Frequency of EGFR mutations in lung adenocarcinoma with malignant pleural effusion: Implication of cancer biological behaviour regulated by EGFR mutation

Analysis of tumor abnormal protein expression and epidermal growth factor receptor mutation status in non-small cell lung cancer

BACKGROUND

The level of tumor abnormal protein (TAP) level has a significant impact on tumor growth, recurrence, and metastasis. Previous studies have highlighted the influence of the mutations in exons 19 and 21 of the epidermal growth factor receptor (EGFR), particularly the sensitivity displayed by tumor cells to epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) therapy. Our study is centered on exploring the clinical relevance of TAP and EGFR mutations in patients with non-small cell lung cancer (NSCLC).

MATERIAL AND METHODS

In this study, tissue samples were collected from a total of 176 patients diagnosed with non-small cell lung cancer (NSCLC). Real-time PCR technology was utilized to detect mutations within exons 19 and 21 of the epidermal growth factor receptor (EGFR) gene in these samples. This approach enables precise identification of EGFR mutations associated with NSCLC. Furthermore, the study investigated the impact of various tumor markers, including tumor abnormal protein (TAP) and carcinoembryonic antigen (CEA), on EGFR mutation status. Established assays were employed to evaluate TAP and CEA levels, aiming to ascertain their potential correlation with EGFR mutation in NSCLC patients.

RESULTS

EGFR exhibited mutation rates of 23.86% and 12.50% in exons 19 and 21, respectively. EGFR mutations were more prevalent in younger women (< 60 years old) and in cases with pleural invasion, vessel invasion, CEA > 6.5 ng/mL, and TAP > 228 µm2 for both genders. Increased TAP levels independently predicted EGFR mutations (P = 0.001 for males; P = 0.000 for females). An area under the curve (AUC) of 0.833 indecated EGFR mutation prediction with sensitivity and specificity of 79.7% and 87.0%, respectively. For females, the sensitivity increased to 89.7% and specificity increased to 93.8%.

CONCLUSIONS

TAP effectively predicts EGFR mutations in NSCLC patients with moderate accuracy, particularly benefiting diagnosis in females with high sensitivity and specificity. Integrating TAP assessment into EGFR mutation testing can significantly enhance diagnostic precision, especially in female NSCLC cases.

Efficacy of osimertinib in patients with EGFR-mutation positive non-small cell lung cancer with malignant pleural effusion

BACKGROUND

As an epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), osimertinib has emerged as a standard EGFR-mutation positive treatment for non-small cell lung cancer (NSCLC). However, the efficacy of osimertinib for malignant pleural effusion (MPE) remains understudied. This study aimed to evaluate the impact of osimertinib on time to treatment failure (TTF) and overall survival (OS) in patients with EGFR-mutation positive NSCLC, comparing those with and without MPE.

METHODS

This retrospective analysis included patients with advanced or recurrent NSCLC treated with osimertinib at our hospital between April 2016 and June 2021. TTF was defined as the duration from osimertinib initiation to discontinuation, and OS as the duration until death, irrespective of the reason.

RESULTS

Among 229 patients receiving osimertinib, 84 had MPE before administration, 39 acquired EGFR exon20 T790M mutation following previous EGFR-TKI therapy, and 45 were EGFR-TKI-naive. Among EGFR-TKI-naive patients, median TTF was 14.8 and 19.8 months for those with and without MPE, respectively (hazard ratio [HR] 1.40; 95% confidence interval [CI]: 0.90-2.18; p = 0.12). Median OS was 32.0 and 42.0 months for patients with and without MPE, respectively (HR 1.43; 95% CI: 0.86-2.38; p = 0.16). Among patients with T790M mutation, median TTF was 12.3 and 13.1 months for patients with and without MPE, respectively (HR 1.03; 95% CI: 0.69-1.55; p = 0.88). Median OS for patients with and without MPE was 23.2 and 24.7 months, respectively (HR 1.09; 95% CI: 0.72-1.67; p = 0.68).

CONCLUSION

Among patients with EGFR-mutation positive NSCLC, the evidence of MPE has little effect on survival with osimertinib.

Efficacy of osimertinib in epidermal growth factor receptor-mutated non-small-cell lung cancer patients with pleural effusion

Background

Osimertinib is a standard first-line treatment for advanced non-small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations. Although malignant pleural effusion (PE) is a common clinical problem in NSCLC, information about the efficacy of osimertinib in patients with PE is limited, especially regarding its efficacy in EGFR T790M-negative patients with PE remains unclear.

