Targeting oncogenic drivers (genomic alterations critical to cancer development and maintenance) has transformed the care of patients with lung adenocarcinomas. The Lung Cancer Mutation Consortium was formed to perform multiplexed assays testing adenocarcinomas of the lung for drivers in 10 genes to enable clinicians to select targeted treatments and enroll patients into clinical trials.
To determine the frequency of oncogenic drivers in patients with lung adenocarcinomas and to use the data to select treatments targeting the identified driver(s) and measure survival.
DESIGN, SETTING, AND PARTICIPANTS
From 2009 through 2012, 14 sites in the United States enrolled patients with metastatic lung adenocarcinomas and a performance status of 0 through 2 and tested their tumors for 10 drivers. Information was collected on patients, therapies, and survival.
Tumors were tested for 10 oncogenic drivers, and results were used to select matched targeted therapies.
MAIN OUTCOMES AND MEASURES
Determination of the frequency of oncogenic drivers, the proportion of patients treated with genotype-directed therapy, and survival.
From 2009 through 2012, tumors from 1007 patients were tested for at least 1 gene and 733 for 10 genes (patients with full genotyping). An oncogenic driver was found in 466 of 733 patients (64%). Among these 733 tumors, 182 tumors (25%) had the KRAS driver; sensitizing EGFR, 122 (17%); ALK rearrangements, 57 (8%); other EGFR, 29 (4%); 2 or more genes, 24 (3%); ERBB2 (formerly HER2), 19 (3%); BRAF, 16 (2%); PIK3CA, 6 (<1%); MET amplification, 5 (<1%); NRAS, 5 (<1%); MEK1, 1 (<1%); AKT1, 0. Results were used to select a targeted therapy or trial in 275 of 1007 patients (28%). The median survival was 3.5 years (interquartile range [IQR], 1.96-7.70) for the 260 patients with an oncogenic driver and genotype-directed therapy compared with 2.4 years (IQR, 0.88-6.20) for the 318 patients with any oncogenic driver(s) who did not receive genotype-directed therapy (propensity score–adjusted hazard ratio, 0.69 [95% CI, 0.53-0.9], P = .006).
CONCLUSIONS AND RELEVANCE
Actionable drivers were detected in 64% of lung adenocarcinomas. Multiplexed testing aided physicians in selecting therapies. Although individuals with drivers receiving a matched targeted agent lived longer, randomized trials are required to determine if targeting therapy based on oncogenic drivers improves survival.
Patient-reported outcomes are increasingly used in routine outpatient cancer care to guide clinical decisions and enhance communication. Prior evidence suggests good patient compliance with reporting at scheduled clinic visits, but there is limited evidence about compliance with long-term longitudinal reporting between visits.
Patients and Methods
Patients receiving chemotherapy for lung, gynecologic, genitourinary, or breast cancer at a tertiary cancer center, with access to a home computer and prior e-mail experience, were asked to self-report seven symptomatic toxicities via the Web between visits. E-mail reminders were sent to participants weekly; patient-reported high-grade toxicities triggered e-mail alerts to nurses; printed reports were provided to oncologists at visits. A priori threshold criteria were set to determine if this data collection approach merited further development based on monthly (≥ 75% participants reporting at least once per month on average) and weekly compliance rates (60% at least once per week).
Between September 2006 and November 2010, 286 patients were enrolled (64% were women; 88% were white; median age, 58 years). Mean follow-up was 34 weeks (range, 2 to 214). On average, monthly compliance was 83%, and weekly compliance was 62%, without attrition until the month before death. Greater compliance was associated with older age and higher education but not with performance status. Compliance was greatest during the initial 12 weeks. Symptomatic illness and technical problems were rarely barriers to compliance.
Monthly compliance with home Web reporting was high, but weekly compliance was lower, warranting strategies to enhance compliance in routine care settings.
We hypothesize that among patients with lung cancers the KRAS/EGFR mutation profile and overall survival of “collegiate smokers” (former smokers who smoked between 101 lifetime cigarettes and 5 pack years) are distinct from those of never smokers and former smokers with ≥ 15 pack years.
