Inflammatory myofibroblastic tumor (IMT) is a neoplasm which typically occurs in children. The genetic landscape of this tumor is incompletely understood and therapeutic options are limited. While 50% of IMTs harbor ALK rearrangements, no therapeutic targets have been identified in ALK negative tumors. We report for the first time that IMTs harbor other actionable targets, including ROS1 and PDGFRβ fusions. We detail the case of an 8 year old boy with treatment-refractory ALK negative IMT. Molecular tumor profiling revealed a ROS1 fusion, and he had a dramatic response to the ROS1 inhibitor, crizotinib. This case prompted assessment of a larger series of IMTs. Next generation sequencing revealed that 85% of cases evaluated harbored kinase fusions, involving ALK, ROS1, or PDGFRβ. Our study represents the most comprehensive genetic analysis of IMTs to date and also provides rationale for routine molecular profiling of these tumors to detect therapeutically actionable kinase fusions.
Inflammatory myofibroblastic tumor; ALK; ROS1; PDGFRβ; tyrosine kinase; tyrosine kinase inhibitor; crizotinib; cancer; sarcoma; targeted therapeutics; next generation sequencing; gene rearrangement; gene fusion
Anaplastic lymphoma kinase (ALK) fusion positive non-small cell lung cancer (NSCLC) is a relatively novel molecular subtype in lung cancer. ALK targeted therapies such as crizotinib increase survival benefit in this patient population. However, further understanding of the disease subtype including patterns of metastasis and pathways of treatment resistance are needed. We describe a 50 year-old-woman diagnosed with stage IV NSCLC, T2N3M1b, ALK fusion positive disease. Although her initial sites of metastasis included the liver and bone, her story is notable for crizotinib resistant growth of a metastatic lesion to her adnexa. This report brings to attention unique mechanisms of metastasis in ALK positive patients.
Non-small cell lung cancer; Adnexa; Metastasis; Anaplastic lymphoma kinase
Recurrent “driver” mutations at specific loci in BRAF, NRAS, KIT, GNAQ, and GNA11 define clinically-relevant molecular subsets of melanoma, but >30% are “pan-negative” for these recurrent mutations. We sought to identify additional potential drivers in “pan-negative” melanoma.
Using a targeted next-generation sequencing (NGS) assay (FoundationOne™) and targeted RNA sequencing, we identified a novel PAPSS1-BRAF fusion in a “pan-negative” melanoma. We then analyzed NGS data from 51 additional melanomas genotyped by FoundationOne™, as well as melanoma RNA, whole genome and whole exome sequencing data in The Cancer Genome Atlas (TCGA), to determine the potential frequency of BRAF fusions in melanoma. We characterized the signaling properties of confirmed molecular alterations by ectopic expression of engineered cDNAs in 293H cells.
Activation of the mitogen-activated protein kinase (MAPK) pathway in cells by ectopic expression of PAPSS1-BRAF was abrogated by MEK inhibition but not by BRAF inhibition. NGS data analysis of 51 additional melanomas revealed a second BRAF fusion (TRIM24-BRAF) in a “pan-negative” sample; MAPK signaling induced by TRIM24-BRAF was also MEK inhibitor sensitive. Through mining TCGA skin cutaneous melanoma dataset, we further identified two potential BRAF fusions in another 49 “pan-negative” cases.
BRAF fusions define a new molecular subset of melanoma, potentially comprising 4–8% of “pan-negative” cases. Their presence may explain an unexpected clinical response to MEK inhibitor therapy or assist in selecting patients for MEK directed therapy.
