Micropapillary lung adenocarcinoma: EGFR, K-ras, and BRAF mutational profile

The clinicopathological features and possible physiological mechanisms of only the EGFR-T790M primary mutation in patients with lung adenocarcinoma

BACKGROUND

The treatment of non-small cell lung cancer (NSCLC) patients can be complicated by the presence of the EGFR-T790M mutation. Although primary or secondary EGFR-T790M mutations have been extensively studied worldwide, there are few reports on the clinicopathological characteristics and physiological mechanisms of lung adenocarcinoma (LUAD) with only the EGFR-T790M primary mutation.

METHODS

The clinical data of all LUAD patients with only the EGFR-T790M primary mutation were collected. Immunohistochemical staining was performed on cell cycle-related proteins, targeted therapy indicators, and prognosis-related proteins in the specimens obtained from puncture biopsies or surgeries.

OBJECTIVES

The aim of this study is to analyze the clinicopathological features and possible physiological mechanisms of only the EGFR-T790M primary mutation in LUAD, and to offer recommendations for clinical management.

RESULTS

Two patients who have only the T790M de novo mutation were both female (2/12,928, 0.02%). β-catenin and Cyclin D1 were both highly expressed. In case 1, IHC results showed a positive Ki67 and mutant P53 and there was a significant increase in serum CYFRA 21-1. Third-generation of EGFR TKIs resulted in a partial response (PR) time of less than 8 months in case 1. In case 2, the patient underwent surgical resection and adjuvant chemotherapy, resulting in a progression-free survival (PFS) time of 25 months.

CONCLUSION

The results suggest that abnormal activation of the Wnt signaling pathway may be specifically associated with the EGFR-T790M primary mutation in LUAD. Furthermore, it has been observed that patients with significant Ki67, mutant P53, and CYFRA 21-1 expression tend to have a poor prognosis.

Genomic and clinicopathological features of lung adenocarcinomas with micropapillary component

BACKGROUND

Lung adenocarcinoma (LA) with a micropapillary component (LAMPC) is a histological subtype of lung cancer that has received increasing attention due to its correlation with poor prognosis, and its tendency to recur and metastasize. At present, comprehensive genomic profiles and clinicopathological features for LAMPC remain unclear and require further investigation.

METHODS

From September 2009 to October 2020, a total of 465 LAMPC patients were recruited and divided into four groups according to MPC proportions, and the correlations between varying proportions of MPCs and clinicopathological characteristics were analyzed. Twenty-nine (29) LAMPC patients and 89 LA patients without MPC (non-MPC) that had undergone NGS testing were selected for further study The comprehensively analyze genomic variations and the difference between LAMPC and MPC were determined. In addition, Gene alterations of LAMPC between Chinese and Western populations were also compared using cBioPortal data.

RESULTS

A higher proportion of MPCs, associated with higher tumor stage, pleural invasion, and vascular tumor thrombus formation, was determined in LA patients. Compared to non-MPC patients, LAMPC patients were determined to have a lower frequency of single nucleotide variants and a higher frequency of insertion-deletion mutations. Mutations in TP53, CTNNB1, and SMAD4, and ALK rearrangements/fusions were significantly more frequent in LAMPC patients. ERBB2 mutations were only detected in non-MPC patients. Gene mutations in the Wnt pathway were significantly more common in LAMPC patients as compared to non-MPC patients. ALK fusions were more prevalent in younger patients. Patients with KRAS or LBP1B mutations had significantly larger tumor diameters than patients with wild-type KRAS or LBP1B. Patients with KRAS mutations were more likely to develop vascular tumor thrombus. Using the cBioPortal public database, we determined that mutations in EGFR were significantly higher in Chinese patients than in a Memorial Sloan Kettering Cancer Center (MSKCC) Western cohort. ALK fusions were exclusively detected in the Chinese cohort, while mutations in KEAP1 and NOTCH4 were only detected in the MSKCC cohort. Our analysis of signaling pathways revealed that Wnt pathway gene mutations were significantly higher in the Chinese cohort.

CONCLUSION

LA patients with higher proportions of MPCs were determined to have a higher tumor stage, pleural invasion, and vascular tumor thrombosis formation. We comprehensively analyzed the genomic mutation characteristics of LAMPC patients and identified multiple, novel MPC-related gene alterations and pathway changes. Our data provide further understanding of the nature of the LAMPC and potential drug-targeted gene alterations, which may lead to new therapeutic strategies.

Transposon Mutagenesis Reveals RBMS3 Silencing as a Promoter of Malignant Progression of BRAFV600E-Driven Lung Tumorigenesis

Mutationally activated BRAF is detected in approximately 7% of human lung adenocarcinomas, with BRAFT1799A serving as a predictive biomarker for treatment of patients with FDA-approved inhibitors of BRAFV600E oncoprotein signaling. In genetically engineered mouse (GEM) models, expression of BRAFV600E in the lung epithelium initiates growth of benign lung tumors that, without additional genetic alterations, rarely progress to malignant lung adenocarcinoma. To identify genes that cooperate with BRAFV600E for malignant progression, we used Sleeping Beauty-mediated transposon mutagenesis, which dramatically accelerated the emergence of lethal lung cancers. Among the genes identified was Rbms3, which encodes an RNA-binding protein previously implicated as a putative tumor suppressor. Silencing of RBMS3 via CRISPR/Cas9 gene editing promoted growth of BRAFV600E lung organoids and promoted development of malignant lung cancers with a distinct micropapillary architecture in BRAFV600E and EGFRL858R GEM models. BRAFV600E/RBMS3Null lung tumors displayed elevated expression of Ctnnb1, Ccnd1, Axin2, Lgr5, and c-Myc mRNAs, suggesting that RBMS3 silencing elevates signaling through the WNT/β-catenin signaling axis. Although RBMS3 silencing rendered BRAFV600E-driven lung tumors resistant to the effects of dabrafenib plus trametinib, the tumors were sensitive to inhibition of porcupine, an acyltransferase of WNT ligands necessary for their secretion. Analysis of The Cancer Genome Atlas patient samples revealed that chromosome 3p24, which encompasses RBMS3, is frequently lost in non-small cell lung cancer and correlates with poor prognosis. Collectively, these data reveal the role of RBMS3 as a lung cancer suppressor and suggest that RBMS3 silencing may contribute to malignant NSCLC progression.

SIGNIFICANCE

Loss of RBMS3 cooperates with BRAFV600E to induce lung tumorigenesis, providing a deeper understanding of the molecular mechanisms underlying mutant BRAF-driven lung cancer and potential strategies to more effectively target this disease.

Genetic determinants of lung cancer: Understanding the oncogenic potential of somatic missense mutations

BACKGROUND

Treatment of lung cancer is getting more personalized nowadays and medical practitioners are moving away from conventional histology-driven empirical treatments, platinum-based chemotherapy, and other invasive surgical resections and have started adopting alternate therapies in which therapeutic targets are patient's molecular oncogenic drivers.

AIM

The aim of the current study is to extract meaningful information from the online somatic mutation data (retrieved from cBioPortal) of 16 most significantly mutated oncogenes in non-small-cell lung cancer (NSCLC), namely EGFR, NRAS, KRAS, HER2 (ERBB2), RET, MET, ROS1, FGFR1, BRAF, AKT1, MEK1 (MAP2K1), PIK3CA, PTEN, DDR2, LKB1 (STK11) and ALK, for improving our understanding of the pathobiology of the lung cancer that can aid decision-making on critical clinical and therapeutic considerations.