We collected age, sex, stage, survival, and smoking history for patients evaluated from 2004 to 2009 with advanced stage lung cancers and known KRAS/EGFR status. Mutation profile and overall survival were compared using Fisher’s exact test and log-rank test, respectively.
Data were available for 852 patients with advanced stage lung cancers with known KRAS/EGFR status. 6% were “collegiate smokers”, 36% were never smokers, and 30% were former smokers with ≥ 15 pack years. The mutation profile of “collegiate smokers” (15% KRAS mutations, 27% EGFR mutations) was distinct from those of never smokers (p < .001) and former smokers with ≥ 15 pack years (p < .001)and not significantly different from those of former smokers with 5 to 15 pack years (p = 0.9). Median overall survival for “collegiate smokers” was 25 months, compared to 32 months for never smokers (p = 0.4), 33 months for former smokers with 5–15 pack years (p = 0.48),and 21 months for former smokers with ≥ 15 pack years (p = 0.63).
“Collegiate smokers” with advanced stage lung cancers represent a distinct subgroup of patients with a higher frequency of KRAS mutations and lower frequency of EGFR mutations compared to never smokers. These observations reinforce the recommendation for routine mutation testing for all patients with lung cancers and that no degree of tobacco exposure is safe.
Collegiate Smokers; non-small cell lung cancers; epidermal growth factor receptor mutation; KRAS mutation
The mutually exclusive pattern of the major driver oncogenes in lung cancer suggests that other mutually exclusive oncogenes exist. We performed a systematic search for tyrosine kinase (TK) fusions by screening all TKs for aberrantly high RNA expression levels of the 3′ kinase domain (KD) exons relative to more 5′ exons.
We studied 69 patients (including 5 never smokers and 64 current or former smokers) with lung adenocarcinoma negative for all major mutations in KRAS, EGFR, BRAF, MEK1, and HER2, and for ALK fusions (termed “pan-negative”). A NanoString-based assay was designed to query the transcripts of 90 TKs at two points: 5′ to the KD and within the KD or 3′ to it. Tumor RNAs were hybridized to the NanoString probes and analyzed for outlier 3′ to 5′ expression ratios. Presumed novel fusion events were studied by rapid amplification of cDNA ends (RACE) and confirmatory RT-PCR and FISH.
We identified 1 case each of aberrant 3′ to 5′ ratios in ROS1 and RET. RACE isolated a GOPC-ROS1 (FIG-ROS1) fusion in the former and a KIF5B-RET fusion in the latter, both confirmed by RT-PCR. The RET rearrangement was also confirmed by FISH. The KIF5B-RET patient was one of only 5 never smokers in this cohort.
The KIF5B-RET fusion defines an additional subset of lung cancer with a potentially targetable driver oncogene enriched in never smokers with “pan-negative” lung adenocarcinomas. We also report for the first time in lung cancer the GOPC-ROS1 fusion previously characterized in glioma.
lung cancer; kinase; gene fusion; RET; ROS1; ALK
Bevacizumab improves survival in patients with advanced non-small cell lung cancer (NSCLC). This phase II clinical trial assessed the effects of the addition of bevacizumab to neoadjuvant chemotherapy in resectable non-squamous NSCLC.
Patients with resectable stage IB-IIIA non-squamous NSCLC were treated with bevacizumab followed by imaging 2 weeks later to assess single agent effect. They then received 2 cycles of bevacizumab with 4 cycles of cisplatin and docetaxel followed by surgical resection. Resected patients were eligible for adjuvant bevacizumab. The primary endpoint was the rate of pathological downstaging (decrease from pretreatment clinical stage to post-treatment pathological stage). Secondary endpoints included overall survival, safety and radiologic response.
Fifty patients were enrolled. Thirty-four (68%) were clinical stage IIIA. All 3 doses of neoadjuvant bevacizumab were delivered to 40/50 patients. Six (12%) patients discontinued due to bevacizumab-related adverse events. The rate of downstaging (38%), response to chemotherapy (45%), and perioperative complications (12%) were comparable to historical data. No partial responses were observed to single-agent bevacizumab but 18% developed new intratumoral cavitation with a trend toward improved pathologic response (57% vs. 21%, p=0.07). A major pathologic response (≥90% treatment effect) was associated with survival at 3 years (100% vs. 49%, p=0.01). No patients with KRAS-mutant NSCLC (0/10) had a pathologic response as compared with 11/31 with wild-type KRAS.
