Phase II Multi-institutional Clinical Trial Result of Concurrent Cetuximab and Nivolumab in Recurrent and/or Metastatic Head and Neck Squamous Cell Carcinoma.

PURPOSE: A phase II multi-institutional clinical trial was conducted to determine overall survival (OS) in patients with recurrent and/or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) treated with a combination of cetuximab and nivolumab. PATIENTS AND METHODS: Patients with R/M HNSCC were treated with cetuximab 500 mg/m2 i.v. on day 14 as a lead-in followed by cetuximab 500 mg/m2 i.v. and nivolumab 240 mg i.v. on day 1 and day 15 of each 28-day cycle. Expression of p16 and programmed cell death-ligand 1 (PD-L1) in archived tumors were determined. Tumor-tissue-modified human papillomavirus (TTMV) DNA was quantified in plasma. RESULTS: Ninety-five patients were enrolled, and 88 patients were evaluable for OS with a median follow-up of 15.9 months. Median OS in the 45 patients who had prior therapy for R/M HNSCC (cohort A) was 11.4 months, with a 1 year OS 50% [90% confidence interval (CI), 0.43-0.57]. Median OS in the 43 patients who had no prior therapy (cohort B) was 20.2 months, with a 1-year OS 66% (90% CI, 0.59-0.71). In the combined cohorts, the p16-negative immunostaining was associated with higher response rate (RR; P = 0.02) but did not impact survival while higher PD-L1 combined positive score was associated with higher RR (P = 0.03) and longer OS (log-rank P = 0.04). In the p16-positive patients, lower median (1,230 copies/mL) TTMV DNA counts were associated with higher RR (P = 0.01) and longer OS compared with higher median (log-rank P = 0.05). CONCLUSIONS: The combination of cetuximab and nivolumab is effective in patients with both previously treated and untreated R/M HNSCC and warrants further evaluation.

Molecular profiling of cancer patients enables personalized combination therapy: the I-PREDICT study.

Cancer treatments have evolved from indiscriminate cytotoxic agents to selective genome- and immune-targeted drugs that have transformed the outcomes of some malignancies1. Tumor complexity and heterogeneity suggest that the 'precision medicine' paradigm of cancer therapy requires treatment to be personalized to the individual patient2-6. To date, precision oncology trials have been based on molecular matching with predetermined monotherapies7-14. Several of these trials have been hindered by very low matching rates, often in the 5-10% range15, and low response rates. Low matching rates may be due to the use of limited gene panels, restrictive molecular matching algorithms, lack of drug availability, or the deterioration and death of end-stage patients before therapy can be implemented. We hypothesized that personalized treatment with combination therapies would improve outcomes in patients with refractory malignancies. As a first test of this concept, we implemented a cross-institutional prospective study (I-PREDICT, NCT02534675 ) that used tumor DNA sequencing and timely recommendations for individualized treatment with combination therapies. We found that administration of customized multidrug regimens was feasible, with 49% of consented patients receiving personalized treatment. Targeting of a larger fraction of identified molecular alterations, yielding a higher 'matching score', was correlated with significantly improved disease control rates, as well as longer progression-free and overall survival rates, compared to targeting of fewer somatic alterations. Our findings suggest that the current clinical trial paradigm for precision oncology, which pairs one driver mutation with one drug, may be optimized by treating molecularly complex and heterogeneous cancers with combinations of customized agents.

Comprehensive Genomic Profiling of Hodgkin Lymphoma Reveals Recurrently Mutated Genes and Increased Mutation Burden.

