Epidermal growth factor receptor mutation and p53 overexpression during the multistage progression of small adenocarcinoma of the lung

GMILT: A Novel Transformer Network That Can Noninvasively Predict EGFR Mutation Status

Noninvasively and accurately predicting the epidermal growth factor receptor (EGFR) mutation status is a clinically vital problem. Moreover, further identifying the most suspicious area related to the EGFR mutation status can guide the biopsy to avoid false negatives. Deep learning methods based on computed tomography (CT) images may improve the noninvasive prediction of EGFR mutation status and potentially help clinicians guide biopsies by visual methods. Inspired by the potential inherent links between EGFR mutation status and invasiveness information, we hypothesized that the predictive performance of a deep learning network can be improved through extra utilization of the invasiveness information. Here, we created a novel explainable transformer network for EGFR classification named gated multiple instance learning transformer (GMILT) by integrating multi-instance learning and discriminative weakly supervised feature learning. Pathological invasiveness information was first introduced into the multitask model as embeddings. GMILT was trained and validated on a total of 512 patients with adenocarcinoma and tested on three datasets (the internal test dataset, the external test dataset, and The Cancer Imaging Archive (TCIA) public dataset). The performance (area under the curve (AUC) =0.772 on the internal test dataset) of GMILT exceeded that of previously published methods and radiomics-based methods (i.e., random forest and support vector machine) and attained a preferable generalization ability (AUC =0.856 in the TCIA test dataset and AUC =0.756 in the external dataset). A diameter-based subgroup analysis further verified the efficiency of our model (most of the AUCs exceeded 0.772) to noninvasively predict EGFR mutation status from computed tomography (CT) images. In addition, because our method also identified the "core area" of the most suspicious area related to the EGFR mutation status, it has the potential ability to guide biopsies.

Differential Prognostic Value of Vascular Invasion in Resected Lung Adenocarcinomas According to Epidermal Growth Factor Receptor Mutational Status

BACKGROUND

It is unclear whether all patients with stage IB to IIIA epidermal growth factor receptor (EGFR)-mutant adenocarcinoma should receive adjuvant osimertinib. We investigated the prognostic value of vascular invasion for risk stratification according to EGFR mutational status.

MATERIALS AND METHODS

This retrospective study evaluated patients with stage IB to IIIA lung adenocarcinoma resected between 2011 and 2016 at a tertiary care center. The study outcome was overall survival (OS). The prognostic value of vascular invasion was analyzed using the adjusted log-rank test and multivariable Cox regression with clinico-pathological factors as covariates. A sensitivity analysis, which included the presence of ground-glass opacity on CT scans as an additional covariate, and subgroup analyses according to the pathological stage were performed.

RESULTS

In total, 272 patients were included (146 women; median age, 66 years [interquartile range: 58, 72 years]; 128 EGFR-mutant adenocarcinomas). The 5-year OS rate was 90.8% (95% CI: 84.0%, 98.1%) in EGFR-mutant, vascular invasion-absent lung adenocarcinomas, which was higher than in other subgroups (P < .05). Vascular invasion was an independent, negative prognostic factor in EGFR-mutant lung adenocarcinomas (adjusted log-rank test, P = .02; adjusted hazard ratio, 3.01; 95% CI: 1.30, 7.02; P = .01). However, the prognosis of EGFR wild-type adenocarcinomas was not associated with the presence of vascular invasion (adjusted log-rank test, P = .95; adjusted hazard ratio, 1.32; 95% CI: 0.74, 2.34; P = .35). Similar results were observed in the sensitivity analysis and subgroup analyses.

CONCLUSIONS

Vascular invasion-absent, EGFR-mutant, resected lung adenocarcinomas showed a very good prognosis, and vascular invasion had a differential prognostic value according to EGFR mutational status.

Landscape of EGFR mutations in lung adenocarcinoma: a single institute experience with comparison of PANAMutyper testing and targeted next-generation sequencing

Background

Activating mutations in the tyrosine kinase domain of epidermal growth factor receptor (EGFR) are predictive biomarkers for response to EGFR–tyrosine kinase inhibitor (TKI) therapy in lung adenocarcinoma (LUAD). Here, we characterized the clinicopathologic features associated with EGFR mutations via peptide nucleic acid clamping-assisted fluorescence melting curve analysis (PANAMutyper) and evaluated the feasibility of targeted deep sequencing for detecting the mutations.

