Counseling.

Genetic counseling (GC) and genetic testing (GT) identifies high-risk individuals who benefit from enhanced medical management. Not all individuals undergo GT following GC and understanding the reasons why can impact clinical efficiency, reduce GT costs through appropriate identification of high-risk individuals, and demonstrate the value of pre-GT GC. A collaborative project sponsored by the Michigan Department of Health and Human Services prospectively collects anonymous data on BRCA-related GC visits performed by providers in Michigan, including demographics, patient/family cancer history, GT results, and reasons for declining GT. From 2008 to 2012, 10,726 patients underwent GC; 3476 (32.4%) did not pursue GT. Primary reasons included: not the best test candidate (28.1%), not clinically indicated (23.3%), and insurance/out of pocket cost concerns (13.6%). Patient disinterest was the primary reason for declining in 17.1%. Insurance/out of pocket cost concerns were the primary reason for not testing in 13.4% of untested individuals with private insurance. Among untested individuals with breast and/or ovarian cancer, 22.5% reported insurance/out of pocket cost concerns as the primary reason for not testing and 6.6% failed to meet Medicare criteria. In a five-year time period, nearly one-third of patients who underwent BRCA GC did not pursue GT. GT was not indicated in almost half of patients. Insurance/out of pocket cost concerns continue to be barriers.

Mutation spectrum and risk of colorectal cancer in African American families with Lynch syndrome.

BACKGROUND & AIMS: African Americans (AAs) have the highest incidence of and mortality resulting from colorectal cancer (CRC) in the United States. Few data are available on genetic and nongenetic risk factors for CRC among AAs. Little is known about cancer risks and mutations in mismatch repair (MMR) genes in AAs with the most common inherited CRC condition, Lynch syndrome. We aimed to characterize phenotype, mutation spectrum, and risk of CRC in AAs with Lynch syndrome. METHODS: We performed a retrospective study of AAs with mutations in MMR genes (MLH1, MSH2, MSH6, and PMS2) using databases from 13 US referral centers. We analyzed data on personal and family histories of cancer. Modified segregation analysis conditioned on ascertainment criteria was used to estimate age- and sex-specific CRC cumulative risk, studying members of the mutation-carrying families. RESULTS: We identified 51 AA families with deleterious mutations that disrupt function of the MMR gene product: 31 in MLH1 (61%), 11 in MSH2 (21%), 3 in MSH6 (6%), and 6 in PMS2 (12%); 8 mutations were detected in more than 1 individual, and 11 have not been previously reported. In the 920 members of the 51 families with deleterious mutations, the cumulative risks of CRC at 80 years of age were estimated to be 36.2% (95% confidence interval [CI], 10.5%-83.9%) for men and 29.7% (95% CI, 8.31%-76.1%) for women. CRC risk was significantly higher among individuals with mutations in MLH1 or MSH2 (hazard ratio, 13.9; 95% CI, 3.44-56.5). CONCLUSIONS: We estimate the cumulative risk for CRC in AAs with MMR gene mutations to be similar to that of individuals of European descent with Lynch syndrome. Two-thirds of mutations were found in MLH1, some of which were found in multiple individuals and some that have not been previously reported. Differences in mutation spectrum are likely to reflect the genetic diversity of this population.

Integrative Clinical Sequencing in the Management of Refractory or Relapsed Cancer in Youth.