Methods

We retrospectively reviewed the medical records of patients with NSCLC harboring EGFR mutations who were treated with osimertinib in our institution between May 2016 and December 2020.

Results

A total of 63 patients with EGFR mutated NSCLC were treated with osimertinib; 33 (12 with PE) had no EGFR T790M mutation, while 30 (12 with PE) had EGFR T790M mutation. In EGFR T790M-negative NSCLC, the progression-free survival (PFS) of the patients with PE was comparable to that of the patients without PE (median PFS 19.8 vs. 19.8 months, p = 0.693). In EGFR T790M- positive NSCLC, the PFS and overall survival (OS) of the patients with PE were significantly shorter than those of the patients without PE (median PFS 16.8 vs. 8.3 months, p = 0.003; median OS 44.9 vs. 14.2 months, p = 0.007). In the multivariate analysis, the presence of PE was independently associated with shorter PFS and OS in EGFR T790M-positive NSCLC patients, but not EGFR T790M-negative patients.

Conclusions

These data suggest the efficacy of osimertinib may differ between EGFR T790M-positive and -negative NSCLC patients with PE.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09701-2.

Pleural invasion, epidermal growth factor receptor mutation and carcinoembryonic antigen level affect pleural lavage cytology-positive status in non-small-cell lung cancer

OBJECTIVES

Pleural invasion (pl) is strongly associated with the pleural lavage cytology (PLC) status. We analysed tumours with pl and evaluated the relationship between the PLC status and pl.

METHODS

We retrospectively reviewed 428 surgically treated patients who had been diagnosed with non-small-cell lung cancer with pl and had their PLC status examined between 2000 and 2016. We investigated the influence of a PLC-positive status on the prognosis and searched for the factors predictive of a PLC-positive status.

RESULTS

Seventy-eight (18%) patients were PLC positive. The recurrence-free survival of PLC-positive patients was significantly worse than that of PLC-negative patients in pl1 and pl2, but not in pl3 (5-year recurrence-free survival rate, PLC positive versus PLC negative: pl1, 22.0% vs 60.0%, P = 0.002; pl2, 30.4% vs 59.7%, P = 0.015; pl3, 50.0% vs 59.6%, P = 0.427). A multivariable analysis showed that the degree of pl (pl2-3 versus pl1) [odds ratio (OR) 5.34, P < 0.001] was an independent predictive factor for PLC positivity. Epidermal growth factor receptor (EGFR) mutation positivity (OR 5.48, P = 0.042) and carcinoembryonic antigen (CEA) ≥5 ng/ml (OR 3.78, P = 0.042) were associated with a PLC-positive status in patients with pl2-3. We found that the PLC-positive rate in patients with pl2-3 was 35.6%; however, if the tumour was EGFR mutation positive and had CEA ≥5 ng/ml, the PLC-positive rate increased to 77%.

CONCLUSIONS

If a tumour was suspected of being pl2-3 and had EGFR mutation positivity and CEA ≥5 ng/ml, the PLC-positive rate was extremely high.

CLINICAL TRIAL REGISTRATION NUMBER

Hyogo Cancer Center, G-138.

Role of early definitive management for newly diagnosed malignant pleural effusion related to lung cancer

BACKGROUND AND OBJECTIVE

The advent of effective anti-cancer therapy has brought about uncertainty on the benefit of early definitive measures for newly diagnosed MPE from lung cancer. This study aims to investigate the outcomes of MPE in this setting.

METHODS

Lung cancer patients with MPE at first presentation to a tertiary care hospital were followed up till death or censored from 2011 to 2018. Early MPE control measures included chemical pleurodesis or IPC before or shortly after oncological treatment. Predictors of time to MPE re-intervention were identified with Cox proportional hazard analyses.

RESULTS

Of the 509 records screened, 233 subjects were eligible. One hundred and twenty-seven subjects received oral targeted therapy as first-line treatment and 34 (26.8%) underwent early definitive MPE control measures. Early MPE control measures in addition to targeted therapy, as compared to targeted therapy alone, significantly reduced the subsequent need of MPE re-intervention (23.5% vs 53.8%, P = 0.002). Similar benefits from MPE control measures were found in groups receiving systemic anti-cancer therapy or best supportive care (0% vs 52%, P = 0.003; 18% vs 56.7%, P = 0.024, respectively). In the group with targetable mutations, both early MPE control measures (HR: 0.25, 95% CI: 0.12-0.53, P < 0.001) and the use of targeted therapy (HR: 0.22, 95% CI: 0.10-0.46, P < 0.001) were independently associated with longer time to MPE re-interventions.

