K-ras and p53 mutations are an independent unfavourable prognostic indicator in patients with non-small-cell lung cancer

Lung adenocarcinomas with isolated TP53 mutation: A comprehensive clinical, cytopathologic and molecular characterization

BACKGROUND

TP53 mutation is present in about 50.8% of lung adenocarcinomas, frequently in combination with other genetic alterations. However, a rare subset harbors the TP53 mutation alone.

METHODS

Next-generation sequencing was performed in 844 lung adenocarcinomas diagnosed by fine needle aspiration. Fourteen cases (1.7%) showed isolated TP53 alteration and were subjected to a comprehensive analysis.

RESULTS

The average age at diagnosis was 65.7 years (range 48-79); 9 males and 5 females. All were smokers with an average pack-year of 40.7 (range 10-70). Ten had metastases, mostly in the brain (n = 4) and pleura (n = 4). After a follow-up period of up to 102 months, 9 died, 3 were alive free of disease, 1 was alive with disease, and 1 was lost to follow-up. The median survival was 12.2 months. Most tumors exhibited poor differentiation, composed of solid sheets with moderate to severe atypia, increased mitotic activity, and necrotic background. Half were positive for TTF-1 and showed p53 overexpression. PD-L1 was positive in 5 cases. Most alterations were missense mutations in exons 5-8, and this mutation type was associated with p53 overexpression. Tumors with combined missense mutation and truncated protein had higher PD-L1 expression along with a trend towards an increase in tumor mutational burden (TMB). CEBPA deletion of undetermined significance was the most common copy number alteration.

CONCLUSION

Isolated TP53 mutation was seen in association with smoking, high-grade cytomorphologic features, adverse prognosis, and recurrent CEBPA deletions. These tumors tend to have strong PD-L1 expression and high TMB, suggesting potential benefit from immune checkpoint inhibitors. Hence, the recognition of this molecular group has prognostic and therapeutic implications.

Uses of Vascular Endothelial Growth Factor C as a Lung Adenocarcinoma Prognostic Biomarker

Background

Lung adenocarcinoma (LUAD) is the most common type of lung cancer and a leading cause of death worldwide. Vascular endothelial growth factor C (VEGF-C) has been identified as a prognosis prediction marker for LUAD. However, VEGF-C protein expression does not appear to significantly relate to LUAD patient survival in several studies.

Methods

We carried out a bioinformatic analysis to review the effect of VEGF-C mRNA expression on LUAD patient outcomes. GEPIA, UALCAN, TCGAportal, OncoLnc, LCE, GeneMANIA, Metascape, ImmuCellAI, and GSCA online databases were utilized. The expression levels of VEGF-C mRNA between normal tissue and LUAD tissue, overall survival (OS) analysis, function analysis, tumor microenvironment and drug sensitivity were conducted in the current study.

Results

We found that the expression level of VEGF-C mRNA was significantly lower in LUAD than normal tissue. Low expression of VEGF-C mRNA was also associated with better OS. VEGF-C expression was correlated with both NF1 and TP53 mutation status. No relationship was observed between VEGF-C and Tr1 or CD4 T-cell infiltrate scores. Additionally, VEGF-C was associated with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor resistance. The sensitivity of 5-fluorouracil was positively correlated with VEGF-C, and the sensitivity of TGX221 was negatively correlated with VEGF-C. The activity of BI-2536 and BRD-A94377914 was positively correlated with VEGF-C.

Conclusion

Novel LUAD prognostic biomarkers such as VEGF-C mRNA may aid diagnosis and treatment, and may help identify optimal LUAD populations for therapeutic treatments.

MicroRNA-324-5p-CUEDC2 Axis Mediates Gain-of-Function Mutant p53-Driven Cancer Stemness