Methods

We examined EGFR mutations in exons 18 through 21 for 2,088 LUADs from July 2017 to April 2020 using PANAMutyper. Of these, we performed targeted deep sequencing in 73 patients and evaluated EGFR-mutation status and TKI clinical response.

Results

EGFR mutation was identified in 55.7% of LUADs by PANAMutyper, with mutation rates higher in females (69.3%) and never smokers (67.1%) and highest in the age range of 50 to 59 years (64.9%). For the 73 patients evaluated using both methods, next-generation sequencing (NGS) identified EGFR mutation–positive results in 14 of 61 patients (23.0%) who were EGFR-negative according to PANAMutyper testing. Of the 10 patients reportedly harboring a sensitizing mutation according to NGS, seven received TKI treatment, with all showing partial response or stable disease. In the 12 PANAMutyper-positive cases, NGS identified two additional mutations in exon 18, whereas a discordant negative result was observed in two cases.

Conclusions

Although PANAMutyper identified high frequencies of EGFR mutations, targeted deep sequencing revealed additional uncommon EGFR mutations. These findings suggested that appropriate use of NGS may benefit LUAD patients with otherwise negative screening test results.

Therapeutic restoring p53 function with small molecule for oncogene-driven non-small cell lung cancer by targeting serine 392 phosphorylation

p53 inactivation by disabling its function is a hallmark in lung carcinomas, emphasizing the significance of restoring p53 function as an attractive therapeutic strategy. However, the clinical efficacy of existing p53 activators is limited due to their inability to effectively activate p53 within the tumors. Here, we established a p53 activator screening assay in EGFR-driven lung cancer cells and identified a small molecular, MX-C4, as a promising candidate. Using high throughput compound screening and combination analyses, we found that MX-C4 effectively promoted the phosphorylation of p53 at serine-392 (s392). It exhibited potent antitumor activity in a variety of cancer cell lines, but only limited toxicity to NCI-H1299 (p53-null) and normal cell lines such as LX2 and HL-7702. Overexpression of p53 in NCI-H1299 cells by a p53 expressing virus vector sensitized cells to MX-C4 treatment, suggesting a p53-dependent anticancer activity. Furthermore, we demonstrated that MX-C4 bound to p53 and exerted its anticancer activity through cell cycle arrest at G2/M phase and apoptosis induction. Mechanistic study indicated that p53 activation regulated cell cycle and cell survival related targets at protein levels. Moreover, p53 activation raised phospho-p53 translocation to mitochondria and subsequently reorganized the Bcl-xl-Bak complex, thus conformationally activating Bak and inducing apoptosis. It is noteworthy that MX-C4 could effectively activate p53 within the tumors in EGFR-driven xenograft models, where tumor was significantly suppressed without obvious toxicity. Our study identified a promising candidate for lung cancer therapy by restoring p53 function.

Clinicopathologic Features and Genetic Alterations in Adenocarcinoma In Situ and Minimally Invasive Adenocarcinoma of the Lung: Long-Term Follow-Up Study of 121 Asian Patients

BACKGROUND

Adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) are both small tumors with good prognosis after surgical resection, and most of them present as ground glass opacities (GGOs) on computed tomography (CT) screening. However, the differences in clinicopathologic features and genetic alterations between AIS and MIA are poorly elaborated, and few studies have evaluated the prognosis of MIA with different invasive components. Meanwhile, the histological features of lung lesions presenting as unchanged pure GGOs are barely understood.

METHODS

Clinicopathologic features and genetic alterations of AIS (n = 59) and MIA (n = 62) presenting as GGOs were analyzed. Long-term preoperative observation (ranging from 2 to 1967 days) and postoperative follow-up (ranging from 0 to 92 months) was conducted.

