Laser capture microdissection: A tool for the molecular characterization of histologic subtypes of lung adenocarcinoma

The exon 19 and 21 in Epidermal Growth Factor Receptor (EGFR) mutation are the most common subtype of lung adenocarcinoma, and the strongest predictive biomarker for progression-free survival and tumor response. Although some studies have shown differences in radiological features between cases with and without EFGR mutations, they lacked necessary stratification. This article is to evaluate the association of CT features between the wild type and the subtype (exon 19 and 21) of EGFR mutations in patients with lung adenocarcinoma. Of the 721 finally included patients, 132 were positive for EGFR mutation in exon 19, 140 were positive for EGFR mutation in exon 21, and 449 were EGFR wild type. EGFR mutation in exon 19 was associated with a small-maximum diameter (28.51 ± 14.07) (p < 0.0001); sex (p < 0.0001); pleural retraction (p = 0.0034); and the absence of fibrosis (p < 0.0001), while spiculated margins (p = 0.0095), subsolid density (p < 0.0001) and no smoking (p < 0.0001) were associated with EGFR mutation in exon 21. Receiver Operating Characteristic (ROC) curves suggested that the maximum Area Under the Curve (AUC) was related to the female gender (AUC = 0.636) and the absence of smoking (AUC = 0.681). This study demonstrated the radiological and clinical features could be used to prognosticate EGFR mutation subtypes in exon 19 and 21.

The epidermal growth factor receptor (EGFR) mutation status has become one of the most important factors in the treatment of non-small cell lung cancer. However, the relationship between EGFR mutation and the histologic subtype of lung adenocarcinoma remains to be fully elucidated. We examined the relationship between the predominant subtype of adenocarcinoma and the prognosis and investigated the correlation between a new subtype of adenocarcinoma and EGFR mutations. This study included 182 patients with adenocarcinoma who underwent complete resection. The rate of EGFR mutation-positive patients was significantly higher among female patients, never smokers, patients with small tumors (<3cm in size), patients with well-differentiated tumors, and patients with a pStage I classification. The rates of adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and lepidic-predominant subtype were high in male EGFR mutation-positive patients. The prevalence of the acinar and papillary-predominant subtypes was high among EGFR mutation-positive female patients, as was AIS, MIA, and the lepidic-predominant subtype. The progression-free survival (PFS) of the EGFR mutation-positive patients was significantly better than that of the EGFR mutation-negative patients (75.8 vs 67.1%, p=0.03). However, the multivariate analysis of clinicopathologic and histologic factors did not reveal the prognostic impact of the EGFR mutation status on PFS. The overall survival (OS) of the EGFR mutation-positive patients was significantly better than that of the EGFR mutation-negative patients (93.7 vs 63.4%, p<0.01). However, in the multivariate analysis the EGFR mutation status was not significantly associated with OS.

Objective: To investigate the relationship between the status of epidermal growth factor receptor (EGFR) mutations and brain metastases in patients with lung adenocarcinoma. Methods: From August 2010 to May 2015, a total of 1 063 lung adenocarcinoma patients with identified status of EGFR mutations in Shanxi Cancer Hospital were enrolled, of which 456 patients had EGFR mutations. Multivariate Logistic regression model was used to analyze the correlation between EGFR mutation status and brain metastases in patients with lung adenocarcinoma. Results: In 125 patients with brain metastases before initial treatment, 65 patients had EGFR mutations, including 36 patients with deletion mutations in exon 19. The frequency of EGFR 19 exon mutation was 28.8% (36/125). Among 456 patients with EGFR mutations, 65(14.3%) patients were with brain metastases, in which 36(55.0%) had deletion mutations in exon 19. The multivariate analysis showed that age, Eastern Cooperative Oncology Group (ECOG) score, EGFR mutations and N staging were associated with brain metastases(P<0.05). Further subgroup multivariate analyses showed that age, ECOG score, mutation status in exon 19 and N staging were associated with brain metastases (P<0.05). Conclusions: EGFR mutation status is related to brain metastases. Mutations in EGFR exon 19 is an independent risk factor for brain metastases.