METHODS

Using an integrated approach comprising 4 steps, the oncogenic potential of 661 missense non-synonymous single nucleotide polymorphisms (nsSNPs) in 16 genes was ascertained using 2059 NSCLC (1575 lung adenocarcinomas, 484 lung squamous cell carcinomas) patients' online mutation data. The steps used comprise sequence/structure homology-based prediction, scoring of conservation of mutated residues and positions, prediction of resulting molecular and functional consequences using machine-learning and structure-guided approach.

RESULTS

Out of a total of 661 nsSNPs analyzed, a set of 29 nsSNPs has been identified as conserved high confidence mutations in 10 of 16 genes relevant to the under study. Out of 29 conserved high confidence nsSNPs, 4 nsSNPs (EGFR N1094Y, BRAF M620I, DDR2 R307L, ALK P1350T) have been found to be putative novel rare genetic markers for NSCLC.

CONCLUSIONS

The current study, the first of its kind, has provided a list of deleterious non-synonymous somatic mutations in a selected pool of oncogenes that can be considered as a promising target for future drug design and therapy for patients with lung adenocarcinomas and squamous cell carcinomas.

Advances in anti-BRAF therapies for lung cancer

Non-small cell lung cancer (NSCLC) is one of the most frequent causes of mortality in the western world. v-raf murine sarcoma viral oncogene homolog B (BRAF) is a member of the Raf kinase family and plays a critical role in cellular growth, proliferation, and differentiation through the mitogen-activated protein kinase pathway. The incidence of BRAF mutations in NSCLC is low, accounting for 0-3% of all cases of lung cancer. Given the results obtained in metastatic melanoma, several studies have reported the efficacy of anti-BRAF therapies in NSCLC treatment. In this review, we describe changes in the landscape of BRAF-mutated lung cancer treatment and analyze insights from major clinical trials in the context of future therapeutic prospects.

Integrating Histologic and Genomic Characteristics to Predict Tumor Mutation Burden of Early-Stage Non-Small-Cell Lung Cancer

Tumor mutation burden (TMB) serves as an effective biomarker predicting efficacy of mono-immunotherapy for non-small cell lung cancer (NSCLC). Establishing a precise TMB predicting model is essential to select which populations are likely to respond to immunotherapy or prognosis and to maximize the benefits of treatment. In this study, available Formalin-fixed paraffin embedded tumor tissues were collected from 499 patients with NSCLC. Targeted sequencing of 636 cancer related genes was performed, and TMB was calculated. Distribution of TMB was significantly (p < 0.001) correlated with sex, clinical features (pathological/histological subtype, pathological stage, lymph node metastasis, and lympho-vascular invasion). It was also significantly (p < 0.001) associated with mutations in genes like TP53, EGFR, PIK3CA, KRAS, EPHA3, TSHZ3, FAT3, NAV3, KEAP1, NFE2L2, PTPRD, LRRK2, STK11, NF1, KMT2D, and GRIN2A. No significant correlations were found between TMB and age, neuro-invasion (p = 0.125), and tumor location (p = 0.696). Patients with KRAS p.G12 mutations and FAT3 missense mutations were associated (p < 0.001) with TMB. TP53 mutations also influence TMB distribution (P < 0.001). TMB was reversely related to EGFR mutations (P < 0.001) but did not differ by mutation types. According to multivariate logistic regression model, genomic parameters could effectively construct model predicting TMB, which may be improved by introducing clinical information. Our study demonstrates that genomic together with clinical features yielded a better reliable model predicting TMB-high status. A simplified model consisting of less than 20 genes and couples of clinical parameters were sought to be useful to provide TMB status with less cost and waiting time.

A comprehensive study on the oncogenic mutation and molecular pathology in Chinese lung adenocarcinoma patients

BACKGROUND

Several genetic driver alterations have been identified in micropapillary lung adenocarcinoma (MPA). However, the frequency of co-alteration of ROS1, EGFR, and EML4-ALK is yet unclear. Herein, we investigated the relationship between clinicopathologic characteristics and well-identified driver mutations of MPA compared with non-micropapillary lung adenocarcinoma (LA).

METHODS

Formalin-fixed paraffin-embedded (FFPE) sections derived from lung adenocarcinoma patients who never received adjuvant chemotherapy or radiation therapy prior to surgical resection were collected from October 2016 to June 2019. EGFR mutations, ROS1 rearrangements, and EML4-ALK fusion were identified in a set of 131 MPA and LA cases by using the amplification refractory mutation system (ARMS). The response rate and duration of response were assessed using Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1).

RESULTS

EGFR mutations had occurred in 42 (76.4%) MPA patients and 42 (55.3%) LA patients. Interestingly, ROS1 rearrangements were highly enriched only in the MPA cases (6/55, 10.9%) but rarely in the LA cases (1/76, 1.3%). Furthermore, 7.3% (4/55) MPA samples had double gene mutations, while only 1.3% (1/76) LA cases had double gene alterations. Of 5 patients with harboring two driver oncogene mutations, four patients (80%) obtained partial response, and one patient (20%) suffered recurrence.

CONCLUSIONS

A higher prevalence of ROS1 rearrangement or combined mutations of ROS1, EGFR, and EML4-ALK may play a critical role in the tumorigenesis of MPA. These findings provide a novel therapeutic strategy for patients with malignant MPA through combining TKIs than one TKI.

Prevalence of the EGFR T790M and other resistance mutations in the Australian population and histopathological correlation in a small subset of cases

We sought to review the prevalence of EGFR T790M and other EGFR mutations associated with either proven or probable tyrosine kinase inhibitor (TKI) resistance in the Australasian lung cancer population and to perform histopathological correlation in a subset of cases. Retrospective statistical analysis was performed on a set of targeted lung cancer gene mutation tests (FIND IT gene panel) performed at Sonic Healthcare during 2018 and early 2019. A total of 1833 lung adenocarcinoma tumour samples underwent somatic mutation testing. EGFR mutations were found in 28% (n=514) of patients, in whom 9.3% (n=48) T790M mutations were present (always combined with other EGFR mutations) and 4.8% (n=25) exon 20 insertions were found. We also compared the prevalence of EGFR mutations identified in our population with that of the four largest publicly available lung cancer cohorts (total n=576 samples). Finally, a subset of 38 samples of primary/and or metastatic lung adenocarcinomas from 23 patients, including five with serial biopsies, underwent detailed morphological analysis. No reproducible morphological correlates were found to be associated with T790M, exon 20 resistance mutations or rarer co-occurring EGFR mutations. Although this may be subject to referral bias towards patients with resistant disease, the incidence of EGFR and T790M mutations is higher in this series from an Australasian population than in other similar publicly available lung adenocarcinoma cohorts. We conclude that histopathological features cannot be used to predict the acquisition of EGFR resistance.

Heterogeneous components of lung adenocarcinomas confer distinct EGFR mutation and PD-L1 expression

Background

Lung adenocarcinoma (LAC) is composed of lepidic, papillary, mucinous, micropapillary and solid components in its parenchyma. Complex responses to therapeutics result from intratumoral heterogeneity. However, it remains confused that what components in a mixed LAC tumor are responsible to the heterogeneous EGFR mutation and PD-L1 expression.

Methods

We investigated EGFR status via laser microdissection to capture spatially separated cancer cell subpopulations and digital droplet PCR to determine the abundance of EGFR sensitizing mutation and naïve T790M. Whilst, PD-L1 expression level via tumor proportion score (TPS) was evaluated by Ventana immunohistochemistry using SP263 antibody. PD-L1 expression levels were tiered in < 1, 1–49% and > =50% groups.