Regulation of cancer stemness has recently emerged as a new gain-of-function (GOF) property of mutant p53. In this study, we identify miR-324-5p as a critical epigenetic regulator of cancer stemness and demonstrate its role in mediating GOF-mutant p53-driven stemness phenotypes. We report that miR-324-5p is upregulated in human cancer cell lines and non-small cell lung carcinoma (NSCLC) tumors carrying TP53 GOF mutations. Mechanistically, we show that GOF mutant p53 upregulates miR-324-5p expression via c-Myc, an oncogenic transcription factor in cancer cells. Our experimental results suggest that miR-324-5p-induced CSC phenotypes stem from the downregulation of CUEDC2, a downstream target gene of miR-324-5p. Accordingly, CUEDC2 complementation diminishes elevated CSC marker expression in miR-324-5p-overexpressing cancer cells. We further demonstrate that mutant p53 cancer cells maintain a low level of CUEDC2 that is rescued upon miR-324-5p inhibition. Importantly, we identify CUEDC2 downregulation as a novel characteristic feature of TP53-mutated human cancers. We show that activation of NF-κB due to downregulation of CUEDC2 by miR-324-5p imparts stemness in GOF mutant p53 cancer cells. Finally, we provide evidence that TP53 mutations coupled with high miR-324-5p expression predict poor prognosis in patients with lung adenocarcinoma. Thus, our study delineates an altered miR-324-5p-CUEDC2-NF-κB pathway as a novel regulator of GOF mutant p53-driven cancer stemness. IMPLICATIONS: Our findings implicate miRNA-324-5p as a novel epigenetic modifier of human cancer stemness.

Extended-spectrum of KRAS and NRAS mutations in lung cancer tissue specimens obtained with bronchoscopy

Background

Mutations in the RAS genes, HRAS, KRAS, and NRAS, are the most common modifications in many types of human tumors and are found in approximately 30% of all human cancers. These mutations are usually found in codons 12, 13, or 61.

Methods

The aim of this study is to evaluate mutations in codons 59, 117, and 146 of KRAS and NRAS genes in addition to codons 12,13, and 61 of KRAS gene in lung cancer tissue specimens obtained with bronchoscopy. KRAS and NRAS mutation analyses with pyrosequencing were performed on DNA isolated from formalin-fixed paraffin-embedded (FFPE) tissue samples of 64 patients histopathologically diagnosed as lung cancer after bronchoscopic biopsy.

Results

In all, 20 patients (31.2%) had mutations in KRAS gene (8/27 squamous cell carcinoma, 8/11 adenocarcinoma, 3/16 small cell carcinoma, and 1/1 pleomorphic carcinoma). The most common mutation in codon 12 was in c.35G>T (G12V). When the mutation rate of adenocarcinoma (72.7%) and squamous cell carcinoma (22.9%) patients was compared with each other, a statistically significant difference was observed (P = 0.008). There were no mutations in codons 59, 117, or 146 of KRAS and NRAS genes in patients with lung cancer.

Conclusion

In this study, we firstly examined mutations in codons 59, 117, and 146 of KRAS and NRAS genes in addition to codons 12, 13, and 61 of KRAS gene in Turkish lung cancer patients both in non-small cell lung cancer and small cell lung cancer. Although no mutation was detected in codons 59, 117, and 146 of KRAS and NRAS genes, the frequency of KRAS gene mutation was higher than the rate of mutation in both Asian and Western countries, and multicenter studies including more cases should be performed to further explore our results.

Survival prediction for patients with lung adenocarcinoma: A prognostic risk model based on gene mutations

BACKGROUND

Lung adenocarcinoma is the most common type of lung cancer, and it is one of the most aggressive and rapidly fatal tumor types.

OBJECTIVE

To identify a signature mutation genes for prognostic prediction of lung adenocarcinoma.

METHODS

Four hundred and sixty-two lung adenocarcinoma cases were screened out and downloaded from TCGA database. Mutation data of 18 targeted genes were detected by MuTect. LASSO-COX model was used to screen gene loci, and then a prognosis model was established. Afterwards, 40 clinical patients of lung adenocarcinoma were collected to verify the mutation features and the predictive function of the above prognostic model. The mutations of above 18 genes were sequenced with targeted next generation sequencing (NGS) and analyzed with GATK and MuTect.

RESULTS

TP53 (282, 32.38%), NF1 (82, 9.41%) and EGFR (80, 9.18%) were the top 3 most frequent mutation genes. A total of 7 variables were screened out after lasso-COX analysis (tumor stage, age, diagnostic type, SMARCA4, GNAS, PTCH2, TSC2). SMARCA4, GNAS and TSC2 were a gene mutation signature to predict a poor prognosis.

