EGFR Mutation Is Specific for Terminal Respiratory Unit Type Adenocarcinoma

Clinicopathological, Immunohistochemical, and Genetic Features of Primary Lung Adenocarcinoma Occurring in the Setting of Usual Interstitial Pneumonia Pattern

INTRODUCTION

An association between usual interstitial pneumonia (UIP) and carcinogenesis has been well established. However, few detailed analyses have investigated the clinicopathological, immunohistochemical, and genetic features of patients with primary lung adenocarcinoma (ADC) with UIP (UIP-ADC).

METHODS

We identified 44 patients with ADC in the setting of UIP (the UIP-ADC group) (1.9%) from 2309 patients with primary ADC and compared clinicopathological, immunohistochemical, and genetic features between the UIP-ADC group and patients with ADC without UIP (the non-UIP-ADC group).

RESULTS

Clinicopathological features of UIP-ADC included an older age at occurrence; male predominance; smoking history; predilection for the lower lobe; large tumor size; high incidence of lymph vessel invasion, pleural invasion, and lymph node metastasis; and poor survival rate. However, the cause of death of patients with UIP-ADC was largely influenced by respiratory complications. Histologically, patients in the UIP-ADC group could be stratified according to invasive mucinous-predominant subtype. Genetically, patients in the UIP-ADC group had lower EGFR and higher KRAS mutation rates compared with patients in the non-UIP-ADC group.

CONCLUSIONS

UIP-ADC was associated with a poor prognosis owing to the high frequency of perioperative complications rather than the malignancy of the tumor itself. There was a high prevalence of the invasive mucinous-predominant subtype in cases of UIP-ADC. UIP-ADC also had a low prevalence of EGFR mutations and a high prevalence of KRAS mutations. These findings suggest that UIP-ADC should be distinct from non-UIP-ADC.

Could molecular pathology testing in lung cancer be more cost-effective?

AIMS

EGFR and ALK analysis is routinely undertaken prior to targeted treatment of non-squamous non-small cell lung carcinoma (NSCLC). Increasingly, limited resources require molecular pathology services to be cost-effective without detriment to patient care.

METHODS

Data from an audit of molecular pathology testing in the South East Scotland Cancer Network (SCAN) network have been used to explore different testing strategies with the aim of reducing costs; including investigation of thyroid transcription factor 1 (TTF1) expression as a negative predictor for EGFR mutations.

RESULTS

TTF1 immunohistochemistry had a high negative predictive value for EGFR mutations (99%). Reflex testing all non-squamous NSCLC, as expected, had the highest costs, whereas limiting testing to those who might be considered for treatment would lead to a cost reduction of only 7.5%; however, a serial testing model could save 32.7%.

CONCLUSIONS

Testing only patients being considered for EGFR and ALK inhibitors represented small savings; more significant savings would be achievable if testing algorithms used known associations between clinical biomarkers.

Concordant and Discordant EGFR Mutations in Patients With Multifocal Adenocarcinomas: Implications for EGFR-Targeted Therapy

PURPOSE

Adenocarcinoma remains the most common subtype of lung cancer in the United States. Most patients present with tumors that are invasive and often metastatic, but in some patients, multiple precursor in situ or minimally invasive adenocarcinoma tumors develop that can be synchronous and metachronous. These precursor lesions harbor the same spectrum of genetic mutations found in purely invasive adenocarcinomas, such as EGFR, KRAS, and p53 mutations. It is less clear, however, whether separate lesions in patients who present with multifocal disease share common underlying genetic driver mutations.

METHODS

Here we review the relevant literature on molecular driver alterations in adenocarcinoma precursor lesions. We then report 4 patients with multifocal EGFR mutant adenocarcinomas in whom we performed molecular testing on 2 separate lesions.

FINDINGS

In 2 of these patients, the mutations are concordant, and in 2 patients, the mutations are discordant. A review of the literature demonstrates increasing evidence that lesions with discordant mutations may confer a more favorable prognosis because they are unlikely to represent metastases.

IMPLICATIONS

Our findings suggest that the emergence of the dominant EGFR driver alteration is often independent between lesions in patients with multifocal adenocarcinomas, and thus the same targeted therapy may not be effective for all lesions. However, genetic testing of multiple lesions can help to distinguish separate primary tumors from metastatic disease.

Expression of Na+-K+-2Cl- cotransporter isoform 1 (NKCC1) predicts poor prognosis in lung adenocarcinoma and EGFR-mutated adenocarcinoma patients

BACKGROUND

Sodium-potassium-chloride cotransporter isoform 1 (NKCC1) is an active ions cotransporter and modulates cellular volume and migration. NKCC1 blockers can inhibit cancer cell growth.

AIM

We aimed to elucidate the expression and prognostic significance of NKCC1 in non-small cell lung cancer (NSCLC).

METHODS

We retrospectively analyzed 788 NSCLC patients with either adenocarcinoma (n = 503) or squamous cell carcinoma (n = 285) by immunohistochemistry to correlate NKCC1 expression with clinicopathologic and survival outcomes.

RESULTS

In adenocarcinoma, high NKCC1 expression was associated with larger tumor size (P = 0.013), vascular invasion (P < 0.001), lymphatic invasion (P < 0.001), perineural invasion (P = 0.019) and advanced pathologic stage (P < 0.001), but there are no significant correlations between NKCC1 expression and clinicopathological parameters in squamous cell carcinoma. Patients with high NKCC1 expression had significantly shorter disease-free survival (DFS;P < 0.001) and shorter overall survival (OS;P < 0.001) than those with low NKCC1 expression in adenocarcinoma. In squamous cell carcinoma, NKCC1 expression was not associated with prognosis. Multivariate analysis revealed that high NKCC1 expression was an independent prognostic factor for DFS in lung adenocarcinomas (HR, 1.709; 95% CI 1.029-2.130;P = 0.033) and for OS inEGFR-mutated adenocarcinoma patients (HR, 3.165; 95% CI 1.424-7.035;P = 0.005).

CONCLUSION

NKCC1 high expression predicted a bad clinical outcome for lung adenocarcinoma patients andEGFR-mutated subgroup. Therefore, NKCC1 may play a role in lung adenocarcinoma and novel therapeutic tactics could be developed by targeting NKCC1 protein.

Targeted sequencing reveals clonal genetic changes in the progression of early lung neoplasms and paired circulating DNA

Lungs resected for adenocarcinomas often harbour minute discrete foci of cytologically atypical pneumocyte proliferations designated as atypical adenomatous hyperplasia (AAH). Evidence suggests that AAH represents an initial step in the progression to adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA) and fully invasive adenocarcinoma. Despite efforts to identify predictive markers of malignant transformation, alterations driving this progression are poorly understood. Here we perform targeted next-generation sequencing on multifocal AAHs and different zones of histologic progression within AISs and MIAs. Multiregion sequencing demonstrated different genetic drivers within the same tumour and reveal that clonal expansion is an early event of tumorigenesis. We find that KRAS, TP53 and EGFR mutations are indicators of malignant transition. Utilizing droplet digital PCR, we find alterations associated with early neoplasms in paired circulating DNA. This study provides insight into the heterogeneity of clonal events in the progression of early lung neoplasia and demonstrates that these events can be detected even before neoplasms have invaded and acquired malignant potential.