BACKGROUND: The genomic landscape of Hodgkin lymphoma (HL) has been difficult to characterize due to the paucity of neoplastic cells and an abundant microenvironment. Such characterization is needed in order to improve treatment strategies. MATERIALS AND METHODS: We performed comprehensive genomic profiling (CGP) using targeted next-generation sequencing on archival formalin-fixed paraffin embedded tumor samples from 63 patients to analyze the landscape of HL. RESULTS: CGP was successful for 49/63 archival specimens (78%), and revealed aberrations impacting genes including B2M, TP53, and XPO1 (E571). Of the 34 patients for whom total mutation burden (TMB; mutations/megabase [Mb]) was assessed, 5 (15%) had high TMB (≥20 mutations/Mb), 18 (53%) had intermediate TMB (6-19 mutations/Mb), and 11 (32%) had low TMB (≤5 mutations/Mb). We next tested 13 patients' plasma cell-free DNA with droplet digital polymerase chain reaction for the presence of XPO1 E571 mutation, which was confirmed in the plasma of 31% of patients. In three patients with serially collected plasma samples, XPO1 E571K allelic frequency changes corresponded with changes in tumor size on conventional radiographic imaging. CONCLUSION: The study demonstrates that comprehensive genomic profiling of archival Hodgkin lymphoma tumor samples is feasible and leads to the identification of genes that are recurrently mutated and that Hodgkin lymphoma has increased mutation burden in the majority of samples analyzed. Furthermore, tracking of XPO1 E571 mutant allele frequency in a subset of patients may also represent a potential disease-monitoring strategy and warrants further investigation. IMPLICATIONS FOR PRACTICE: This study provides the first evidence that comprehensive genomic profiling can be performed to map the genomic landscape of Hodgkin lymphoma and that a subpopulation of patients has mutations in TP53, B2M, XPO1, and other genes. It was found that 15% of patients have high mutation burden, which, in cancers such as melanoma, may indicate sensitivity to immune checkpoint inhibitors, and may thus be explored for Hodgkin lymphoma. Lastly, this work demonstrates that changes in the mutant allele frequency of XPO1 in serially collected plasma cell-free DNA samples correspond with treatment outcomes measured with conventional radiographic imaging.

Hybrid Capture-Based Genomic Profiling of Circulating Tumor DNA from Patients with Advanced Non-Small Cell Lung Cancer.

INTRODUCTION: Genomic profiling informs selection of matched targeted therapies as part of routine clinical care in NSCLC. Tissue biopsy is the criterion standard; however, genomic profiling of blood-derived circulating tumor DNA (ctDNA) has emerged as a minimally invasive alternative. METHODS: Hybrid capture-based genomic profiling of 62 genes was performed on blood-based ctDNA from 1552 patients with NSCLC. RESULTS: Evidence of ctDNA was detected in 80% of samples, and in 86% of these cases, at least one reportable genomic alteration (GA) was detected. Frequently altered genes were tumor protein p53 gene (TP53) (59%), EGFR (25%), and KRAS (17%). Comparative analysis with a tissue genomic database (N = 21,500) showed similar frequencies of GAs per gene, although KRAS mutation and EGFR T790M were more frequent in tissue and ctDNA, respectively (both p < 0.0001), likely reflecting the use of liquid versus tissue biopsy after relapse during targeted therapy. In temporally matched ctDNA and tissue samples from 33 patients with evidence of ctDNA in their blood, 64% of GAs detected in tissue were also detected in ctDNA, including 78% of short variants (58 of 74) and 100% of rearrangements (four of four), but only 16% of amplifications (four of 25). CONCLUSIONS: Genomic profiling of ctDNA detected clinically relevant GAs in a significant subset of NSCLC cases. Most alterations detected in matched tissue were also detected in ctDNA. These results suggest the utility of ctDNA testing in advanced NSCLC as a complementary approach to tissue testing. Blood-based ctDNA testing may be particularly useful at the time of progression during targeted therapy.

Clinical utility of tumor genomic profiling in patients with high plasma circulating tumor DNA burden or metabolically active tumors.