While preoperative bevacizumab plus chemotherapy was feasible, it did not improve downstaging in unselected patients. New cavitation after single-agent bevacizumab is a potential biomarker. Alternative strategies are needed for KRAS-mutant tumors.
For patients with resected stage II-III non-small cell lung cancers (NSCLCs), adjuvant cisplatin-based chemotherapy improves survival over surgery alone. For cisplatin ineligible patients, there is no standard adjuvant option. We evaluated drug delivery and toxicity of docetaxel and vinorelbine in patients who could not receive cisplatin.
Patients with completely resected stage IB-III NSCLCs were treated with up to 4 cycles of docetaxel and vinorelbine at the recommended phase II dose. The primary endpoint was drug delivery compared to historical delivery of adjuvant cisplatin plus vinorelbine. Secondary endpoints were toxicity and feasibility.
Twenty-five patients were enrolled. Overall, 13/25 (52%, 95% CI 34 – 70%) completed 4 cycles, and 19/25 (76%, 95% CI 60 – 87%) completed ≥ 3 cycles. Twenty of 25 patients (80%) experienced a Grade 3 or 4 adverse event.
Delivery of this dose and schedule of docetaxel and vinorelbine was difficult with a dose delivery comparable to cisplatin plus vinorelbine, and cisplatin plus docetaxel, used in this setting.
vinorelbine; docetaxel; adjuvant chemotherapy; early-stage non-small cell lung cancer
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.
PIK3CA encodes the p110α subunit of the mitogenic signaling protein phosphatidylinositol 3-kinase (PI3K). PIK3CA mutations in the helical binding domain and the catalytic subunit of the protein have been associated with tumorigenesis and treatment resistance in various malignancies. Characteristics of patients with PIK3CA-mutant lung adenocarcinomas have not been reported.
We examined EGFR, KRAS, BRAF, HER2, PIK3CA, AKT1, NRAS, MEK1, and ALK in patients with adenocarcinoma of the lung to identify driver mutations. Clinical data were obtained from the medical records of individuals with mutations in PIK3CA.
Twenty-three of 1125 (2%, 95% confidence interval (CI) 1–3%) patients had a mutation in PIK3CA, 12 in Exon 9 (10 E545K, 2 E542K) and 11 in Exon 20 (3 H1047L, 8 H1047R). The patients (57% women) had a median age of 66 at diagnosis (range 34–78). Eight patients (35%) were never smokers. Sixteen of 23 (70%, 95% CI 49 – 86%) had coexisting mutations in other oncogenes - 10 KRAS, 1 MEK1, 1 BRAF, 1 ALK rearrangement, and 3 EGFR exon 19 deletions.
We conclude that PIK3CA mutations occur in lung adenocarcinomas, usually concurrently with EGFR, KRAS, and ALK. The impact of PIK3CA mutations on the efficacy of targeted therapies such as erlotinib and crizotinib is unknown. Given the high frequency of overlapping mutations, comprehensive genotyping should be performed on tumor specimens from patients enrolling on clinical trials of PI3K and other targeted therapies.
lung adenocarcinoma; oncogene; PIK3CA
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.
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
Lung adenocarcinomas can be distinguished by identifying mutated driver oncogenes including EGFR and KRAS. Mutations in EGFR are associated with both an improved survival as well as response to treatment with erlotinib and gefitinib. However, the prognostic significance of KRAS has not been evaluated in large numbers of patients and remains controversial. We examined the association of EGFR and KRAS mutations with survival among patients with advanced lung adenocarcinomas.
We analyzed data from patients with advanced lung adenocarcinomas and known EGFR and KRAS mutation status evaluated between 2002 and 2009. We collected clinical variables including age, gender, Karnofsky Performance Status, smoking history, and treatment history. Overall survival from diagnosis of advanced disease was analyzed using Kaplan-Meier and Cox proportional hazard methods.