Atypical adenomatous hyperplasia is thought to be a precursor lesion for lung adenocarcinoma. Here, using targeted deep sequencing, the authors demonstrate that hyperplastic lesions contain somatic mutations associated with malignant disease and that these can be detected in circulating tumour cells.

Classification of different patterns of pulmonary adenocarcinomas

The epidemic increase of adenocarcinoma histology accounting for more than 50% of primary lung malignancies and the advent of effective molecular targeted-therapies against specific gene alterations characterizing this tumor type have led to the reconsideration of the pathologic classification of lung cancer. The new 2015 WHO classification provided the basis for a multidisciplinary approach emphasizing the close correlation among clinical, radiologic and molecular characteristics and histopathologic pattern of lung adenocarcinoma. The terms 'bronchioloalveolar carcinoma' and 'mixed adenocarcinoma' have been eliminated, introducing the concepts of 'adenocarcinoma in situ', 'minimally invasive adenocarcinoma' and the use of descriptive predominant patterns in invasive adenocarcinomas (lepidic, acinar, papillary, solid and micropapillary patterns). 'Invasive mucinous adenocarcinoma' is the new definition for mucinous bronchioloalveolar carcinoma, and some variants of invasive adenocarcinoma have been included, namely colloid, enteric and fetal-type adenocarcinomas. A concise update of the immunomorphologic, radiological and molecular characteristics of the different histologic patterns of lung adenocarcinoma is reported here.

M, Mills GB, Heymach JV, Wistuba II, Wang J, Byers. LA. An Integrated Molecular Analysis of Lung Adenocarcinomas Identifies Potential Therapeutic Targets among TTF1-Negative Tumors, Including DNA Repair Proteins and Nrf2

PURPOSE

Thyroid transcription factor-1 (TTF1) immunohistochemistry (IHC) is used clinically to differentiate primary lung adenocarcinomas (LUAD) from squamous lung cancers and metastatic adenocarcinomas from other primary sites. However, a subset of LUAD (15%-20%) does not express TTF1, and TTF1-negative patients have worse clinical outcomes. As there are no established targeted agents with activity in TTF1-negative LUAD, we performed an integrated molecular analysis to identify potential therapeutic targets.

EXPERIMENTAL DESIGN

Using two clinical LUAD cohorts (274 tumors), one from our institution (PROSPECT) and The Cancer Genome Atlas, we interrogated proteomic profiles (by reverse phase protein array, RPPA), gene expression, and mutational data. Drug response data from 74 cell lines were used to validate potential therapeutic agents.

RESULTS

Strong correlations were observed between TTF1 IHC and TTF1 measurements by RPPA (Rho = 0.57, P < 0.001) and gene expression (NKX2-1, Rho = 0.61, P < 0.001). Established driver mutations (e.g., BRAF and EGFR) were associated with high TTF1 expression. In contrast, TTF1-negative LUAD had a higher frequency of inactivating KEAP1 mutations (P = 0.001). Proteomic profiling identified increased expression of DNA repair proteins (e.g., Chk1 and the DNA repair score) and suppressed PI3k/mTOR signaling among TTF1-negative tumors, with differences in total proteins confirmed at the mRNA level. Cell line analysis showed drugs targeting DNA repair to be more active in TTF1-low cell lines.

CONCLUSIONS

Combined genomic and proteomic analyses demonstrated infrequent alteration of validated lung cancer targets (including the absence of BRAF mutations in TTF1-negative LUAD), but identified novel potential targets for TTF1-negative LUAD, including KEAP1/Nrf2 and DNA repair pathways.

Overview of clinicopathologic features of ALK-rearranged lung adenocarcinoma and current diagnostic testing for ALK rearrangement

Patients with non-small cell lung cancer (NSCLC) who harbor anaplastic lymphoma kinase (ALK) gene rearrangements can derive significant clinical benefit from ALK tyrosine kinase inhibitor. Accurate patient identification is absolutely crucial for successful using ALK inhibitor treatment. However, lung cancer patients with ALK gene rearrangement after ALK inhibitor therapy eventually develop acquired resistance to treatment. In this review, the authors summarize the clinicopathologic features of ALK-rearranged NSCLC and the pros and cons of current diagnostic testing. In addition, we discuss the current diagnostic flow of ALK testing and consideration of rebiopsy sample during disease progression in patients treated by ALK inhibitors.

ROR1 as a novel therapeutic target for EGFR-mutant non-small-cell lung cancer patients with the EGFR T790M mutation

BACKGROUND

Activation of bypass signaling pathways, impairment of apoptosis and mutation of epidermal growth factor receptor (EGFR) to a drug-resistant state are well known mechanisms of resistance to single-agent erlotinib therapy in non-small-cell lung cancer (NSCLC) driven by EGFR mutations. Orphan receptor 1 (ROR1) knockdown inhibited the growth of NCI-H1975 cells (harboring EGFR L858R and T790M mutations). A pro-survival function for ROR1/MEK/ERK signaling in cooperation with AKT has been demonstrated.

METHODS

We have assessed ROR1 expression in 45 patients from the EURTAC trial (clinicaltrials.gov NCT00446225), 27 of whom harbored pretreatment concomitant EGFR T790M mutations, and correlated results with outcome.

RESULTS

Progression-free survival (PFS) was 11.8 months for erlotinib-treated patients with low/intermediate and 5.8 months for those with high ROR1 levels. PFS for chemotherapy-treated patients was 5.6 and 9 months, respectively (P=0.0165). A total of 15 erlotinib-treated patients harbored concomitant T790M mutations; for these patients, PFS was 10.8 months for those with low/intermediate compared to 2.7 months for those with high ROR1 levels. In contrast, among 12 chemotherapy-treated patients with concomitant T790M mutations, PFS was 5.8 months for those with low/intermediate, compared to 14.2 months for those with high ROR1 levels (P=0.0138).

CONCLUSIONS

ROR1 expression has a differential effect on outcome to erlotinib and chemotherapy in EGFR-mutant NSCLC patients. High ROR1 expression significantly limits PFS in erlotinib-treated patients with T790M mutations and ROR1-directed therapies can enhance the efficacy of treatment. In contrast, high ROR1 expression confers longer PFS to chemotherapy in the same group of patients. The role of chemotherapy and erlotinib in EGFR-mutant NSCLC patients with high ROR1 expression warrants further investigation.