IMPORTANCE: Cancer is caused by a diverse array of somatic and germline genomic aberrations. Advances in genomic sequencing technologies have improved the ability to detect these molecular aberrations with greater sensitivity. However, integrating them into clinical management in an individualized manner has proven challenging. OBJECTIVE: To evaluate the use of integrative clinical sequencing and genetic counseling in the assessment and treatment of children and young adults with cancer. DESIGN, SETTING, AND PARTICIPANTS: Single-site, observational, consecutive case series (May 2012-October 2014) involving 102 children and young adults (mean age, 10.6 years; median age, 11.5 years, range, 0-22 years) with relapsed, refractory, or rare cancer. EXPOSURES: Participants underwent integrative clinical exome (tumor and germline DNA) and transcriptome (tumor RNA) sequencing and genetic counseling. Results were discussed by a precision medicine tumor board, which made recommendations to families and their physicians. MAIN OUTCOMES AND MEASURES: Proportion of patients with potentially actionable findings, results of clinical actions based on integrative clinical sequencing, and estimated proportion of patients or their families at risk of future cancer. RESULTS: Of the 104 screened patients, 102 enrolled with 91 (89%) having adequate tumor tissue to complete sequencing. Only the 91 patients were included in all calculations, including 28 (31%) with hematological malignancies and 63 (69%) with solid tumors. Forty-two patients (46%) had actionable findings that changed their cancer management: 15 of 28 (54%) with hematological malignancies and 27 of 63 (43%) with solid tumors. Individualized actions were taken in 23 of the 91 (25%) based on actionable integrative clinical sequencing findings, including change in treatment for 14 patients (15%) and genetic counseling for future risk for 9 patients (10%). Nine of 91 (10%) of the personalized clinical interventions resulted in ongoing partial clinical remission of 8 to 16 months or helped sustain complete clinical remission of 6 to 21 months. All 9 patients and families with actionable incidental genetic findings agreed to genetic counseling and screening. CONCLUSIONS AND RELEVANCE: In this single-center case series involving young patients with relapsed or refractory cancer, incorporation of integrative clinical sequencing data into clinical management was feasible, revealed potentially actionable findings in 46% of patients, and was associated with change in treatment and family genetic counseling for a small proportion of patients. The lack of a control group limited assessing whether better clinical outcomes resulted from this approach than outcomes that would have occurred with standard care.

Traditional roles in a non-traditional setting: genetic counseling in precision oncology.

Next generation sequencing technology is increasingly utilized in oncology with the goal of targeting therapeutics to improve response and reduce side effects. Interpretation of tumor mutations requires sequencing of paired germline DNA, raising questions about incidental germline findings. We describe our experiences as part of a research team implementing a protocol for whole genome sequencing (WGS) of tumors and paired germline DNA known as the Michigan Oncology Sequencing project (MI-ONCOSEQ) that includes options for receiving incidental germline findings. Genetic counselors (GCs) discuss options for return of results with patients during the informed consent process and document family histories. GCs also review germline findings and actively participate in the multi-disciplinary Precision Medicine Tumor Board (PMTB), providing clinical context for interpretation of germline results and making recommendations about disclosure of germline findings. GCs have encountered ethical and counseling challenges with participants, described here. Although GCs have not been traditionally involved in molecular testing of tumors, our experiences with MI-ONCOSEQ demonstrate that GCs have important applicable skills to contribute to multi-disciplinary care teams implementing precision oncology. Broader use of WGS in oncology treatment decision making and American College of Medical Genetics and Genomics (ACMG) recommendations for active interrogation of germline tissue in tumor-normal dyads suggests that GCs will have future opportunities in this area outside of research settings.

ERBB2 (HER2) amplifications and co-occurring KRAS alterations in the circulating cell-free DNA of pancreatic ductal adenocarcinoma patients and response to HER2 inhibition.