We evaluated 1036 patients, including 610 women (59%) and 344 never-smokers (33%). Patients had a median age of 65 (range, 25–92) and the majority (81%) had a KPS ≥80%. In multivariate analysis, EGFR mutations were associated with a longer overall survival (HR= 0.6, p<0.001) and KRAS mutations with a shorter survival (HR=1.21, p=0.048).
KRAS mutations predict shorter survival for patients with advanced lung adenocarcinomas. The presence of EGFR and KRAS mutations define distinct subsets of patients with lung adenocarcinomas, and should be determined in patients upon diagnosis of advanced disease. Clinical trial reports should include EGFR and KRAS mutation status along with other prognostic factors.
non-small cell lung cancer; adenocarcinomas; EGFR; KRAS; survival; prognostic factors
EGFR mutations underlie the sensitivity of lung cancers to erlotinib and gefitinib and can occur in any patient with this illness. Here we examine the frequency of EGFR mutations in smokers and men.
We determined the frequency of EGFR mutations and characterized their association with cigarette smoking status and male sex.
We tested 2,142 lung adenocarcinoma specimens for the presence of EGFR exon 19 deletions and L858R. EGFR mutations were found in 15% of tumors from former smokers (181 of 1,218; 95% CI, 13% to 17%), 6% from current smokers (20 of 344; 95% CI, 4% to 9%), and 52% from never smokers (302 of 580; 95% CI, 48% to 56%; P < .001 for ever v never smokers). EGFR mutations in former or current smokers represented 40% of all those detected (201 of 503; 95% CI, 36% to 44%). EGFR mutations were found in 19% (157 of 827; 95% CI, 16% to 22%) of tumors from men and 26% (346 of 1,315; 95% CI, 24% to 29%) of tumors from women (P < .001). EGFR mutations in men represented 31% (157 of 503; 95% CI, 27% to 35%) of all those detected.
A large number of EGFR mutations are found in adenocarcinoma tumor specimens from men and people who smoked cigarettes. If only women who were never smokers were tested, 57% of all EGFR mutations would be missed. Testing for EGFR mutations should be considered for all patients with adenocarcinoma of the lung at diagnosis, regardless of clinical characteristics. This strategy can extend the use of EGFR tyrosine kinase inhibitors to the greatest number individuals with the potential for substantial benefit.
The detection of mutations in the epidermal growth factor receptor (EGFR) gene, which predict sensitivity to treatment with EGFR tyrosine kinase inhibitors (TKIs), represents a major advance in the treatment of lung adenocarcinoma. KRAS mutations confer resistance to EGFR -TKIs. The prevalence of these mutations in African-American patients has not been thoroughly investigated.
We collected formalin-fixed, paraffin-embedded material from resected lung adenocarcinomas from African-American patients at three institutions for DNA extraction. The frequencies of EGFR exon 19 deletions, exon 21 L858R substitutions and KRAS mutations in tumor specimens from African-American patients were compared to data in Caucasian patients (n=476).
EGFR mutations were detected in 23 of the 121 specimens from African-American patients (19%, 95% CI 13–27%), while KRAS mutations were found in 21 (17%, 95% CI 12−25%). There was no significant difference between frequencies of EGFR mutations comparing African-American and Caucasian patients, 19% vs. 13% (61/476, 95% CI 10–16%) (p=0.11). KRAS mutations were more likely among Caucasians, 26% (125/476, 95% CI 23−30%) (p=0.04).
This is the largest study to date examining the frequency of mutations in lung adenocarcinomas in African-Americans. Although KRAS mutations were somewhat less likely, there was no difference between the frequencies of EGFR mutations in African-American patients as compared to Caucasians. These results suggest that all patients with advanced lung adenocarcinomas should undergo mutational analysis prior to initiation of therapy.