Results

EGFR mutation harbored in 154 (59%) of 261 LAC patients and more frequently occurred in papillary, lepidic and micropapillary constituents. Higher levels of PD-L1 were found in LACs at stage III and IV (68.3%) versus those at stage I and II (31.7%) (P = 0.04). Solid predominant LACs (41.3%) expressed PD-L1 with TPS > =50%, versus mucinous and lepidic LACs (P < 0.01). LACs with solid constituents also had more positive proportion of PD-L1 protein. Cut-offs < 1, 1–49% or > =50% were associated with patients’ progression-free survival and longer in the < 1% group (22.9 month, 95% CI 17.6–28.2) (P < 0.05). LACs consisting of two constituents with PD-L1 TPS < 1% had a better prognosis than the groups with single component and more than two components (P < 0.05). Eighteen LACs (6.9%) had concomitantly deletion in exon 19 or L858R and naïve T790M mutation. The abundance of T790M varied diversely with sensitizing mutation. PD-L1 expression was not concordant in same components and usually negative in the EGFR-mutated constituents. Heterogeneous PD-L1 expression occurred in the vicinity of stromal tissues. 58.8, 29.4 and 11.8% in ALK positive LACs (N = 17) were found PD-L1 expression via cutoffs of < 1, 1–49% and > =50%, respectively (P > 0.05).

Conclusion

Intratumoral genetic heterogeneity of LACs was demonstrated associated with histological patterns. Heterogeneous PD-L1 expression in higher level usually occurred in solid component both in EGFR mutated and EGFR wild-typed LACs. EGFR mutated LACs heterogeneously had sensitizing and resistant mutation and was accompanied with PD-L1 expression, but discordant among histological constituents. Immune checkpoint inhibitor combined with third generation EGFR tyrosine kinase inhibitor should be more effective to these LACs.

Diagnostic and Predictive Immunohistochemistry for Non-Small Cell Lung Carcinomas

Non-small cell lung carcinoma (NSCLC) accounts for significant morbidity and mortality worldwide, with most patients diagnosed at advanced stages and managed increasingly with targeted therapies and immunotherapy. In this review, we discuss diagnostic and predictive immunohistochemical markers in NSCLC, one of the most common tumors encountered in surgical pathology. We highlight 2 emerging diagnostic markers: nuclear protein in testis (NUT) for NUT carcinoma; SMARCA4 for SMARCA4-deficient thoracic tumors. Given their highly aggressive behavior, proper recognition facilitates optimal management. For patients with advanced NSCLCs, we discuss the utility and limitations of immunohistochemistry (IHC) for the "must-test" predictive biomarkers: anaplastic lymphoma kinase, ROS1, programmed cell death protein 1, and epidermal growth factor receptor. IHC using mutant-specific BRAF V600E, RET, pan-TRK, and LKB1 antibodies can be orthogonal tools for screening or confirmation of molecular events. ERBB2 and MET alterations include both activating mutations and gene amplifications, detection of which relies on molecular methods with a minimal role for IHC in NSCLC. IHC sits at the intersection of an integrated surgical pathology and molecular diagnostic practice, serves as a powerful functional surrogate for molecular testing, and is an indispensable tool of precision medicine in the care of lung cancer patients.

Chromosome 7 Multiplication in EGFR-positive Lung Carcinomas Based on Tissue Microarray Analysis

BACKGROUND/AIM

Epidermal growth factor receptor (EGFR) over-activation is observed in significant proportions of non-small cell lung carcinomas (NSCLC). Our aim was to investigate the role of chromosome 7 multiplication with regard to its influence in EGFR expression, combined or not with gene amplification.

MATERIALS AND METHODS

Using tissue microarray technology, fifty (n=50) primary NSCLCs were cored and re-embedded into the final recipient block. Immunohistochemistry (IHC) and also chromogenic in situ hybridization (CISH) were performed.

RESULTS

EGFR expression at any level was detected in 40/50 (80%) cores. Over-expression was observed in 23/40 (57.5%) cases. Gene amplification was identified in 11/50 (22%) cases whereas chromosome 7 polysomy in 8/50 (16%) cases. Pure chromosome 7 multiplication alone led to low or moderate levels of expression. Overall EGFR expression was correlated with gene (p=0.001) and interestingly with chromosome 7 centromere numerical imbalances (p=0.004).

CONCLUSION

EGFR expression is associated not only with amplification, but also with chromosome 7 centromere multiple copies. Chromosome 7 multiplication -due to centromere region amplification or true polysomy- is critical for applying monoclonal antibody targeted therapeutic strategies excluding the pure non-amplified cases.

Cervical carcinomas with a micropapillary component: a clinicopathological study of eight cases

AIMS

Micropapillary carcinomas, or carcinomas with a micropapillary component, are well recognised in the breast and other anatomical sites. However, they have seldom been described in the cervix. In this article, we present a clinicopathological analysis of eight cervical tumours that showed at least a focal (≥5%) component of micropapillary carcinoma.

METHODS AND RESULTS

The study group comprised eight cervical carcinomas (four adenocarcinomas and four adenosquamous carcinomas) with a micropapillary component. The median patient age was 41.5 years (range 27-65 years). At presentation, five patients were stage IB, two were stage IIB, and one was stage IV. The micropapillary component accounted for ≤25% of the tumour on initial biopsy or resection specimens in all but one case. Immunohistochemistry showed 'inside-out' (reverse polarity) mucin 1 staining along the cell membrane abutting the stroma. Four patients developed metastasis, all of whom showed a pure micropapillary pattern; this led to a misdiagnosis of an apparently independent peritoneal serous carcinoma in one case. All tumours showed diffuse p16 expression, and all three cases that were tested were positive for human papillomavirus (HPV) 18. Three of the six patients with at least 12 months of follow-up died of disease, and one is alive with distant metastasis.

CONCLUSIONS

Usual-type (HPV-related) cervical carcinomas may show micropapillary differentiation, usually as a focal finding, and the cells show reverse polarity like similar tumours arising in other sites. Micropapillary cervical carcinoma appears to be a clinically aggressive malignancy, although this needs to be confirmed in larger studies.

EGFR, KRAS, and BRAF mutational profiles of female patients with micropapillary predominant invasive lung adenocarcinoma

Background/aim: This study aimed to analyze EGFR, KRAS, and BRAF mutations in females with micropapillary predominant invasive lung adenocarcinoma and their relationships with immunohistochemical and clinicopathological patterns.Materials and methods: A total of 15 females with micropapillary lung adenocarcinoma were selected. Mutational analysis of the EGFR, KRAS, and BRAF genes was carried out. Information regarding the demographic data, tumor size, treatment, and survival time for each patient was collated, and the predominant cell type, secondary architectural growth patterns, psammoma bodies, necrosis, and visceral pleural and angiolymphatic invasions were evaluated.Results: We identified EGFR mutation in six cases, KRAS mutation in three cases, and BRAF mutation in one case. EGFR, c-kit, VEGFR, and bcl-2 positivity was observed in ten, seven, four, and six cases, respectively. All cases were positive for VEGF (strong positivity in 11 cases and weak positivity in four cases) and bcl-2 (strong positivity in nine cases and weak positivity in six cases). Seven (46.6%) cases were positive for c-kit and 10 (66.6%) cases were positive for EGFR. Conclusion: EGFR mutation occurred at a higher incidence rate in micropapillary predominant invasive adenocarcinoma than has previously been found in conventional lung adenocarcinomas. KRAS mutation was observed as having a similar frequency to what was previously observed, but the frequency of BRAF mutation was lower than previously reported.