RESULTS

The tumor size and consolidation/tumor ratio were significantly larger in the MIA cohort than those in the AIS cohort both on CT and microscopy images. Immunohistochemically, the expression of p53, Ki67, and cyclin D1 was higher in MIA than in AIS. The EGFR mutation rate was significantly higher in MIA, while other genetic alterations showed no differences. Six MIA cases showed recurrence or metachronous adenocarcinoma and all the cases with a predominant micropapillary invasive pattern demonstrated this feature.

CONCLUSIONS

The current CT measurements may be helpful in distinguishing AIS from MIA, but show limited utility in predicting the histology of unchanged pure GGOs. The invasive pattern may have an influence on the postoperative process of MIA; therefore, further studies are needed to evaluate the current diagnostic criteria and treatment strategy for MIA.

Lung Cancer Staging and Associated Genetic and Epigenetic Events

The first step in treating lung cancer is to establish the stage of the disease, which in turn determines the treatment options and prognosis of the patient. Many factors are involved in lung cancer staging, but all involve anatomical information. However, new approaches, mainly those based on the molecular biology of cancer, have recently changed the paradigm for lung cancer treatment and have not yet been incorporated into staging. In a group of patients of the same stage who receive the same treatment, some may experience unexpected recurrence or metastasis, largely because current staging methods do not reflect the findings of molecular biological studies. In this review, we provide a brief summary of the latest research on lung cancer staging and the molecular events associated with carcinogenesis. We hope that this paper will serve as a bridge between clinicians and basic researchers and aid in our understanding of lung cancer.

In situ growth in early lung adenocarcinoma may represent precursor growth or invasive clone outgrowth-a clinically relevant distinction

The switch from in situ to invasive tumor growth represents a crucial stage in the evolution of lung adenocarcinoma. However, the biological understanding of this shift is limited, and 'Noguchi Type C' tumors, being early lung adenocarcinomas with mixed in situ and invasive growth, represent those that are highly valuable in advancing our understanding of this process. All Noguchi Type C adenocarcinomas (n = 110) from the LATTICE-A cohort were reviewed and two patterns of in situ tumor growth were identified: those deemed likely to represent a true shift from precursor in situ to invasive disease ('Noguchi C1') and those in which the lepidic component appeared to represent outgrowth of the invasive tumor along existing airspaces ('Noguchi C2'). Overall Ki67 fraction was greater in C2 tumors and only C1 tumors showed significant increasing Ki67 from in situ to invasive disease. P53 positivity was acquired from in situ to invasive disease in C1 tumors but both components were positive in C2 tumors. Likewise, vimentin expression was increased from in situ to invasive tumor in C1 tumors only. Targeted next generation sequencing of 18 C1 tumors identified four mutations private to the invasive regions, including two in TP53, while 6 C2 tumors showed no private mutations. In the full LATTICe-A cohort, Ki67 fraction classified as either less than or greater than 10% within the in situ component of lung adenocarcinoma was identified as a strong predictor of patient outcome. This supports the proposition that tumors of all stages that have 'high grade' in situ components represent those with aggressive lepidic growth of the invasive clone. Overall these data support that the combined growth of Noguchi C tumors can represent two differing biological states and that 'Noguchi C1' tumors represent the genuine biological shift from in situ to invasive disease.

Targeted next-generation sequencing for analyzing the genetic alterations in atypical adenomatous hyperplasia and adenocarcinoma in situ

PURPOSE

Atypical adenomatous hyperplasia (AAH) and adenocarcinoma in situ (AIS) have been defined as preinvasive pulmonary adenocarcinoma lesions according to the 2015 World Health Organization lung adenocarcinoma classification. We aimed to search for the most common gene mutations in patients with AAH and AIS and investigate the distinctions between the two groups at the molecular level.

METHODS

We performed targeted next-generation sequencing on 18 cases with AAH and 28 cases with AIS to screen for mutations with the Ion Torrent Oncomine Solid Tumor DNA panel. ALK and ROS1 fusions were detected by real-time PCR.

RESULTS

Forty-six mutations were identified in 29 cases (76.1%), including 9 (50%) of 18 cases with AAH and 20 (71.4%) of 28 cases with AIS, in the following genes: EGFR, BRAF, KRAS, ERBB2, TP53, and FGFR3. The mutations in EGFR, BRAF, KRAS, ERBB2, and TP53 genes were more common in AIS lesions than in AAH lesions, whereas the FGFR3 gene was more frequently mutated in AAH compared to AIS. ALK and ROS1 fusions were not detected in any of the lesions.