CONCLUSIONS

We established a prognostic model for lung adenocarcinoma, and further concluded that SMARCA4, GNAS and TSC2 were a gene signature which plays a prognostic role.

Association of Mutation Profiles with Postoperative Survival in Patients with Non-Small Cell Lung Cancer

Simple Summary

In this study, we comprehensively and synthetically analyzed mutations in lung cancer based on the next generation sequencing data of lung tumors surgically removed from the patients, and identified the mutation-related factors that can affect clinical outcomes. Detailed understanding of the genomic landscape of lung cancers will establish the ideal model for best surgical outcomes in the era of “precision medicine”.

Abstract

Findings on mutations, associated with lung cancer, have led to advancements in mutation-based precision medicine. This study aimed to comprehensively and synthetically analyze mutations in lung cancer, based on the next generation sequencing data of surgically removed lung tumors, and identify the mutation-related factors that can affect clinical outcomes. Targeted sequencing was performed on formalin-fixed paraffin-embedded surgical specimens obtained from 172 patients with lung cancer who underwent surgery in our hospital. The clinical and genomic databases of the hospital were combined to determine correlations between clinical factors and mutation profiles in lung cancer. Multivariate analyses of mutation-related factors that may affect the prognosis were also performed. Based on histology, TP53 was the driver gene in 70.0% of the cases of squamous cell carcinoma. In adenocarcinoma cases, driver mutations were detected in TP53 (26.0%), KRAS (25.0%), and epidermal growth factor receptor (EGFR) (23.1%). According to multivariate analysis, the number of pathogenic mutations (≥3), presence of a TP53 mutation, and TP53 allele fraction >60 were poor prognostic mutational factors. The TP53 allele fraction tended to be high in caudally and dorsally located tumors. Moreover, TP53-mutated lung cancers located in segments 9 and 10 were associated with significantly poorer prognosis than those located in segments 1–8. This study has identified mutation-related factors that affect the postoperative prognosis of lung cancer. To our knowledge, this is the first study to demonstrate that the TP53 mutation profile varies with the site of lung tumor, and that postoperative prognosis varies accordingly.

Computational analysis of TP53 mutational landscape unveils key prognostic signatures and distinct pathobiological pathways in head and neck squamous cell cancer

Background

Mutations of the tumour-suppressor gene TP53 are the most frequent somatic genomic alterations in head and neck squamous cell carcinoma (HNSCC). However, it is not yet clear whether specific TP53 mutations bear distinct clinical and pathophysiological significance in different HNSCC subgroups.

Methods

A systematic bioinformatics appraisal of TP53 mutations was performed on 415 HNSCC cases available on The Cancer Genome Atlas (TCGA). The following features were analysed and correlated with known clinicopathological variables: mutational profile of TP53, location (within secondary structure and predicted domains of p53 protein) and well-known hotspot mutations. Interactome–genome–transcriptome network analysis highlighted different gene networks. An algorithm was generated to develop a new prognostic classification system based on patients’ overall survival.

Results

TP53 mutations in HNSCCs exhibited distinct differences in different anatomical sites. The mutational profile of TP53 was an independent prognostic factor in HNSCC. High risk of death mutations, identified by our novel classification algorithm, was an independent prognostic factor in TCGA HNSCC database. Finally, network analysis suggested that distinct p53 molecular pathways exist in a site- and mutation-specific manner.

Conclusions

The mutational profile of TP53 may serve as an independent prognostic factor in HNSCC patients, and is associated with distinctive site-specific biological networks.

Incorporating deep learning and multi-omics autoencoding for analysis of lung adenocarcinoma prognostication

Lung cancer is the most occurring cancer type, and its mortality rate is also the highest, among them lung adenocarcinoma (LUAD) accounts for about 40 % of lung cancer. There is an urgent need to develop a prognosis prediction model for lung adenocarcinoma. Previous LUAD prognosis studies only took single-omics data, such as mRNA or miRNA, into consideration. To this end, we proposed a deep learning-based autoencoding approach for combination of four-omics data, mRNA, miRNA, DNA methylation and copy number variations, to construct an autoencoder model, which learned representative features to differentiate the two optimal patient subgroups with a significant difference in survival (P = 4.08e-09) and good consistency index (C-index = 0.65). The multi-omics model was validated though four independent datasets, i.e. GSE81089 for mRNA (n = 198, P = 0.0083), GSE63805 for miRNA (n = 32, P = 0.018), GSE63384 for DNA methylation (n = 35, P = 0.009), and TCGA independent samples for copy number variations (n = 94, P = 0.0052). Finally, a functional analysis was performed on two survival subgroups to discover genes involved in biological processes and pathways. This is the first study incorporating deep autoencoding and four-omics data to construct a robust survival prediction model, and results show the approach is useful at predicting LUAD prognostication.