melanoma; BRAF fusion; BRAF rearrangement; next-generation sequencing; BRAF inhibitor; MEK inhibitor; vemurafenib; trametinib
EGFR-mutant lung cancers responsive to reversible EGFR inhibitors (gefitinib/erlotinib) develop acquired resistance, mediated by second-site EGFR T790M mutation in >50% cases. Preclinically, afatinib (irreversible ErbB family blocker) plus cetuximab (anti-EGFR monoclonal antibody) overcomes T790M-mediated resistance. This phase Ib study combining afatinib and cetuximab enrolled heavily pretreated patients with advanced EGFR-mutant lung cancer and acquired resistance to erlotinib/gefitinib. Patients provided post-acquired-resistance tumor samples for profiling EGFR mutations. Among 126 patients, objective response rate (overall 29%) was comparable in T790M-positive and T790M-negative tumors (32% vs. 25%; P = 0.341). Median progression-free survival was 4.7 months (95% confidence interval, 4.3–6.4); median duration of confirmed objective response was 5.7 months (range, 1.8–24.4). Therapy-related grade 3/4 adverse events occurred in 44%/2% of patients. Afatinib/cetuximab demonstrated robust clinical activity and a manageable safety profile in EGFR-mutant lung cancers with acquired resistance to gefitinib or erlotinib, both with and without T790M mutations, warranting further investigation.
afatinib; cetuximab; acquired resistance
The discovery of RET fusions in lung cancers has uncovered a new therapeutic target for patients whose tumors harbor these changes. In an unselected population of non–small cell lung carcinomas (NSCLCs), RET fusions are present in 1% to 2% of cases. This incidence increases substantially, however, in never-smokers with lung adenocarcinomas that lack other known driver oncogenes. Although preclinical data provide experimental support for the use of RET inhibitors in the treatment of RET fusion-positive tumors, clinical data on response are lacking. We report preliminary data for the first three patients treated with the RET inhibitor cabozantinib on a prospective phase II trial for patients with RET fusion-positive NSCLCs (NCT01639508). Confirmed partial responses were observed in 2 patients, including one harboring a novel TRIM33–RET fusion. A third patient with a KIF5B–RET fusion has had prolonged stable disease approaching 8 months (31 weeks). All three patients remain progression-free on treatment.
Suspected metastatic site lesions that are poorly differentiated present a diagnostic challenge when morphologic and immunohistochemical profiling cannot establish the primary tumor site. Here we present a patient diagnosed with both a malignant neoplasm in the lung and a right upper extremity (RUE) neoplasm of unclear histogenetic origin. Immunohistochemical staining performed on the latter specimen was inconclusive in determining the site of origin. Although the lung biopsy sample was insufficient for molecular testing, hybrid capture-based comprehensive genomic profiling (FoundationOne) identified an EML4-ALK rearrangement in the RUE lesion. Crizotinib treatment resulted in a major response in both the RUE and the lung lesions. This report illustrates the utility of comprehensive genomic profiling employed at the initial presentation of an unknown primary malignant neoplasm, which resulted in the front-line use of targeted therapy and a significant and sustained antitumor response.
Crizotinib; ALK; Unknown primary tumor site; Poorly differentiated lung neoplasm
In this study, the authors hypothesized that genomic profiling of clinical intrahepatic cholangiocarcinoma samples would identify genomic alterations that are linked to targeted therapies and that could facilitate a personalized approach to therapy. Two-thirds of patients in this study harbored genomic alterations that are associated with targeted therapies and that have the potential to personalize therapy selection individual patients.
Intrahepatic cholangiocarcinoma (ICC) is a subtype of primary liver cancer that is rarely curable by surgery and is rapidly increasing in incidence. Relapsed ICC has a poor prognosis, and current systemic nontargeted therapies are commonly extrapolated from those used in other gastrointestinal malignancies. We hypothesized that genomic profiling of clinical ICC samples would identify genomic alterations that are linked to targeted therapies and that could facilitate a personalized approach to therapy.
DNA sequencing of hybridization-captured libraries was performed for 3,320 exons of 182 cancer-related genes and 36 introns of 14 genes frequently rearranged in cancer. Sample DNA was isolated from 40 μm of 28 formalin-fixed paraffin-embedded ICC specimens and sequenced to high coverage.