Purpose: Despite accumulating data regarding the genomic landscape of pancreatic ductal adenocarcinoma (PDAC), olaparib is the only biomarker-driven FDA-approved targeted therapy with a PDAC-specific approval. Treating ERBB2(HER2)-amplified PDAC with anti-HER2 therapy has been reported with mixed results. Most pancreatic adenocarcinomas have KRAS alterations, which have been shown to be a marker of resistance to HER2-targeted therapies in other malignancies, though the impact of these alterations in pancreatic cancer is unknown. We describe two cases of ERBB2-amplified pancreatic cancer patients treated with anti-HER2 therapy and provide data on the frequency of ERBB2 amplifications and KRAS alterations identified by clinical circulating cell-free DNA testing. Methods: De-identified molecular test results for all patients with pancreatic cancer who received clinical cell-free circulating DNA analysis (Guardant360) between 06/2014 and 01/2018 were analyzed. Cell-free circulating DNA analysis included next-generation sequencing of up to 73 genes, including select small insertion/deletions, copy number amplifications, and fusions. Results: Of 1,791 patients with pancreatic adenocarcinoma, 36 (2.0%) had an ERBB2 amplification, 26 (72.2%) of whom had a KRAS alteration. Treatment data were available for seven patients. Two were treated with anti-HER2 therapy after their cell-free circulating DNA result, with both benefiting from therapy, including one with a durable response to trastuzumab and no KRAS alteration detected until progression. Conclusion: Our case series illustrates that certain patients with ERBB2-amplified pancreatic adenocarcinoma may respond to anti-HER2 therapy and gain several months of prolonged survival. Our data suggests KRAS mutations as a possible mechanism of primary and acquired resistance to anti-HER2 therapy in pancreatic cancer. Additional studies are needed to clarify the role of KRAS in resistance to anti-HER2 therapy.

Minimal Residual Disease using a Plasma-Only Circulating Tumor DNA Assay to Predict Recurrence of Metastatic Colorectal Cancer Following Curative Intent Treatment.

PURPOSE: Minimal residual disease (MRD) detection identifies patients with colorectal adenocarcinoma (CRC) likely to recur following definitive treatment. We evaluated a plasma only MRD assay to predict recurrence and survival in metastatic CRC patients undergoing curative intent procedures (surgery and/or radiotherapy), with or without (neo)adjuvant chemotherapy. The primary objective of this study was to assess the correlation of post-procedure tumor cfDNA detection status with radiographic disease recurrence (RFS). EXPERIMENTAL DESIGN: Pre- and post-procedure longitudinal samples were collected from 53 patients and analyzed with a multiomic MRD assay detecting circulating tumor DNA (ctDNA) from genomic and epigenomic signals. Pre- and post-procedure ctDNA detection correlated with recurrence-free and overall survival. RESULTS: 230/233 samples from 52 patients were successfully analyzed. At the time of data cutoff, 36 (69.2%) patients recurred with median follow-up of 31 months. 19/42 patients (45.2%) with ctDNA analyzed 3 weeks post-procedure had detectable ctDNA. ctDNA detection 3 weeks post-procedure was associated with shorter median RFS (HR 5.27; 95% CI, 2.31-12.0, p<0.0001) and overall survival (OS) (HR 12.83; 95% CI, 3.6-45.9, p<0.0001). Pre-procedure ctDNA detection status was not associated with RFS but was associated with improved OS (HR 4.65; 95% CI, 1.4-15.2, p=0.0111). Undetectable ctDNA pre-procedure had notable long-term overall survival, >90% 3 years post-procedure. CONCLUSION: In this cohort of oligometastatic CRC, detection of ctDNA pre- or post-procedure was associated with inferior outcomes even after accounting for prognostic clinicopathologic variables. This suggests ctDNA may enhance current risk stratification methods helping evaluate novel treatments and surveillance strategies toward improving patient outcomes.

An American founder mutation in MLH1.

