EGFR-mutant Adenocarcinoma Research Articles

The Allelic Context of the C797S Mutation Acquired upon Treatment with Third-Generation EGFR Inhibitors Impacts Sensitivity to Subsequent Treatment Strategies.

A secondary EGFR mutation, T790M, is the most common resistance mechanism in EGFR-mutant adenocarcinomas that have progressed on erlotinib. Third-generation EGFR inhibitors capable of inhibiting mutant EGFR with T790M produce responses in nearly two thirds of patients. However, acquired resistance mechanisms in patients treated with these drugs are yet to be described. To study acquired resistance to third-generation EGFR inhibitors, T790M-positive cells derived from an erlotinib-resistant cancer were made resistant to a third-generation TKI and then characterized using cell and molecular analyses. Cells resistant to a third-generation TKI acquired an additional EGFR mutation, C797S, which prevented suppression of EGFR. Our results demonstrate that the allelic context in which C797S was acquired may predict responsiveness to alternative treatments. If the C797S and T790M mutations are in trans, cells will be resistant to third-generation EGFR TKIs, but will be sensitive to a combination of first- and third-generation TKIs. If the mutations are in cis, no EGFR TKIs alone or in combination can suppress activity. If C797S develops in cells wild-type for T790 (when third-generation TKIs are administered in the first-line setting), the cells are resistant to third-generation TKIs, but retain sensitivity to first-generation TKIs. Mutation of C797S in EGFR is a novel mechanism of acquired resistance to third-generation TKIs. The context in which the C797S develops with respect to the other EGFR alleles affects the efficacy of subsequent treatments.

Metabolic phenotype of stage IV lung adenocarcinoma: relationship with epidermal growth factor receptor mutation.

Epidermal growth factor receptor (EGFR) mutation status is important in treatment stratification of stage IV lung adenocarcinoma. We evaluated the relationship between the SUV max measured on PET/CT and EGFR mutations and the value of SUV max in predicting EGFR mutations. Seventy-one stage IV lung adenocarcinoma patients with verified EGFR mutations (48 EGFR mutant, 23 EGFR wild-type) having pretreatment PET/CT were retrospectively reviewed. SUV max values of the primary tumors (n = 71), nodal (n = 246), and distant metastases (n = 618) were compared between EGFR-mutant and EGFR wild-type adenocarcinoma by Mann-Whitney U test. The receiver operating characteristics curve and logistic regression were performed for factors, SUV max, age, sex, and smoking status. The significant predictors were assessed individually and in combination in discriminating EGFR mutation status. Statistical significance was assumed at P < 0.05 RESULTS: The metastases in EGFR-mutant adenocarcinoma had lower SUV max than EGFR wild-type adenocarcinoma (nodal SUV max 3.4 vs 5.5, distant metastasis SUV max 3.4 vs 4.7, respectively; both P < 0.001). No statistical significant difference was observed in the primary tumors SUV max between the 2 groups (SUV max 7.4 vs 8.1, P = 0.311). A receiver operating characteristics-derived SUV max less than or equal to 7.2 in metastasis could separate EGFR-mutant from EGFR wild-type adenocarcinoma (area under the curve, 0.71-0.74; P < 0.05). SUV max was a significant independent predictor, and when combined with age, sex, and smoking status, it is highly predictive of EGFR mutation status (area under the curve, 0.90). Low SUV max in the metastasis favors the presence of EGFR mutations in stage IV lung adenocarcinoma, and SUV max is an independent predictor of EGFR mutations.

EGFR遺伝子変異を認めるもゲフィチニブに早期獲得耐性を示した粘液産生肺腺癌の1例

EGFR遺伝子変異を認めるもゲフィチニブに早期獲得耐性を示した粘液産生肺腺癌の1例

Analysis of BIM (BCL-2 like 11 gene) deletion polymorphism in Chinese non-small cell lung cancer patients.

