Lung carcinoma in the era of personalized medicine: the role of cytology.

In 2004, three groups working independently [1–3] , almost simultaneously, reported remarkable findings: that activating mutations in the epidermal growth factor receptor (EGFR) were common in certain lung carcinomas and that these mutations correlated with the response of those lung tumors to therapy with gefitinib and erlotinib, both EGFR tyrosine kinase inhibitors (TKIs). This was the first time driver mutations in lung cancer that responded to targeted therapy had been identified, marking the beginning of a new era of personalized medicine in lung cancer. Prior to the discovery of these mutations, patients had been treated with EGFR TKIs but predicting who would respond and who would not was only imperfectly correlated with the histologic appearance of the tumor and the clinical profile of the patient

Suitability of Thoracic Cytology for New Therapeutic Paradigms in Non-small Cell Lung Carcinoma: High Accuracy of Tumor Subtyping and Feasibility of EGFR and KRAS Molecular Testing

Introduction:The two essential requirements for pathologic specimens in the era of personalized therapies for non-small cell lung carcinoma (NSCLC) are accurate subtyping as adenocarcinoma (ADC) versus squamous cell carcinoma (SqCC) and suitability for EGFR and KRAS molecular testing. The aim of this study was to comprehensively review the performance of cytologic specimens for the above two goals in a high-volume clinical practice.Methods:Subtyping of primary lung carcinomas by preoperative cytology was correlated with subsequent resection diagnoses during a 1-year period (n = 192). The contribution of various clinicopathologic parameters to subtyping accuracy and utilization of immunohistochemistry (IHC) for NSCLC subtyping were analyzed. In addition, the performance of cytologic specimens submitted for EGFR/KRAS molecular testing during a 1-year period (n = 128) was reviewed.Results:Of the 192 preoperative cytology diagnoses, tumor subtype was definitive versus favored versus unclassified in 169 (88%) versus 15 (8%) versus 8 (4%) cases, respectively. Overall accuracy of cytologic tumor subtyping (concordance with histology) was 93% and accuracy of definitive diagnoses 96%. For a group of patients with ADC and SqCC (n = 165), the rate of unclassified cytologic diagnoses was 3% and overall accuracy 96%. IHC was used for subtyping of 9% of those cases, yielding 100% accuracy. The strongest predictors of difficulty in subtyping of ADC and SqCC were poor differentiation (p = 0.0004), low specimen cellularity (p = 0.019), and squamous histology (p = 0.003). Of 128 cytologic specimens submitted for molecular testing, 126 (98%) were suitable for analysis, revealing EGFR and KRAS mutations in 31 (25%) and 25 (20%) cases, respectively.Conclusions:Cytologic subtyping of NSCLC is feasible and accurate, particularly when morphologic assessment is combined with IHC. Furthermore, routine cytologic specimens can be successfully used for EGFR/KRAS mutation analysis. Our data strongly support the suitability of cytologic specimens for the new therapeutic paradigms in NSCLC

Distinct Clinical Course of EGFR-Mutant Resected Lung Cancers: Results of Testing of 1118 Surgical Specimens and Effects of Adjuvant Gefitinib and Erlotinib

Background:EGFR and KRAS mutations are mutually exclusive and predict outcomes with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) treatment in patients with stage IV lung cancers. The clinical significance of these mutations in patients with resected stage I–III lung cancers is unclear.Methods:At our institution, resection specimens from patients with stage I–III lung adenocarcinomas are tested for the presence of EGFR or KRAS mutations during routine pathology analysis such that the results are available before consideration of adjuvant therapy. In a cohort of 1118 patients tested over 8 years, overall survival was analyzed using multivariate analysis to control for potential confounders, including age, sex, stage, and smoking history. The impact of adjuvant erlotinib or gefitinib was examined in an independent data set of patients exclusively with EGFR mutation, in which date of recurrence was recorded.Results:In the overall population, we identified 227 KRAS (25%) and 222 EGFR (20%) mutations. Patients with EGFR-mutant lung cancers had a lower risk of death compared with those without EGFR mutations, overall survival (OS) HR 0.51 (95% confidence interval [CI]: 0.34–0.76, p < 0.001). Patients with KRAS-mutant lung cancers had similar outcomes compared with individuals with KRAS wild-type tumors, OS HR 1.17 (95% CI: 0.87–1.57, p = 0.30). A separate data set includes only patients with EGFR-mutant lung cancers identified over 10 years (n = 286). In patients with resected lung cancers and EGFR mutation, treatment with adjuvant erlotinib or gefitinib was associated with a lower risk of recurrence or death, disease-free survival HR 0.43 (95% CI: 0.26–0.72, p = 0.001), and a trend toward improved OS.Conclusions:Patients with resected stage I–III lung cancers and EGFR mutation have a lower risk of death compared with patients without EGFR mutation. This may be because of treatment with EGFR TKIs. Patients with, and without KRAS mutation have similar OS. These data support reflex testing of resected lung adenocarcinomas for EGFR mutation to provide prognostic information and identify patients for enrollment on prospective clinical trials of adjuvant EGFR TKIs

KRAS Mutations and Primary Resistance of Lung Adenocarcinomas to Gefitinib or Erlotinib