The prognostic impact of TP53 comutation in EGFR mutant lung cancer patients: a systematic review and meta-analysis

Background The prognostic value of TP53 commutation in epidermal growth factor receptor (EGFR) mutant lung cancer is controversial and we therefore conducted this systematic review and meta-analysis. Methods A systematic search was carried out in Pubmed, Web of Science, the Cochrane Library, Medline and Embase up to 19 April 2018. The pooled hazard ratio (HR) of overall survival (OS) and progression-free survival (PFS), the relative risk (RR) of objective response rate (ORR) were calculated. Results Overall, a total of eight studies comprising 2979 patients were included. When generally comparing TP53 mutation group with TP53 wild-type group, we confirmed the prognostic value of poor OS of TP53 in EGFR mutant lung cancers (HR 1.73, 95% CI 1.22-2.44, P = 0.002). In subgroup analysis of OS, the prognostic value was maintained in patients treated with EGFR tyrosine kinase inhibitors (TKIs) but not in those treated with non-targeted therapy (HR 2.29, 95% CI 1.39-3.76, P = 0.001), and was also maintained in patients with advanced-stage lung cancers rather than those of all stages (HR 2.00, 95% CI 1.11-3.61, P = 0.021). For patients treated with EGFR TKIs, TP53 commutation was predictive of a poor PFS (HR 2.18, 95% CI 1.42-3.36, P < 0.001) but the prognostic value on ORR was not observed (RR 1.15, 95% CI 0.92-1.44, P = 0.212). Additional subgroup analysis based on TP53 mutation subtypes was not pooled due to limited data. Conclusion Generally we confirmed the prognostic value of poor OS and PFS of TP53 commutation in EGFR mutant lung cancers, and it should be further investigated and validated regarding the prognostic role of TP53 mutation subtypes.

Concurrent Alterations in EGFR-Mutant Lung Cancers Associated with Resistance to EGFR Kinase Inhibitors and Characterization of MTOR as a Mediator of Resistance

Purpose: To identify molecular factors that determine duration of response to EGFR tyrosine kinase inhibitors and to identify novel mechanisms of drug resistance, we molecularly profiled EGFR-mutant tumors prior to treatment and after progression on EGFR TKI using targeted next-generation sequencing.Experimental Design: Targeted next-generation sequencing was performed on 374 consecutive patients with metastatic EGFR-mutant lung cancer. Clinical data were collected and correlated with somatic mutation data. Erlotinib resistance due to acquired MTOR mutation was functionally evaluated by in vivo and in vitro studies.Results: In 200 EGFR-mutant pretreatment samples, the most frequent concurrent alterations were mutations in TP53, PIK3CA, CTNNB1, and RB1 and focal amplifications in EGFR, TTF1, MDM2, CDK4, and FOXA1 Shorter time to progression on EGFR TKI was associated with amplification of ERBB2 (HR = 2.4, P = 0.015) or MET (HR = 3.7, P = 0.019), or mutation in TP53 (HR = 1.7, P = 0.006). In the 136 posttreatment samples, we identified known mechanisms of acquired resistance: EGFR T790M (51%), MET (7%), and ERBB2 amplifications (5%). In the 38 paired samples, novel acquired alterations representing putative resistance mechanisms included BRAF fusion, FGFR3 fusion, YES1 amplification, KEAP1 loss, and an MTOR E2419K mutation. Functional studies confirmed the contribution of the latter to reduced sensitivity to EGFR TKI in vitro and in vivoConclusions:EGFR-mutant lung cancers harbor a spectrum of concurrent alterations that have prognostic and predictive significance. By utilizing paired samples, we identified several novel acquired alterations that may be relevant in mediating resistance, including an activating mutation in MTOR further validated functionally. Clin Cancer Res; 24(13); 3108-18. ©2018 AACR.