BACKGROUND: This retrospective study was undertaken to determine if the plasma circulating tumor DNA (ctDNA) level and tumor biological features in patients with advanced solid tumors affected the detection of genomic alterations (GAs) by a plasma ctDNA assay. METHOD: Cell-free DNA (cfDNA) extracted from frozen plasma (N = 35) or fresh whole blood (N = 90) samples were subjected to a 62-gene hybrid capture-based next-generation sequencing assay FoundationACT. Concordance was analyzed for 51 matched FoundationACT and FoundationOne (tissue) cases. The maximum somatic allele frequency (MSAF) was used to estimate the amount of tumor fraction of cfDNA in each sample. The detection of GAs was correlated with the amount of cfDNA, MSAF, total tumor anatomic burden (dimensional sum), and total tumor metabolic burden (SUVmax sum) of the largest ten tumor lesions on PET/CT scans. RESULTS: FoundationACT detected GAs in 69 of 81 (85%) cases with MSAF > 0. Forty-two of 51 (82%) cases had ≥ 1 concordance GAs matched with FoundationOne, and 22 (52%) matched to the National Comprehensive Cancer Network (NCCN)-recommended molecular targets. FoundationACT also detected 8 unique molecular targets, which changed the therapy in 7 (88%) patients who did not have tumor rebiopsy or sufficient tumor DNA for genomic profiling assay. In all samples (N = 81), GAs were detected in plasma cfDNA from cancer patients with high MSAF quantity (P = 0.0006) or high tumor metabolic burden (P = 0.0006) regardless of cfDNA quantity (P = 0.2362). CONCLUSION: This study supports the utility of using plasma-based genomic assays in cancer patients with high plasma MSAF level or high tumor metabolic burden.

Multiple configurations of EGFR exon 20 resistance mutations after first- and third-generation EGFR TKI treatment affect treatment options in NSCLC.

After sequential treatment with first- and third-generation EGFR tyrosine kinase inhibitors (TKIs), EGFR-mutant non-small cell lung cancers frequently harbor multiple resistance mutations in exon 20 of EGFR including T790M, mediating resistance to first-generation TKIs, and at codons 792, 796, or 797 mediating resistance to third-generation TKIs. However, whether these resistance mutations are in cis or trans has therapeutic implications for patients. We analyzed a cohort of 29 patients with NSCLC harboring EGFR mutations at codons 792, 796, or 797 to establish the configuration of these mutations. We performed hybrid capture-based, next-generation sequencing on formalin-fixed paraffin-embedded biopsy tissue or liquid biopsy. 27 samples had both a T790M mutation and a mutation at codons 792, 796, or 797. In all of these cases, the mutations were found in the cis configuration; the trans configuration was not observed. Two patients' samples harbored a mutation at codon 797 but no T790M mutation. In these two cases, longitudinal analysis showed earlier biopsies harbored EGFR T790M, which was undetectable following osimertinib treatment. Treatment of one these patients with both first- and third-generation EGFR TKIs resulted in a mixed response. Here we describe multiple configurations of EGFR T790M and third-generation TKI resistance mutations at codons 792, 796, and 797. These mutations are most commonly found in cis, which confers resistance to all current EGFR TKIs. We also describe two patients that exhibited T790M loss with acquisition of a mutation at codon 797. In addition, one of these patients, with an EGFR C797S in a lung biopsy was subsequently found to have EGFR C797N in a later biopsy of pleural fluid, highlighting the dynamic multiclonal nature of advanced NSCLC.

Diverse EGFR Exon 20 Insertions and Co-Occurring Molecular Alterations Identified by Comprehensive Genomic Profiling of NSCLC.

INTRODUCTION: EGFR exon 20 insertions (EGFRex20ins) comprise an uncommon subset of EGFR-activating alterations relatively insensitive to first- and second-generation EGFR tyrosine kinase inhibitors (TKIs). However, recent early clinical data suggests these patients may benefit from newer-generation EGFR-TKIs. Comprehensive genomic profiling (CGP) identifies a broad spectrum of EGFRex20ins and associated co-occurring genomic alterations (GAs) present in NSCLC. METHODS: Hybrid capture-based CGP was performed prospectively on 14,483 clinically annotated consecutive NSCLC specimens to a mean coverage depth of greater than 650X for 236 or 315 cancer-related genes. RESULTS: Of 14,483 NSCLC cases, CGP identified 263 (1.8%) cases with EGFRex20ins, representing 12% (263 of 2251) of cases with EGFR mutations. Sixty-four unique EGFRex20ins were identified, most commonly D770_N771>ASVDN (21%) and N771_P772>SVDNP (20%). EGFR amplification occurred in 22% (57 of 263). The most common co-occurring GAs effected tumor protein p53 (TP53) (56%), cyclin dependent kinase inhibitor 2A (CDKN2A) (22%), cyclin dependent kinase inhibitor 2B (CDKN2B) (16%), NK2 homeobox 1 (NKX2-1) (14%) and RB transcriptional corepressor 1 (RB1) (11%); co-occurring GAs in other known lung cancer drivers were rare (5%). Average tumor mutational burden was low (mean 4.3, range 0 to 40.3 mutations/Mb). Clinical outcomes to first- and second-generation EGFR TKIs were obtained for five patients and none responded. CONCLUSIONS: In the largest series of EGFRex20ins NSCLC, diverse EGFRex20ins were detected in 12% of EGFR-mutant NSCLC, a higher frequency than previously reported in smaller single-institution studies. Clinical outcomes showed lack of response to EGFR TKIs. Tumor mutational burden was low, consistent with non-smoking associated NSCLC. Comprehensive sequencing revealed increased proportion and wide variety of EGFRex20ins, representing a population of patients significant enough for focused efforts on effective interventions.