CONCLUSIONS

Based on the molecular evidence, the proposal that AAH and AIS are preinvasive lesions of pulmonary adenocarcinomas is of great significance, and it is necessary to distinguish AAH from AIS. Our study provided insights into the genetic alterations in the early stage of lung adenocarcinoma, which could be beneficial for the pathologic diagnosis and early detection of these lesions.

Overexpression of MAGEA2 has a prognostic significance and is a potential therapeutic target for patients with lung cancer

Melanoma-associated antigens (MAGE) are expressed in different type of cancers including lung cancer and have been shown to be functionally related to p53 tumor suppressor gene. Little is known about the relationship between MAGE genes and p53 aberrant expression in lung cancer. The aims of this study were to observe the expression of MAGEA2, examine the role of MAGEA2 in lung cancer survival, investigate its correlation between MAGEA2 and p53, and explore its clinicopathologic significance as a prognostic marker. Quantitative reverse transcription-polymerase chain reaction was performed to detect the expression of MAGEA2 using 36 primary tumors and 31 metastatic lymph nodes from patients with lung cancer. The role of MAGEA2 in cancer cell growth and in the regulation of p53 downstream genes were examined using small interfering RNA. The expression of MAGEA2 and p53 were analyzed immunohistochemically using tissue microarray from 353 resected lung specimens. High-level expression of MAGEA2 (High-MAGEA2) was confirmed in lung tumors with high frequency. Inhibiting MAGEA2 expression effectively suppressed cancer cell growth and decreased the expression of p53 downstream target genes in vitro. In adenocarcinoma, High-MAGEA2 was strongly associated with aberrant p53 expression (P<0.001) and was associated with worse clinical outcomes (5-year OS, 87.1% in low vs. 74.1% in high, P=0.014). Aberrant p53 expression was also significant worse prognostic factor (P=0.029). Among the adenocarcinoma patients with wild-type p53, High-MAGEA2 had poorer prognosis than low-level MAGEA2 groups (5-year OS, 90.1% vs. 72.1%, P=0.037), whereas had no difference in p53 aberrant tumors. On multivariate analysis, MAGEA2 was independently associated with survival (hazard ratio; 2.12, P=0.030). In conclusion, suppression of MAGEA2 in lung cancer cells significantly reduced the growth/survival of cancer cells. High-MAGEA2 was identified as an independent prognostic factor in lung adenocarcinoma. Specific inhibition of MAGEA2 may be a promising therapeutic strategy for patients with lung cancer.

High Discrepancy of Driver Mutations in Patients with NSCLC and Synchronous Multiple Lung Ground-Glass Nodules

BACKGROUND

The aim of this study was to investigate the discordance rates of eight known driver mutations among multiple matched intrapulmonary ground-glass nodules (GGNs) in non-small-cell lung cancer (NSCLC) patients.

METHODS

Tumors from 35 patients with multiple lesions resected, including confirmed NSCLC and at least one GGN, were analyzed for mutations in EGFR, KRAS, HER2, BRAF, and PIK3CA together with fusions in ALK, ROS1, and RET.

RESULTS

From 35 patients, a total of 72 lesions (60 were GGNs) were analyzed. These included nine adenocarcinoma in situ, nine minimal invasive adenocarcinoma, and 54 invasive adenocarcinoma. Among them, 33 tumor lesions (45.8 %) were found harboring EGFR mutations: 13 tumors with exon 19 deletion, 18 with L858R on exon 21, and two with both exon 19 del and L858R mutation. There were 5 tumors (6.9 %) harboring EML4-ALK fusion, four HER2 mutations (5.6%), three KRAS mutations (4.2%), one ROS1 fusion and one BRAF mutation. When we used the matched tumors to determine the intertumor discrepancy, only six out of 30 patients harbored identical mutations. The discordance rate of driver mutations was 80% (24 of 30) in those patients harboring at least one of the detected driver mutations. The median disease-free survival was 41.2 months (95% confidence interval: 35.8-52.6 months) and the median overall survival was "still not reached" in this cohort.