BACKGROUND: Somatic mutations in the gene for the epidermal growth factor receptor (EGFR) are found in adenocarcinomas of the lung and are associated with sensitivity to the kinase inhibitors gefitinib (Iressa) and erlotinib (Tarceva). Lung adenocarcinomas also harbor activating mutations in the downstream GTPase, KRAS, and mutations in EGFR and KRAS appear to be mutually exclusive. METHODS AND FINDINGS: We sought to determine whether mutations in KRAS could be used to further enhance prediction of response to gefitinib or erlotinib. We screened 60 lung adenocarcinomas defined as sensitive or refractory to gefitinib or erlotinib for mutations in EGFR and KRAS. We show that mutations in KRAS are associated with a lack of sensitivity to either drug. CONCLUSION: Our results suggest that treatment decisions regarding use of these kinase inhibitors might be improved by determining the mutational status of both EGFR and KRAS

High Expression Levels of Total IGF-1R and Sensitivity of NSCLC Cells In Vitro to an Anti-IGF-1R Antibody (R1507)

© 2009 Gong et al

Mutational Analysis of EGFR and Related Signaling Pathway Genes in Lung Adenocarcinomas Identifies a Novel Somatic Kinase Domain Mutation in FGFR4

BACKGROUND: Fifty percent of lung adenocarcinomas harbor somatic mutations in six genes that encode proteins in the EGFR signaling pathway, i.e., EGFR, HER2/ERBB2, HER4/ERBB4, PIK3CA, BRAF, and KRAS. We performed mutational profiling of a large cohort of lung adenocarcinomas to uncover other potential somatic mutations in genes of this signaling pathway that could contribute to lung tumorigenesis. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed genomic DNA from a total of 261 resected, clinically annotated non-small cell lung cancer (NSCLC) specimens. The coding sequences of 39 genes were screened for somatic mutations via high-throughput dideoxynucleotide sequencing of PCR-amplified gene products. Mutations were considered to be somatic only if they were found in an independent tumor-derived PCR product but not in matched normal tissue. Sequencing of 9MB of tumor sequence identified 239 putative genetic variants. We further examined 22 variants found in RAS family genes and 135 variants localized to exons encoding the kinase domain of respective proteins. We identified a total of 37 non-synonymous somatic mutations; 36 were found collectively in EGFR, KRAS, BRAF, and PIK3CA. One somatic mutation was a previously unreported mutation in the kinase domain (exon 16) of FGFR4 (Glu681Lys), identified in 1 of 158 tumors. The FGFR4 mutation is analogous to a reported tumor-specific somatic mutation in ERBB2 and is located in the same exon as a previously reported kinase domain mutation in FGFR4 (Pro712Thr) in a lung adenocarcinoma cell line. CONCLUSIONS/SIGNIFICANCE: This study is one of the first comprehensive mutational analyses of major genes in a specific signaling pathway in a sizeable cohort of lung adenocarcinomas. Our results suggest the majority of gain-of-function mutations within kinase genes in the EGFR signaling pathway have already been identified. Our findings also implicate FGFR4 in the pathogenesis of a subset of lung adenocarcinomas

Characterizing the cancer genome in lung adenocarcinoma

Somatic alterations in cellular DNA underlie almost all human cancers(1). The prospect of targeted therapies(2) and the development of high-resolution, genome-wide approaches(3-8) are now spurring systematic efforts to characterize cancer genomes. Here we report a large-scale project to characterize copy-number alterations in primary lung adenocarcinomas. By analysis of a large collection of tumours ( n = 371) using dense single nucleotide polymorphism arrays, we identify a total of 57 significantly recurrent events. We find that 26 of 39 autosomal chromosome arms show consistent large-scale copy-number gain or loss, of which only a handful have been linked to a specific gene. We also identify 31 recurrent focal events, including 24 amplifications and 7 homozygous deletions. Only six of these focal events are currently associated with known mutations in lung carcinomas. The most common event, amplification of chromosome 14q13.3, is found in similar to 12% of samples. On the basis of genomic and functional analyses, we identify NKX2-1 ( NK2 homeobox 1, also called TITF1), which lies in the minimal 14q13.3 amplification interval and encodes a lineage-specific transcription factor, as a novel candidate proto-oncogene involved in a significant fraction of lung adenocarcinomas. More generally, our results indicate that many of the genes that are involved in lung adenocarcinoma remain to be discovered.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62944/1/nature06358.pd

The Role of Fine Needle Aspiration Cytology in the Diagnosis and Management of Thymic Neoplasia

Background:Fine needle aspiration biopsy is commonly used to document the metastasis to the mediastinum. It is less often used to make the primary diagnosis of tumors, particularly thymic neoplasms. This is due to fear of sampling error, rarity of thymic tumors, multiplicity of lesions in the mediastinum, and inexperience on the part of the cytopathologist. We show that needle aspiration sampling of thymic tumors, both thymoma and thymic carcinoma, is an accurate method of diagnosis.Methods and Results:In our series of 22 thymic tumors aspirated preoperatively and compared with the subsequent surgical resection, the accuracy of a diagnosis of thymoma was 100%, and the accuracy of a diagnosis of carcinoma was 100%. Difficulties were encountered when vague terminology was used, and insufficient information was conveyed. Immunohistochemical stains can be applied to cytologic material to aid in the identification of the epithelial and lymphocytic components of thymoma.Discussion:Correlation with clinical and radiographic information is necessary, and wording of the cytology report should be as complete and clear as possible