Analytical Validation of a Hybrid Capture-Based Next-Generation Sequencing Clinical Assay for Genomic Profiling of Cell-Free Circulating Tumor DNA.

Genomic profiling of circulating tumor DNA derived from cell-free DNA (cfDNA) in blood can provide a noninvasive method for detecting genomic biomarkers to guide clinical decision making for cancer patients. We developed a hybrid capture-based next-generation sequencing assay for genomic profiling of circulating tumor DNA from blood (FoundationACT). High-sequencing coverage and molecular barcode-based error detection enabled accurate detection of genomic alterations, including short variants (base substitutions, short insertions/deletions) and genomic re-arrangements at low allele frequencies (AFs), and copy number amplifications. Analytical validation was performed on 2666 reference alterations. The assay achieved >99% overall sensitivity (95% CI, 99.1%-99.4%) for short variants at AF >0.5%, >95% sensitivity (95% CI, 94.2%-95.7%) for AF 0.25% to 0.5%, and 70% sensitivity (95% CI, 68.2%-71.5%) for AF 0.125% to 0.25%. No false positives were detected in 62 samples from healthy volunteers. Genomic alterations detected by FoundationACT demonstrated high concordance with orthogonal assays run on the same clinical cfDNA samples. In 860 routine clinical FoundationACT cases, genomic alterations were detected in cfDNA at comparable frequencies to tissue; for the subset of cases with temporally matched tissue and blood samples, 75% of genomic alterations and 83% of short variant mutations detected in tissue were also detected in cfDNA. On the basis of analytical validation results, FoundationACT has been approved for use in our Clinical Laboratory Improvement Amendments-certified/College of American Pathologists-accredited/New York State-approved laboratory.

Distinct age-associated molecular profiles in acute myeloid leukemia defined by comprehensive clinical genomic profiling.

Large scale comprehensive genomic profiling (CGP) has led to an improved understanding of oncogenic mutations in acute myeloid leukemia (AML), as well as identification of alterations that can serve as targets for potential therapeutic intervention. We sought to gain insight into age-associated variants in AML through comparison of extensive DNA and RNA-based GP results from pediatric and adult AML. Sequencing of 932 AML specimens (179 pediatric (age 0-18), 753 adult (age ≥ 19)) from diagnostic, relapsed, and refractory times points was performed. Comprehensive DNA (405 genes) and RNA (265) sequencing to identify a variety of structural and short variants was performed. We found that structural variants were highly prevalent in the pediatric cohort compared to the adult cohort (57% vs. 30%; p < 0.001), with certain structural variants detected only in the pediatric cohort. Fusions were the most common structural variant and were highly prevalent in AML in very young children occurring in 68% of children < 2 years of age. We observed an inverse trend in the prevalence of fusions compared to the average number of mutations per patient. In contrast to pediatric AML, adult AML was marked by short variants and multiple mutations per patient. Mutations that were common in adult AML were much less common in the adolescent and young adult cohort and were rare or absent in the pediatric cohort. Clinical CGP demonstrates the biologic differences in pediatric vs. adult AML that have significant therapeutic impacts on prognosis, therapeutic allocation, disease monitoring, and the use of more targeted therapies.