The most commonly observed alterations were within ARID1A (36%), IDH1/2 (36%), and TP53 (36%) as well as amplification of MCL1 (21%). Twenty cases (71%) harbored at least one potentially actionable alteration, including FGFR2 (14%), KRAS (11%), PTEN (11%), CDKN2A (7%), CDK6 (7%), ERBB3 (7%), MET (7%), NRAS (7%), BRCA1 (4%), BRCA2 (4%), NF1 (4%), PIK3CA (4%), PTCH1 (4%), and TSC1 (4%). Four (14%) of the ICC cases featured novel gene fusions involving the tyrosine kinases FGFR2 and NTRK1 (FGFR2-KIAA1598, FGFR2-BICC1, FGFR2-TACC3, and RABGAP1L-NTRK1).
Two thirds of patients in this study harbored genomic alterations that are associated with targeted therapies and that have the potential to personalize therapy selection for to individual patients.
Intrahepatic cholangiocarcinoma; Next-generation sequencing; Driver mutations; Targeted therapy
Neoadjuvant chemotherapy (NAC) induces a pathologic complete response (pCR) in approximately 30% of patients with triple-negative breast cancers (TNBC). In patients lacking a pCR, NAC selects a subpopulation of chemotherapy-resistant tumor cells. To understand the molecular underpinnings driving treatment-resistant TNBCs, we performed comprehensive molecular analyses on the residual disease (RD) of 74 clinically-defined TNBCs after NAC including next-generation sequencing (NGS) on 20 matched pre-treatment biopsies. Combined NGS and digital RNA expression analysis identified diverse molecular lesions and pathway activation in drug-resistant tumor cells. Ninety percent of the tumors contained a genetic alteration potentially treatable with a currently available targeted therapy. Thus, profiling residual TNBCs after NAC identifies targetable molecular lesions in the chemotherapy-resistant component of the tumor which may mirror micro-metastases destined to recur clinically. These data can guide biomarker-driven adjuvant studies targeting these micro-metastases to improve the outcome of patients with TNBC who do not respond completely to NAC.
next-generation sequencing; breast cancer; neoadjuvant chemotherapy
Carcinoma of unknown primary (CUP) accounts for 3–5% of all adult solid tumors. An extensive search for the anatomic site of origin is often undertaken in an attempt to tailor systemic treatment, but the latter often has limited efficacy – especially in the setting of an initial treatment failure. Molecularly targeted therapy is an emerging approach that may offer greater efficacy and less toxicity but is most likely to be effective when pairing a tumor harboring a sensitizing genomic alteration with an agent directed at the altered gene product. We report a patient with a CUP harboring a MET amplification with a complete metabolic response to crizotinib despite also harboring a KRAS mutation.
Ge-nomic profiling was performed using a clinical next-generation-sequencing-based assay, FoundationOne®, in a CAP-accredited laboratory certified by Clinical Laboratory Improvement Amendments (Foundation Medicine, Cambridge, Mass., USA).
The CUP harbored both MET amplification (16 copies) and a KRAS G12V mutation. The patient was treated with crizotinib, a MET inhibitor, and has experienced a complete normalization of tumor metabolic activity for more than 19 months. Conclusions: Genomic profiling of CUP may reveal clinically meaningful genomic alterations that can guide targeted therapy decision-making. The use of this approach should be studied prospectively as a strategy for the effective treatment of CUP patients and for avoiding resource-intensive workups to identify the tumor site of origin.