CONCLUSION

Early MPE control measures in lung cancer has additional benefits on reducing the need and prolonging the time to MPE re-intervention, independent of anti-cancer therapies.

Multiplexed molecular profiling of lung cancer with malignant pleural effusion using next generation sequencing in Chinese patients

Lung cancer is the most common type of cancer and the leading cause of cancer-associated death worldwide. Malignant pleural effusion (MPE), which is observed in ~50% of advanced non-small cell lung cancer (NSCLC) cases, and most frequently in lung adenocarcinoma, is a common complication of stage III-IV NSCLC, and it can be used to predict a poor prognosis. In the present study, multiple oncogene mutations were detected, including 17 genes closely associated with initiation of advanced lung cancer, in 108 MPE samples using next generation sequencing (NGS). The NGS data of the present study had broader coverage, deeper sequencing depth and higher capture efficiency compared with NGS findings of previous studies on MPE. In the present study, using NGS, it was demonstrated that 93 patients (86%) harbored EGFR mutations and 62 patients possessed mutations in EGFR exons 18-21, which are targets of available treatment agents. EGFR L858R and exon 19 indel mutations were the most frequently observed alterations, with frequencies of 31 and 25%, respectively. In 1 patient, an EGFR amplification was identified and 6 patients possessed a T790M mutation. ALK + EML4 gene fusions were identified in 6 patients, a ROS1 + CD74 gene fusion was detected in 1 patient and 10 patients possessed a BIM (also known as BCL2L11) 2,903-bp intron deletion. In 4 patients, significant KRAS mutations (G12D, G12S, G13C and A146T) were observed, which are associated with resistance to afatinib, icotinib, erlotinib and gefitinib. There were 83 patients with ERBB2 mutations, but only two of these mutations were targets of available treatments. The results of the present study indicate that MPE is a reliable specimen for NGS based detection of somatic mutations.

Targeted deep sequencing from multiple sources demonstrates increased NOTCH1 alterations in lung cancer patient plasma

Introduction

Targeted therapies are based on specific gene alterations. Various specimen types have been used to determine gene alterations, however, no systemic comparisons have yet been made. Herein, we assessed alterations in selected cancer‐associated genes across varying sample sites in lung cancer patients.

Materials and Methods

Targeted deep sequencing for 48 tumor‐related genes was applied to 153 samples from 55 lung cancer patients obtained from six sources: Formalin‐fixed paraffin‐embedded (FFPE) tumor tissues, pleural effusion supernatant (PES) and pleural effusion cell sediments (PEC), white blood cells (WBCs), oral epithelial cells (OECs), and plasma.

Results

Mutations were detected in 96% (53/55) of the patients and in 83% (40/48) of the selected genes. Each sample type exhibited a characteristic mutational pattern. As anticipated, TP53 was the most affected sequence (54.5% patients), however this was followed by NOTCH1 (36%, across all sample types). EGFR was altered in patient samples at a frequency of 32.7% and KRAS 10.9%. This high EGFR/ low KRAS frequency is in accordance with other TCGA cohorts of Asian origin but differs from the Caucasian population where KRAS is the more dominant mutation. Additionally, 66% (31/47) of PEC samples had copy number variants (CNVs) in at least one gene. Unlike the concurrent loss and gain in most genes, herein NOTCH1 loss was identified in 21% patients, with no gain observed. Based on the relative prevalence of mutations and CNVs, we divided lung cancer patients into SNV‐dominated, CNV‐dominated, and codominated groups.

Conclusions

Our results confirm previous reports that EGFR mutations are more prevalent than KRAS in Chinese lung cancer patients. NOTCH1 gene alterations are more common than previously reported and reveals a role of NOTCH1 modifications in tumor metastasis. Furthermore, genetic material from malignant pleural effusion cell sediments may be a noninvasive manner to identify CNV and participate in treatment decisions.

EGFR mutations are significantly associated with visceral pleural invasion development in non-small-cell lung cancer patients

OBJECTIVES

A retrospective study was performed to investigate the association between EGFR mutations and visceral pleural invasion (VPI), and evaluate the prognostic value of EGFR in resected non-small-cell lung cancer (NSCLC) patients with VPI.