Targeted genomic landscape of metastases compared to primary tumours in clear cell metastatic renal cell carcinoma.

BACKGROUND: The genomic landscape of primary clear cell renal cell carcinoma (ccRCC) has been well described. However, little is known about cohort genomic alterations (GA) landscape in ccRCC metastases, or how it compares to primary tumours in aggregate. The genomic landscape of metastases may have biological, clinical, and therapeutic implications. METHODS: We collected targeted next-generation sequencing mutation calls from two independent cohorts and described the metastases GA landscape and descriptively compared it to the GA landscape in primary tumours. RESULTS: The cohort 1 (n = 578) consisted of 349 primary tumours and 229 metastases. Overall, the most common mutations in the metastases were VHL (66.8%), PBRM1 (41.87%), and SETD2 (24.7%). TP53 was more frequently mutated in metastases compared to primary tumours (14.85% versus 8.9%; p = 0.031). No other gene had significant difference in the cohort frequency of mutations between the metastases and primary tumours. Mutation burden was not significantly different between the metastases and primary tumours or between metastatic sites. The second cohort (n = 257) consisted of 177 primary tumours and 80 metastases. No differences in frequency of mutations or mutational burden were observed between primaries and metastases. CONCLUSIONS: These data support the theory that ccRCC primary tumours and metastases encompass a uniform distribution of common genomic alterations tested by next-generation sequencing targeted panels. This study does not address variability between matched primary tumours and metastases or the change in genomic alterations over time and after sequential systemic therapies.

Hybrid Capture-Based Comprehensive Genomic Profiling Identifies Lung Cancer Patients with Well-Characterized Sensitizing Epidermal Growth Factor Receptor Point Mutations That Were Not Detected by Standard of Care Testing.

BACKGROUND: In our recent study, of cases positive for epidermal growth factor receptor (EGFR) exon 19 deletions using comprehensive genomic profiling (CGP), 17/77 (22%) patients with prior standard of care (SOC) EGFR testing results available were previously negative for exon 19 deletion. Our aim was to compare the detection rates of CGP versus SOC testing for well-characterized sensitizing EGFR point mutations (pm) in our 6,832-patient cohort. MATERIALS AND METHODS: DNA was extracted from 40 microns of formalin-fixed paraffin-embedded sections from 6,832 consecutive cases of non-small cell lung cancer (NSCLC) of various histologies (2012-2015). CGP was performed using a hybrid capture, adaptor ligation-based next-generation sequencing assay to a mean coverage depth of 576×. Genomic alterations (pm, small indels, copy number changes and rearrangements) involving EGFR were recorded for each case and compared with prior testing results if available. RESULTS: Overall, there were 482 instances of EGFR exon 21 L858R (359) and L861Q (20), exon 18 G719X (73) and exon 20 S768I (30) pm, of which 103 unique cases had prior EGFR testing results that were available for review. Of these 103 cases, CGP identified 22 patients (21%) with sensitizing EGFR pm that were not detected by SOC testing, including 9/75 (12%) patients with L858R, 4/7 (57%) patients with L861Q, 8/20 (40%) patients with G719X, and 4/7 (57%) patients with S768I pm (some patients had multiple EGFR pm). In cases with available clinical data, benefit from small molecule inhibitor therapy was observed. CONCLUSION: CGP, even when applied to low tumor purity clinical-grade specimens, can detect well-known EGFR pm in NSCLC patients that would otherwise not be detected by SOC testing. Taken together with EGFR exon 19 deletions, over 20% of patients who are positive for EGFR-activating mutations using CGP are previously negative by SOC EGFR mutation testing, suggesting that thousands of such patients per year in the U.S. alone could experience improved clinical outcomes when hybrid capture-based CGP is used to inform therapeutic decisions. IMPLICATIONS FOR PRACTICE: This study points out that genomic profiling, as based on hybrid capture next-generation sequencing, can identify lung cancer patients with point mutation in epidermal growth factor receptor (EGFR) missed by standard molecular testing who can likely benefit from anti-EGFR targeted therapy. Beyond the specific findings regarding false-negative point mutation testing for EGFR, this study highlights the need for oncologists and pathologists to be cognizant of the performance characteristics of testing deployed and the importance of clinical intuition in questioning the results of laboratory testing.