EGFR L858R mutation is associated with lung adenocarcinoma patients with dominant ground-glass opacity

OBJECTIVES

To retrospectively identify quantitative computed tomographic (CT) features that correlate with the three major driver gene mutations in surgically resected lung adenocarcinomas with dominant ground-glass opacity (GGO) stratified by the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS) classification in a Chinese cohort of patients.

MATERIALS AND METHODS

Surgically resected lung adenocarcinomas from Shanghai Pulmonary Hospital were enrolled. EGFR, KRAS and EML4-ALK mutations were detected by qPCR. Clinical and pathological characteristics including gender, age, TNM stage, smoking status and CT pattern were analyzed. Histologic subtype was classified according to IASLC/ATS/ERS classification. At preoperative chest CT, the percentage of GGO volume, diameter, solid volume and total tumor volume of each tumor were measured by using a semiautomated algorithm. Distribution of driver gene mutations was evaluated by using the Fisher exact test, the Student's t test, and Pearson correlation analysis.

RESULTS AND CONCLUSION

788 in total and 158 GGO tumors were taken in this cohort. GGO pattern occurred at a significantly higher frequency in younger, female and non-smoking patients. EGFR/KRAS mutations and EML4-ALK fusions were similar between GGO and solid adenocarcinomas. GGO volume and diameter showed correlation with EGFR mutation. With regard to association between lung adenocarcinoma histological subtypes and GGO features, GGO proportion was significantly higher in lepidic predominant adenocarcinomas, including adenocarcinoma in situ, minimally invasive adenocarcinoma, and lepidic predominant invasive adenocarcinoma. No significant differences of driver gene mutations were found between subtypes of lung adenocarcinoma. It is important that we understand GGO lesions of lung adenocarcinoma to identify molecular biomarkers including EGFR, KRAS and EML4-ALK. These markers would offer useful information for determining the appropriate strategy to treat lung adenocarcinoma with GGO lesions detected by helical CT.

Epidermal growth factor receptor mutations and anaplastic lymphoma kinase rearrangements in lung cancer with nodular ground-glass opacity

Background

Nodular ground-glass opacities (nGGO) are a specific type of lung adenocarcinoma. ALK rearrangements and driver mutations such as EGFR and K-ras are frequently found in all types of lung adenocarcinoma. EGFR mutations play a role in the early carcinogenesis of nGGOs, but the role of ALK rearrangement remains unknown.

Methods

We studied 217 nGGOs resected from 215 lung cancer patients. Pathology, tumor size, tumor disappearance rate, and the EGFR and ALK markers were analyzed.

Results

All but one of the resected nGGOs were adenocarcinomas. ALK rearrangements and EGFR mutations were found in 6 (2.8%) and 119 (54.8%) cases. The frequency of ALK rearrangement in nGGO was significantly lower than previously reported in adenocarcinoma. Advanced disease stage (p = 0.018) and larger tumor size (p = 0.037) were more frequent in the ALK rearrangement-positive group than in ALK rearrangement-negative patients. nGGOs with ALK rearrangements were associated with significantly higher pathologic stage and larger maximal and solid diameter in comparison to EGFR-mutated lesions.

Conclusion

ALK rearrangement is rare in lung cancer with nGGOs, but is associated with advanced stage and larger tumor size, suggesting its association with aggressive progression of lung adenocarcinoma. ALK rearrangement may not be important in early pathogenesis of nGGO.

ECT2 amplification and overexpression as a new prognostic biomarker for early-stage lung adenocarcinoma

Genetic abnormality in early-stage lung adenocarcinoma was examined to search for new prognostic biomarkers. Six in situ lung adenocarcinomas and nine small but invasive adenocarcinomas were examined by array-comparative genomic hybridization, and candidate genes of interest were screened. To examine gene abnormalities, 83 cases of various types of lung carcinoma were examined by quantitative real-time genomic PCR and immunohistochemistry. The results were then verified using another set of early-stage adenocarcinomas. Array-comparative genomic hybridization indicated frequent amplification at chromosome 3q26. Of the seven genes located in this region, we focused on the epithelial cell transforming sequence 2 (ECT2) oncogene, as ECT2 amplification was detected only in invasive adenocarcinoma, and not in in situ carcinoma. Quantitative PCR and immunohistochemistry analyses also detected overexpression of ECT2 in invasive adenocarcinoma, and this was correlated with both the Ki-67 labeling index and mitotic index. In addition, it was associated with disease-free survival and overall survival of patients with lung adenocarcinoma. These results were verified using another set of early-stage adenocarcinomas resected at another hospital. Abnormality of the ECT2 gene occurs at a relatively early stage of lung adenocarcinogenesis and would be applicable as a new biomarker for prognostication of patients with lung adenocarcinoma.

Spectrum of somatic EGFR, KRAS, BRAF, PTEN mutations and TTF-1 expression in Brazilian lung cancer patients

Lung cancer is the leading global cause of cancer-related mortality. Inter-individual variability in treatment response and prognosis has been associated with genetic polymorphisms in specific genes: EGFR, KRAS, BRAF, PTEN and TTF-1. Somatic mutations in EGFR and KRAS genes are reported at rates of 15-40% in non-small cell lung cancer (NSCLC) in ethnically diverse populations. BRAF and PTEN are commonly mutated genes in various cancer types, including NSCLC, with PTEN mutations exerting an effect on the therapeutic response of EGFR/AKT/PI3K pathway inhibitors. TTF-1 is expressed in approximately 80% of lung adenocarcinomas and its positivity correlates with higher prevalence of EGFR mutation in this cancer type. To determine molecular markers for lung cancer in Brazilian patients, the rate of the predominant EGFR, KRAS, BRAF and PTEN mutations, as well as TTF-1 expression, was assessed in 88 Brazilian NSCLC patients. EGFR exon 19 deletions (del746-750) were detected in 3/88 (3·4%) patients. Activating KRAS mutations in codons 12 and 61 were noted in five (5·7%) and two (2·3%) patients, respectively. None of the common somatic mutations were detected in either the BRAF or PTEN genes. TTF-1 was overexpressed in 40·7% of squamous-cell carcinoma (SCC). Our findings add to a growing body of data that highlights the genetic heterogeneity of the abnormal EGFR pathway in lung cancer among ethnically diverse populations.

Current readings: pathology, prognosis, and lung cancer

The 2011 International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society international multidisciplinary classification of lung adenocarcinoma introduced the new categories of adenocarcinoma in situ, minimally invasive adenocarcinoma, and invasive mucinous adenocarcinoma, and replaced the category of mixed subtype adenocarcinoma with lepidic, acinar, papillary, micropapillary, and solid predominant adenocarcinoma. The aim of this manuscript is to evaluate whether the new classification can be applied successfully in determining prognosis of surgically resected patients. Six consecutive clinicopathologic studies using the new classification that were published between spring 2011 and fall 2012 were reviewed. Overall, they demonstrated excellent outcome for adenocarcinoma in situ and minimally invasive adenocarcinoma; intermediate outcome for lepidic, acinar, and papillary predominant adenocarcinoma; and poor outcome for solid and micropapillary predominant adenocarcinoma and invasive mucinous adenocarcinoma. As the new classification remains a proposal at this time, it is hoped that thoracic surgeons will play a leading role in its worldwide dissemination for clinical care and research.