Carcinoma of unknown primary; MET amplification; KRAS mutation; Crizotinib; Next-generation sequencing
Spitzoid neoplasms are a group of melanocytic tumors with distinctive histopathologic features. They include benign tumors (Spitz nevi), malignant tumors (spitzoid melanomas), and tumors with borderline histopathologic features and uncertain clinical outcome (atypical Spitz tumors). Their genetic underpinnings are poorly understood, and alterations in common melanoma-associated oncogenes are typically absent. Here we show that spitzoid neoplasms harbor kinase fusions of ROS1 (17%), NTRK1 (16%), ALK (10%), BRAF (5%), and RET (3%) in a mutually exclusive pattern. The chimeric proteins are constitutively active, stimulate oncogenic signaling pathways, are tumorigenic, and are found in the entire biologic spectrum of spitzoid neoplasms, including 55% of Spitz nevi, 56% of atypical Spitz tumors, and 39% of spitzoid melanomas. Kinase inhibitors suppress the oncogenic signaling of the fusion proteins in vitro. In summary, kinase fusions account for the majority of oncogenic aberrations in spitzoid neoplasms, and may serve as therapeutic targets for metastatic spitzoid melanomas.
For patients with metastatic papillary thyroid carcinoma (PTC) refractory to radioactive iodine (RAI) treatment, systemic chemotherapy has limited efficacy. Such tumors frequently harbor BRAF V600E, and this alteration may predict responsiveness to vemurafenib treatment.
We report a metastatic PTC patient refractory to RAI treatment that underwent genomic profiling by next-generation sequencing. The sole genomic alteration identified was BRAF V600E on a near diploid genome with trisomy 1q. With vemurafenib treatment, the patient experienced a dramatic radiographic and clinical improvement, with the duration of an ongoing antitumor response exceeding 23 months.
Hybridization capture of 3,769 exons of 236 cancer-related genes and the introns of 19 genes frequently rearranged in cancer was applied to >50 ng of DNA extracted from a formalin-fixed, paraffin-embedded biopsy of a lymph node containing metastatic PTC and was sequenced to a high, uniform coverage of ×616.
A BRAF V600E alteration was identified with no other somatic genomic alterations present within a near diploid tumor genome. The patient initially received vemurafenib at 960 mg twice daily that was reduced to 480 mg twice daily due to rash and diarrhea and has experienced an ongoing antitumor response exceeding 23 months by both PET-CT and dedicated CT imaging.
Genomic profiling in metastatic, RAI-refractory PTC can reveal a targetable BRAF V600E alteration without compounding somatic alterations, and such patients may derive a more prolonged benefit from vemurafenib treatment. Prospective clinical trials are ongoing to confirm our preliminary observation.
Papillary thyroid carcinoma; BRAF V600E; Vemurafenib
Concurrent signal transduction inhibition with the epidermal growth factor receptor (EGFR) inhibitor gefitinib and the mammalian target-of-rapamycin inhibitor everolimus has been hypothesized to result in enhanced antitumor activity in patients with non-small cell lung cancer (NSCLC). This phase II trial assessed the efficacy of the combination of gefitinib and everolimus in patients with advanced NSCLC.
Two cohorts of 31 patients with measurable stage IIIB/IV NSCLC were enrolled: (1) no prior chemotherapy and (2) previously treated with cisplatin or carboplatin and docetaxel or pemetrexed. All patients received daily everolimus 5 mg and gefitinib 250 mg. Response was assessed after 1 month and then every 2 months. Pretreatment tumor specimens were collected for mutation testing.
Sixty-two patients were enrolled (median age: 66 years, 50% women, 98% stage IV, all current/former smokers, and 85% adenocarcinoma). Partial responses were seen in 8 of 62 patients (response rate: 13%; 95% confidence interval: 5–21%); five responders had received no prior chemotherapy. Three partial responders had an EGFR mutation. Both patients with a KRAS (G12F) mutation responded. The median time to progression was 4 months. Median overall survival was 12 months, 27 months for no prior chemotherapy patients, and 11 months for patients previously treated with chemotherapy.
The 13% partial response rate observed did not meet the prespecified response threshold to pursue further study of the combination of gefitinib and everolimus. The response rate in patients with non-EGFR mutant tumors was 8%, likely reflecting activity of everolimus. Further investigation of mammalian target-of-rapamycin inhibitors in patients with NSCLC with KRAS G12F-mutated tumors is warranted.
Non-small cell lung cancer; Gefitinib; Everolimus.