Micropapillary and/or Solid Histologic Subtype Based on Pre-Treatment Biopsy Predicts Local Recurrence After Thermal Ablation of Lung Adenocarcinoma

BACKGROUND

To investigate whether histologic subtyping from biopsies can predict local recurrence after thermal ablation for lung adenocarcinoma.

METHODS

Patients treated with CT-guided thermal ablation for lung adenocarcinoma that had pre-ablation needle biopsy with analysis of histologic components were identified. Age, gender, smoking status, treatment indication (primary stage 1 tumor versus salvage), histologic subtype, ground-glass radiographic appearance, tumor size, ablation modality, and ablation margin were evaluated in relation to time to local recurrence (TTLR). Cumulative incidence of recurrence (CIR) was calculated using competing risks analysis and compared across groups using Fine and Grey method with clustering. Multivariate analysis was conducted with stepwise regression.

RESULTS

There were 53 patients with 57 tumors diagnosed as adenocarcinoma on pre-ablation biopsy and with histologic subtype analysis. Of these, 19% (11) had micropapillary components, 14% (8) had solid components, and 26% (15) had micropapillary and/or solid components. In the univariate analysis, solid (subdistribution hazard ratio [SHR] = 4.04, p = 0.0051, 95% confidence interval [CI] = 1.52-10.7), micropapillary (SHR = 3.36, p = 0.01, CI = 1.33-8.47), and micropapillary and/or solid components (SHR = 5.85, p = 0.00038, CI = 2.21-15.5) were significantly correlated with shorter TTLR. On multivariate analysis, the presence of micropapillary and/or solid component (SHR = 11.4, p = 0.00021, CI: 3.14-41.3) was the only independent predictor of TTLR. The 1-, 2-, and 3-year CIR in patients with micropapillary and/or solid components was 33, 49, and 66% compared to 5, 14, and 18% in patients with no micropapillary or solid components on biopsy specimens.

CONCLUSION

Micropapillary and/or solid histologic components identified in pre-ablation biopsy are associated with shorter TTLR after thermal ablation of lung adenocarcinoma.

Utility of Genomic Analysis in Differentiating Synchronous and Metachronous Lung Adenocarcinomas from Primary Adenocarcinomas with Intrapulmonary Metastasis

Distinguishing synchronous and metachronous primary lung adenocarcinomas from adenocarcinomas with intrapulmonary metastasis is essential for optimal patient management. In this study, multiple lung adenocarcinomas occurring in the same patient were evaluated using comprehensive histopathologic evaluation supplemented with molecular analysis. The cohort included 18 patients with a total of 52 lung adenocarcinomas. Eleven patients had a new diagnosis of multiple adenocarcinomas in the same lobe (n = 5) or different lobe (n = 6). Seven patients had a history of lung cancer and developed multiple new tumors. The final diagnosis was made in resection specimens (n = 49), fine needle aspiration (n = 2), and biopsy (n = 1). Adenocarcinomas were non‐mucinous, and histopathologic comparison of tumors was performed. All tumors save for one were subjected to ALK gene rearrangement testing and targeted Next Generation Sequencing (NGS). Using clinical, radiologic, and morphologic features, a confident conclusion favoring synchronous/metachronous or metastatic disease was made in 65% of patients. Cases that proved challenging included ones with more than three tumors showing overlapping growth patterns and lacking a predominant lepidic component. Genomic signatures unique to each tumor were helpful in determining the relationship of multiple carcinomas in 72% of patients. Collectively, morphologic and genomic data proved to be of greater value and achieved a conclusive diagnosis in 94% of patients. Assessment of the genomic profiles of multiple lung adenocarcinomas complements the histological findings, enabling a more comprehensive assessment of synchronous, metachronous, and metastatic lesions in most patients, thereby improving staging accuracy. Targeted NGS can identify genetic alterations with therapeutic implications.

An aggressive non-small cell lung cancer in nonsmokers: A case report of an unusual presentation of micropapillary lung adenocarcinoma

We describe a case of an unusual fast growing lung micropapillary-predominant adenocarcinoma in a nonsmoker male patient without pre-existing lung disease. Adenocarcinomas have been described to be slow growing tumors, however our patient presented a fast-growing rate over a period of 21 days. When the patient failed broad spectrum antibiotic coverage, malignancy became part of the differential diagnosis. Once malignancy was detected, prompt identification and treatment was started in order to improve prognosis of the patients.

Expression level of CRKL and AXL combined with exon 19 deletion in EGFR and ALK status confer differential prognosis of lung adenocarcinoma subtypes

Non-small cell lung cancer (NSCLC) is a lethal cancer-related disease in population. Adenocarcinoma (AC) is subclassified into several subtypes based on the new classification by the International Association for the Study of Lung Cancer, American Thoracic Society and European Respiratory Society in 2011. Correlation between original expression of Crk-like (CRKL) and anaplastic lymphoma receptor tyrosine kinase in diverse histological components of AC and epidermal growth factor receptor (EGFR) or ALK status was evaluated by immunohistochemistry and sequencing in present study. A total of 106 cases, including 83 patients (78.3%) with mixed-type ACs, were assessed in the present study using eligible follow-up data. The ACs consisted of 32 acinar, 12 papillary, 5 mucinous, 11 micropapillary and 46 solid-predominant ACs. In total, 69.8% samples were composed of 2 or 3 histological components, with different expression levels of CRKL and AXL. ACs with EGFR mutation had a higher level of AXL expression compared with ACs without mutation (P=0.019). Multivariate survival analysis showed that AC subtypes and EGFR mutation subtypes were significantly associated with the progression-free survival (PFS) time. Acinar AC was the subtype with the most notable PFS time (30.6 months), which was significantly different from the PFS time of papillary, mucinous, micropapillary and solid-predominant ACs (hazard ratio, 0.4; 95% CI, 0.21-0.75; P=0.005). Among the ACs with exon 19 mutation, the median PFS time (28.8 months) of patients with a lower level of AXL protein expression was increased compared with the PFS time of patients with the L858R mutation and wild-type EGFR (9.1 months and 11 months, respectively; P=0.03), whereas no significant difference in ACs with an increased level of AXL expression. However, AC patients with higher level of CRKL expression had better PFS (28.8 months) than patients with the L858R mutation and wild-type EGFR (9.1 months and 11.3 months, respectively). Exon 19 deletion is an important status that is associated with an improved response to conventional chemotherapy. The identification of EGFR mutations combined with CRKL and AXL status may potentially alter the way that lung AC is treated.

Integrated Analysis of DNA Methylation and mRNA Expression Profiles Data to Identify Key Genes in Lung Adenocarcinoma

Introduction. Lung adenocarcinoma (LAC) is the most frequent type of lung cancer and has a high metastatic rate at an early stage. This study is aimed at identifying LAC-associated genes. Materials and Methods. GSE62950 downloaded from Gene Expression Omnibus included a DNA methylation dataset and an mRNA expression profiles dataset, both of which included 28 LAC tissue samples and 28 adjacent normal tissue samples. The differentially expressed genes (DEGs) were screened by Limma package in R, and their functions were predicted by enrichment analysis using TargetMine online tool. Then, protein-protein interaction (PPI) network was constructed using STRING and Cytoscape. Finally, LAC-associated methylation sites were identified by CpGassoc package in R and mapped to the DEGs to obtain LAC-associated DEGs. Results. Total 913 DEGs were identified in LAC tissues. In the PPI networks, MAD2L1, AURKB, CCNB2, CDC20, and WNT3A had higher degrees, and the first four genes might be involved in LAC through interaction. Total 8856 LAC-associated methylation sites were identified and mapped to the DEGs. And there were 29 LAC-associated methylation sites located in 27 DEGs (e.g., SH3GL2, BAI3, CDH13, JAM2, MT1A, LHX6, and IGFBP3). Conclusions. These key genes might play a role in pathogenesis of LAC.