MATERIALS AND METHODS

Clinicopathological characteristics and follow-up information were collected from 508 consecutive patients with surgically resected stage I-III NSCLC, and EGFR mutations were detected based on real-time PCR technology. Significant results (P<0.05) from univariate logistic regression analysis were involved as covariates to adjust confounding factors in the analysis of independent factors.

RESULTS

VPI and EGFR mutations were detected in 229 (45.1%) and 243 (47.8%) cases in NSCLC, respectively. There was a significant association between EGFR mutations and VPI development. Both 19-del (adjusted OR =2.13, 95%CI =1.13-3.99, P=0.019) and L858R (adjusted OR =2.89, 95%CI =1.59-5.29, P=0.001) could significantly increase the risk of VPI development compared with EGFR wild-type. Higher frequency of L858R (adjusted OR =2.63, 95%CI =1.42-4.88, P=0.002) was detected in VPI patients compared with non-VPI patients. 19-del (adjusted HR =0.31, 95%CI =0.12-0.80, P=0.015) was an independent prognostic factor for a better disease-free survival (DFS) in non-VPI patients. No significant association was shown between EGFR mutations and DFS in VPI patients.

CONCLUSION

EGFR mutations were significantly associated with VPI development in NSCLC, but no significant association was observed between EGFR mutations and DFS in the patients with VPI. 19-del was a favorable prognostic factor for DFS in non-VPI patients.

Effect of postoperative systemic therapy on pulmonary adenocarcinoma with unexpected pleural spread detected during thoracotomy or thoracoscopy

Background

Occasionally, malignant pleural disease is only detected unexpectedly during surgery in patients with pulmonary adenocarcinoma. Previous studies mostly focused on the role of main tumor resection on patient's outcome, barely addressing the position of postoperative systemic therapy.

Methods

The medical records of 5321 non-small cell lung cancer patients who underwent thoracic surgery between January 1990 and December 2012 were reviewed. Pulmonary adenocarcinoma patients with unexpected pleural spread noted during surgery were included. The clinical and postoperative treatment variables were assessed for correlation with overall survival.

Results

In 134 patients identified, main tumor resection was performed in 87 (64.9%) patients, while 89 (66.4%) and 57 (42.5%) patients received postoperative chemotherapy and epidermal growth factor receptor- tyrosine kinase inhibitor (EGFR -TKI) therapy, respectively. Overall, the 5-year survival rate was 30.2% and median survival time was 29.3 months. Multivariate analysis showed main tumor resection and EGFR-TKI therapy were associated with better survival. Mutational status of EGFR was available in 57 patients and 43 (75.4%) had activating mutations. Resection of the main tumor conferred a better outcome in patients without EGFR mutation or with unknown EGFR mutation status and had not been treated with EGFR-TKI therapy (P = 0.003), but not in those with activating EGFR mutation and had been treated with EGFR-TKI (P = 0.857).

Conclusions

In pulmonary adenocarcinoma patients with unexpected pleural spread detected during surgery, main tumor resection and EGFR-TKI therapy correlated with better survival. Identifying EGFR mutation status before surgery can provide useful information for clinical decision during surgery.

Comprehensive Genomic Profiling of Malignant Effusions in Patients with Metastatic Lung Adenocarcinoma

Cytology samples are increasingly used for comprehensive molecular testing. Although fine-needle aspirates are adequate substrates for high-throughput sequencing, the suitability of malignant body fluids remains largely unexplored. We investigated the adequacy and utility of performing targeted next-generation sequencing (NGS) on malignant effusions from patients with metastatic lung adenocarcinoma. Thirty-two effusion samples submitted for hybrid capture-based NGS using a clinically validated solid tumor genotyping panel were examined. All cases showed ≥5% tumor cellularity; however, 28 (88%) provided sufficient DNA for NGS (≥1 ng/μL). The sequencing reads showed satisfactory quality control statistics, and the variant allele frequencies were correlated with tumor cellularity. Furthermore, pathogenic or likely pathogenic genomic alterations were identified in 26 of 28 samples (93%), whereas clinically actionable alterations were present in 18 (64%). Notably, nine patients had additional molecular testing performed on preceding or subsequent biopsy specimens, and the results across multiple samples were compared. In two patients, the NGS-based fluid analysis identified clinically actionable alterations that were not detected by other hotspot testing. In four patients treated with tyrosine kinase inhibitors, malignant fluid sequencing confirmed driver alterations from prior testing and revealed new resistance mechanisms. Hence, given adequate DNA input and tumor cellularity, comprehensive genomic profiling of malignant effusions may be used to establish mutational status at diagnosis and inform treatment resistance during targeted therapy.