Mutations in the mismatch repair genes cause Lynch syndrome (LS), conferring high risk of colorectal, endometrial and some other cancers. After the same splice site mutation in the MLH1 gene (c.589-2A>G) had been observed in four ostensibly unrelated American families with typical LS cancers, its occurrence in comprehensive series of LS cases (Mayo Clinic, Germany and Italy) was determined. It occurred in 10 out of 995 LS mutation carriers (1.0%) diagnosed in the Mayo Clinic diagnostic laboratory. It did not occur among 1,803 cases tested for MLH1 mutations by the German HNPCC consortium, while it occurred in three probands and an additional five family members diagnosed in Italy. In the U.S., the splice site mutation occurs on a large (∼4.8 Mb) shared haplotype that also harbors the variant c.2146G>A, which predicts a missense change in codon 716 referred to here as V716M. In Italy, it occurs on a different, shorter shared haplotype (∼2.2 Mb) that does not carry V716M. The V716M variant was found to be present by itself in the U.S., German and Italian populations with individuals sharing a common haplotype of 280 kb, allowing us to calculate that the variant arose around 5,600 years ago (225 generations; 95% confidence interval 183-272). The splice site mutation in America arose or was introduced some 450 years ago (18 generations; 95% confidence interval 14-23); it accounts for 1.0% all LS in the Unites States and can be readily screened for.

Monitoring of Dynamic Changes and Clonal Evolution in Circulating Tumor DNA From Patients With IDH-Mutated Cholangiocarcinoma Treated With Isocitrate Dehydrogenase Inhibitors.

PURPOSE: IDH mutations occur in about 30% of patients with cholangiocarcinoma. Analysis of mutations in circulating tumor DNA (ctDNA) can be performed by droplet digital polymerase chain reaction (ddPCR). The analysis of ctDNA is a feasible approach to detect IDH mutations. METHODS: We isolated ctDNA from the blood of patients with IDH-mutated advanced cholangiocarcinoma collected at baseline, on therapy, and at progression to isocitrate dehydrogenase (IDH) inhibitors. RESULTS: Of 31 patients with IDH1R132 (n = 26) or IDH2R172 mutations (n = 5) in the tumor, IDH mutations were detected in 84% of ctDNA samples analyzed by ddPCR and in 83% of ctDNA samples analyzed by next-generation sequencing (NGS). Patients with a low variant allele frequency of ctDNA detected by NGS at baseline had a longer median time to treatment failure compared to patients with high variant allele frequency of ctDNA (3.6 v 1.5 months; P = .008). Patients with a decrease in IDH-mutated ctDNA on therapy by ddPCR compared with no change/increase had a trend to a longer median survival (P = .07). Most frequent emergent alterations in ctDNA by NGS at progression were ARID1A (n = 3) and TP53 mutations (n = 3). CONCLUSION: Detection of IDH mutations in ctDNA in patients with advanced cholangiocarcinoma is feasible, and dynamic changes in ctDNA can correspond with the clinical course and clonal evolution.

Clinical Outcomes for Plasma-Based Comprehensive Genomic Profiling Versus Standard-of-Care Tissue Testing in Advanced Non-Small Cell Lung Cancer.

BACKGROUND: Somatic genomic testing is recommended by numerous expert guidelines to inform targeted therapy treatment for patients with advanced nonsquamous non-small cell lung cancer (aNSCLC). The NILE study was a prospective observational study that demonstrated noninferiority of cell-free circulating tumor DNA (cfDNA)-based tumor genotyping compared to tissue-based genotyping to find targetable genomic alterations in patients with newly diagnosed nonsquamous aNSCLC. As the cohort has matured, clinical outcomes data can now be analyzed. METHODS: This prospective, multicenter North American study enrolled patients with previously untreated nonsquamous aNSCLC who had standard of care (SOC) tissue genotyping performed and concurrent comprehensive cfDNA analysis (Guardant360). Patients with targetable genomic alterations, as defined by NCCN guidelines, who were treated with physician's choice of therapy had objective response rates, disease control rate, and time to treatment collected and compared to published outcomes. RESULTS: Among 282 patients, 89 (31.6%) had an actionable biomarker, as defined by NCCN, detected by tissue (21.3%) and/or cfDNA (27.3%) analysis. Sixty-one (68.5%) of these were treated with an FDA-approved targeted therapy guided by somatic genotyping results (EGFR, ALK, ROS1). Thirty-three patients were eligible for clinical response evaluation and demonstrated an objective response rate of 58% and disease control rate of 94%. Twenty-five (76%) and 17 (52%) achieved a durable response > 6 months and 12 months, respectively. The time to treatment (TtT) was significantly faster for cfDNA-informed biomarker detection as compared to tissue genotyping (18 vs. 31 days, respectively; P = .0008). CONCLUSIONS: cfDNA detects guideline-recommended biomarkers at a rate similar to tissue genotyping, and therapeutic outcomes based on plasma-based comprehensive genomic profiling are comparable to published targeted therapy outcomes with tissue profiling, even in community-based centers.