Genomic landscape of advanced basal cell carcinoma: Implications for precision treatment with targeted and immune therapies.

Metastatic basal cell cancer (BCC) is an ultra-rare malignancy with no approved therapies beyond Hedgehog inhibitors. We characterized the genomics, tumor mutational burden (TMB), and anti-PD-1 therapy responses in patients with locally advanced or metastatic BCC. Overall, 2,039 diverse cancer samples that had undergone comprehensive genomic profiling (CGP) were reviewed. Eight patients with locally advanced/metastatic BCC were identified (two had two CGP analyses; total, 10 biopsies). Two tumors demonstrated PD-L1 amplification. Seven patients had >1 actionable alteration. The TMB (mutations/mb) (median (range)) was 90 (3-103) for the BCCs versus 4 (1-860) for 1637 cancers other than BCC (P < 0.0001). Median progression-free survival (PFS) for all four patients treated with PD-1 blockade was 10.7 months (range, 3.8 to 17.6+ months); three patients had an objective response. In conclusion, advanced/metastatic BCC often has biological features (high TMB; PD-L1 amplification) predictive of immunotherapy benefit, and patients frequently respond to PD-1 blockade.

Impact of EML4-ALK Variant on Resistance Mechanisms and Clinical Outcomes in ALK-Positive Lung Cancer.

Purpose Advanced anaplastic lymphoma kinase ( ALK) fusion-positive non-small-cell lung cancers (NSCLCs) are effectively treated with ALK tyrosine kinase inhibitors (TKIs). However, clinical outcomes in these patients vary, and the benefit of TKIs is limited as a result of acquired resistance. Emerging data suggest that the ALK fusion variant may affect clinical outcome, but the molecular basis for this association is unknown. Patients and Methods We identified 129 patients with ALK-positive NSCLC with known ALK variants. ALK resistance mutations and clinical outcomes on ALK TKIs were retrospectively evaluated according to ALK variant. A Foundation Medicine data set of 577 patients with ALK-positive NSCLC was also examined. Results The most frequent ALK variants were EML4-ALK variant 1 in 55 patients (43%) and variant 3 in 51 patients (40%). We analyzed 77 tumor biopsy specimens from patients with variants 1 and 3 who had progressed on an ALK TKI. ALK resistance mutations were significantly more common in variant 3 than in variant 1 (57% v 30%; P = .023). In particular, ALK G1202R was more common in variant 3 than in variant 1 (32% v 0%; P < .001). Analysis of the Foundation Medicine database revealed similar associations of variant 3 with ALK resistance mutation and with G1202R ( P = .010 and .015, respectively). Among patients treated with the third-generation ALK TKI lorlatinib, variant 3 was associated with a significantly longer progression-free survival than variant 1 (hazard ratio, 0.31; 95% CI, 0.12 to 0.79; P = .011). Conclusion Specific ALK variants may be associated with the development of ALK resistance mutations, particularly G1202R, and provide a molecular link between variant and clinical outcome. ALK variant thus represents a potentially important factor in the selection of next-generation ALK inhibitors.

Targeting HER2 in colorectal cancer: The landscape of amplification and short variant mutations in ERBB2 and ERBB3.