Epidermal Growth Factor Receptor Gene Mutation in Pleural Lavage Cytology Findings of Primary Lung Adenocarcinoma Cases

PURPOSE

In the present study, we examined the relationship between intraoperative pleural lavage cytology findings and presence of epidermal growth factor receptor (EGFR) gene mutations.

METHODS

We investigated 160 patients who underwent surgical treatment for primary lung adenocarcinoma at our hospital from January 2011 to December 2013 to determine the presence of EGFR gene mutations and pleural lavage cytology.

RESULTS

In all, 52 subjects (31.5%) were positive EGFR gene mutations, of whom 38 were found to possess the Exon 21 L858R mutation. Intraoperative pleural lavage cytology examinations were performed in 160 subjects and 12 had positive results, of whom 6 were positive for EGFR gene mutations, which was the Exon 21 L858R mutation in all. In a comparison between subjects possessing the Exon 21 L858R mutation and those negative for EGFR gene mutations, lavage cytology-positive (p = 0.02) and vascular infiltration-negative (p = 0.01) were characteristics of the Exon 21 L868R mutation-positive group.

CONCLUSION

Subjects positive for the EGFR Exon 21 L858R mutation had a higher positive rate of intraoperative pleural lavage cytology than those not possessing EGFR mutations.

Peripheral lung adenocarcinomas harboring epithelial growth factor receptor mutations with microRNA-135b overexpression are more likely to invade visceral pleura

Lung adenocarcinoma, characterized by its early and aggressive local invasion and high metastatic potential, is the most frequently observed histological type of non-small-cell lung cancer (NSCLC). Visceral pleural invasion (VPI) caused by peripheral lung adenocarcinomas is closely associated with the poor prognosis of patients with NSCLC. The association between VPI and some clinicopathological characteristics has been observed in the past few decades. However, the molecular mechanism of VPI in lung adenocarcinomas is unknown. In the present, the expression level of microRNA (miR-)135b and epidermal growth factor receptor (EGFR) mutations using the reverse transcription-quantitative polymerase chain reaction and DNA sequencing, respectively. In addition, the present study aimed at exploring the association between the miR-135b level, EGFR mutations and VPI in peripheral lung adenocarcinoma. The results of the present study demonstrated that miR-135b was significantly upregulated in lung adenocarcinoma compared with adjacent normal tissue and positively associated EGFR mutations in peripheral lung adenocarcinoma. Furthermore, it was identified that lung adenocarcinomas with EGFR mutations and miR-135b overexpression were more likely to invade visceral pleura. Taken together, these findings indicate that miR-135b overexpression is positively associated with mutations to EGFR, which may promote the development of peripheral lung adenocarcinomas by the formation of VPI. This indicates that the two factors may serve as prognostic markers and molecular targets for the treatment of peripheral lung adenocarcinomas.

Malignant pleural effusions because of lung cancer

PURPOSE OF REVIEW

The discovery of a pleural effusion in the setting of lung cancer has diagnostic, prognostic, and therapeutic challenges, some of which are addressed in this review.

RECENT FINDINGS

Around 20% of patients with lung cancer have minimal pleural effusions, which are not amenable to a diagnostic thoracentesis. These patients have a poorer overall survival (∼7.5 months) than those without effusions (∼12-18 months), although slightly better than those with proven malignant fluids (∼5.5 months). Tumor genotype techniques are feasible on pleural fluid specimens and clinically helpful in identifying patients who may benefit from targeted therapies. If limited pleural involvement is detected during lung cancer surgery despite the presurgical imaging studies, macroscopic complete resection of the lung tumor is still a treatment option. Cytological examination for cancer cells in pleural cavity washings at the time of thoracotomy (pleural lavage cytology) is recommended to uncover pleural dissemination. Patients with non-small cell lung cancer with visceral pleural invasion might be considered candidates for postsurgical adjuvant therapy.

SUMMARY

Some predictors of adverse survival in patients with lung cancer include the presence of a minimal pleural effusion, positive pleural lavage cytology, visceral pleural invasion on pathologic examination, and unexpected pleural involvement during surgery.