A subset of lung adenocarcinomas appears preferentially sensitive to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). EGFR-activating mutations and never smoking are associated with response to TKIs.
To describe the morphology of adenocarcinomas responsive to TKIs, compare it to tumors in nonresponding patients, and correlate findings with EGFR mutations, gene copy number, and protein expression.
Material from 52 EGFR TKI-treated patients was studied: 29 responders and 23 nonresponders. Adenocarcinoma subtypes and morphologic features were defined in histologic and cytologic material. EGFR mutations were detected by sequencing, copy number by chromogenic in situ hybridization, and expression by immunohistochemistry.
Tumors from TKI responders tended to be better-differentiated adenocarcinomas with bronchioloalveolar carcinoma components. Nonresponders showed more heterogeneous morphology, higher grade, and more subtypes, and were more likely to show solid growth. In nonresponders, the only pure bronchioloalveolar carcinoma was mucinous, a subtype known to be negative for EGFR mutations. Using World Health Organization criteria, all tumors in both groups other than pure bronchioloalveolar carcinomas would be classified as adenocarcinomas, mixed subtype, thereby obscuring some of these distinctions. EGFR mutations were significantly more common in responders (22/29 vs 0/23; P < .001). Immunohistochemistry and chromogenic in situ hybridization results were not significantly correlated with EGFR mutations or response to TKIs in this study.
Overall, histologic differences exist between tumors that respond to TKIs and those that do not, although sampling affects classification, and there is significant histologic overlap between the 2 groups. Response is strongly associated with EGFR mutations.
Our analysis of the tumors of 57 women with metastatic breast cancer with next generation sequencing (NGS) demonstrates that each patient's tumor is unique in its molecular fingerprint. We observed 216 somatic aberrations in 70 different genes, including 131 distinct aberrations. The most common gene alterations (in order of decreasing frequency) included: TP53, PIK3CA, CCND1, MYC, HER2 (ERBB2), MCL1, PTEN, FGFR1, GATA3, NF1, PIK3R1, BRCA2, EGFR, IRS2, CDH1, CDKN2A, FGF19, FGF3 and FGF4. Aberrations included mutations (46%), amplifications (45%), deletions (5%), splices (2%), truncations (1%), fusions (0.5%) and rearrangements (0.5%), with multiple distinct variants within the same gene. Many of these aberrations represent druggable targets, either through direct pathway inhibition or through an associated pathway (via ‘crosstalk’). The ‘molecular individuality’ of these tumors suggests that a customized strategy, using an “N-of-One” model of precision medicine, may represent an optimal approach for the treatment of patients with advanced tumors.
Genomics; Breast Cancer; PI3K; Clinical Trials
All patients with EGFR mutant lung cancers eventually develop acquired resistance to EGFR tyrosine kinase inhibitors (TKIs). Smaller series have identified various mechanisms of resistance, but systematic evaluation of a large number of patients to definitively establish the frequency of various mechanisms has not been performed.
Patients with lung adenocarcinomas and acquired resistance to erlotinib or gefitinib enrolled onto a prospective biopsy protocol and underwent a re-biopsy after the development of acquired resistance. Histology was reviewed. Samples underwent genotyping for mutations in EGFR, AKT1, BRAF, ERBB2, KRAS, MEK1, NRAS and PIK3CA, and FISH for MET and HER2.
Adequate tumor samples for molecular analysis were obtained in 155 patients. Ninety-eight had second-site EGFR T790M mutations (63%, 95% CI 55-70%) and four had small cell transformation (3%, 95% CI 0-6%). MET amplification was seen in 4/75 (5%, 95% CI 1-13%). HER2 amplification was seen in 3/24 (13%, 95% CI 3-32%). We did not detect any acquired mutations in PIK3CA, AKT1, BRAF, ERBB2, KRAS, MEK1, or NRAS. (0/88, 0%, 95% CI 0-4%). Overlap among mechanisms of acquired resistance was seen in 4%.