BACKGROUND: In contrast to lung cancer, few precision treatments are available for colorectal cancer (CRC). One rapidly emerging treatment target in CRC is ERBB2 (human epidermal growth factor receptor 2 [HER2]). Oncogenic alterations in HER2, or its dimerization partner HER3, can underlie sensitivity to HER2-targeted therapies. METHODS: In this study, 8887 CRC cases were evaluated by comprehensive genomic profiling for genomic alterations in 315 cancer-related genes, tumor mutational burden, and microsatellite instability. This cohort included both colonic (7599 cases; 85.5%) and rectal (1288 cases; 14.5%) adenocarcinomas. RESULTS: A total of 569 mCRCs were positive for ERBB2 (429 cases; 4.8%) and/or ERBB3 (148 cases; 1.7%) and featured ERBB amplification, short variant alterations, or a combination of the 2. High tumor mutational burden (≥20 mutations/Mb) was significantly more common in ERBB-mutated samples, and ERBB3-mutated CRCs were significantly more likely to have high microsatellite instability (P<.002). Alterations affecting KRAS (27.3%) were significantly underrepresented in ERBB2-amplified samples compared with wild-type CRC samples (51.8%), and ERBB2- or ERBB3-mutated samples (49.0% and 60.8%, respectively) (P<.01). Other significant differences in mutation frequency were observed for genes in the PI3K/MTOR and mismatch repair pathways. CONCLUSIONS: Although observed less often than in breast or upper gastrointestinal carcinomas, indications for which anti-HER2 therapies are approved, the percentage of CRC with ERBB genomic alterations is significant. Importantly, 32% of ERBB2-positive CRCs harbor short variant alterations that are undetectable by routine immunohistochemistry or fluorescence in situ hybridization testing. The success of anti-HER2 therapies in ongoing clinical trials is a promising development for patients with CRC. Cancer 2018;124:1358-73. © 2018 Foundation Medicine, Inc. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society.

Hybrid Capture-Based Genomic Profiling of Circulating Tumor DNA from Patients with Advanced Cancers of the Gastrointestinal Tract or Anus.

Purpose: Genomic profiling of tumor biopsies from advanced gastrointestinal and anal cancers is increasingly used to inform treatment. In some cases, tissue biopsy can be prohibitive, and we sought to investigate whether analysis of blood-derived circulating tumor DNA (ctDNA) may provide a minimally invasive alternative.Experimental Design: Hybrid capture-based genomic profiling of 62 genes was performed on blood-based ctDNA from 417 patients with gastrointestinal carcinomas to assess the presence of genomic alterations (GA) and compare with matched tissue samples.Results: Evidence of ctDNA was detected in 344 of 417 samples (82%), and of these, ≥1 reportable GA was detected in 89% (306/344) of samples. Frequently altered genes were TP53 (72%), KRAS (35%), PIK3CA (14%), BRAF (8%), and EGFR (7%). In temporally matched ctDNA and tissue samples available from 25 patients, 86% of alterations detected in tissue were also detected in ctDNA, including 95% of short variants, but only 50% of amplifications. Conversely, 63% of alterations detected in ctDNA were also detected in matched tissue. Examples demonstrating clinical utility are presented.Conclusions: Genomic profiling of ctDNA detected potentially clinically relevant GAs in a significant subset of patients with gastrointestinal carcinomas. In these tumor types, most alterations detected in matched tissue were also detected in ctDNA, and with the exception of amplifications, ctDNA sequencing routinely detected additional alterations not found in matched tissue, consistent with tumor heterogeneity. These results suggest feasibility and utility of ctDNA testing in advanced gastrointestinal cancers as a complementary approach to tissue testing, and further investigation is warranted. Clin Cancer Res; 24(8); 1881-90. ©2018 AACR.

A FISH assay efficiently screens for BRAF gene rearrangements in pancreatic acinar-type neoplasms.

Approximately 1-2% of pancreatic neoplasms are acinar cell carcinomas. Recently, BRAF gene rearrangements were identified in over 20% of acinar-type neoplasms, which included both pure acinar cell carcinomas and mixed carcinomas with acinar differentiation, using next-generation sequencing-based platforms, providing a potential therapeutic target for patients with these neoplasms. Thus, it is clinically important to develop a rapid, cost- and material-efficient assay to screen for BRAF gene fusions in pancreatic acinar-type neoplasms. We developed a dual color, break-apart FISH assay to detect BRAF gene rearrangements in these neoplasms and evaluated its performance in comparison to next-generation sequencing-based studies. A blinded BRAF rearrangement FISH investigation was performed on 31 acinar-type neoplasms that had been studied previously by next-generation sequencing-based analysis as well as on 18 additional acinar-type neoplasms that were accrued over the past 2 years. In total, BRAF fusions were identified in 12/49 (24%) acinar-type neoplasms by FISH. BRAF fusion partners were uncovered by using targeted next-generation sequencing studies in 11 FISH-positive cases that had sufficient material for next-generation sequencing studies. SND1 was the most frequent fusion partner involved in BRAF-fusion acinar-type neoplasms (50%), followed by HERPUD1 (18%). No BRAF fusions were identified by next-generation sequencing in any of the FISH-negative cases investigated. FISH analysis showed that BRAF rearrangements were diffusely present across tumor-rich areas in BRAF-fusion acinar-type neoplasms, which is consistent with an oncogenic driver alteration pattern. Thus, we demonstrated that, in comparison to targeted next-generation sequencing-based technologies, the FISH assay is highly sensitive and specific as well as time- and cost-efficient in the detection of BRAF fusions in acinar-type neoplasms. The FISH assay can be easily implemented in diagnostic settings to identify acinar-type neoplasms patients potentially suitable for targeted therapy to inhibit MAPK pathway activity.