The role of molecular analyses in the diagnosis and treatment of non-small-cell lung carcinomas

Non-small-cell lung cancer (NSCLC) subtyping has recently been a key factor in determining patient management with novel drugs. In addition, the identification of distinct oncogenic driver mutations frequently associated with NSCLC histotype and coupled to the clinical responses to targeted therapies have revolutionized the impact of histologic type and molecular biomarkers in lung cancer. Several molecular alterations involving different genes (EGFR, KRAS, ALK, BRAF, and HER2) seem to have a remarkable predilection for adenocarcinoma and specific inhibitors of EGFR and ALK are now available for patients with adenocarcinoma harboring the relevant gene alterations. The efficacy of histology-based and molecular-targeted therapies had a deep impact in (1) re-defining classification of lung cancer (particularly adenocarcinomas) and (2) routine clinical practice of pathologists involved in optimization of handling of tissue samples in order to guarantee NSCLC subtyping with the help of immunohistochemistry and adequately preserve tumor cells for molecular analysis. In agreement with the modern multidisciplinary approach to lung cancer, we reviewed here the diagnostic and predictive value of molecular biomarkers according to the clinical, pathologic, and molecular biologist viewpoints.

KRAS mutations are associated with solid growth pattern and tumor-infiltrating leukocytes in lung adenocarcinoma

KRAS mutations define a clinically distinct subgroup of lung adenocarcinoma patients, characterized by smoking history, resistance to EGFR-targeted therapies, and adverse prognosis. Whether KRAS-mutated lung adenocarcinomas also have distinct histopathological features is not well established. We tested 180 resected lung adenocarcinomas for KRAS and EGFR mutations by high-sensitivity mass spectrometry-based genotyping (Sequenom) and PCR-based sizing assays. All tumors were assessed for the proportion of standard histological patterns (lepidic, acinar, papillary, micropapillary, solid, and mucinous), several other histological and clinical parameters, and TTF-1 expression by immunohistochemistry. Among 180 carcinomas, 63 (35%) had KRAS mutations (KRAS+), 35 (19%) had EGFR mutations (EGFR+), and 82 (46%) had neither mutation (KRAS-/EGFR-). Solid growth pattern was significantly over-represented in KRAS+ carcinomas: the mean±s.d. for the amount of solid pattern in KRAS+ carcinomas was 27±34% compared with 3±10% in EGFR+ (P<0.001) and 15±27% in KRAS-/EGFR- (P=0.033) tumors. Furthermore, at least focal (≥20%) solid component was more common in KRAS+ (28/63; 44%) compared with EGFR+ (2/35; 6%; P<0.001) and KRAS-/EGFR- (21/82; 26%; P=0.022) carcinomas. KRAS mutations were also over-represented in mucinous carcinomas and were significantly associated with the presence of tumor-infiltrating leukocytes and heavier smoking history. EGFR mutations were associated with non-mucinous non-solid patterns, particularly lepidic and papillary, lack of necrosis, lack of cytological atypia, hobnail cytology, TTF-1 expression, and never/light smoking history. In conclusion, extended molecular and clinicopathological analysis of lung adenocarcinomas reveals a novel association of KRAS mutations with solid histology and tumor-infiltrating inflammatory cells and expands on several previously recognized morphological and clinical associations of KRAS and EGFR mutations. Solid growth pattern was recently shown to be a strong predictor of aggressive behavior in lung adenocarcinomas, which may underlie the unfavorable prognosis associated with KRAS mutations in these tumors.

Detection of EGFR gene mutations in non-small cell lung cancer: lessons from a single-institution routine analysis of 1,403 tumor samples

Activating mutations of the epidermal growth factor receptor (EGFR) in lung tumors are associated with a dramatic response to tyrosine kinase inhibitors. Therefore, routine analysis of pathological specimens is mandatory in clinical practice. We have prospectively tested tumors from Caucasian lung tumor patients between January 2010 and June 2012. DNA was extracted from formalin-fixed paraffin-embedded tissues following macrodissection. The p.L858R substitution was assessed by allele-specific PCR and exon 19 deletions by PCR and DNA fragment analysis. Using a robust process from patient sampling to screening methods, we analyzed samples from 1,403 patients. The EGFR status could be successfully determined for 1,322 patients. EGFR mutations were detected in 179 (13.5%) patients, with female and adenocarcinoma histology predominance. Mutated patients were significantly older than non-mutated patients. Similar mutation rates were obtained with primary tumors and metastases, and with surgical resection, bronchial biopsies, CT-guided needle biopsies and transbronchial needle aspiration. The sensitivity of our assays allowed us to detect EGFR mutations in samples poor (<10%) in tumor cells. Finally, the mutation rate was much higher in tumors expressing the TTF-1 antigen (145/820; 17.7%) than in TTF-1 negative tumors (3/218; 1.4%). The results obtained through routine analysis of more than 1,300 samples indicated that all types of specimen can be analyzed without any significant bias. TTF-1 immunostaining may be used to predict negative EGFR mutation status.

HepPar-1 expression in primary lung adenocarcinoma

OBJECTIVES

To study a subset of lung adenocarcinomas with aberrant HepPar-1 antigen expression.

METHODS

We performed a clinicopathologic review of 16 cases.

RESULTS

Of 241 primary lung adenocarcinomas tested for expression of the HepPar-1 antigen, 16 (6.6%) were positive. The cases occurred in older smokers with an equal sex distribution. Morphologically, these pulmonary adenocarcinomas had an acinar-predominant architecture, and prominent cribriform growth, with HepPar-1-expressing tumor cells being uniformly columnar with abundant bipolar lightly eosinophilic cytoplasm. HepPar-1 was coexpressed with thyroid transcription factor 1 in 94% of cases. No EGFR mutations were identified, while 31% of cases were positive for KRAS codon 12 mutations.

CONCLUSIONS

Although aberrant HepPar-1 expression was frequently seen in tumors with visceral pleural and angiolymphatic invasion, its prognostic significance is uncertain.

Common and rare EGFR and KRAS mutations in a Dutch non-small-cell lung cancer population and their clinical outcome

INTRODUCTION

In randomly assigned studies with EGFR TKI only a minor proportion of patients with NSCLC have genetically profiled biopsies. Guidelines provide evidence to perform EGFR and KRAS mutation analysis in non-squamous NSCLC. We explored tumor biopsy quality offered for mutation testing, different mutations distribution, and outcome with EGFR TKI.