EGFR mutation; KRAS; African-Americans; racial differences
In contrast to other primary EGFR mutations in lung adenocarcinomas, insertions in exon 20 of EGFR have been generally associated with resistance to EGFR tyrosine kinase inhibitors. Their molecular spectrum, clinicopathologic characteristics and prevalence are not well established. Tumors harboring EGFR exon 20 insertions were identified through an algorithmic screen of 1500 lung adenocarcinomas. Cases were first tested for common mutations in EGFR (exons 19 and 21) and KRAS (exon 2) and, if negative, further analyzed for EGFR exon 20 insertions. All samples underwent extended genotyping for other driver mutations in EGFR, KRAS, BRAF, NRAS, PIK3CA, MEK1 and AKT by mass spectrometry; a subset was evaluated for ALK rearrangements. We identified 33 EGFR exon 20 insertion cases (2.2%, 95% CI 1.6 to 3.1%), all mutually exclusive with mutations in the other genes tested (except PIK3CA). They were more common among never-smokers (p<0.0001). There was no association with age, sex, race, or stage. Morphologically, tumors were similar to those with common EGFR mutations, but with frequent solid histology. Insertions were highly variable in position and size, ranging from 3 to 12bp, resulting in 13 different insertions which, by molecular modeling, are predicted to have potentially different effects on erlotinib binding. EGFR exon 20 insertion testing identifies a distinct subset of lung adenocarcinomas, accounting for at least 9% of all EGFR mutated cases, representing the third most common type of EGFR mutation after exon 19 deletions and L858R. Insertions are structurally heterogeneous with potential implications for response to EGFR inhibitors.
EGFR exon 20; EGFR; epidermal growth factor receptor; lung adenocarcinoma; driver oncogenes
Despite the growing number of elderly patients with lung cancers, we lack adequate information about how best to treat them. A phase III trial demonstrated a survival benefit of doublet chemotherapy in elderly patients with lung cancers compared to single agents at the cost of increased toxicity. We undertook this study to identify and describe chemotherapy-associated toxicity patterns among elderly patients treated for lung cancers.
Materials and methods
We reviewed records of patients age 70 or older with metastatic lung cancers who received initial chemotherapy at the Memorial Sloan-Kettering Cancer Center during 2008 and 2009.
We identified 70 patients: 28 (40%) completed at least 4 cycles of chemotherapy without dose reduction but 31 (44%) required hospitalization for toxicity. Baseline albumin <3.5 g/dL and anemia were associated with grade 3–5 chemotherapy-associated toxicity. Also, an increase in platelets from cycle 1 to cycle 2 was associated with chemotherapy-associated toxicity. No other statistically significant associations between chemotherapy-associated toxicity and putative biologic and functional risk factors, including age and performance status, were identified.
Patients deemed eligible for chemotherapy by their physicians were just as likely to have severe chemotherapy-associated toxicity requiring hospitalization as to finish an initial course of therapy without any serious problems. An increase in platelet count from cycle 1 to cycle 2 was associated with increased toxicity. Additional research, such as exploration of inflammatory cytokines (PDGF, IL6, and IGF-1) to identify the mechanisms of chemotherapy tolerance and prospective evaluation and validation of existing metrics, is needed so that all patients can be appropriately risk stratified.
Elderly; Chemotherapy toxicity; Lung cancers; Geriatric assessment
Activating mutations in the tyrosine kinase domain of HER2 (ERBB2) have been described in a subset of lung adenocarcinomas (ADCs) and are mutually exclusive with EGFR and KRAS mutations. The prevalence, clinicopathologic characteristics, prognostic implications, and molecular heterogeneity of HER2-mutated lung ADCs are not well established in US patients.
Lung ADC samples (n=1478) were first screened for mutations in EGFR (exons 19 and 21) and KRAS (exon 2) and negative cases were then assessed for HER2 mutations (exons 19–20) using a sizing assay and mass spectrometry. Testing for additional recurrent point mutations in EGFR, KRAS, BRAF, NRAS, PIK3CA, MEK1 and AKT was performed by mass spectrometry. ALK rearrangements and HER2 amplification were assessed by FISH.