This is the largest series reporting mechanisms of acquired resistance to EGFR TKI therapy. We identified EGFR T790M as the most common mechanism of acquired resistance, while MET amplification, HER2 amplification, and small cell histologic transformation occur less frequently. More comprehensive methods to characterize molecular alterations in this setting are needed to improve our understanding of acquired resistance to EGFR TKIs.
EGFR mutant lung cancer; lung adenocarcinoma; targeted therapy; acquired resistance; tyrosine kinase inhibitor therapy
Leptomeningeal metastases (LM) occur in 5–10% of patients with solid tumors and are associated with a dismal prognosis. We describe LM from lung adenocarcinoma harboring a mutation in the epidermal growth factor receptor (EGFR) gene that confers sensitivity to the EGFR tyrosine kinase inhibitors (EGFR-TKIs) erlotinib and gefitinib. The CSF concentration of EGFR-TKIs achieved by standard daily dosing may be insufficient for therapeutic effect. However, intermittent (pulsatile) high dose administration (1000–1500 mg/week) achieves a higher CSF concentration than standard dosing, and successfully controlled LM in this patient.
Leptomeningeal metastases; EGFR; Lung cancer; Erlotinib
Cancers can exhibit dramatic tumor regression following oncogene inhibition through the phenomenon of “oncogene addiction”. The ability to predict when a tumor will exhibit oncogene addiction would be useful in the development of targeted therapeutics. Oncogene addiction is likely the consequence of many cellular programs. However, we reasoned that many of these inputs may converge on aggregate survival and death signals. To test this, we measured the sequence of changes that occur upon oncogene inactivation in conditional genetically engineered mouse models of K-rasG12D- or MYC-induced lung tumors and lymphoma. We combined quantitative imaging with an in situ analysis of biomarkers of proliferation and apoptosis. Indeed, oncogene addiction could be modeled as differential changes in intracellular survival and death signals following oncogene inactivation. Our model used different imaging methods (CT and bioluminescence imaging) and histochemical markers of proliferation and apoptosis (Ki-67 and caspase 3) to blindly predict the differential in dynamics of several pro-survival and pro-death signaling factors (phosphorylated Erk1/2, Akt1, Stat3/5 and p38) that contribute to the aggregate survival and death signals. The model was predictive of different oncogenes (K-rasG12D and MYC) in multiple tumor types (lung and lymphoma). Furthermore, we could predict the influence of specific genetic lesions (p53-/-, Stat3-d358L and myr-Akt1) on tumor regression upon oncogene inactivation. Finally, our model could utilize quantitative imaging data to predict both EGFR genotype and progression-free survival in human patients with lung cancer shortly after the initiation of treatment with the targeted therapy erlotinib. Hence, the consequences of oncogene inactivation can be accurately modeled based on a relatively small number of parameters that may predict when targeted therapeutics will elicit oncogene addiction.
Oncologic patients who are extreme responders to molecularly targeted therapy provide an important opportunity to better understand the biologic basis of response and, in turn, inform clinical decision making. Malignant neoplasms with an uncertain histologic and immunohistochemical characterization present challenges both on initial diagnostic workups and then later in management, as current treatment algorithms are based on a morphologic diagnosis. Herein, we report a case of a difficult to characterize sarcoma-like lesion for which genomic profiling with clinical next generation sequencing (NGS) identified the molecular underpinnings of arrested progression(stable disease) under combination targeted therapy within a phase I clinical trial.
Genomic profiling with clinical next generation sequencing was performed on the FoundationOne™ platform (Foundation Medicine, Cambridge MA). Histopathology and immunohistochemical studies were performed in the Department of Pathology, MD Anderson Cancer Center (Houston, TX). Treatment was administered in the context of a phase I clinical trial ClinicalTrials.gov Identifier: (NCT01187199).