PATIENT AND METHODS

Clinical data from 8 regional hospitals were studied for patient and tumor characteristics, treatment and overall survival. Biopsies sent to the central laboratory were evaluated for DNA quality and subsequently analyzed for mutations in exons 18-21 of EGFR and exon 2 of KRAS by bidirectional sequence analysis.

RESULTS

Tumors from 442 subsequent patients were analyzed. For 74 patients (17%) tumors were unsuitable for mutation analysis. Thirty-eight patients (10.9%) had EGFR mutations with 79% known activating mutations. One hundred eight patients (30%) had functional KRAS mutations. The mutation spectrum was comparable to the Cosmic database. Following treatment in the first or second line with EGFR TKI median overall survival for patients with EGFR (n = 14), KRAS (n = 14) mutations and wild type EGFR/KRAS (n = 31) was not reached, 20 and 9 months, respectively.

CONCLUSION

One out of every 6 tumor samples was inadequate for mutation analysis. Patients with EGFR activating mutations treated with EGFR-TKI have the longest survival.

Lung adenocarcinoma in the era of targeted therapies: histological classification, sample prioritization, and predictive biomarkers

The arrival of targeted therapies has presented both a conceptual and a practical challenge in the treatment of patients with advanced non-small cell lung carcinomas (NSCLCs). The relationship of these treatments with specific histologies and predictive biomarkers has made the handling of biopsies the key factor for success. In this study, we highlight the balance between precise histological diagnosis and the practice of conducting multiple predictive assays simultaneously. This can only be achieved where there is a commitment to multidisciplinary working by the tumor board to ensure that a sensible protocol is applied. This proposal for prioritizing samples includes both recent technological advances and the some of the latest discoveries in the molecular classification of NSCLCs.

NKX2-1/TTF-1: an enigmatic oncogene that functions as a double-edged sword for cancer cell survival and progression

Emerging evidence indicates that NKX2-1, a homeobox-containing transcription factor also known as TTF-1, plays a role as a "lineage-survival" oncogene in lung adenocarcinomas. In T cell acute lymphoblastic leukemia, gene rearrangements lead to aberrant expression of NKX2-1/TTF-1. Despite accumulating evidence supporting its oncogenic role, it has become apparent that NKX2-1/TTF-1 expression also has biological and clinical functions in the opposite direction that act against tumor progression. Herein, we review recent findings showing these enigmatic double-edged characteristics, with special attention given to the roles of NKX2-1/TTF-1 in lung development and carcinogenesis.

Diagnosis of lung adenocarcinoma in resected specimens: implications of the 2011 International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification

A new lung adenocarcinoma classification has been published by the International Association for the Study of Lung Cancer, the American Thoracic Society, and the European Respiratory Society. This new classification is needed to provide uniform terminology and diagnostic criteria, most especially for bronchioloalveolar carcinoma. It was developed by an international core panel of experts representing all 3 societies with oncologists/pulmonologists, pathologists, radiologists, molecular biologists, and thoracic surgeons.This summary focuses on the aspects of this classification that address resection specimens. The terms bronchioloalveolar carcinoma and mixed subtype adenocarcinoma are no longer used. For resection specimens, new concepts are introduced, such as adenocarcinoma in situ and minimally invasive adenocarcinoma for small solitary adenocarcinomas with either pure lepidic growth (adenocarcinoma in situ) and predominant lepidic growth with invasion of 5 mm or less (minimally invasive adenocarcinoma), to define the condition of patients who will have 100% or near 100% disease-specific survival, respectively, if they undergo complete lesion resection. Adenocarcinoma in situ and minimally invasive adenocarcinoma are usually nonmucinous, but rarely may be mucinous. Invasive adenocarcinomas are now classified by predominant pattern after using comprehensive histologic subtyping with lepidic (formerly most mixed subtype tumors with nonmucinous bronchioloalveolar carcinoma), acinar, papillary, and solid patterns; micropapillary is added as a new histologic subtype. Variants include invasive mucinous adenocarcinoma (formerly mucinous bronchioloalveolar carcinoma), colloid, fetal, and enteric adenocarcinoma.It is possible that this classification may impact the next revision of the TNM staging classification, with adjustment of the size T factor according to only the invasive component pathologically in adenocarcinomas with lepidic areas.

A case of synchronous bilateral lung cancers: EML4-ALK positive adenocarcinoma in the right lung and adenocarcinoma in situ (the former bronchioloalveolar carcinoma) in the left lung

BACKGROUND

Recently it has been revealed that lung adenocarcinomas with distinct gene mutations or fusions are associated with particular histopathological entities. For example, epidermal growth factor receptor (EGFR) gene mutations are often associated with well differentiated adenocarcinoma of the lung with bronchioloalveolar pattern. On the other hand, echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) fusion gene in a subset of lung adenocarcinoma is related to mucinous cribriform histology.

CASE PRESENTATION

Reported herein is a case of synchronous EML4-ALK positive lung adenocarcinoma and adenocarcinoma in situ in the bilateral lungs of a 55-year-old Japanese woman. The woman had EML4-ALK positive lung adenocarcinoma in the right lower lung while adenocarcinoma in situ in the left upper lung, which was EML4-ALK negative.

CONCLUSION

To our knowledge, this is the first report of synchronous, bilateral lung adenocarcinomas composed of EML4-ALK positive and negative ones.

Epidermal growth factor receptor mutation in lung adenocarcinomas: relationship with CT characteristics and histologic subtypes

PURPOSE

To retrospectively identify quantitative computed tomographic (CT) features that correlate with epidermal growth factor receptor (EGFR) mutation in surgically resected lung adenocarcinomas stratified by the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS) classification in an East Asian cohort of patients known to have a high prevalence of EGFR mutations.

MATERIALS AND METHODS

An institutional review board approved this study and waived informed consent. In 153 surgically resected lung adenocarcinomas, EGFR mutation was determined by direct DNA sequencing. Histologic subtype was classified according to IASLC/ATS/ERS classification of lung adenocarcinoma. At preoperative chest CT, the percentage of ground-glass opacity (GGO) volume and total tumor volume of each tumor were measured by using a semiautomated algorithm. Distribution of EGFR mutation according to histologic subtype, percentage of GGO volume, and total tumor volume was evaluated by using the Fisher exact test, the Student t test, trend analysis, and multiple logistic regression analysis.

RESULTS

Exon 21 missense mutation was more frequent in lepidic predominant adenocarcinomas than in other histologic subtypes (odds ratio, 3.44; 95% confidence interval: 1.53, 7.74; P = .003). GGO volume percentage in tumors with exon 21 missense mutation (61.7% ± 31.9 [standard deviation]) was significantly higher than that in EGFR wild-type tumors (30.0% ± 38.5) (P = .0001) and exon 19-mutated tumors (28.9% ± 37.7) (P = .0006). A significant trend of prevalence of exon 21 missense mutation increasing along with increasing GGO volume (P = .0008) was found.