CONCLUSIONS

We found a high discrepancy of driver mutations among NSCLC patients with GGNs and a favorable prognosis after multiple lesions resection, which support surgical resection in this situation as a reasonable approach.

Increased expressions of claudin 4 and 7 in atypical adenomatous hyperplasia and adenocarcinoma of the lung

Abnormal expression of claudin (Cldn), the main constituent of tight junctions, may play a crucial role in carcinogenesis. To elucidate these abnormalities of tight junctions in lung adenocarcinoma during carcinogenesis, we examined immunohistochemical expressions of Cldn4 and Cldn7 in human lung resection materials. Lung resection specimens from 86 patients were studied, including 16 atypical adenomatous hyperplasia (AAH), 19 adenocarcinoma in situ (AIS), 32 invasive adenocarcinoma (ADC), 5 AIS with AAH, 2 ADC with AAH, 10 ADC with AIS, and 2 ADC with AIS and AAH. The immunohistochemical staining (IHC) score was defined for both the extent and intensity of staining. IHC score for Cldn4 in AIS and ADC was significantly higher than that in alveolar epithelium (AE) and AAH (p < 0.001 for both). In addition, the AAH score was significantly higher than that in AE (p < 0.001). The Cldn7 score in ADC was significantly increased compared with AE and AAH (p < 0.001 for both). These results suggested that increase of Cldn4-expression may be involved in early molecular events during carcinogenesis of adenocarcinoma, whereas increase of Cldn7-expression may be associated with tumor invasion or progression.

Chronic lung injury by constitutive expression of activation-induced cytidine deaminase leads to focal mucous cell metaplasia and cancer

Activation-induced cytidine deaminase (AID) is an enzyme required for antibody diversification, and it causes DNA mutations and strand breaks. Constitutive AID expression in mice invariably caused lung lesions morphologically similar to human atypical adenomatous hyperplasia (AAH), which can be a precursor of bronchioloalveolar carcinoma. Similar to AAH, mouse AAH-like lesion (MALL) exhibited signs of alveolar differentiation, judging from the expression of alveolar type II (AT2) cell marker surfactant protein C (SP-C). However, electron microscopy indicated that MALL, which possessed certain features of a mucous cell, is distinct from an AAH or AT2 cell. Although MALL developed in all individuals within 30 weeks after birth, lung tumors occurred in only 10%; this suggests that the vast majority of MALLs fail to grow into visible tumors. MALL expressed several recently described markers of lung alveolar regeneration such as p63, keratin 5, keratin 14, leucine-rich repeat containing G protein-coupled receptor 5 (Lgr5), and Lgr6. Increased cell death was observed in the lungs of AID transgenic mice compared with wild-type mice. Based on these observations, we speculate that MALL is a regenerating tissue compensating for cellular loss caused by AID cytotoxicity. AID expression in such regenerating tissue should predispose cells to malignant transformation via its mutagenic activity.

Mapping of actionable mutations to histological subtype domains in lung adenocarcinoma: implications for precision medicine

Precision medicine depends on the accurate identification of actionable mutations in a tumor sample. It is unknown how heterogeneous the distribution of such mutations can be in a tumor. Morphological (i.e. histopathological) heterogeneity is well described in lung adenocarcinoma and has been specifically recognized in the most recent official clinico-pathological classification. The most predominant subtype present is now used to classify each lung adenocarcinoma. No molecular profile exists to explain the intratumoral differences in lung adenocarcinoma morphology, despite the consistently observed association between specific predominant subtypes and poorer survival. Given a recent proposal stratifying lung adenocarcinoma into subtypes of differing metastatic potential, we questioned the assumption that major mutations are present uniformly throughout tumors; especially those showing discrete different subtypes.

We selected formalin-fixed paraffin embedded lung adenocarcinoma specimens that showed discrete areas of different subtypes, extracted subtype DNA samples from those areas and screened for mutations in hotspot regions of the EGFR, KRAS and BRAF genes using high resolution melting. Sanger sequencing was used to confirm all identified mutations. Chromogenic in situ hybridization (CISH) was used to identify mutant allele specific imbalances in tumors with EGFR mutations.