Micropapillary: A component more likely to harbour heterogeneous EGFR mutations in lung adenocarcinomas

The micropapillary (MP) subtype has recently been established to be a distinct marker of poor prognosis in lung adenocarcinomas (LACs). According to the 2015 WHO classification system, LAC constituents are required to be precisely reported. T790M mutation and an insertion in exon 20 (E20ins) are associated with EGFR-TKI resistance. A total of 211 LAC patients were involved in this study, and EGFR mutations were determined using an amplification refractory mutation system (ARMS). Sex, smoking history, lymph node status, and clinical stage differed significantly between the EGFR wild type and mutant groups (p < 0.05). The EGFR mutation occurred more frequently in female, non-smokers, ACs with papillary (85.7%) or MP components (91.4%) (p < 0.001). Twenty ACs with naïve T790M or E20ins were microdissected. The AC constituents metastasizing to lymph nodes exhibited a phenotype and EGFR status that was consistent with the primary loci constituents. Glomerulus-like solid components exhibited the same EGFR status as the surrounding T790M-mutated MP components. The MP and glomerulus-like portions in AC tumours exhibited a congenial EGFR status, but the acinar cells with papillary cells were heterogeneous. The naïve T790M mutants, although minor in the MP component, dramatically increased after EGFR-TKI therapy and indicate that the MP components feature intrinsic heterogeneity.

Genetic alterations in lung adenocarcinoma with a micropapillary component

Pulmonary adenocarcinoma (PA) with a micropapillary component (PA-MPC) is known as an aggressive subtype of PA. The molecular profiles of PA-MPC have not been well characterized. the pathological reports of patients who underwent surgical resection for lung cancer between April, 2004 and May, 2012 were reviewed. Of the 674 patients diagnosed with PA, 28 were found to have MPC. A total of 138 resected PAs without MPC were selected in the same period to serve as age-, gender- and smoking status-matched controls to the PA-MPC group. Mutational status was determined by the following two methods: SNaPshot assay based on multiplex polymerase chain reaction (PCR), primer extension and capillary electrophoresis that was designed to assess 38 somatic mutations in 8 genes [AKT1, BRAF, endothelial growth factor receptor (EGFR), Kirsten rat sarcoma viral oncogene homolog (KRAS), mitogen-activated protein kinase kinase 1, neuroblastoma RAS viral oncogene homolog, phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit α (PIK3CA) and phosphatase and tensin homolog]; and a PCR-based sizing assay that assesses EGFR exon 19 (deletions), EGFR exon 20 (insertions) and human epidermal growth factor receptor 2 exon 20 (insertions). echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase fusion gene (EML4-ALK) was screened by ALK immunohistochemistry and confirmed using the reverse transcription PCR assay and the break-apart fluorescence in situ hybridization assay. Regarding genetic alterations, 13 (46.4%) of the 28 PA-MPCs harbored mutually exclusive mutations: 9 (32.1%) EGFR mutations, 1 (3.6%) KRAS mutation and 3 (10.7%) EML4-ALK fusion genes. PAs without MPC harbored 42 (30.4%) EGFR mutations, 17 (12.3%) KRAS mutations, 3 (2.2%) EML4-ALK fusion genes and 1 (0.7%) PIK3CA mutation. EML4-ALK fusion genes appeared to occur significantly more frequently in PA-MPCs compared with PAs without MPC (P=0.027). Although the sample size was small, our study suggests that the molecular pathogenesis of PA-MPC may be different from that of other adenocarcinomas.

[Advances of Pulmonary Adenocarcinoma with Micropapillary Pattern]

伴微乳头结构(micropapillary pattern, MPP)肺腺癌是一种临床少见的具有高度侵袭性的恶性肿瘤，近年来因其高死亡率被人们所重视。2011年关于肺腺癌的病理新分类将其作为一种独立的病理类型，此后针对该类肺癌个体化治疗的相关研究逐渐展开。近期的相关研究发现，伴MPP肺腺癌在转移机制、临床病理学、影像学、治疗及预后方面具有显著异质性。本文对伴MPP肺腺癌转移机制及相关临床研究进展进行探讨。

A comprehensive investigation of molecular features and prognosis of lung adenocarcinoma with micropapillary component

INTRODUCTION

Both micropapillary predominant lung adenocarcinoma according to the IASLC/ATS/ERS classification and lung adenocarcinoma with a micropapillary component have been reported to be associated with poor prognosis. However, whether they have different prognosis remains undetermined.

METHODS

Out of 1302 lung adenocarcinoma patients, 21 patients with micropapillary predominant lung adenocarcinoma (MPP) and 100 patients with nonmicropapillary predominant tumors harboring a micropapillary component of at least 5% (MPC) were investigated for clinicopathologic characteristics, recurrence-free survival (RFS), overall survival (OS), and spectrum of well-identified driver mutations including EGFR, KRAS, HER2, BRAF, ALK, ROS1, and RET.

RESULTS

Twenty out of 21 (95.2%) micropapillary predominant lung adenocarcinoma harbored driver mutations in EGFR (85.7%), HER2 (4.8%), or RET (4.8%). MPP had significantly worse RFS than MPC in stage I patients (p = 0.003), but not in stages II-III patients. The overall survival was comparable between MPP and MPC regardless of disease stages. Objective response was achieved in 13 out of the 18 MPP or MPC patients with EGFR mutations who received EGFR tyrosine kinase inhibitors (TKIs) after disease recurrence. The postrecurrence survival was significantly better in EGFR-mutated patients who were treated with EGFR TKIs compared to those who did not receive TKIs (p = 0.003).

CONCLUSIONS

Micropapillary predominant lung adenocarcinoma is a disease that could be largely defined by targetable driver mutations. For stage I lung adenocarcinoma, MPP was even more likely to recur than MPC. EGFR TKIs might help to control the recurrent disease for MPP or MPC patients harboring EGFR mutations.

BRAF mutations in non-small cell lung cancer

BACKGROUND

BRAF is a proto-oncogene encoding a serine/threonine protein kinase which promotes cell proliferation and survival. BRAF mutations are commonly seen in melanoma and papillary thyroid carcinoma. We aimed to investigate the prevalence and clinicopathological features of BRAF mutations in non-small cell lung cancer (NSCLC) cases submitted for routine mutation testing at our institution.

METHODS

Mutation analysis for BRAF, EGFR and KRAS was performed using Sequenom MassARRAY platform with OncoCarta panel v1.0. Pathological features were reviewed and immunohistochemistry for BRAF V600E was also performed.

RESULTS

Seven out of 273 cases (2.6%) had BRAF mutations (three males and four females, median age 70 years, all smokers), with six adenocarcinomas and one NSCLC, not otherwise specified (NOS). All had wild-type EGFR and KRAS. The identified BRAF mutations were V600E (4/7, 58%), K601N, L597Q and G469V. BRAF V600E immunohistochemistry was positive in two cases with V600E and negative in one case with K601N (tissue available in three cases only). No significant difference in age or gender was found (BRAF mutant vs. wild-type).