CONCLUSION

GGO volume percentage in tumors with exon 21 missense mutation was significantly higher than that in tumors with other EGFR mutation status. This can be related to the fact that exon 21 missense mutation was significantly more frequent in lepidic predominant adenocarcinomas, including adenocarcinoma in situ, minimally invasive adenocarcinoma, and lepidic predominant invasive adenocarcinoma, according to IASLE/ATS/ERS classification.

Negative NKX2-1 (TTF-1) as temporary surrogate marker for treatment selection during EGFR-mutation analysis in patients with non-small-cell lung cancer

INTRODUCTION

In the past decade, major progress has been made toward personalized medical treatment of non-small-cell lung cancer (NSCLC) through the discovery of epithelial growth factor receptor (EGFR) mutations. However, mutation analysis takes extra time and additional costs in the diagnostic evaluation of lung cancer patients. It has been hypothesized that EGFR mutations are restricted to terminal respiratory unit -type adenocarcinoma expressing thyroid transcription factor-1 (official symbol NKX2-1) as determined by immunohistochemistry. The aim of the current study is to evaluate the potential of NKX2-1 immunohistochemistry as a prescreening test for EGFR mutation analysis.

METHODS

From 2004 to December 2010, 810 consecutive NSCLC tumor specimens were tested for EGFR mutations in a routine diagnostic procedure. Immunohistochemistry for NKX2-1 was performed (clone 8G7G3/1 [Dako]) and the results were compared with tumor EGFR-mutation status and clinicopathological characteristics.

RESULTS

EGFR mutations were detected in 114 specimens (14%). NKX2-1 expression was present in 68%. In the cases with EGFR mutation, NKX2-1 staining was positive in 92%. NKX2-1 immunohistochemical (IHC) staining was significantly associated with the presence of EGFR mutations (p = 5.3×10). NKX2-1 increased the negative predictive value in NSCLC to more than 95%.

CONCLUSIONS

In case of a negative NKX2-1 IHC staining, and only if clinically urgent, the high negative predictive value of more than 95% for EGFR mutations is a suitable temporary surrogate marker for the choice of starting with chemotherapy. In case of positive NKX2-1 IHC, the best strategy is to wait for the outcome of EGFR-mutation analysis and then choose the appropriate treatment.

Association between a genome-wide association study-identified locus and the risk of lung cancer in Japanese population

BACKGROUND

Genome-wide association studies have identified 15q25 and 5p15 as lung cancer risk chromosomal regions in whites. The genetic structures of these loci differ between Asians and whites, however, indicating the need for additional studies in Asian populations. To examine the impact of 15p25 and 5p15 on lung cancer risk and smoking intensity, we conducted a case-control study in Japanese population. We also examined whether these loci modify the effect of smoking behavior on lung cancer risk.

METHODS

Subjects were 716 Japanese patients with lung cancer and 716 controls. Associations were examined by logistic regression models with adjustment for potential confounders.

RESULTS

We found that the variants of rs12914385 and rs931794 on 15q25 modified the effect of cumulative tobacco smoking on lung cancer risk but that these two loci showed no statistically significant main effects on lung cancer risk. Compared with never smoking without the risk allele of rs931794, odds ratio for heavy smoking without the risk allele was 4.03 (95% confidence interval: 2.45-6.62) and that with the risk allele was 8.09 (5.09-12.9), and the joint effect of rs931734 and cumulative tobacco consumption was statistically significant (pinteraction < 0.001). A similar impact was observed with rs12914385 at chromosome 15q25 (pinteraction = 0.021). Associations for the TERT-CLPM1L locus on 5p15 with lung cancer risk in Japanese patients were of a similar magnitude to those in whites.

CONCLUSIONS

These results support the contribution of 15q25 and 5p15 to lung cancer and indicate that the 15q25 region modifies the well-established effect of smoking on the risk of lung cancer in a Japanese population.

Role of epidermal growth factor receptor in breast cancer

Decades of research in molecular oncology have brought about promising new therapies which are designed to target specific molecules which promote tumor growth and survival. The epidermal growth factor receptor (EGFR) is one of the first identified important targets of these novel antitumor agents. Approximately half of cases of triple-negative breast cancer (TNBC) and inflammatory breast cancer (IBC) overexpress EGFR. Thus, EGFR inhibitors for treatment of breast cancer have been evaluated in several studies. However, results so far have been disappointing. One of the reasons for these unexpected results is the lack of biomarkers for predicting which patients are most likely to respond to EGFR inhibitors. Recent studies have shown that EGFR and its downstream pathway regulate epithelial-mesenchymal transition, migration, and tumor invasion and that high EGFR expression is an independent predictor of poor prognosis in IBC. Further, recent studies have shown that targeting EGFR enhances the chemosensitivity of TNBC cells by rewiring apoptotic signaling networks in TNBC. These studies indicate that EGFR-targeted therapy might have a promising role in TNBC and IBC. Further studies of the role of EGFR in TNBC and IBC are needed to better understand the best way to use EGFR-targeted therapy-e.g., as a chemosensitizer or to prevent metastases-to treat these aggressive diseases.

Ciliated adenocarcinomas of the lung: a tumor of non-terminal respiratory unit origin

Whereas most carcinomas occur through a sequential step, atypical adenomatous hyperplasia and bronchioloalveolar carcinoma pathway is known for pulmonary adenocarcinoma. This type is known as terminal respiratory unit adenocarcinoma. Based on our observation of transitions from normal ciliated columnar cells to adenocarcinoma via dysplastic mucous columnar cells, we reviewed our archive of pulmonary adenocarcinoma. Terminal respiratory unit type adenocarcinoma was defined as adenocarcinoma with type II pneumocyte, Clara cell, or bronchiolar cell morphology according to previous reports. Among 157 cases, 121 cases have been identified as terminal respiratory unit type adenocarcinoma and 36 cases as non-terminal respiratory unit type adenocarcinoma. Among non-terminal respiratory unit type adenocarcinoma, 24 cases revealed mucous columnar cell changes that were continuous with bronchial ciliated columnar cells. The mucous columnar cells became dysplastic showing loss of cilia, disorientation, and enlarged nuclei. Adenocarcinoma arose from these dysplastic mucous columnar cells and, characteristically, this type of adenocarcinoma showed acute inflammation, and honeycombing changes in the background. TTF1 immunostaining was consistently negative. In a case study with 14 males and 10 females, including 12 smokers or ex-smokers, EGFR and KRAS mutations were detected in 3 and 6 patients, respectively. We think that this kind of adenocarcinoma arising through mucous columnar cell change belongs to non-terminal respiratory unit type adenocarcinoma, and mucous columnar cell change is a precursor lesion of pulmonary adenocarcinoma.