ObjectiveOur prospective study aims to define the correlation of EGFR(epidermal growth factor receptor) mutations with major histological subtypes of lung adenocarcinoma from resected and non-resected specimens, according to the WHO 2015 classification, in Moroccan North East Population.MethodsEpidermal growth factor receptor mutations of 150 primary lung adenocarcinoma were performed using Real-Time PCR or SANGER sequencing. SPSS 21 was used to assess the relationship between histological subtypes of lung adenocarcinoma and EGFR mutation status.Results25 mutations were detected in the series of 150 lung adenocarcinomas, most of which were found in cases with papillary, acinar, patterns than without these patterns and more frequently occurred in the cases without solid pattern than with this pattern. A significant correlation was observed between EGFR mutation and acinar (P = 0,024), papillary pattern (P = 0,003) and, negative association with a solid pattern (P < 0,001). In females, EGFR mutations were significantly correlated with the acinar pattern (P = 0,02), whereas in males with the papillary pattern (P = 0,01). Association between the histologic component and exon 19 deletions and exon 21 mutations were also evaluated and, we found a significant correlation between the papillary major pattern with exon 19 mutations (P = 0,004) and, ex21 with the acinar component (P = 0,03).ConclusionAn analysis of resected and non-resected lung ADC specimens in 150 Moroccan Northeast patients, revealed that acinar and papillary patterns may predict the presence of a mutation in the EGFR gene. While the solid major pattern may indicate a low mutation rate of the EGFR gene.

The current study was to investigate the volume doubling time (VDT) of lung adenocarcinomas considering epidermal growth factor receptor (EGFR) mutation status of exon 19 and 21, when compared with EGFR wide type. Eighty-eight patients with pathologically proven adenocarcinomas, which underwent two or more computed tomography (CT) scans spared by 25 or more days, were included. EGFR mutations at exons 19 and 21 were determined using amplification refractory mutation system and all patients were divided into three groups-EGFR wide type group, EGFR mutation in exon 19 and 21 groups. Three-dimensional manual segmentations for all tumors were performed on first and latest follow-up CT scans; subsequently, VDTs were calculated and compared among three groups. Clinicopathoradiologic characters were also collected for subgroup analysis. EGFR mutations occurred in 49 (55.7%) patients, 19 in exon 19 and 30 in exon 21, respectively. The median VDT of all patients (33 men, 55 women; median age, 62 years) was 214 days (range, -4,092 to 10,920 days). Highly differentiated adenocarcinomas (median, 408 days) demonstrated longer VDT than those moderately (median, 172 days) or poorly (median, 144 days) differentiated (P=0.04). The VDT distribution was similar among EGFR wide type group (median, 207 days), EGFR mutation in exon 19 group (median, 288 days) and exon 21 group (median, 144 days) (P=0.21). In subgroup analysis, the median VDT of adenocarcinomas with EGFR mutation in exon 19 was longer than that of EGFR wide type for males (P=0.03) or patients without spiculation sign in chest CT (P=0.04). Totally 24 adenocarcinomas presented negative VDTs, most of which tended to be stable. Positive VDT values were used for all median description. Overall VDT of lung adenocarcinomas seems not affected by EGFR mutation status. Researches with large population are warranted for further study.

18049 Background: Thymic epithelial tumor has been reported to express the epidermal growth factor receptor (EGFR), and thymic carcinoma has recently been described to have overexpression of KIT. We investigated the prevalence of EGFR and KIT mutations in patients with thymoma and thymic carcinoma to explore the potential for a targeted therapy with tyrosine kinase inhibitors. Methods: Genomic DNA was isolated from 41 paraffin-embedded tumor samples including 24 thymoma and 17 thymic carcinoma. EGFR mutations in exons 18, 19 and 21, and KIT mutations in exons 9, 11, 13 and 17, were analyzed by PCR and direct sequencing. Protein expressions of EGFR and KIT were also evaluated by immunohistochemistry. Results: We detected the EGFR mutation in 2 of 20 thymoma, but none of thymic carcinoma had mutation. All of the detected EGFR mutations were missense mutations in exon 21 (L858R and G863D, respectively). Expression of EGFR was seen in 71% of thymoma and 53% of thymic carcinoma. On mutational analysis of KIT, only one thymic carcinoma displayed a missense mutation in exon 11 (L576P). Expression of KIT was observed in 88% of thymic carcinoma and 0% of thymoma. Conclusions: Our findings indicate that a small number of patients with thymic epithelial tumor exhibit somatic mutations of EGFR or KIT although expressions of EGFR or KIT are present frequently in thymic epithelial tumor. Further investigations are warranted to determine their susceptibility to tyrosine kinase inhibitors in the treatment of thymoma and thymic carcinoma with EGFR or KIT mutations. No significant financial relationships to disclose.