The histology of the tumor was that of a spindle cell neoplasm, grade 2 by FNCLCC standards. Immunohistochemical staining was positive for S100 and CD34. Genomic profiling identified the following alterations: a KIAA1549-BRAF gene fusion resulting from a tandem duplication event, a homozygous deletion of PTEN, and frameshift insertion/deletions in CDKN2A A68fs*51, SUFU E283fs*3, and MAP3K1 N325fs*3. The patient had a 25% reduction in tumor (RECIST v1.1) following combination therapy consisting of sorafenib, temsirolimus, and bevazicumab within a phase I clinical trial.
The patient responded to combination targeted therapy that fortuitously targeted KIAA1549-BRAF and PTEN loss within a spindle cell neoplasm, as revealed by genomic profiling based on NGS. This is the first report of a tumor driven by a KIAA1549-BRAF fusion responding to sorafenib-based combination therapy.
Spindle cell neoplasm; Sarcoma; KIAA1549-BRAF; BRAF; Targeted therapy; Sorafenib; mTOR; Bevacizumab; Next generation sequencing; N = 1 trial
We previously demonstrated that stage IIIB/IV non-small cell lung cancer (NSCLC) never smokers lived 50% longer than former/current smokers. This observation persisted after adjusting for age, performance status, and gender. We hypothesized that smoking-dependent differences in the distribution of driver mutations might explain differences in prognosis between these subgroups.
We reviewed 293 never smokers and 382 former/current smokers with lung adenocarcinoma who underwent testing for EGFR and KRAS mutations and rearrangements in ALK between 2009 and 2010. Clinical outcomes and patient characteristics were collected. Survival probabilities were estimated using the Kaplan-Meier method. Group comparison was performed with log-rank tests and Cox proportional hazards methods.
While the overall incidence of these mutations was nearly identical (55% never smokers vs. 57% current/former smokers, p=0.48), there were significant differences in the distribution of mutations between these groups: EGFR mutations- 37% never smokers vs. 14% former/current smokers (p<0.0001); KRAS mutations- 4% never smokers vs. 43% former/current smokers (p<0.0001); ALK rearrangements- 12% never smokers vs. 2% former/current smokers (p<0.0001). Among never smokers and former/current smokers, prognosis differed significantly by genotype. Patients harboring KRAS mutations demonstrated the poorest survival. Smoking status, however, had no influence on survival within each genotype.
Never smokers and former/current smokers with lung adenocarcinomas are not homogeneous subgroups. Each is made up of individuals whose tumors have a unique distribution of driver mutations which are associated with different prognoses, irrespective of smoking history.
non-small cell lung cancer; adenocarcinoma; EGFR; KRAS; ALK; never smoker
EGFR-mutant lung cancers eventually become resistant to treatment with EGFR tyrosine kinase inhibitors (TKIs). The combination of EGFR-TKI afatinib and anti-EGFR antibody cetuximab can overcome acquired resistance in mouse models and human patients. Since afatinib is also a potent HER2 inhibitor, we investigated the role of HER2 in EGFR-mutant tumor cells. We show in vitro and in vivo that afatinib plus cetuximab significantly inhibits HER2 phosphorylation. HER2 overexpression or knockdown confers resistance or sensitivity, respectively, in all studied cell line models. Fluorescent in situ hybridization analysis revealed that HER2 was amplified in 12% of tumors with acquired resistance versus only 1% of untreated lung adenocarcinomas. Notably, HER2 amplification and EGFR T790M were mutually exclusive. Collectively, these results reveal a previously unrecognized mechanism of resistance to EGFR TKIs and provide a rationale to assess the status and possibly target HER2 in EGFR mutant tumors with acquired resistance to EGFR TKIs.