A review of statistical methods for testing genetic anticipation: looking for an answer in Lynch syndrome.

Anticipation, manifested through decreasing age of onset or increased severity in successive generations, has been noted in several genetic diseases. Statistical methods for genetic anticipation range from a simple use of the paired t-test for age of onset restricted to affected parent-child pairs to a recently proposed random effects model which includes extended pedigree data and unaffected family members [Larsen et al., 2009]. A naive use of the paired t-test is biased for the simple reason that age of onset has to be less than the age at ascertainment (interview) for both affected parent and child, and this right truncation effect is more pronounced in children than in parents. In this study, we first review different statistical methods for testing genetic anticipation in affected parent-child pairs that address the issue of bias due to right truncation. Using affected parent-child pair data, we compare the paired t-test with the parametric conditional maximum likelihood approach of Huang and Vieland [1997] and the nonparametric approach of Rabinowitz and Yang [1999] in terms of Type I error and power under various simulation settings and departures from the modeling assumptions. We especially investigate the issue of multiplex ascertainment and its effect on the different methods. We then focus on exploring genetic anticipation in Lynch syndrome and analyze new data on the age of onset in affected parent-child pairs from families seen at the University of Michigan Cancer Genetics clinic with a mutation in one of the three main mismatch repair (MMR) genes. In contrast to the clinic-based population, we re-analyze data on a population-based Lynch syndrome cohort, derived from the Danish HNPCC-register. Both datasets indicate evidence of genetic anticipation in Lynch syndrome. We then expand our review to incorporate recently proposed statistical methods that consider family instead of affected pairs as the sampling unit. These prospective censored regression models offer additional flexibility to incorporate unaffected family members, familial correlation and other covariates into the analysis. An expanded dataset from the Danish HNPCC-register is analyzed by this alternative set of methods.

Allele-specific expression of APC in adenomatous polyposis families.

BACKGROUND & AIMS: Germline mutations in the APC gene cause of most cases of familial adenomatous polyposis (FAP) and a lesser proportion of attenuated FAP (AFAP). Systematic analysis of APC at the RNA level could provide insight into the pathogenicity of identified mutations and the molecular basis of FAP/AFAP in families without identifiable mutations. Here, we analyzed the prevalence of imbalances in the allelic expression of APC in polyposis families with germline mutations in the gene and without detectable mutations in APC and/or MUTYH. METHODS: Allele-specific expression (ASE) was determined by single nucleotide primer extension using an exon 11 polymorphism as an allele-specific marker. In total, 52 APC-mutation-positive (36 families) and 24 APC/MUTYH-mutation-negative (23 families) informative patients were analyzed. Seventy-six controls also were included. RESULTS: Of the APC-mutation-positive families, most of those in whom the mutation was located before the last exon of the gene (12 of 14) had ASE imbalance, which is consistent with a mechanism of nonsense-mediated decay. Of the APC/MUTYH-mutation-negative families, 2 (9%) had ASE imbalance, which might cause the disease. Normal allele expression was restored shortly after lymphocytes were cultured with puromycin, supporting a 'nonsense-mediated' hypothesis. CONCLUSIONS: ASE analysis might be used to determine the pathogenesis of some cases of FAP and AFAP in which APC mutations are not found. ASE also might be used to prioritize the order in which different areas of APC are tested. RNA-level studies are important for the molecular diagnosis of FAP.