We identified 25 cases with HER2 mutations, representing 6% of EGFR/KRAS/ALK-negative specimens. Small insertions in exon 20 accounted for 96% (24/25) of the cases. Compared to insertions in EGFR exon 20, there was less variability, with 83% (20/24) being a 12bp insertion causing duplication of amino acids YVMA at codon 775. Morphologically, 92% (23/25) were moderately or poorly differentiated ADC. HER2 mutation was not associated with concurrent HER2 amplification in 11 cases tested for both. HER2 mutations were more frequent among never-smokers (p<0.0001) but there were no associations with sex, race, or stage.
HER2 mutations identify a distinct subset of lung ADCs. Given the high prevalence of lung cancer worldwide and the availability of standard and investigational therapies targeting HER2, routine clinical genotyping of lung ADC should include HER2.
HER2; ERBB2; lung adenocarcinoma; EGFR; driver oncogenes
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
The molecular epidemiology of most EGFR and KRAS mutations in lung cancer remains unclear.
We genotyped 3026 lung adenocarcinomas for the major EGFR (exon 19 deletions and L858R) and KRAS (G12, G13) mutations and examined correlations with demographic, clinical and smoking history data.
EGFR mutations were found in 43% of never smokers (NS) and in 11% of smokers. KRAS mutations occurred in 34% of smokers and in 6% of NS. In patients with smoking histories up to 10 pack-years, EGFR predominated over KRAS. Among former smokers with lung cancer, multivariate analysis showed that, independent of pack-years, increasing smoking-free years raise the likelihood of EGFR mutation. NS were more likely than smokers to have KRAS G>A transition mutation (mostly G12D) (58% vs. 20%, p=0.0001). KRAS G12C, the most common G>T transversion mutation in smokers, was more frequent in women (p=0.007) and these women were younger than men with the same mutation (median 65 vs. 69, p=0.0008) and had smoked less.
The distinct types of KRAS mutations in smokers vs. NS suggest that most KRAS-mutant lung cancers in NS are not due to secondhand smoke exposure. The higher frequency of KRAS G12C in women, their younger age, and lesser smoking history together support a heightened susceptibility to tobacco carcinogens.
lung cancer; tobacco; EGFR; KRAS; molecular epidemiology
We sought to determine the frequency and clinical characteristics of patients with lung cancer harboring NRAS mutations. We used preclinical models to identify targeted therapies likely to be of benefit against NRAS mutant lung cancer cells.
Patients and Methods
We reviewed clinical data from patients whose lung cancers were identified at 6 institutions or reported in the Catalogue of Somatic Mutations in Cancer (COSMIC) to harbor NRAS mutations. 6 NRAS mutant cell lines were screened for sensitivity against inhibitors of multiple kinases (i.e. EGFR, ALK, MET, IGF-1R, BRAF, PI3K and MEK).
Among 4562 patients with lung cancers tested, NRAS mutations were present in 30 (0.7%; 95% confidence interval, 0.45% to 0.94%); 28 of these had no other driver mutations. 83% had adenocarcinoma histology with no significant differences in gender. While 95% of patients were former or current smokers, smoking-related G:C>T:A transversions were significantly less frequent in NRAS mutated lung tumors compared to KRAS-mutant NSCLCs (NRAS: 13% (4/30), KRAS: 66% (1772/2733), p<0.00000001). 5 of 6 NRAS mutant cell lines were sensitive to the MEK inhibitors, selumetinib and trametinib, but not to other inhibitors tested.
NRAS mutations define a distinct subset of lung cancers (~1%) with potential sensitivity to MEK inhibitors. While NRAS mutations are more common in current/former smokers, the types of mutations are not those classically associated with smoking.
NRAS mutation; EGFR mutation; KRAS mutation; lung cancer; non-small cell lung cancer; driver mutation; MEK inhibitor; erlotinib; gefitinib; crizotinib
Although progression-based endpoints, such as progression-free survival, are often key clinical trial endpoints for anticancer agents, the clinical meaning of “objective progression” is much less certain. As scrutiny of progression-based endpoints in clinical trials increases, it should be remembered that the Response Evaluation Criteria In Solid Tumors (RECIST) progression criteria were not developed as a surrogate for survival. Now that progression-free survival has come to be an increasingly important trial endpoint, the criteria that define progression deserve critical evaluation to determine whether alternate definitions of progression might facilitate the development of stronger surrogate endpoints and more meaningful trial results. In this commentary, we review the genesis of the criteria for progression, highlight recent data that question their value as a marker of treatment failure, and advocate for several research strategies that could lay the groundwork for a clinically validated definition of disease progression in solid tumor oncology.