Interestingly, we found that KRAS and BRAF mutations could be confined to morphological domains of higher grade. On the other hand, EGFR mutations were found through all histological subtypes in each tumor consistent with the driver status of this mutation.

Intratumoral heterogeneity has major implications for tumorigenesis, chemoresistance and the role of histopathology in molecular screening for precision medicine. This study not only confirms that intratumoral mutational heterogeneity does occur, but also that it is associated with morphologically distinct regions in some tumors. From a practical perspective, small biopsies may not adequately represent a tumor's full mutational profile, particularly for later arising but prognostically important mutations such as those in the KRAS and BRAF genes.

Maspin expression patterns differ in the invasive versus lepidic growth pattern of pulmonary adenocarcinoma

Aims

To test whether changes in the subcellular localization of maspin parallel morphological progression in pulmonary adenocarcinoma, we compared its expression between lepidic and invasive growth patterns.

Methods

Applying immunohistochemistry, we compared maspin expression in lepidic and invasive growth patterns occurring in different tumours (series #1, n = 86) as well as within the same tumour and in the same section (series #2, n = 29).

Results

In both series, the lepidic growth pattern (n = 45) was significantly associated with nuclear maspin, while the invasive (n = 70) with combined nuclear and cytoplasmic maspin (P < 0.05). In the second series, transition from a lepidic to an invasive pattern in the same tumour was associated predominantly with a shift respectively from a nuclear to a combined nuclear and cytoplasmic maspin (15/29) or preservation of nuclear expression (8/29). A shift from nuclear maspin to negative expression (3/29) or other patterns (3/29) were also observed.

Conclusions

Nuclear maspin is a typical but not exclusive feature of the lepidic growth pattern of pulmonary adenocarcinoma, whereas combined nuclear and cytoplasmic maspin characterizes invasion. These data show that changes of expression and subcellular localization of maspin may constitute an important biological end point of tumour progression and aid in the classification of lung adenocarcinoma.

FGFR1 amplification is associated with poor prognosis and smoking in non-small-cell lung cancer

FGFR1 amplification has been identified recently as an important therapeutic target in non-small-cell lung cancer (NSCLC), particularly squamous cell carcinoma (SqCC). However, data from previous studies on the clinical implications of FGFR amplification in NSCLC are inconsistent. We evaluated FGFR1 gene copy number (GCN) in 369 cases of surgically resected NSCLC using five previously reported criteria and investigated associations between clinicopathologic parameters and FGFR1 amplification. FGFR1 amplification was found in 32/369 (8.7 %) of NSCLC and was more frequent in SqCC (18.0 % in SqCC, 3.0 % in adenocarcinoma; p < 0.001) and in smokers (p < 0.001). On univariate analysis, FGFR1 amplification was significantly associated with shorter overall survival (OS, 58.6 vs 80.0 months; p = 0.033) and shorter disease-free survival (DFS, 58.5 vs 80.0 months; p = 0.042) in patients with SqCC, but this was not statistically significant on multivariate analysis (OS: hazard ratio [HR] = 1.79, 95 % confidence interval [CI] = 0.83-3.87, p = 0.139; DFS: HR = 1.73, 95 % CI = 0.93-3.21, p = 0.081). The correlation between FGFR1 amplification and protein expression was poor (rho = 0.08; p = 0.123). These results suggest that FGFR1 amplification is associated with smoking history and squamous cell carcinoma histology and might indicate poor prognosis.

Clinicopathology and genetic profile of synchronous multiple small adenocarcinomas: implication for surgical treatment of an uncommon lung malignancy

PURPOSE

Synchronous multiple small adenocarcinomas are detected more frequently than in the past; however, the genetic profile, treatment, and prognosis of patients remain unclear. For treatment decisions and prognostic applications, we evaluated epidermal growth factor receptor (EGFR), p53, and KRAS somatic mutations in synchronous multiple small lung adenocarcinomas.

METHODS

The presence of EGFR, p53, and KRAS somatic mutations was determined in 64 synchronous multiple lung adenocarcinomas ≤2 cm in maximal dimension. Mutational analysis was performed on DNA extracted from paraffin-embedded tumors.