Erlotinib for Japanese patients with activating EGFR mutation-positive non-small-cell lung cancer: combined analyses from two Phase II studies

AIMS

We evaluated the efficacy and safety of erlotinib, and patient characteristics affecting progression-free survival (PFS), by analyzing data from two Phase II studies of first-line erlotinib in activating EGFR mutation-positive non-small-cell lung cancer.

METHODS

Data were combined from patients who received first-line erlotinib monotherapy in JO22903 (single-arm study; JapicCTI-101085) and JO25567 (randomized study; JapicCTI-111390).

RESULTS

Median PFS was 10.9 months in efficacy-evaluable patients (n = 177). Major adverse events were dermatologic; no new safety signals were observed. Baseline pleural/cardiac effusion notably affected PFS (yes median 8.0 months vs no median 15.3 months) as confirmed in multivariate analysis (hazard ratio: 0.38; 95% CI: 0.25-0.58).

CONCLUSION

Efficacy and safety of erlotinib monotherapy were consistent with previous studies. Baseline pleural/pericardial effusion was associated with shorter PFS.

ALK gene expression status in pleural effusion predicts tumor responsiveness to crizotinib in Chinese patients with lung adenocarcinoma

Objective

The relationship between anaplastic lymphoma kinase (ALK) expression in malignant pleural effusion (MPE) samples detected only by Ventana immunohistochemistry (IHC) ALK (D5F3) and the efficacy of ALK-tyrosine kinase inhibitor therapy is uncertain.

Methods

Ventana anti-ALK (D5F3) rabbit monoclonal primary antibody testing was performed on 313 cell blocks of MPE samples from Chinese patients with advanced lung adenocarcinoma, and fluorescence in situ hybridization (FISH) was used to verify the ALK gene status in Ventana IHC ALK (D5F3)-positive samples. The follow-up clinical data on patients who received crizotinib treatment were recorded.

Results

Of the 313 MPE samples, 27 (8.6%) were confirmed as ALK expression-positive, and the Ventana IHC ALK (D5F3)-positive rate was 17.3% (27/156) in wild-type epidermal growth factor receptor (EGFR) MPE samples. Twenty-three of the 27 IHC ALK (D5F3)-positive samples were positive by FISH. Of the 11 Ventana IHC ALK (D5F3)-positive patients who received crizotinib therapy, 2 patients had complete response (CR), 5 had partial response (PR) and 3 had stable disease (SD).

Conclusions

The ALK gene expression status detected by the Ventana IHC ALK (D5F3) platform in MPE samples may predict tumor responsiveness to crizotinib in Chinese patients with advanced lung adenocarcinoma.

Adequacy of Malignant Pleural Effusion for Epidermal Growth Factor Receptor Mutation Analysis Using the Pyrosequencing Method

Background:

Epidermal growth factor receptor (EGFR) mutation analysis is a standard approach for initial therapeutic decision in patients with metastatic adenocarcinoma of the lung (MAL). The feasibility of performing EGFR mutation testing using pleural fluid specimen is not well characterized.

Objectives:

The aim of this study is to report the percentage of patients eligible for EGFR mutation testing based on the percentage of malignant cells (PMCs) in the pleural fluid using the pyrosequencing method.

Methods:

From our database, we reviewed the clinical data of 61 patients with malignant pleural effusion (MPE) secondary to MAL. The PMCs were divided into 2 categories with a cutoff point of 10% (PMC1 is defined as ≤10% and PMC2 is defined as >10%). For the pyrosequencing method, only patients in the PMC2 group were eligible for EGFR mutation testing.

Results:

Of 61 patients with MPE secondary to MAL, 38 (62.3%) were in the PMC2 group, which represents the percentage of patients eligible for EGFR mutation testing. Of these 38 patients, 15 patients had the testing done on the MPE. Quantity was not sufficient for testing only in 1 patient. Therefore, in PMC2 patients group, the rate of successful EGFR mutation testing was 93% (14 of 15). The thoracentesis volume was not significantly different between PMC1 and PMC2.

Conclusion:

Performing EGFR mutation analysis on the MPE in patients with MAL is feasible in 62% of patients. The rate of successful testing on the eligible samples is 93%.