Drug resistance significantly weakens the efficacy of cancer treatment, and the BIM (also known as the BCL2L11 gene) deletion polymorphism has been identified as a potential biomarker for drug resistance. In this retrospective study, we included a total of 290 patients with advanced non-small cell lung cancer (NSCLC) who received treatment with epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) and chemotherapy. The BIM deletion polymorphism of each patient was detected by polymerase chain reaction. EGFR mutations were detected by denaturing high-performance liquid chromatography methods and the amplification refractory mutation system. The BIM deletion polymorphism was detected in 45/290 (15.5%) Chinese NSCLC patients. No associations were observed between the BIM deletion and clinic-pathologic characteristics of patients. The BIM deletion polymorphism was predictive of shorter progression-free survival in Chinese patients with EGFR-mutant adenocarcinoma and who were treated with EGFR-TKIs (7.30 vs. 9.53 months, P = 0.034). Additionally, we found that the BIM deletion polymorphism was an effective predictor of short progression-free survival in individuals with EGFR-mutant NSCLC and treated with chemotherapy containing pemetrexed (3.32 vs. 5.30, P = 0.012) or second-/beyond-line chemotherapy containing taxanes (1.53 vs. 2.61 months, P = 0.025). The BIM deletion was not correlated with overall survival. The BIM deletion polymorphism occurs in 15.5% of Chinese NSCLC patients, and is a biomarker for resistance to TKIs and chemotherapy. However, BIM deletion was not a decisive factor in overall survival.

Abstract 1531: Cross-entity mutation analysis of lung neuroendocrine tumors sheds light into their molecular origin and identifies new therapeutic targets

Abstract Lung neuroendocrine tumors (LNETs) comprise small-cell lung cancer (SCLC), large-cell neuroendocrine tumors (LCNEC), and pulmonary carcinoids (PCA), and account for 25% of all lung cancer cases. The low 5-year survival rate of the highly aggressive LNETs (SCLC and LCNEC) combined with the lack of an effective treatment, suggest that understanding how these tumors arise and identifying therapeutic targets are unmet needs. We performed genome/exome, and transcriptome sequencing of 29 SCLC (Ref.1), 60 LCNEC, and 45 PCA to better understand their molecular origin and identify altered genes that may offer therapeutic opportunities. In contrast to SCLC and LCNEC, we found that RB1 and TP53 mutations were rare events in PCA suggesting that PCA are not early progenitor lesions of SCLC or LCNEC, but arise through independent mechanisms. Moreover, GSEA analysis showed that genes of the RB1 pathway were downregulated in SCLC but not in PCA. Our data also show that inactivation of chromatin-remodeling genes, specifically genes involved in histone methylation and subunits of the SWI/SNF complex, is sufficient to drive transformation in PCA. In a preliminary analysis of 15 LCNEC (Ref.2) we observed a predominance of mutations typical of SCLC, such as RB1, TP53, and CREBBP/EP300. In this larger series, we additionally found samples with mutations frequent in adenocarcinoma (AD) or squamous (SQ) lung cancer. We could then distinguish two well-defined groups of LCNEC: a SCLC-like group, carrying MYCL1 amplifications and mutations in both RB1 and TP53 genes; and an AD/SQ-like group, harbouring CDKN2A deletions, TTF1 amplifications, and frequent mutations in KEAP1 and STK11. Interestingly, RB1, STK11, and KEAP1 mutations happened in an almost mutually exclusive way. These data suggest that LCNEC might represent an evolutionary trunk that can branch to SCLC or AD/SQ, and also that LNETs and non-LNETs are not completely different entities. This is already suggested by the fact that one of the resistance mechanisms of EGFR-mutant adenocarcinomas to tyrosine-kinase inhibitors is through trans-differentiation to SCLC (Ref.3). Finally, we also identified new targetable driver genes in SCLC and LCNEC: FGFR1 amplifications were observed in 6% and 18% of the cases respectively; PTEN mutations were identified in 10% of the SCLC cases; and interestingly, one of the LCNEC samples (belonging to the SCLC-like group) harboured an activating RFWD2-NTRK1 fusion gene suggesting that fusions affecting NTRK1 may not only be a targetable opportunity for AD (Ref.4) but also for LCNEC and, based on the molecular similarities, also SCLC. (1) Peifer and Fernandez-Cuesta et al. Nat Genetics 2012 (2) The Clinical Lung Cancer Genome Project (CLCGP) and Network Genomic Medicine (NGM) Sci Transl Med 2013 (3) Sequist et al., Sci Transl Med 2011 (4) Vaishnavi et al. Nat Medicine 2013 Citation Format: Lynnette Fernandez-Cuesta, Martin Peifer, Xin Lu, Danila Seidel, Thomas Zander, Frauke Leenders, Luka Ozretić, Odd-Terje Brustugun, John K. Field, Gavin Wright, Benjamin Solomon, Reinhard Buettner, Christian Brambilla, Elisabeth Brambilla, Roman K. Thomas. Cross-entity mutation analysis of lung neuroendocrine tumors sheds light into their molecular origin and identifies new therapeutic targets. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1531. doi:10.1158/1538-7445.AM2014-1531