BRAF internal deletions and resistance to BRAF/MEK inhibitor therapy.

BRAF and MEK inhibitors have improved clinical outcomes in advanced, BRAFV600 -mutated melanomas. Acquired resistance occurs in most patients, with numerous and diverse drivers. We obtained pretreatment and progression biopsies from a patient who progressed on dabrafenib and trametinib. In addition to a preserved BRAFV600E mutation, an internal deletion (rearrangement) of BRAF was observed in the progression sample. This deletion involved exons 2-8, which includes the Ras-binding domain, and is analogous to previously documented BRAF fusions and splice variants known to reactivate RAS-RAF-MEK-ERK signaling. In a large cohort of melanomas, 10 additional internal deletions were identified (0.4% of all melanomas; nine of which had concurrent BRAF mutations), as well as sporadically in other tumor types. Thus, we describe a novel mechanism of resistance to BRAF and MEK inhibition.

Characterization of Clinical Cases of Advanced Papillary Renal Cell Carcinoma via Comprehensive Genomic Profiling.

BACKGROUND: Papillary renal cell carcinoma (PRCC) is a rare subset of RCC. The Cancer Genome Atlas (TCGA) data largely reflect localized disease, and there are limited data for advanced PRCC. OBJECTIVE: To characterize the frequency of genomic alterations (GAs) in patients with advanced PRCC for whom comprehensive genomic profiling (CGP) was performed in the context of routine clinical care. DESIGN, SETTING, AND PARTICIPANTS: Formalin-fixed, paraffin-embedded tissue was obtained for 169 consecutive patients with confirmed PRCC. DNA was extracted and comprehensive genomic profiling was performed in a certified central laboratory. MEASUREMENTS: Hybrid-capture, adaptor ligation-based libraries of up to 315 genes were sequenced to a median coverage of 648×. All classes of GAs were identified, including substitutions, insertions/deletions, copy number alterations, and rearrangements. RESULTS AND LIMITATIONS: From 169 patients, either primary tumor tissue (102 patients, 60%) or metastatic tissue (67 patients, 40%) was collected. In patients with type 1 PRCC, commonly altered genes were MET (33%; 8 activating mutations, 5 amplifications at >6 copies), TERT (30%), CDKN2A/B (13%), and EGFR (8%). In patients with type 2 PRCC, commonly altered genes were CDKN2A/B (18%), TERT (18%), NF2 (13%), and FH (13%); MET GAs (5 mutations, 3 amplifications) were observed in 7% of type 2 cases. Notable differences from TCGA data include higher frequencies of MET, NF2, and CDKN2A/B GAs, association of alterations in SWI/SNF complex genes with type 2 PRCC, and observation of frequent CDKN2A/B alterations in both type 1 and type 2 disease. CONCLUSIONS: Both the current study and the TCGA experience represent similarly sized cohorts of patients with PRCC. Key differences in GA frequency probably underscore the marked difference in stage distribution between these data sets. These results may inform planned precision medicine trials for metastatic PRCC. PATIENT SUMMARY: Papillary renal cell carcinoma (PRCC) is a rare subtype of kidney cancer, and understanding of the biology of advanced PRCC is limited. This report highlights some of the unique biologic features of PRCC that may inform on future use of targeted therapies for the treatment of metastatic disease.