RESULTS

Five-year disease-free survival (DFS) was 86.1 %, and overall survival was 95.8 %. EGFR, p53, and KRAS mutations were detected in 41 (64.1 %), 8 (12.5 %), and 4 (6.3 %) patients, respectively. The high frequency of genetic mutations resulted in a high discrimination rate of tumor clonality (68.8 %; 44/64) in the study group. Fourteen (31.8 %) patients were assessed as having the same clonality, whereas 30 (68.2 %) patients had different clonality, which further supported the concept of field cancerization. Multivariate analysis showed lymph node metastasis (p = 0.003) and smoking (p = 0.011) were significantly correlated with tumor relapse. Surgical method, clonality, and tumor location were not correlated with tumor relapse.

CONCLUSIONS

Whether these tumors are different or the same clonal, sublobar resection of each lesion can achieve long-term DFS and is the treatment of choice for synchronous multiple small lung adenocarcinomas. Patients with lymph node metastasis are at risk of relapse and adjuvant chemotherapy is indicated.

Comparison of Direct Sequencing, PNA Clamping-Real Time Polymerase Chain Reaction, and Pyrosequencing Methods for the Detection of EGFR Mutations in Non-small Cell Lung Carcinoma and the Correlation with Clinical Responses to EGFR Tyrosine Kinase Inhibitor Treatment

Background

The aims of this study were to evaluate the abilities of direct sequencing (DS), peptide nucleic acid (PNA) clamping, and pyrosequencing methods to detect epidermal growth factor receptor (EGFR) mutations in formalin-fixed paraffin-embedded (FFPE) non-small cell lung carcinoma (NSCLC) samples and to correlate EGFR mutational status as determined by each method with the clinical response to EGFR tyrosine kinase inhibitors (TKIs).

Methods

Sixty-one NSCLC patients treated with EGFR TKIs were identified to investigate somatic mutations in the EGFR gene (exons 18-21).

Results

Mutations in the EGFR gene were detected in 38 of the 61 patients (62%) by DS, 35 (57%) by PNA clamping and 37 (61%) by pyrosequencing. A total of 44 mutations (72%) were found by at least one of the three methods, and the concordances among the results were relatively high (82-85%; kappa coefficient, 0.713 to 0.736). There were 15 discordant cases (25%) among the three different methods.

Conclusions

All three EGFR mutation tests had good concordance rates (over 82%) for FFPE samples. These results suggest that if the DNA quality and enrichment of tumor cells are assured, then DS, PNA clamping, and pyrosequencing are appropriate methods for the detection of EGFR mutations.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Expression and prognostic significance of centromere protein A in human lung adenocarcinoma

BACKGROUND

Centromere protein A (CENP-A), one of the fundamental components of the human active kinetochore, is frequently upregulated in many cancers and plays important roles in cell cycle regulation, cell survival, and genetic stability. The aim of the present study was to explore the expression and prognostic significance of CENP-A in lung adenocarcinoma.

EXPERIMENTAL DESIGN

The expression of CENP-A was detected in 20 fresh human lung adenocarcinoma specimens and corresponding non-tumorous lung tissues by real-time polymerase chain reaction (RT-PCR) and Western blotting analysis. Using immunohistochemistry, we analyzed CENP-A protein expression in additional 309 lung adenocarcinomas. The clinicopathological and prognostic significance of CENP-A expression was analyzed.

RESULTS

RT-PCR and Western blotting analysis revealed an enhanced expression of CENP-A in lung adenocarcinomas relative to adjacent non-tumorous lung tissues at both transcriptional and translational levels. Immunohistochemistry showed that 146 of 309 lung adenocarcinomas (47.3%) had high expression of CENP-A. CENP-A overexpression was significantly correlated with pathological grade (P=0.009), pT status (P=0.017), pN status (P=0.002), pleural invasion (P=0.013), high Ki-67 expression (P=0.003), and P53 positivity (P=0.001). Patients with high CENP-A expression had shorter overall survival time compared with those with low CENP-A expression. Multivariate analysis identified CENP-A as an independent prognostic factor for lung adenocarcinoma.

CONCLUSION

Our results demonstrate that elevated CENP-A expression is closely associated with lung adenocarcinoma progression and has an independent prognostic value in predicting overall survival for patients with lung adenocarcinoma.