CONCLUSIONS

BRAF mutations occur in a small proportion of NSCLC that lack other driver mutations. The clinicopathological profile differs from that of EGFR mutant tumours. The potential benefits of BRAF-inhibitors should be investigated.

Bronchial-pulmonary adenocarcinoma subtyping relates with different molecular pathways

Lung cancer is one of the most common cancers in the world with a high mortality rate. We analyzed 45 surgical samples of the adenocarcinoma, 13 with lymph node metastasis. APC, BCL2, chromogranin A, CK 5/6/18 (LP34), CK20, CK7, cyclin D1, EGFR, ERCC1, HER2, Ki67, LRP, MRP, P53, RB and TTF1 expressions were evaluated by immunohistochemistry (IHC). Higher Ki67, APC, ERCC1 expressions and lower TTF1 expression were identified in advanced stages (IIA and IIIA) of adenocarcinomas, which reflect a more aggressive, less differentiated, possibly a non-TRU adenocarcinoma. Acinar, micropapillary and BA/lepidic adenocarcinoma patterns were the most similar patterns and papillary was the most different pattern followed by solid pattern, according to expression of these markers. Different adenocarcinoma patterns are engaged with different molecular pathways for carcinogenesis, based on the differences of expression. Acinar, BA/lepidic and micropapillary showed higher TTF1 expression (type TRU), and papillary and solid patterns revealed less TTF1 expression, exhibiting a non-TRU/bronchial phenotype. Solid pattern revealed lower HER2 and higher EGFR and ERCC1 (this compared to papillary) expression; papillary higher HER2 and lower ERCC1 expressions; micropapillary higher RB expression; and acinar lower ERCC1 and higher EGFR expressions. Ciclin D1 seems to have more importance in acinar and BA/lepidic patterns than in micropapillary. ERCC1 protein expression in micropapillary, solid and BA/lepidic patterns may indicate DNA repair activation. Inhibition of apoptosis could be explained by BCL2 overexpression, present in all adenocarcinoma patterns. MRP-1 and LRP were overexpressed in all patterns, which may have implications for drug resistance. Further studies are needed to interpret these data regarding to therapy response in advanced staged bronchial-pulmonary carcinomas.

Prevalent and up-regulated vimentin expression in micropapillary components of lung adenocarcinomas and its adverse prognostic significance

The factors conferring the increased malignancy on lung adenocarcinoma with micropapillary component (AC-MPC) remain to be elucidated. On proteomics based on 2-dimensional gel electrophoresis, 19 proteins differentially expressed by more than 1.5-fold between AC-MPC and conventional adenocarcinoma (CAC); in particular, vimentin, one of the proteins, was 3.5-fold up-regulated in AC-MPC. Subsequent semi-quantitative investigation by immunohistochemistry with large cohorts comprised 101 AC-MPC and 119 CAC, respectively, of different stages revealed that vimentin was expressed in MPC of 95 (94.1%) AC-MPC and the expression scores were higher than those of well- and moderately differentiated CAC, as well as the background non-MPC of the AC-MPC (P < 0.0001), but not significantly different from those of poorly differentiated CAC (P = 0.561). Even within the AC-MPC entity, higher vimentin expression was correlated with more frequent vascular invasion and more advanced node metastasis (P < 0.02), and multivariate analysis showed that high vimentin expression and worse node statuses were independent indicators of adverse prognosis (P < 0.048). In conclusion, vimentin expression is prevalent and markedly up-regulated in MPC, which might reflect the biological essence of poorer differentiation or dedifferentiation of MPC, and this might have a role in the acquisition and increase of invasiveness and consequent more malignant nature of MPC.

Increased BRAF copy number in lung adenocarcinoma

Point mutation of the BRAF gene is a genetic event that occurs in a subset of lung adenocarcinoma cases. For example, BRAF V600E is a driver mutation that can be effectively targeted using selective BRAF and/or MEK inhibitors. The present study hypothesized that an increase in BRAF copy number may be correlated with certain clinicopathological features of lung adenocarcinoma in Japanese patients. The BRAF gene copy number was analyzed using quantitative polymerase chain reaction amplifications in 29 surgically treated lung adenocarcinoma cases without EGFR or Kras mutations from Nagoya City University Hospital (Nagoya, Japan). Seven BRAF-mutant cases were included. Increased BRAF gene copy number was identified in three lung adenocarcinoma patients (10.3%), all of which exhibited the V600E mutation. Using fluorescence in situ hybridization with BRAF-specific and chromosome 7 centromeric probes, increased copy number status was associated with gene amplification or gain of chromosome 7. Although increased BRAF copy number was correlated with BRAF V600E mutations, numerical changes in BRAF copy number were rare and mild in lung adenocarcinoma, resulting in no significant difference in pathological tumor status or tumor stage.

The 2011 IASLC/ATS/ERS pulmonary adenocarcinoma classification: a landmark in personalized medicine for lung cancer management

In 2011, three authoritative academic communities, International Association for the Study of Lung Cancer, the American Thoracic Society, and the European Respiratory Society (IASLC/ATS/ERS), published a novel lung adenocarcinoma histologic classification. The major modifications of this classification include the abolishment of the term "bronchioloalveolar carcinoma (BAC)", the establishment of new classification systems for resection and small biopsy or cytology specimens, the emphasis of molecular test and comprehensive histologic evaluation for tumor specimens, etc. This new lung adenocarcinoma classification signifies the era of personalized medicine comes to real-world practice in lung cancer field. Here, we introduce the background why the lung adenocarcinoma classification needs to be revised, and what we should consider in clinical practice according to this new classification.

Implementing the new IASLC/ATS/ERS classification of lung adenocarcinomas: results from international and Chinese cohorts

A new histologic classification of lung adenocarcinoma was proposed by the International Association for the Study of Lung Cancer, American Thoracic Society, and European Respiratory Society (IASLC/ATS/ERS) in 2011 to provide uniform terminology and diagnostic criteria for multidisciplinary strategic management. This classification proposed a comprehensive histologic subtyping (lepidic, acinar, papillary, micropapillary, and solid pattern) and a semi-quantitative assessment of histologic patterns (in 5% increments) in an effort to choose a single, predominant pattern in invasive adenocarcinomas. The prognostic value of this classification has been validated in large, independent cohorts from multiple countries. In patients who underwent curative-intent surgery, those with either an adenocarcinoma in situ (AIS) or a minimal invasive adenocarcinoma have nearly 100% disease-free survival and are designated "low grade tumors". For invasive adenocarcinomas, the acinar and papillary predominant histologic subtypes were usually designated as "intermediate grade" while the solid and micropapillary predominant histologic subtypes were designated "high grade" tumors; this was based on the statistic difference of overall survival. This classification, coupled with additional prognostic factors [nuclear grade, cribriform pattern, high Ki-67 labeling index, thyroid transcription factor-1 (TTF-1) immunohistochemistry, immune markers, and (18)F-fluorodeoxyglucose uptake on positron emission tomography (PET)] that we have published on, could further stratify patients into prognostic subgroups and may prove helpful for individual patient care. With regard to Chinese oncologists, the implementation of this new classification only requires hematoxylin and eosin (H&E) stained slides and basic pathologic training, both of which require no additional costs. More importantly, this new classification system could provide informative data for better selection and stratification of clinical trials and molecular studies.