Clinicopathologic and prognostic significance of c-MYC copy number gain in lung adenocarcinomas.

Background:c-MYC copy number gain (c-MYC gain) has been associated with aggressive behaviour in several cancers. However, the role of c-MYC gain has not yet been determined in lung adenocarcinomas classified by genetic alterations in epidermal growth factor receptor (EGFR), KRAS, and anaplastic lymphoma kinase (ALK) genes. We investigated the clinicopathologic and prognostic significance of c-MYC gain for disease-free survival (DFS) and overall survival (OS) according to EGFR, KRAS, and ALK gene status and stages in lung adenocarcinomas.Methods:In 255 adenocarcinomas resected in Seoul National University Bundang Hospital from 2003 to 2009, fluorescence in situ hybridisation (FISH) with c-MYC probe and centromeric enumeration probe 8 (CEP8) was analysed using tissue microarray containing single representative core per each case. EGFR (codon 18 to 21) and KRAS (codon 12, 13, and 61) mutations were analysed by polymerase chain reaction and direct sequencing method from formalin-fixed, paraffin-embedded tissue sections. ALK rearrangement was determined by FISH method. c-MYC gain was defined as >2 copies per nucleus, chromosome 8 gain as ⩾3 copies per nucleus, and gain of c-MYC:CEP8 ratio (hereafter, c-MYC amplification) as ⩾2.Results:We observed c-MYC gain in 20% (51 out of 255), chromosome 8 gain in 5.5% (14 out of 255), c-MYC amplification in 2.4% (6 out of 255), EGFR mutation in 49.4% (118 out of 239), KRAS mutation in 5.7% (7 out of 123), and ALK rearrangement in 4.9% (10 out of 205) of lung adenocarcinomas. c-MYC gain was observed in 19% (22 out of 118) of patients with lung adenocarcinomas with an EGFR mutation, but not in any patients with a KRAS mutation, or an ALK rearrangement. c-MYC gain (but not chromosome 8 gain or c-MYC amplification) was an independent poor-prognostic factor in the full cohort of lung adenocarcinoma (P=0.022, hazard ratio (HR)=1.71, 95% confidence interval (CI), 1.08–2.69 for DFS; P=0.032, HR=2.04, 95% CI, 1.06–3.91 for OS), as well as in stage I subgroup (P=0.023, HR=4.70, 95% CI, 1.24–17.78 for DFS; P=0.031, HR=4.65, 95% CI, 1.15–18.81 for OS), and in EGFR-mutant subgroup (P=0.022; HR=2.14; 95% CI, 1.11–4.10 for DFS).Conclusions:c-MYC gain (but not chromosome 8 gain or c-MYC amplification) was an independent poor-prognostic factor for DFS and OS in lung adenocarcinomas, both in full cohort and stage I cancer, and possibly for DFS in EGFR-mutant adenocarcinomas. Additional studies are required to determine if patients with lung adenocarcinoma with c-MYC gain are candidates for additional first-line treatment to mitigate their increased risk for disease progression and death.