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
Pulmonary large cell carcinoma - a diagnostically and clinically controversial entity - is defined as a non-small cell carcinoma lacking morphologic differentiation as either adenocarcinoma or squamous cell carcinoma, but suspected to represent an end-stage of poor differentiation of these tumor types. Given the recent advances in immunohistochemistry to distinguish adenocarcinoma and squamous cell carcinoma, and the recent insights that several therapeutically-relevant genetic alterations are distributed differentially in these tumors, we hypothesized that immunophenotyping may stratify large cell carcinomas into subsets with distinct profiles of targetable driver mutations. We therefore analyzed 102 large cell carcinomas by immunohistochemistry for TTF-1 and ΔNp63/p40 as classifiers for adenocarcinoma and squamous cell carcinoma, respectively, and correlated the resulting subtypes with 9 therapeutically-relevant genetic alterations characteristic of adenocarcinoma (EGFR, KRAS, BRAF, MAP2K1/MEK1, NRAS, ERBB2/HER2 mutations and ALK rearrangements) or more common in squamous cell carcinoma (PIK3CA and AKT1 mutations). The immunomarkers classified large cell carcinomas as variants of adenocarcinoma (n=62; 60%), squamous cell carcinoma (n=20; 20%), or marker-null (n=20; 20%). Genetic alterations were found in 38 cases (37%), including EGFR (n=1), KRAS (n=30), BRAF (n=2), MAP2K1 (n=1), ALK (n=3) and PIK3CA (n=1). All molecular alterations characteristic of adenocarcinoma occurred in tumors with immunoprofiles of adenocarcinoma or marker-null, but not in tumors with squamous immunoprofiles (combined mutation rate 50% vs 30% vs 0%, respectively; P<0.001), whereas the sole PIK3CA mutation occurred in a tumor with squamous profile (5%). Furthermore, marker-null large cell carcinomas were associated with significantly inferior disease-free (P<0.001) and overall (P=0.001) survival. In conclusion, the majority (80%) of large cell carcinomas can be classified by immunomarkers as variants of adenocarcinoma or squamous cell carcinoma, which stratifies these tumors into subsets with a distinct distribution of driver mutations and distinct prognoses. These findings have practical implications for diagnosis, predictive molecular testing and therapy selection.
large cell carcinoma; TTF-1; ΔNp63/p40; EGFR; KRAS; ALK
Patients with stage IV lung adenocarcinoma and EGFR mutation derive clinical benefit from treatment with EGFR tyrosine kinase inhibitors (TKI). Whether treatment with TKI improves outcomes in patients with resected lung adenocarcinoma and EGFR mutation is unknown.
Data were analyzed from a surgical database of patients with resected lung adenocarcinoma harboring EGFR exon 19 or 21 mutations. In a multivariate analysis, we evaluated the impact of treatment with adjuvant TKI.
The cohort consists of 167 patients with completely resected stage I–III lung adenocarcinoma. 93 patients (56%) had exon 19 del, 74 patients (44%) had exon 21 mutations, 56 patients (33%) received perioperative TKI. In a multivariate analysis controlling for sex, stage, type of surgery and adjuvant platinum chemotherapy, the 2-year DFS was 89% for patients treated with adjuvant TKI compared with 72% in control group (hazard ratio [HR] = 0.53; 95% confidence interval [CI] 0.28 to 1.03; p = 0.06). The 2-year OS was 96% with adjuvant EGFR TKI and 90% in the group that did not receive TKI (HR 0.62; 95% CI 0.26 to 1.51; p = 0.296).
Compared to patients who did not receive adjuvant TKI, we observed a trend toward improvement in disease free survival among individuals with resected stages I–III lung adenocarcinomas harboring mutations in EGFR exons 19 or 21 who received these agents as adjuvant therapy. Based on these data, 320 patients are needed for a randomized trial to prospectively validate this DFS benefit.
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