Pulmonary adenocarcinoma: implications of the recent advances in molecular biology, treatment and the IASLC/ATS/ERS classification

A decade ago, lung cancer could conveniently be classified into two broad categories-either the small cell lung carcinoma (SCLC), or the non-small cell lung carcinoma (NSCLC), mainly to assist in further treatment related decision making. However, the understanding regarding the eligibility of adenocarcinoma histology for treatments with agents such as pemetrexed and bevacizumab made it a necessity for NSCLC to be classified into more specific sub-groups. Then, the availability of molecular targeted therapy with oral tyrosine kinase inhibitors (TKIs) such as gefitinib and erlotinib not only further emphasized the need for accurate sub-classification of lung cancer, but also heralded the important role of molecular profiling of lung adenocarcinomas. Given the remarkable advances in molecular biology, oncology and radiology, a need for felt for a revised classification for lung adenocarcinoma, since the existing World Health Organization (WHO) classification of lung cancer, published in the year 2004 was mainly a pathological system of classification. Thus, there was a combined effort by the International Association for the Study of Lung Cancer (IASLC), the American Thoracic Society (ATS) and the European Respiratory Society (ERS) with an effort to inculcate newly established perspectives from clinical, molecular and radiological aspects in evolving a modern classification for lung adenocarcinomas. This review provides a summary of the recent advances in molecular biology and molecular targeted therapy with respect to lung adenocarcinoma. Also, a brief summation of the salient recommendations provided in the IASLC/ATS/ERS classification of lung adenocarcinomas is provided. Lastly, a discussion regarding the future prospects with lung adenocarcinoma is included.

WITHDRAWN: Bronchial-pulmonary adenocarcinoma subtyping relates with different molecular pathways

This article has been withdrawn for editorial reasons because the journal will be published only in English. In order to avoid duplicated records, this article can be found at http://dx.doi.org/10.1016/j.rppnen.2014.05.006. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Recent advances and clinical implications of the micropapillary histological subtype in lung adenocarcinomas

Micropapillary (MIP) histologic subtype included in the classification of lung adenocarcinomas (ADCs) is associated with both size- and stage-independent poor prognoses. MIP pattern in lung ADCs, even at small, early stages, correlates with high lymphovascular invasion, visceral pleural invasion and lymph node metastases. Recently, we reported that patients with a MIP component are at a higher risk of locoregional recurrence after limited resection. Identification of a MIP pattern is only possible with permanent pathologic sections; preoperative imaging, cytology or intraoperative frozen section specimens remain unreliable. The intermixed, heterogenous morphology of lung ADC presents a technical challenge in investigating the molecular biology of cells with MIP morphology. A comprehensive understanding of the biology of MIP morphology is vital for therapeutic interventions.

Differential expression of CRKL and AXL genes in lung adenocarcinoma subtypes according to the epidermal growth factor receptor and anaplastic lymphoma kinase gene status

Non-small-cell lung cancer (NSCLC) is the most common cause of cancer-related mortality. Adenocarcinoma (AC) is the predominant histological type of NSCLC; however, AC consists of several subtypes. It has not yet been determined whether there is a correlation of CRKL and AXL expression with epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) gene status in lung AC. We assayed exons 18 through 21 of the EGFR gene by direct sequencing; ALK rearrangement and the expression of CRKL and AXL were detected by immunostaining. A total of 212 cases of AC were included in this study, diagnosed using the novel classification system established by the International Association for the Study of Lung Cancer, the American Thoracic Society and the European Respiratory Society in 2011, including 69 acinar ACs, 17 lepidic predominant ACs (LPAs), 63 papillary, 14 mucinous, 17 micropapillary and 32 solid ACs. Of the 212 cases, 101 harbored EGFR mutations. The most common subtypes carrying delK745-S753 were papillary and acinar ACs. ALK rearrangement was found in 23 cases (11%) of lung ACs. Acinar and solid ACs were the most frequent subtypes with ALK aberrance, particularly in acinar ACs with cribriform structure (4/5 cases, 80%). The expression of CRKL was significantly different among the AC subtypes (P=0.01), with the highest and lowest expression levels of CRKL protein in papillary ACs and LPAs, respectively (P<0.05). AXL expression was also significantly different among the AC subtypes (P=0.002) and was correlated with lymph node infiltration in acinar ACs. ACs with EGFR mutations exhibited high levels of AXL protein expression compared to those without mutations (P<0.001). Acinar AC with cribriform structure is a distinct subtype that frequently harbors ALK rearrangement. The activation of AXL may be one of the factors contributing to the invasion of acinar and micropapillary ACs.

Clinicopathological features of nonsmall cell lung carcinomas with BRAF mutations

BACKGROUND

Recently, driver tyrosine kinase gene mutations have been detected in malignant tumors, including lung tumors. Notwithstanding their attractiveness as targets for molecular therapy, limited information is available regarding BRAF-mutated lung carcinomas.

MATERIALS AND METHODS

BRAF mutation status was determined in 2001 surgically resected nonsmall-cell lung cancer (NSCLC) cases using high-resolution melting analysis (HRMA) followed by Sanger sequencing and/or deep sequencing using next generation sequencer.

RESULTS

BRAF mutations were detected in 26 (1.3%) of 2001 NSCLC cases (25 adenocarcinomas and 1 squamous cell carcinoma). In the 26 cases, 13 mutation genotypes were identified, including V600E (8 of 26; 30.8%), G469A (6 of 26; 23.1%), K601E (4 of 26; 15.4%), and other residual mutations (1 of 26; 0.04%). Of the 13 genotypes, 4 genotypes (G464E, G596R, A598T, and G606R) had not been previously reported in lung cancer. The overall survival rate was not significantly different between patients with wild-type BRAF and those with V600E or non-V600E BRAF mutations (P = 0.49 and P = 0.15, respectively). Histomorphological analysis revealed that focal clear cell changes were present in 75% of V600E-mutated tumors. All V600E BRAF-mutated tumors were negative for other driver gene alterations including epidermal growth factor receptor (EGFR) and KRAS mutations and the anaplastic lymphoma kinase gene translocation, whereas five tumors with non-V600E BRAF mutations (four G469A and one G464E/G466R) showed concomitant EGFR mutations.

CONCLUSION

The frequency of BRAF mutations in lung cancer was low in an Asian cohort. Furthermore, BRAF mutation status lacked prognostic significance in this patient population.

Expression of MUC2, MUC5AC, MUC5B, and MUC6 mucins in colorectal cancers and their association with the CpG island methylator phenotype

Mucinous differentiation is associated with both CpG island methylator phenotype and microsatellite instability in colorectal cancer. The mucinous phenotype derives from abundant expression of the colonic goblet cell mucin, MUC2, and de novo expression of gastric foveolar mucin, MUC5AC. We, therefore, investigated the protein expression levels of MUC2 and MUC5AC, as well as MUC5B and MUC6, in molecular subtypes of colorectal cancer. Seven-hundred and twenty-two incident colorectal carcinomas occurring in 702 participants of the Melbourne Collaborative Cohort Study were characterized for methylator status, MLH1 methylation, somatic BRAF and KRAS mutations, microsatellite-instability status, MLH1, MSH2, MSH6, and PMS2 mismatch repair, and p53 protein expression, and their histopathology was reviewed. Protein expression levels of MUC2, MUC5AC, MUC5B, MUC6, and the putative mucin regulator CDX2 were compared with molecular and clinicopathological features of colorectal cancers using odds ratios and corresponding 95% confidence intervals. MUC2 overexpression (>25% positive tumor cells) was observed in 33% colorectal cancers, MUC5B expression in 53%, and de novo MUC5AC and MUC6 expression in 50% and 39%, respectively. Co-expression of two or more of the mucins was commonly observed. Expression of MUC2, MUC5AC and MUC6 was strongly associated with features associated with tumorigenesis via the serrated neoplasia pathway, including methylator positivity, somatic BRAF p.V600E mutation, and mismatch repair deficiency, as well as proximal location, poor differentiation, lymphocytic response, and increased T stage (all P<0.001). Overexpression was observed in tumors with and without mucinous differentiation. There were inverse associations between expression of all four mucins and p53 overexpression. CDX2 expression was inversely associated with MUC2, MUC5AC and MUC6 expression. Our results suggest that, in methylator-positive tumors, mucin genes on chromosome 11p15.5 region undergo increased expression via mechanisms other than direct regulation by CDX2.