Erlotinib Versus Radiation Therapy for Brain Metastases in Patients With EGFR-Mutant Lung Adenocarcinoma

Radiation therapy (RT) is the principal modality in the treatment of patients with brain metastases (BM). However, given the activity of EGFR tyrosine kinase inhibitors in the central nervous system, it is uncertain whether upfront brain RT is necessary for patients with EGFR-mutant lung adenocarcinoma with BM. Patients with EGFR-mutant lung adenocarcinoma and newly diagnosed BM were identified. 222 patients were identified. Exclusion criteria included prior erlotinib use, presence of a de novo erlotinib resistance mutation, or incomplete data. Of the remaining 110 patients, 63 were treated with erlotinib, 32 with whole brain RT (WBRT), and 15 with stereotactic radiosurgery (SRS). The median overall survival (OS) for the whole cohort was 33 months. There was no significant difference in OS between the WBRT and erlotinib groups (median, 35 vs 26 months; P=.62), whereas patients treated with SRS had a longer OS than did those in the erlotinib group (median, 64 months; P=.004). The median time to intracranial progression was 17 months. There was a longer time to intracranial progression in patients who received WBRT than in those who received erlotinib upfront (median, 24 vs 16 months, P=.04). Patients in the erlotinib or SRS group were more likely to experience intracranial failure as a component of first failure, whereas WBRT patients were more likely to experience failure outside the brain (P=.004). The survival of patients with EGFR-mutant adenocarcinoma with BM is notably long, whether they receive upfront erlotinib or brain RT. We observed longer intracranial control with WBRT, even though the WBRT patients had a higher burden of intracranial disease. Despite the equivalent survival between the WBRT and erlotinib group, this study underscores the role of WBRT in producing durable intracranial control in comparison with a targeted biologic agent with known central nervous system activity.

Year in review 2013: Lung cancer, respiratory infections, tuberculosis, cystic fibrosis, pleural diseases, bronchoscopic intervention and imaging

This Year in Review examines the most relevant articles published on lung cancer, respiratory infections, tuberculosis (TB), cystic fibrosis (CF), pleural diseases, and interventional pulmonology and imaging in Respirology and other respiratory medicine journals during 2013. Important findings are highlighted with comments in the following sections, each of which was contributed by an author as named in the beginning of each section.

Abstract C189: CD24 plays an important role on NSCLC cell functions relevant to tumor growth.

Abstract CD24 is a heavily glycosylated glycosylphosphatidylinositol-anchored protein that is over-expressed in many different tumor types including lung cancer (NSCLC and SCLC), and has been shown to correlate with disease progression. Around 70% of the primary NSCLC was shown to overexpress CD24 and these patients tended to have higher risk of disease progression. CD24 plays a role in regulating cancer cell proliferation and tumor microenvironment interactions. The mechanism by which CD24 regulates cell survival and proliferation is not very well understood. It is better known that CD24 modulates cancer cell adhesion to the vasculature wall and cancer cell-platelet thrombi formation by its binding to P-selectin expressed on activated platelets and endothelial cells. The aim of this study was to investigate CD24 as a target for NSCLC therapy. In order to assess CD24 as a target for NSCLC, we have investigated CD24 expression at the mRNA level in NSCLC tissues. CD24 mRNA was shown to be expressed both in squamous cell carcinoma, and in KRas and EGFR mutant adenocarcinoma tumors (123/168 samples). In order to investigate if CD24 has a critical role in cancer cell functions, we performed knock-down experiments using siRNA and several different NSCLC lines. CD24 siRNA treatment significantly affected NSCLC cancer cell line survival in vitro, by causing cell viability inhibition of 38 to 92% (depending on the cell line tested and the siRNA used), as measured by MTS assay. CD24 knockdown also caused inhibition of H358 colony formation in a soft agar anchorage-independent growth assay. Moreover, CD24 knock-down caused a 4-13 fold increase in apoptosis, as measured by propidium iodide staining. To further test the impact of CD24 knock-down on cell viability, we developed an in vitro 3D model system that is more reflective of the tumor microenvironment, containing basement membrane extract and lung cancer associated fibroblasts (CAFs) in co-culture with H358 lung tumor cells. CD24 knock-down significantly decreased cell viability and inhibited spheroid formation by H358 lung cancer cells grown alone or with CAFs. The migration of H358 cells in the scratch-wound assay was also significantly inhibited by CD24 knock down. Finally, using the H358 xenograft tumor model, we tested the effect of an anti-mouse CD24 antibody (SWA11). Treatment was initiated on the same day of cell implantation and repeated twice a week for 2 weeks. SWA11 significantly inhibited tumor formation. Together, these results demonstrate that CD24 expression affects both the viability and motility of lung cancer cell lines and is a potential target for NSCLC treatment. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):C189. Citation Format: Luciana F. Macedo, Elizabeth Kaiser, Haiyan Jiang, Hillary Millar, E. Christine Pietsch, Fred Kaplan, Diana Wiley, Linda A. Snyder, Debbie Marshall. CD24 plays an important role on NSCLC cell functions relevant to tumor growth. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr C189.