Recent understanding of the molecular mechanisms for the efficacy and resistance of EGF receptor-specific tyrosine kinase inhibitors in non-small cell lung cancer

INTRODUCTION

The epidermal growth factor receptor (EGFR) and its family members are involved in many aspects of tumor biological processes. Aberrant activation of the EGFR tyrosine kinase by mutations or protein overexpression is observed in various types of human cancer, including lung cancer. EGFR tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib and erlotinib, are highly effective in lung cancer patients who harbor active mutations in the EGFR gene. However, patients who are initially sensitive to EGFR-TKIs eventually relapse within few years.

AREAS COVERED

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and is associated with a high frequency of EGFR mutations. This review describes the EGFR mutations that determine the sensitivity to EGFR-TKIs and the current understanding of the molecular mechanisms of acquired resistance to EGFR-TKIs in NSCLC. Furthermore, the authors describe recent strategies developed to overcome acquired resistance using second-generation EGFR-TKIs and combination therapies with several molecular-targeting drugs.

EXPERT OPINION

Although recent findings have contributed to our understanding of the mechanism of acquired resistance and helped the development of novel strategies to overcome such resistance, the underlying mechanisms are complex and additional research is necessary to develop effective therapeutic strategies for individual patients with lung cancer.

High incidence of EGFR mutations in Korean men smokers with no intratumoral heterogeneity of lung adenocarcinomas: correlation with histologic subtypes, EGFR/TTF-1 expressions, and clinical features

INTRODUCTION

Epidermal growth factor receptor (EGFR) mutation has been known to be associated with adenocarcinoma with bronchioloalveolar carcinoma (BAC; lepidic) feature. This study was aimed to characterize the frequency of EGFR mutations and their association with histologic subtypes in Korean nonsmall cell lung cancer (NSCLC) patients.

METHODS

Three hundred eighty-two (88 biopsies and 294 resections) NSCLC patients were investigated for EGFR mutations (exons 18-21) by polymerase chain reaction and direct sequencing method. For the resected adenocarcinoma specimens, histologic subtypes were classified according to both 2004 World Health Organization classification and 2011 International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification. The results were correlated with EGFR mutation and clinicopathologic features.

RESULTS

EGFR mutations were detected in 196 of 382 NSCLCs (51.3%) and were more frequent in women than in men (65.7% versus 34.3%, p < 0.001) and in nonsmokers than in smokers (63.4% versus 32.0%, p < 0.001). Regarding histologic subtypes of adenocarcinoma, mixed acinar and BAC pattern showed the most frequent EGFR mutation (67.6%), followed by mixed papillary and acinar (65.2%), mixed solid and acinar (38.2%), micropapillary and acinar (30.4%), and acinar and mucinous BAC (13.3%). In addition, EGFR mutations were more frequently observed in tumors with BAC or papillary components than those with mucinous BAC or solid components. Identical EGFR mutations were detected in a single tumor showing mixed histological features. EGFR protein expression was seen more frequently in tumors with EGFR mutations than those without EGFR mutations (75.3% versus 24.7%, p=0.003). EGFR mutations were significantly more common in tumors with thyroid transcription factor-1 (TTF-1) expression than those without TTF-1 (p < 0.001), and almost all (92.7%) mutated adenocarcinomas were TTF-1 positive.

CONCLUSIONS

The incidence of EGFR mutations is variable according to histologic subtypes, gender, and smoking history. The mixed acinar and BAC and papillary and acinar subtypes, the presence of BAC (lepidic) or papillary components, EGFR, and TTF-1 protein expression can predict higher EGFR mutation in lung adenocarcinoma. However, intratumoral heterogeneity of EGFR mutation was not found. In addition, relatively high incidence of EGFR mutations in Korean men who smoked with adenocarcinoma histology suggests that these patients should not be left behind EGFR mutation test.

Differential pathogenesis of lung adenocarcinoma subtypes involving sequence mutations, copy number, chromosomal instability, and methylation

Background

Lung adenocarcinoma (LAD) has extreme genetic variation among patients, which is currently not well understood, limiting progress in therapy development and research. LAD intrinsic molecular subtypes are a validated stratification of naturally-occurring gene expression patterns and encompass different functional pathways and patient outcomes. Patients may have incurred different mutations and alterations that led to the different subtypes. We hypothesized that the LAD molecular subtypes co-occur with distinct mutations and alterations in patient tumors.

Methodology/Principal Findings

The LAD molecular subtypes (Bronchioid, Magnoid, and Squamoid) were tested for association with gene mutations and DNA copy number alterations using statistical methods and published cohorts (n = 504). A novel validation (n = 116) cohort was assayed and interrogated to confirm subtype-alteration associations. Gene mutation rates (EGFR, KRAS, STK11, TP53), chromosomal instability, regional copy number, and genomewide DNA methylation were significantly different among tumors of the molecular subtypes. Secondary analyses compared subtypes by integrated alterations and patient outcomes. Tumors having integrated alterations in the same gene associated with the subtypes, e.g. mutation, deletion and underexpression of STK11 with Magnoid, and mutation, amplification, and overexpression of EGFR with Bronchioid. The subtypes also associated with tumors having concurrent mutant genes, such as KRAS-STK11 with Magnoid. Patient overall survival, cisplatin plus vinorelbine therapy response and predicted gefitinib sensitivity were significantly different among the subtypes.

Conclusions/ Significance

The lung adenocarcinoma intrinsic molecular subtypes co-occur with grossly distinct genomic alterations and with patient therapy response. These results advance the understanding of lung adenocarcinoma etiology and nominate patient subgroups for future evaluation of treatment response.

NKX2-1/TITF1/TTF-1-Induced ROR1 is required to sustain EGFR survival signaling in lung adenocarcinoma

We and others previously identified NKX2-1, also known as TITF1 and TTF-1, as a lineage-survival oncogene in lung adenocarcinomas. Here we show that NKX2-1 induces the expression of the receptor tyrosine kinase-like orphan receptor 1 (ROR1), which in turn sustains a favorable balance between prosurvival PI3K-AKT and pro-apoptotic p38 signaling, in part through ROR1 kinase-dependent c-Src activation, as well as kinase activity-independent sustainment of the EGFR-ERBB3 association, ERBB3 phosphorylation, and consequential PI3K activation. Notably, ROR1 knockdown effectively inhibited lung adenocarcinoma cell lines, irrespective of their EGFR status, including those with resistance to the EGFR tyrosine kinase inhibitor gefitinib. Our findings thus identify ROR1 as an "Achilles' heel" in lung adenocarcinoma, warranting future development of therapeutic strategies for this devastating cancer.

Napsin A is an independent prognostic factor in surgically resected adenocarcinoma of the lung

INTRODUCTION

Napsin A is regarded as a marker of lung adenocarcinoma. However, no comprehensive analyses of napsin A-positive lung ADCs or the prognostic significance of napsin A expression have been reported to date.

METHODS

110 primary lung adenocarcinoma cases were analyzed for clinicopathologic parameters, including overall survival, stage, histology, napsin A and TTF-1 expression, EGFR mutation, and ALK rearrangement.