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.

Correlation of mutation status and survival with predominant histologic subtype according to the new IASLC/ATS/ERS lung adenocarcinoma classification in stage III (N2) patients

INTRODUCTION

We investigated the relationship between predominant subtype, according to the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society International Multidisciplinary Lung Adenocarcinoma Classification; mutation status; and patient outcome in stage III (N2) lung adenocarcinoma.

METHODS

We identified 69 patients with stage III (N2) lung adenocarcinoma operated on with curative intent between 1993 and 2011 who had adequate tumor tissue for molecular analysis and adequate follow-up time for survival analysis. DNA was isolated and tested for mutations using Sequenom's OncoCarta Panel (v1.0; Sequenom, San Diego, CA).

RESULTS

The majority of tumors were acinar (26 of 69 tumors; 38%), solid (24 of 69 tumors; 35%), and micropapillary predominant (13 of 69 tumors; 19%) subtypes. EGFR and KRAS mutations were identified in 17 of 59 tumors (29%) and 13 of 59 tumors (22%), respectively. EGFR mutations occurred most often in acinar (11 of 25 tumors; 44%) and micropapillary predominant tumors (five of 13 tumors; 38%) (p = 0.009), whereas KRAS mutations occurred most often in solid predominant tumors (nine of 21 tumors; 43%) (p = 0.016). Patients with acinar predominant tumors had significantly improved overall survival compared with those with non-acinar predominant tumors (hazard ratio: 0.45; 95% confidence interval: 0.22-0.91; p = 0.026), which remained significant after adjustment for EGFR status, T-stage, sex, and age. Patients with EGFR-mutant micropapillary predominant tumors had similar survival to those with EGFR-mutant acinar predominant tumors. The predominant subtype in the primary tumor was most often seen in the N2 node in micropapillary and solid predominant tumors but not in acinar predominant tumors.

CONCLUSIONS

The predominant subtype in the primary tumor was associated with overall survival in resected stage III (N2) lung adenocarcinoma and was independent of mutation status. Histologic subtyping provides important prognostic information and potentially molecular correlates.

[Molecular pathology of the lungs. New perspectives by next generation sequencing]

Lung cancer is one of the most frequent malignancies in the western world. Its frequent association with a wide spectrum of mutations in genes encoding various signal transducers that are often linked to therapy response, emphasizes the obvious need for improved, fast and highly efficient approaches in molecular pathology. Comprehensive analyses of the mutation status of progression and therapy relevant genes can be performed by the novel sequencing forms named next generation sequencing (NGS) providing extremely high capacities for ultra-deep sequence analyses. The 454 pyrosequencing method, the sequencing by synthesis and the semiconductor sequencing platform are now available for parallel sequencing approaches of multitudinous target genes linked to multiple tumor DNA applications. The "one molecule, one clone, one read" principle by the NGS approaches supplies not only information on allele frequencies and mutation rates but also has the advantage of a very sensitive detection of low frequency variants.

Pulmonary Langerhans cell histiocytosis: profiling of multifocal tumors using next-generation sequencing identifies concordant occurrence of BRAF V600E mutations

BACKGROUND

Pulmonary Langerhans cell histiocytosis is a localized proliferation of Langerhans cells in the lung that presents without systemic manifestations as bilateral nodular lung disease in adult cigarette smokers. The molecular basis for this proliferation is unknown.

METHODS

Twenty-two concurrent nodules in five patients were microdissected from formalin-fixed paraffin-embedded tissue and analyzed by next-generation sequencing for mutations in 46 cancer genes with the Ion AmpliSeq Cancer Panel on an Ion PGM (Personal Genome Machine) Sequencer (Life Technologies Corporation). Mutation confirmation was performed by conventional Sanger sequencing or by sensitive coamplification at lower denaturation polymerase chain reaction/fluorescence melting curve analysis.

RESULTS

Small amounts of DNA (10 ng) isolated from nodules were sufficient for successful interrogation of 740 mutational hot spots in 46 cancer genes by the Ion PGM Sequencer, with an average depth of coverage of 2,783 reads per hot spot and with uniformity of coverage of 92%. BRAF V600E mutation was detected in all concurrent nodules studied in two of the five patients, whereas in three of the five patients, no oncogene mutations were found.

CONCLUSIONS

Pulmonary Langerhans cell histiocytosis appears to be a clonal proliferation that may or may not have BRAF V600E mutations. For those with BRAF V600E mutations, new targeted therapies, such as vemurafenib, may be used in progressive cases.

The new 2011 international association for the study of lung cancer/american thoracic society/european respiratory society classification of lung adenocarcinoma in resected specimens: clinicopathologic relevance and emerging issues

Pathologists play an increasingly important role in personalized medicine for patients with lung cancer as a result of the newly recognized relationship between histologic classification and molecular change. In 2011, the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) proposed a new architectural classification for invasive lung adenocarcinomas to provide uniform terminology and diagnostic criteria. This review highlighted the evolution of the classification of lung adenocarcinomas in resected specimens with special respect to both histologic subtyping and invasion. Histologic subtyping of lung adenocarcinoma has been updated based on five major predominant patterns. New concepts of adenocarcinoma in situ and minimally invasive adenocarcinomas have been introduced to define the condition of patients who are expected to have excellent survival. Although the new IASLC/ATS/ERS classification has promising clinical relevance, significant clarification remains necessary for the definitions of subtyping and invasion. More precise definitions and subsequent better education on the interpretation of terminology will be helpful for future studies.

BRAF V600E Mutations in Endometrial Adenocarcinoma

The BRAF V600E somatic mutation is recognized as an oncogenic driver of many human cancers involving the MAPK/ERK pathway. Colorectal and lung cancers associated with the BRAF V600E mutation often demonstrated mucinous morphology. This study hypothesized that the BRAF V600E mutation may be associated with mucinous morphology in endometrial cancer and aimed to investigate its prevalence in mucinous (endometrial) carcinoma (MC) and endometrioid adenocarcinoma with significant mucinous differentiations (ECMD) (>10% neoplastic cells). Twenty-eight cases of endometrial cancer were selected, including 17 (60.7%) cases of MC or ECMD. All patients were Caucasian with age ranging from 50 to 87 years old (median 65). Genomic DNA was extracted from formalin-fixed paraffin-embedded tumor tissue and subjected to both real-time mutant allele-specific amplification polymerase chain reaction (PCR) and PCR amplification, followed by direct sequencing. Three (3/28, 10.7%) BRAF V600E mutations were detected by real-time mutant allele-specific amplification PCR and confirmed by direct sequencing. Two of 3 cases positive for BRAF V600E mutation were ECMDs with "surface epithelial changes." KRAS mutations were found in 9 cases (32.1%), none with BRAF mutation. This is the first report of BRAF V600E mutation in endometrial cancer, indicating that it may contribute to tumorigenesis of endometrial cancer, although at a low frequency compared with KRAS mutations.