FDG‐PET SUV‐max values do not correlate with epidermal growth factor receptor mutation status in lung adenocarcinoma

Previous reports suggest a correlation between positron emission tomography with fluorodeoxyglucose maximum standardized uptake value (SUVmax) and epidermal growth factor receptor (EGFR) mutation status in lung cancer. We analysed positron emission tomography with fluorodeoxyglucose SUVmax in 14 patients with EGFR mutations, and a control group of 14 subjects with wild-type EGFR adenocarcinomas. The mean SUV value was 10.7 for EGFR-mutated adenocarcinomas and 9.9 for wild-type tumours. There was no correlation between SUV values and EGFR mutation status. Omitting EGFR testing in lung cancers with low SUVmax is not appropriate.

Lessons Learned From Lung Cancer Genomics: The Emerging Concept of Individualized Diagnostics and Treatment

The advent of novel therapeutics that specifically target signaling pathways activated by genetic alterations has revolutionized the way patients with lung cancer are treated. Although only few and largely ineffective chemotherapeutic regimens were available 10 years ago, a lung tumor diagnosed today requires extensive pathologic subtyping and diagnosis of genome alterations to afford more effective treatment (eg, in EGFR-mutant adenocarcinoma). This change of paradigm has several profound implications, ranging from preclinical work on the mechanism of action to a novel, more biologically oriented taxonomy and from genome diagnostics to trial design. Here, we have summarized these developments into six conceptual paradigms that illustrate the transition from empirical cancer medicine to mechanistically based individualized oncology.

How Sensitive Are Epidermal Growth Factor Receptor–Tyrosine Kinase Inhibitors for Squamous Cell Carcinoma of the Lung Harboring EGFR Gene–Sensitive Mutations?

Epidermal growth factor receptor (EGFR) mutations are found mostly in adenocarcinoma, and rarely in squamous cell carcinoma (SQC). Little is known about SQC harboring EGFR mutations. Between April 2006 and October 2010, we investigated the incidence of EGFR activating mutations in SQC of the lung using the peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp method. The efficacy of EGFR-tyrosine kinase inhibitors (TKIs) was retrospectively evaluated in patients with EGFR-mutated SQC. Further pathologic analyses were performed using immunohistochemistry. Thirty-three of 249 patients with SQC (13.3%) had EGFR mutations, including exon 19 deletion (19 of 33 patients, 58%), L858R point mutation in exon 21 (12 of 33, 36%), and G719S point mutation in exon 18 (2 of 33, 6%). Twenty of these 33 patients received EGFR-TKI therapy, and five of these 20 responded to EGFR-TKIs with a response rate of 25.0% (95% confidence interval [CI], 8.7%-49.1%). The patients' median progression-free survival and median overall survival were 1.4 months (95% CI, 0.7-5.8 months) and 14.6 months (95% CI, 2.9-undeterminable months), respectively. Approximately one third of the EGFR-mutated SQC patients achieved progression-free survival for longer than 6 months. Some of these patients had high carcinoembryonic antigen levels or a history of never smoking, or were positive for thyroid transcription factor-1. Although EGFR-TKIs seem to be generally less effective in EGFR-mutated SQC than in EGFR-mutated adenocarcinoma, some EGFR-mutated SQC patients can obtain clinical benefit from EGFR-TKIs. To better identify these patients, not only EGFR mutation status, but also clinical factors and pathologic findings should be taken into consideration.