EGFR mutations; lung cancer; EGFR tyrosine kinase inhibitors; erlotinib; afatinib; cetuximab; HER2 amplification; EGFR T790M; acquired resistance
Lung adenocarcinoma, the most common subtype of non-small cell lung cancer, is responsible for over 500,000 deaths per year worldwide. Here, we report exome and genome sequences of 183 lung adenocarcinoma tumor/normal DNA pairs. These analyses revealed a mean exonic somatic mutation rate of 12.0 events/megabase and identified the majority of genes previously reported as significantly mutated in lung adenocarcinoma. In addition, we identified statistically recurrent somatic mutations in the splicing factor gene U2AF1 and truncating mutations affecting RBM10 and ARID1A. Analysis of nucleotide context-specific mutation signatures grouped the sample set into distinct clusters that correlated with smoking history and alterations of reported lung adenocarcinoma genes. Whole genome sequence analysis revealed frequent structural re-arrangements, including in-frame exonic alterations within EGFR and SIK2 kinases. The candidate genes identified in this study are attractive targets for biological characterization and therapeutic targeting of lung adenocarcinoma.
Lung Cancer; Novel ALK Rearrangement; Crizotinib
Treatment of patients with oncogene-addicted cancers with tyrosine kinase inhibitors (TKI) is biologically and clinically different than with cytotoxic chemotherapy. We have observed that some patients with EGFR-mutant lung cancer and acquired resistance to erlotinib or gefitinib (RECIST progression after initial benefit) have accelerated progression of disease after discontinuation of TKI. To examine this observation and define the course of patients following TKI discontinuation, we systematically evaluated patients enrolled on clinical trials of agents to treat acquired resistance to erlotinib or gefitinib.
We evaluated patients with EGFR-mutant lung cancer who participated in trials for patients with acquired resistance which mandated TKI discontinuation prior to administration of study therapy. Disease flare was defined as hospitalization or death attributable to disease progression during the “washout” period.
Fourteen of 61 patients (23%; 95% CI 14-35%) experienced a disease flare. The median time to disease flare after TKI discontinuation was 8 days (range 3-21). Factors associated with disease flare included shorter time to progression on initial TKI (p=0.002) and the presence of pleural (p=0.03) or CNS disease (p=0.01). There was no association between disease flare and the presence of T790M at the time of acquired resistance.
In patients with EGFR-mutant lung cancer and acquired resistance to EGFR TKIs, discontinuation of erlotinib or gefitinib prior to initiation of study treatment is associated with a clinically significant risk of accelerated disease progression. Clinical trials in this patient population must minimize protocol mandated washout periods.
EGFR; adenocarcinoma of lung; drug resistance
We undertook this phase II study to measure postoperative drug delivery and toxicity of cisplatin plus docetaxel in patients with resected stage I-III non-small cell lung cancer.
The primary endpoint was amount of cisplatin delivered over a planned four cycles of adjuvant chemotherapy. Statistical design required a cohort to close if the regimen proved unlikely to improve cisplatin delivery compared with published phase III data. The first cohort was treated with docetaxel 35 mg/m2 intravenously (IV) on days 1, 8, and 15, and cisplatin 80 mg/m2 IV on day 15, every 4 weeks for four planned cycles. A second cohort was treated with docetaxel 75 mg/m2 IV plus cisplatin 80 mg/m2 IV on day 1 every 3 weeks for four planned cycles.
Sixteen patients were treated with weekly docetaxel and cisplatin every 4 weeks, with five of 16 (31%) unable to complete three cycles. Subsequently, 11 patients were treated with docetaxel and cisplatin every 3 weeks, with six of 11 (55%) unable to complete three cycles. Among the 11 patients who failed to complete three cycles, the reasons for stopping included one or more of the following: fatigue (n = 8), nausea (n = 4), febrile neutropenia (n = 1), hypotension (n = 1), and nephrotoxicity (n = 1).
The combination of cisplatin at 80 mg/m2 with docetaxel 35 mg/m2 weekly or 75 mg/m2 every 3 weeks is no better tolerated than older chemotherapy regimens. The most common reason to stop chemotherapy was intolerable fatigue. These results suggest that the most common dose-limiting toxicities are attributable to the cisplatin, given similar problems were encountered whether the docetaxel was delivered as a single dose every 3 weeks or as a lower weekly dose.
Non-small cell lung cancer; Adjuvant chemotherapy; Cisplatin; Docetaxel