EGFR-L858R mutant enhances lung adenocarcinoma cell invasive ability and promotes malignant pleural effusion formation through activation of the CXCL12-CXCR4 pathway

Malignant pleural effusion (MPE) is a common clinical problem in non-small cell lung carcinoma (NSCLC) patients; however, the underlying mechanisms are still largely unknown. Recent studies indicate that the frequency of the L858R mutant form of the epidermal growth factor receptor (EGFR-L858R) is higher in lung adenocarcinoma with MPE than in surgically resected specimens, suggesting that lung adenocarcinoma cells harboring this mutation tend to invade the adjacent pleural cavity. The purpose of this study was to clarify the relationship between the EGFR-L858R mutation and cancer cell invasion ability and to investigate the molecular mechanisms involved in the formation of MPE. We found that expression of EGFR-L858R in lung cancer cells resulted in up-regulation of the CXCR4 in association with increased cancer cell invasive ability and MPE formation. Ectopic expression of EGFR-L858R in lung cancer cells acted through activation of ERK signaling pathways to induce the expression of CXCR4. We also indicated that Inhibition of CXCR4 with small interfering RNA, neutralizing antibody, or receptor antagonist significantly suppressed the EGFR-L858R–dependent cell invasion. These results suggest that targeting the production of CXCR4 and blocking the CXCL12-CXCR4 pathway might be effective strategies for treating NSCLCs harboring a specific type of EGFR mutation.

[Research Progress of Mechanisms on Intracranial Metastasis of Non-small Cell Lung Cancer after Clinical Benefit from EGFR-TKI]

表皮生长因子受体酪氨酸激酶抑制剂（epidermal growth factor receptor tyrosine kinase inhibitor, EGFR-TKI）广泛用于治疗EGFR突变阳性的非小细胞肺癌（non-small cell lung cancer, NSCLC）。然而，部分患者在接受EGFR-TKI治疗后、原发病灶稳定甚至缩小的同时，却出现了新发颅内转移灶或者原有颅内病灶进展，其机制未明。近年来多项研究表明，这种现象可能与EGFR-TKI的药物代谢动力学、NSCLC原发灶与转移灶的异质性、EGFR突变本身特质及患者生存期的延长有关。因此，本文就NSCLC患者在EGFR-TKI治疗临床获益后发生颅内转移的相关机制研究进展作一综述。

Switching off malignant pleural effusion formation-fantasy or future?

Malignant pleural effusion (MPE) is common and difficult to treat. In the vast majority of patients the presence of MPE heralds incurable disease, associated with poor quality of life, morbidity and mortality. Current therapeutic approaches are inefficient and merely offer palliation of associated symptoms. Recent scientific progress has shed light in the biologic processes governing the mechanisms behind the pathobiology of MPE. Pleural based tumors interfere with pleural fluid drainage, as well as the host vasculature and immune system, resulting in decreased fluid absorption and increased pleural fluid production via enhanced plasma extravasation into the pleural space. In order to achieve this feat, pleural based tumors must elicit critical vasoactive events in the pleura, thus forming a favorable microenvironment for tumor dissemination and MPE development. Such properties involve specific transcriptional signaling cascades in addition to secretion of important mediators which attract and activate host cell populations which, in turn, impact tumor cell functions. The dissection of the biologic steps leading to MPE formation provides novel therapeutic targets and recent research findings provide encouraging results towards future therapeutic innovations in MPE management.

Pleural involvement in lung cancer

The pleural space, a sterile secluded environment in the thoracic cavity, represents an attractive metastatic site for various cancers of lung, breast and gastrointestinal origins. Whereas lung and breast adenocarcinomas could invade the pleural space because of their anatomic proximity, "distant" cancers like ovarian or gastrointestinal tract adenocarcinomas may employ more active mechanisms to the same end. A pleural metastasis is often accompanied by a malignant pleural effusion (MPE), an unfavorable complication that severely restricts the quality of life and expectancy of the cancer patient. MPE is the net "product" of three different processes, namely inflammation, enhanced angiogenesis and vascular leakage. Current efforts are focusing on the identification of cancer cell autocrine (specific mutation spectra and biochemical pathways) and paracrine (cytokine and chemokine signals) characteristics as well as host features (immunological or other) that underlie the MPE phenotype. Herein we examine the pleural histology, cytology and molecular characteristics that make the pleural cavity an attractive metastasis destination for lung adenocarcinoma. Mesothelial and tumor features that may account for the tumor's ability to invade the pleural space are highlighted. Finally, possible therapeutic interventions specifically targeting MPE are discussed.