The prognosis of esophageal squamous cell carcinoma (ESCC) is poor. It is urgent to improve this situation. Epidermal growth factor receptor (EGFR)-targeted therapy possesses a promising clinical efficacy. Mutations of EGFR and V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) have been identified in esophageal carcinoma, but corresponding Chinese data are limited. So we investigated the mutation status of EGFR and KRAS in Chinese patients with ESCC, and explored their correlations with clinicopathological features. Formalin-fixed paraffin-embedded surgically resected tumor samples were obtained from 50 randomly selected Chinese patients with ESCC. EGFR mutations in exons 18-21 were detected by Scorpions amplification refractory mutation system technology. KRAS mutations in codons 12, 13 were detected by direct sequencing of polymerase chain reaction products. The correlations between clinicopathological features and the mutation status of EGFR and KRAS were analyzed using the Statistical Package for the Social Sciences. In the present study, EGFR mutations were found in 7 (14%) out of 50 patients, including G719X missense mutation (n= 1), in-frame deletion (n= 2), and L858R missense mutation (n= 5). Six (12%) out of 50 patients had KRAS mutations in codon 12. Concurrent EGFR and KRAS mutations were detected in one sample. The presences of EGFR and KRAS mutations were not associated with gender, age, smoking history, cell differentiation, or cancer stage. In conclusion, the incidence of EGFR mutations in Chinese patients with ESCC was higher than that of previous reports, and the incidence of KRAS mutations was not low. EGFR and KRAS mutations were mainly located in exons 19 and 21 and codon 12, respectively. Unlike in NSCLC, concurrent EGFR and KRAS mutations existed.

BackgroundSerum carcinoembryonic antigen (CEA) is usually elevated in lung adenocarcinoma patients, but not in all patients. Lung adenocarcinoma subtypes have been defined by the new International Association for the Study...

e18017 Background: Detecting epidermal growth factor receptor (EGFR) mutations in plasma DNA samples in patients with advanced non-small cell lung cancer is challenging and promising. We compared three methods for detecting plasma EGFR mutations, including direct DNA sequencing, denaturing high-performance liquid chromatography (DHPLC) and Scorpions amplification refractory mutation system (Scorpions ARMS). Methods: Plasma DNA samples from 73 patients with stages IIIB to IV non-small cell lung cancer patients with adenocarcinoma histology were analyzed for EGFR mutations in exons 19 (deletion mutation) and 21 (L858R mutation) by using direct DNA sequencing, DHPLC and Scorpions ARMS . Results: In 73 patients, we detected EGFR mutations in 5 samples (6.85%) by direct DNA sequencing, in 22 samples (30.1%) by DHPLC, and in 28 samples (38.4%) by Scorpions ARMS. we found 13 deletion mutations and 9 L858R mutations by DHPLC, while 15 deletion mutations and 13 L858R mutations by Scorpions ARMS. Among the 73 patients, there was 90.4% concordance between DHPLC and Scorpions ARMS (66/73, κ = 0.71, p < 0.01). Seven patients were detected discordant mutation status by DHPLC and Scorpions ARMS. Six EGFR mutation-positive samples detected by Scorpions ARMS were found mutation-negative by DHPLC, and one EGFR mutation-positive sample detected by DHPLC was found mutation-negative by Scorpions ARMS. In the 73 patients, 46 patients were treated with gefitinib or erlotinib, including 18 patients with mutations and 28 patients without mutations by Scorpions ARMS. The 18 patients with EGFR mutations had a significant longer progression-free survival (PFS) time (median PFS, 21.0 months; 95% confidence interval [CI] 7.5 to 34.5 months) than 28 patients without EGFR mutations (median PFS, 7.0 months; 95% confidence interval [CI] 3.4 to 10.6 months) (p = 0.022). Conclusions: Among the three methods for detecting EGFR mutations in plasma DNA samples in patients with advanced lung adenocarcinoma, direct gene sequencing had the lowest sensitivity, while Scorpion ARMS showed the highest mutation detecting capability. DHPLC is slightly less sensitive than Scorpion ARMS. No significant financial relationships to disclose.