Role of molecular studies in the diagnosis of lung adenocarcinoma

Molecular alterations in adenocarcinoma of the lung have resulted in new therapeutic options for treatment of high-stage disease. Such changes are usually mutually exclusive and can be documented in small specimen samples. Most analyses are DNA-based, utilizing sequencing or fluorescence in situ hybridization to observe amplifications or translocations. Particular success in theranostics has focused on epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase gene (ALK), and BRAF gene changes, each allowing personalized therapies. Interestingly, these molecular changes have correlated with distinct, although not unique, demographics, histopathologies, and response to pharmacological agents.

Intratumor heterogeneity and chemotherapy-induced changes in EGFR status in non-small cell lung cancer

INTRODUCTION

Biomarker expression is increasingly being used to customize treatment in non-small cell lung cancer (NSCLC). The choice of systemic treatment usually depends on biomarker expression in the initial diagnostic biopsy taken before initiation of first-line treatment. Chemotherapy induces DNA damages in the tumor cells, and thus, biomarker expression in the tumor after systemic treatment might not be identical to biomarker expression in the diagnostic biopsy. NSCLC is highly heterogeneous and biomarker expression may vary in different areas within the same tumor. This review explores the tumor heterogeneity and chemotherapy-induced changes in EGFR biomarker status in NSCLC.

METHODS

A literature search was performed in August 2011 using pubmed.

RESULTS

Fifteen trials explored EGFR status in primary tumor and subsequent resected primary tumor, lymph node metastases, or organ metastases. Four papers compared EGFR status in primary tumor or metastases before and after systemic treatment. All trials included relatively few patients and used different chemotherapy regimes, biopsy locations, or time intervals between biopsies.

CONCLUSIONS

Tumor heterogeneity and probably also previous systemic treatment may be an obstacle for correct interpretation of EGFR status in NSCLC. Heterogeneity regarding EGFR mutations is probably rare and previously reported intra and intertumor heterogeneity may be due to methodological issues. In the current and future clinical scenario with many different options for systemic treatment both as 2nd line and beyond, it is increasingly important to further elucidate the role extent of chemotherapy-induced changes in biomarker expression for proper use of biomarkers in order to customize treatment and thus improve prognosis.

DNA methylation profile during multistage progression of pulmonary adenocarcinomas

Multiple genetic and epigenetic alterations are known to be involved in the carcinogenesis of peripheral pulmonary adenocarcinoma (ADC). However, epigenetic abnormalities have not been extensively investigated in the following multistage progression sequence: atypical adenomatous hyperplasia (AAH) to adenocarcinoma in situ (AIS), to invasive ADC. To determine the potential role of promoter methylation during ADC development of the lung, we examined methylation status in 20 normal, 20 AAH, 30 AIS, and 60 ADC lung tissues and compared methylation status among the lesions. The MethyLight assay was used to determine the methylation status of 18 CpG island loci, which were hypermethylated in ADC compared to noncancerous lung tissues. The mean number of methylated CpG island loci was significantly higher in ADC than in AAH and AIS, (p < 0.003 between ADC and AAH, p < 0.005 between ADC and AIS). Aberrant methylation of HOXA1, TMEFF2, and RARB was frequently observed in preinvasive lesions, including AAH and AIS. Furthermore, methylation of PENK, BCL2, RUNX3, DLEC1, MT1G, GRIN2B, CDH13, CCND2, and HOXA10 was significantly more frequent in invasive ADC than AAH or AIS. Our results indicate that epigenetic alterations are involved in the multistep progression of pulmonary ADC development, and aberrant CpG island methylation accumulates during multistep carcinogenesis. In addition, aberrant methylation of HOXA1, TMEFF2, and RARB occurred in preinvasive lesions, which indicates that epigenetic alterations of these genes are involved in the early stages of pulmonary ADC development. In contrast, hypermethylation of PENK, BCL2, RUNX3, DLEC1, MT1G, GRIN2B, CDH13, CCND2, and HOXA10 was more frequent in invasive ADC than in preinvasive lesions, which indicates that methylation of these genes occurs later during tumor invasion in the AAH-AIS-ADC sequence.