RESULTS

Napsin A-positive adenocarcinomas were significantly more prevalent among tumors characterized as relatively small (p = 0.023), non-solid predominant (p < 0.001), non-mucinous/enteric (p < 0.001), positive for TTF-1 expression (p < 0.001), and positive for EGFR mutation (p = 0.001). Multivariate analysis of overall survival demonstrated that the absence of napsin A was an independent prognostic factor for reduced survival time (p = 0.002).

CONCLUSION

Clinicopathologic characteristics associated with napsin A-positive lung ADC are similar to and overlap with those of TTF-1-positive ADCs. The absence of napsin A is an independent poor prognostic factor in surgically resected adenocarcinoma. Further studies are necessary to determine the role of napsin A in the progression of lung adenocarcinoma.

Pulmonary adenocarcinoma: a renewed entity in 2011

Lung cancer, of which non-small-cell lung cancer comprises the majority, is the leading cause of cancer-related deaths in the United States and worldwide. Lung adenocarcinomas are a major subtype of non-small-cell lung cancers, are increasing in incidence globally in both males and females and in smokers and non-smokers, and are the cause for almost 50% of deaths attributable to lung cancer. Lung adenocarcinoma is a tumour with complex biology that we have recently started to understand with the advent of various histological, transcriptomic, genomic and proteomic technologies. However, the histological and molecular pathogenesis of this malignancy is still largely unknown. This review will describe advances in the molecular pathology of lung adenocarcinoma with emphasis on genomics and DNA alterations of this disease. Moreover, the review will discuss recognized lung adenocarcinoma preneoplastic lesions and current concepts of the early pathogenesis and progression of the disease. We will also portray the field cancerization phenomenon and lineage-specific oncogene expression pattern in lung cancer and how both remerging concepts can be exploited to increase our understanding of lung adenocarcinoma pathogenesis for subsequent development of biomarkers for early detection of adenocarcinomas and possibly personalized prevention.

Lung cancer in never smokers

Lung cancer in never smokers (LCINS) is the seventh leading cause of death among solid tumors. The main risk factor for lung cancer is smoking; however, approximately 15% of lung cancer patients have never smoked. LCINS is more frequent in women, irrespective of geographical location, nevertheless, the highest incidence has been found in South-East Asia. The histological incidence of adenocarcinoma is higher in the group of never smokers than squamous cell carcinoma. There is a familial clustering of lung cancer that is more pronounced in never smokers, where the family history was associated with an increased risk. Genome-wide association studies identified certain chromosomal aberrations in LCINS. Furthermore, the oncogenic mutation pattern is distinct in nonsmoking patients: activating mutations of EGFR or anaplastic lymphoma kinase are more frequent. The etiology of LCINS includes several environmental factors as well, such as environmental tobacco smoke, viral and hormonal factors, a variety of pulmonary diseases and certain occupational exposures. It is now established that EGFR-tyrosine kinase inhibitor treatment (erlotinib and geftinib) in lung cancer is more effective in LCINS, owing to the higher incidence of EGFR mutation in nonsmokers. Despite the growing body of information on LCINS in recent years there is a need to further investigate the pathogenesis of this particular lung cancer. Future studies on LCINS should try to tackle the issues of prevention, early diagnosis and the exploration of novel therapeutic targets to combat lung cancer disease.

Histological subtypes of lung adenocarcinoma have differential ¹⁸F-fluorodeoxyglucose uptakes on the positron emission tomography/computed tomography scan

INTRODUCTION

Previous studies have shown that lung squamous cell carcinoma has higher ¹⁸F-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) than adenocarcinoma. We hypothesized that histological subtypes of lung adenocarcinoma were also different in ¹⁸F-FDG uptake.

METHODS

Patients who had preoperative PET/computed tomography (CT) scan and had undergone complete resection for lung adenocarcinoma between April 2007 and December 2009 were enrolled in this study. Because of the limitation of spatial resolution on PET/CT, tumors less than 1 cm were excluded for analysis. Two independent classification systems were used to categorize histological subtypes of adenocarcinoma; one was modified from the current World Health Organization classification and the other used the morphological features of the terminal respiratory unit (TRU). The maximal standardized uptake value (SUVmax) on PET/CT and the glucose transporter type 1 (GLUT-1) expression of the tumors were measured and correlated to the histology of lung adenocarcinoma.

RESULTS

One hundred fifty-two patients with 153 primary lung adenocarcinomas were included. There was a significant difference in SUVmax among different histological subtypes. Namely, solid predominant adenocarcinomas had significantly higher SUVmax than those with other predominant histology (p < 0.001), and TRU-type adenocarcinomas had significantly lower SUVmax than non-TRU-type adenocarcinomas (p < 0.001). Consistently, GLUT-1 expression was higher in tumors with a solid growth pattern than those without (p < 0.001) and in tumors with non-TRU type than TRU type (p < 0.001).

CONCLUSIONS

The histological subtypes of lung adenocarcinomas differ in GLUT-1 expression and ¹⁸F-FDG uptake on the PET/CT scan, suggesting that histological subtyping not only has morphological but also biological implications.

Epidermal growth factor receptor and KRAS mutations in Brazilian lung cancer patients

OBJECTIVE

Epidermal growth factor receptor is involved in the pathogenesis of non-small cell lung cancer and has recently emerged as an important target for molecular therapeutics. The KRAS oncogene also plays an important role in the development of lung cancer. The aim of this study was to evaluate the frequency of epidermal growth factor receptor and KRAS mutations in a population of Brazilian patients with non-small cell lung cancer.

METHODS

A total of 207 specimens from Brazilian patients with non-small cell lung cancer were analyzed for activating epidermal growth factor receptor and KRAS somatic mutations, and their associations with clinicopathological characteristics (including age, gender, ethnicity, smoking habits, and histological subtype) were examined.

RESULTS

We identified 63 cases (30.4%) with epidermal growth factor receptor mutations and 30 cases (14.6%) with KRAS mutations. The most frequent epidermal growth factor receptor mutation we detected was a deletion in exon 19 (60.3%, 38 patients), followed by an L858R amino acid substitution in exon 21 (27%, 17 patients). The most common types of KRAS mutations were found in codon 12. There were no significant differences in epidermal growth factor receptor or KRAS mutations by gender or primary versus metastatic lung cancer. There was a higher prevalence of KRAS mutations in the non-Asian patients. Epidermal growth factor receptor mutations were more prevalent in adenocarcinomas than in non-adenocarcinoma histological types. Being a non-smoker was significantly associated with the prevalence of epidermal growth factor receptor mutations, but the prevalence of KRAS mutations was significantly associated with smoking.

CONCLUSIONS

This study is the first to examine the prevalence of epidermal growth factor receptor and KRAS mutations in a Brazilian population sample with non-small cell lung cancer.