Screening for activating<i>EGFR</i>mutations in surgically resected nonsmall cell lung cancer

The mutation status of epidermal growth factor receptor (EGFR) is correlated with the response of tumors to EGFR tyrosine kinase inhibitors in non-small cell lung cancer (NSCLC), suggesting its usefulness as a biomarker in NSCLC. The incidence of EGFR mutation in NSCLC is higher in China than in the United States and European countries. There have been some case reports concerning cases of gefitinib-responsive small cell lung cancer (SCLC) with EGFR mutations. However, few large studies concerning the mutation status of SCLC patients have been performed. We detected EGFR mutations in exons 19 and 21 of 40 SCLC patients, three of whom had combined SCLC, from the Zhejiang Cancer Hospital using xTAG technology. Only two patients with combined SCLC had an EGFR mutation in exon 19. To determine the EGFR mutation status and clinical features of combined SCLC, we retrospectively analyzed the clinical features of seven patients with combined SCLC who had undergone surgical treatment in Zhejiang Cancer Hospital between 2007 and 2010. EGFR mutations in exons 19 and 21 were detected using the pyrosequencing assay. Of the seven patients with combined SCLCs, 71.4% were male, 71.4% were heavy smokers, most were over 60 years old and 71.4% of the cases were combined adenocarcinoma. Chemotherapy treatment and tumor stage were correlated with survival time. Of the seven cases, one had a mutation in exon 19 of EGFR in both the conventional SCLC and SCLC combined adenocarcinoma components. Combined SCLC commonly occurs in patients who are heavy smokers, male and over 60 years old, and most of the combined type cases are adenocarcinoma. The treatment of combined SCLC may be applied to cases of conventional SCLC. EGFR mutations may therefore occur in combined SCLCs, especially in SCLC combined adenocarcinoma in China.

Direct sequencing is the standard method for the detection of epidermal growth factor receptor (EGFR) mutations in lung cancer, however, its relatively low sensitivity limits its clinical use. Pyrosequencing is a bioluminometric, real-time non-electrophoretic DNA sequencing technique with a number of advantages compared with direct sequencing, including higher sensitivity, speed, automation and cost-effectiveness. Clinical specimens from 202 lung cancer patients were analyzed for EGFR mutations in exons 18, 19, 20 and 21 using the pyrosequencing method following genomic DNA extraction from paraffin-embedded tissue specimens. All clinical data and tumor specimens were obtained from the Konkuk University Hospital (Korea) between July 2006 and December 2008. The results and clinical responses to EGFR-tyrosine kinase inhibitors (TKIs) were compared. Overall, EGFR mutation-positive rate was 26.7% (54/202). Activating EGFR mutations were observed more frequently in female (52.1 vs. 13.0%), non-smoking (47.8 vs. 15.8%) and adenocarcinoma (35.2 vs. 5.2%) patients. However, significant numbers of EGFR mutation-positive patients were identified as male, former or current smokers and non-adenocarcinoma patients. The combinations of favorable clinicopathological factors, including female, non-smoking and adenocarcinoma, were not identified to significantly increase the positive EGFR mutation rate (female, 52.1%; female and non-smoker, 52.6%; female, non-smoker and adenocarcinoma, 51.9%). The present findings indicate that EGFR mutation analysis is a highly useful method for the prediction of response to EGFR-TKI and the use of favorable clinicopathological factors to perform this analysis is not suitable. Exon 19 deletion was the most common mutation (63.6%) and exon 21 L858R substitution was measured at 32.7%. The exon 20 T790M mutation was identified in 1 patient prior to EGFR-TKI treatment. EGFR mutation status is associated with response to EGFR-TKI and the overall response rate in patients who have the activating EGFR mutation was 82.4 vs. 5.9% in patients with a wild-type EGFR. The present study demonstrates that EGFR mutations analyzed by the pyrosequencing method are well correlated with clinicopathological parameters and that this method may be useful in the clinical practice.