412O - Tyrosine Kinase Inhibitors without Radiation Therapy for Brain Metastases from Egfr-Mutant Adenocarcinoma of Lung

ABSTRACT Backgrounds Whole-brain radiation therapy (WBRT) and/or stereotactic radiosurgery (SRS) are standard treatments for brain metastases (BMs). However, patients (pts) treated by radiation therapy (RT) have a risk of decline in learning and memory functions. The aim of this study is to clarify the efficacy and safety of chemotherapy without RT for BMs. Materials and methods BMs from lung adenocarcinomas (Ads) with EGFR-mutation were enrolled. As tyrosine kinase inhibitors (TKIs), gefitinib was used at first, and erlotinib was administrated at tumor progression. Erlotinib was also selected for pts in whom intracranial lesions appeared after gefitinib. The response to TKIs was evaluated on MRI. WBRT or SRS was performed only at tumor progression after TKIs. The primary endpoint was overall survival, and the secondary endpoints were maximum response to TKIs, progression-free survival and time to RT after diagnosis of BMs. Results In this study, 37 pts were enrolled. The types of EGFR-mutations were as follows: Ex19 deletion (Ex19del) in 20, Ex21L858R in 14, and other types of mutations in 3 cases. The maximum response was PD in one, SD in 3, PR in 22 and CR in 9 pts (response rate: 83.8%). The progression-free and overall survival times were 8.9 and 28.3 months. The median time to RT (WBRT in 14 and SRS in 3 cases) from diagnosis of BMs was 14.3 months. During the follow-up period, 9 deaths were observed but none of them were owing to the intracranial lesions. Among these 9 pts, no RT was required in 2. Pneumonitis was observed in one case after gefitinib, but no other severe adverse event was observed. When we divided the pts owing to the types of mutations (Ex19del vs. others), response to TKI was superior in Ex19 deleted cases (p = 0.031), and the progression-free survival time was significantly longer in cases with Ex19del (14.5 months) in compared with those with other types of mutations (8.0 months, p = 0.002). In Ex19 deleted cases, TKIs could delay RT for 18.3 months. Conclusions TKIs showed favorable effect on control of EGFR-mutant BMs, and it delayed RT for more than one year. Ex19del was the significant predictor of response to TKIs in BMs. TKIs without RT was safe and acceptable treatment for BMs from EGFR-mutant lung Ads. Disclosure All authors have declared no conflicts of interest.

Osteonecrosis of the Humeral Head in a Patient with Non-small Cell Lung Cancer Receiving Bevacizumab

A 43-year-old Filipino woman, never-smoker, was diagnosed with stage IV adenocarcinoma of the lung in February 2009, with metastatic disease to the liver and brain. The biopsies of the lung mass and liver confirmed poorly differentiated, TTF-1-positive, EGFR-mutated (exon 19) adenocarcinoma of the lung. The patient underwent a craniotomy followed by brachytherapy for the isolated brain metastases. Subsequently, she initiated erlotinib plus celecoxib versus placebo on a clinical trial in April 2009, to which she responded for 12 months. In February 2010, she initiated second-line carboplatin/pemetrexed/bevacizumab for six cycles with complete resolution of the positron emission tomography uptake to the lung primary and liver metastases. The patient started maintenance bevacizumab in June 2010. In February 2011, she presented with left shoulder pain with absence of trauma or bone metastases. Magnetic resonance imaging of the shoulder revealed avascular necrosis of the left humeral head (Figure 1). The positron emission tomography/ computed tomography scan showed mild fluorodeoxyglucose uptake to the left shoulder and a stable, fluorodeoxyglucosenegative, left upper lobe mass (Figure 2). After the diagnosis of avascular necrosis was made, bevacizumab was discontinued and the patient initiated maintenance pemetrexed. Her pain responded to anti-inflammatory medications. Avascular necrosis of the femoral head has been reported in two patients with colorectal cancer receiving bevacizumab and one patient receiving sunitinib.1 Prolonged antiangiogenic therapy may impair the bone metabolism leading to osteonecrosis.2 To our knowledge, this is a first report of osteonecrosis of the humeral head in a patient treated with bevacizumab alone without bisphosphonates or other agents with increased risk of bone necrosis.