The serum carcinoembryonic antigen (CEA) level can reflect tumor growth, recurrence and metastasis. It has been reported that epidermal growth factor receptor (EGFR) mutations in exons 19 and 21 may have an important relationship with tumor cell sensitivity to EGFR -TKI therapy. In this study, we investigated the clinical value of EGFR mutations and serum CEA in patients with non-small cell lung cancer (NSCLC). The presence of mutations in EGFR exons 19 and 21 in the tissue samples of 315 patients with NSCLC was detected with real-time fluorescent PCR technology, while the serum CEA level in cases who had not yet undergone surgery, radiotherapy, chemotherapy and targeted therapy were assessed by electrochemical luminescence. The mutation rates in EGFR exons 19 and 21 were 23.2% and 14.9%, respectively, with the two combined in 3.81%. Measured prior to the start of surgery, radiotherapy, chemotherapy and targeted treatment, serum CEA levels were abnormally high in 54.3% of the patients. In those with a serum CEA level <5 ng/mL, the EGFR mutation rate was 18.8%, while with 5~19 ng/mL and ≥ 20 ng/mL, the rates were 36.4% and 62.5%. In addition, in the cohort of patients with the CEA level being 20~49 ng/mL, the EGFR mutation rate was 85.7%, while in those with the CEA level ≥ 50 ng/mL, the EGFR mutation rate was only 20.0%, approximately the same as in cases with the CEA level<5 ng/mL. There is a positive correlation between serum CEA expression level and EGFR mutation status in NSCLC patients, namely the EGFR mutation-positive rate increases as the serum CEA expression level rises within a certain range (≥ 20 ng/mL, especially 20~49 ng/mL). If patient samples are not suitable for EGFR mutation testing, or cannot be obtained at all, testing serum CEA levels might be a simple and easy screening method. Hence, for the NSCLC patients with high serum CEA level (≥ 20 ng/mL, especially 20~49 ng/mL), it is worthy of attempting EGFR-TKI treatment, which may achieve better clinical efficacy and quality of life.

High Incidence of EGFR Mutations in Korean Men Smokers with No Intratumoral Heterogeneity of Lung Adenocarcinomas: Correlation with Histologic Subtypes, EGFR/TTF-1 Expressions, and Clinical Features

The discordance of epidermal growth factor receptor (EGFR) mutations between primary lung tumors and the corresponding mediastinal nodal metastases has not yet been well elucidated. We investigate the discordance of EGFR mutations between primary tumors and the corresponding mediastinal nodal metastases, and the discordance of EGFR mutations between different mediastinal lymph node stations in patients operated on for stage N2 non-small cell lung cancer (NSCLC). Two hundred and nineteen surgically resected primary tumors and their 553 corresponding mediastinal nodal metastases were evaluated for EGFR mutations in exon 19 or 21 by TaqMan real-time polymerase chain reaction (PCR) analysis. EGFR mutation was detected in 26.0% (57/219) of the primary tumors and 14.8% (82/553) of the corresponding mediastinal nodal metastases. In 162 cases with EGFR wild-type in primary tumors, none of their 402 corresponding mediastinal nodal metastases had EGFR mutation. In 57 cases with EGFR mutations in primary tumors, EGFR mutations were detected in 82 of all 151 metastatic lymph node stations (54.3%), 34 cases had EGFR mutations in mediastinal nodal metastases, and 23 cases had lost the mutations in mediastinal nodal metastases. Among the 219 cases, 196 cases had at least two metastatic lymph node stations, 9.0% (18/196) of cases with multiple metastatic nodal stations exhibited discordance in EGFR mutations between different lymph node stations. The possibility of discordance in EGFR mutations between primary tumors and corresponding mediastinal nodal metastases, and between different mediastinal lymph node stations should be considered whenever these mutations are used for the selection of patients for EGFR-directed tyrosine kinase inhibitor therapy.