A Blueprint for Advancing Genetics-Based Cancer Therapy

In the era of next-generation sequencing, there are significant challenges to harnessing cancer genome information to develop novel therapies. Key research thrusts in both academia and industry will speed this transition, and lessons learned for cancer will more broadly shape the process for genetic contributions to the therapy of disease more broadly.

Adenosquamous Carcinoma of the Lung

Molecular testing of pulmonary adenocarcinomas for EGFR and KRAS mutations is becoming more common as tyrosine kinase inhibitor therapy is used for EGFR-mutated adenocarcinomas. Adenosquamous carcinomas represent a hybrid carcinoma, and there is no literature addressing the frequency of EGFR and KRAS mutations in this subset of lung carcinomas in Western populations. For this study, 23 adenosquamous carcinomas were microdissected with the glandular and squamous components analyzed for EGFR and KRAS mutations and EGFR amplification. In 3 cases (13%), there were EGFR mutations, with 2 having the identical mutation in the glandular and squamous elements. In 3 cases (13%), there were KRAS mutations in both histologic elements. Great heterogeneity existed in the rates of EGFR amplification in the 2 histologic components. Amplification was most common in both glandular and squamous components (11/23 [48%]). EGFR mutations occur in adenosquamous carcinoma in the same percentages as in conventional adenocarcinoma in the Western population. KRAS mutations are less common.

Abstract 3902: Comparison of allelic profiles of EGFR-mutated and ALK-translocated female adenocarcinomas of the lung by CGH microarrays: Implications for two distinct carcinogenesis pathways in non-smokers

Abstract Background: Adenocarcinoma is the most common form of lung cancer worldwide. In Japan, female adenocarcinomas are increasing, and more than two-thirds of them are non-smokers. EGFR mutation and EML4-ALK fusion, both of which are important for choice of molecular-targeted therapies, have been reported to be mutually exclusive. However, both genetic changes tend to occur in the similar populations, i.e; younger, non-smoking subjects. To examine the global allelic profiles to pursue specific genes for both the groups, SNP-chip-based high-resolution molecular allelo-karyotyping analysis was performed. Methods: 51 female cases, 31 with EGFR mutation and 20 with EML4-ALK translocation, were enrolled in this study. All tumors were surgically resected at the Cancer Institute Hospital, Tokyo. Clinicopathological parameters including, age, pathological stage, differentiation grade of the tumor, tumor size were examined and microscopic lymphatic- and blood-vessel invasions were described. DNA was extracted from snap-frozen specimen. They were analyzed using Affymetrix GeneChip and our robust algorithm, CNAG/AsCNAR, to perform sensitive analysis of copy number alteration and allelic composition. Results: EGFR mutation and EML4-ALK fusion were mutually exclusive. Tumors with EML4-ALK fusion conferred less-differentiated histology and smaller tumor size (P&amp;lt;0.0001, P=0.0017, respectively). No statistical differences were found in age, pathological stage, and microscopic lymphatic/blood vessel invasions. With SNP-chip allelo-karyotyping analysis, among selected 23 amplified and 5 deleted regions, EML4-ALK tumors had significantly lower frequencies of allelic changes than EGFR tumors. For amplification, there were four regions (7p11.2, 16p13.3, 17q12, and 17q25.1) detected more frequently in EGFR tumors than in EML4-ALK tumors, and no regions found more in tumor with EGFR mutations than in those with EML-ALK translocation. For deletion, one region (9p24.1-p23) was again more often deleted in EGFR-mutated than in ALK-translocated tumors. Homozygous deletion was detected only at 9p21.3, including CDKN2A/p16, found in both groups. Conclusions: Allelo-karyotyping analysis using high-resolution array technology revealed that EGFR-mutated tumors had more frequent amplifcations and deletions than ALK-translocated tumors at the particular 5 regions. Among them, 7p11.2 harbors EGFR, 17q12 contains ERBB2, and 9p24.1-p23 includes PTPRD. This study clearly demonstrated that gene dosage alterations were less prevalent in tumors with ALK fusion than those with EGFR mutations, implying two distinct carcinogenesis pathways in non-smokers’ lung cancers. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3902. doi:10.1158/1538-7445.AM2011-3902

KRAS mutant allele-specific imbalance in lung adenocarcinoma

The significance of KRAS mutant allele-specific imbalance (MASI) in lung adenocarcinomas is unknown. KRAS MASI was defined as predominance of the mutant allele over the wild-type allele. We assessed the frequency of KRAS MASI by comparing peak heights of mutant and wild-type alleles on sequencing electropherograms and by KRAS fluorescence in situ hybridization (FISH). A review of sequencing electropherograms of 207 KRAS-mutated lung adenocarcinomas demonstrated 23 (11%) cases with the mutant allele peak higher than the wild-type allele peak and 15 (7%) cases with the mutant allele peak equal to the wild-type allele peak. Of 17 cases with the mutant allele peak higher or equal to the wild-type allele peak, 8 (47%) showed KRAS amplification by FISH. KRAS FISH analysis of 36 KRAS-mutated lung adenocarcinomas with the mutant allele peak lower than the wild-type allele peak, 21 KRAS and EGFR wild-type and 16 EGFR-mutated adenocarcinomas showed no KRAS amplification. KRAS MASI was associated with selective amplification of the KRAS mutant allele (P<0.001). Patients with KRAS MASI showed worse overall survival. The cumulative proportion surviving at 17 months for KRAS MASI group was 35% compared with 84.1% for patients with KRAS mutant allele peak lower than wild-type allele peak (P=0.012). The adverse prognostic significance of KRAS MASI was independent of clinical stage and was maintained among stage I patients. The detection of KRAS MASI in lung adenocarcinomas by sequencing electropherograms may identify patients with more aggressive disease.

EGFR-mutated lung cancer: a paradigm of molecular oncology

The development of EGFR tyrosine kinase inhibitors for clinical use in non-small cell lung cancer and the subsequent discovery of activating EGFR mutations have led to an explosion of knowledge in the fields of EGFR biology, targeted therapeutics and lung cancer research. EGFR-mutated adenocarcinoma of the lung has clearly emerged as a unique clinical entity necessitating the routine introduction of molecular diagnostics into our current diagnostic algorithms and leading to the evidence-based preferential usage of EGFR-targeted agents for patients with EGFR-mutant lung cancers. This review will summarize our current understanding of the functional role of activating mutations, key downstream signaling pathways and regulatory mechanisms, pivotal primary and acquired resistance mechanisms, structure-function relationships and ultimately the incorporation of molecular diagnostics and small molecule EGFR tyrosine kinase inhibitors into our current treatment paradigms.

The molecular pathology of cancer

Rapid technical advances in DNA sequencing and genome-wide association studies are driving the discovery of the germline and somatic mutations that are present in different cancers. Mutations in genes involved in cellular signaling are common, and often shared by tumors that arise in distinct anatomical locations. Here we review the most important molecular changes in different cancers from the perspective of what should be analyzed on a routine basis in the clinic. The paradigms are EGFR mutations in adenocarcinoma of the lung that can be treated with gefitinib, KRAS mutations in colon cancer with respect to treatment with EGFR antibodies, and the use of gene-expression analysis for ER-positive, node-negative breast cancer patients with respect to chemotherapy options. Several other examples in both solid and hematological cancers are also provided. We focus on how disease subtypes can influence therapy and discuss the implications of the impending molecular diagnostic revolution from the point of view of the patients, clinicians, and the diagnostic and pharmaceutical companies. This paradigm shift is occurring first in cancer patient management and is likely to promote the application of these technologies to other diseases.