Effects of the expectorant drug ambroxol hydrochloride on chemically induced lung inflammatory and neoplastic lesions in rodents

Ambroxol hydrochloride (AH) is an expectorant drug used to stimulate pulmonary surfactant and serous airway secretion. Surfactant proteins (SPs) are essential for maintaining respiratory structure and function, although SP expression has also been reported in lung inflammatory and proliferative lesions. To determine whether AH exerts modulatory effects on these lung lesions, we examined its effects on pleural thickening induced by intrathoracic administration of dipotassium titanate (TISMO) in A/JJmsSlc (A/J) mice. We also analyzed the modulatory effects of AH on neoplastic lung lesions induced by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in A/J mice and by N-nitrosobis (2-hydroxypropyl) amine (DHPN) in F344/DuCrlCrj (F344) rats. A/J mice treated with TISMO showed decreased body weight, increased white blood cell (WBC) counts, and pleural thickening caused by pleuritis and poor general condition. However, A/J mice treated with TISMO + 120 ppm showed significant recovery of body weight and WBC counts to the same levels as those of A/J mice not treated with TISMO, although no significant differences were observed in histopathological changes including the immunohistopathological expression of IL-1β in the lung and maximum pleural thickness regardless of AH treatment. In the NNK and DHPN experiments, no significant differences in body weight, hematology, plasma biochemistry, and histopathological changes were associated with AH concentration. These results suggest that AH potentially exerts anti-inflammatory effects but does not have a direct suppressive effect on lung tumorigenesis in rodents.

TP53 mutation is associated with a poor clinical outcome for non-small cell lung cancer: Evidence from a meta-analysis

A number of studies have examined the association between tumor protein 53 (TP53) mutations and the clinical outcome in patients with non-small-cell lung cancer (NSCLC), although these have yielded conflicting results. In the present study, electronic databases updated to September 2015 were searched to find relevant studies. A meta-analysis was performed on the eligible studies, which quantitatively evaluated the association between the TP53 mutations and the survival of patients with NSCLC. Subgroup and sensitivity analyses were performed. A total of 19 studies that involved a total of 6,084 patients with NSCLC were included. When the TP53 mutation group (n=1,406) was compared with the wild-type group (lacking TP53 mutations; n=1,965), the wild-type group was associated with a significantly higher overall survival rate [hazard ratio (HR), 1.26; 95% confidence interval (CI) 1.12–1.41, P<0.0001]. Significant benefits of overall survival in the wild-type group were found in the subgroup involving patients with NSCLC in the early stages, including the I/II phases (HR, 1.93, 95% CI, 1.17–3.19, P=0.01; heterogeneity, I²=0.0%, P=0.976) and patients with adenocarcinoma (HR, 3.06; 95% CI, 1.66–5.62, P<0.0001; heterogeneity: I²=0.0%, P=0.976). This meta-analysis has indicated that TP53 gene alteration may be an indicator of a poor prognosis in patients with NSCLC. Furthermore, the results also suggested that the role of TP53 mutations may differ according to different pathological types and clinical stages. The presence of these mutations may define a subset of patients with NSCLC appropriate for investigational therapeutic strategies.

FDG uptake in non-small cell lung cancer is not an independent predictor of EGFR or KRAS mutation status: a retrospective analysis of 206 patients

PURPOSE

Data in the literature regarding the use of F-FDG avidity of non-small cell lung cancer (NSCLC) as an imaging biomarker to predict the status of epidermal growth factor receptor (EGFR) mutation are conflicting. Association between KRAS mutation and FDG avidity of NSCLC on PET/CT is not well known. We assessed whether the EGFR or KRAS mutation status in NSCLC can be predicted by FDG avidity by performing several different subgroup analyses to better compare with various published results.

PATIENTS AND METHODS

After obtaining institutional review board approval, we enrolled patients (1) who had FDG PET/CT performed for staging of NSCLC, (2) with EGFR and KRAS mutational status of tumor identified, and (3) without uncontrolled diabetes. Univariate and multivariate regression analyses were performed to assess the relationship between the independent clinical variables (sex, age, smoking history, tumor histology, tumor size, stage, and SUV-derived variables) and the EGFR and KRAS mutation status. Separate analyses were performed for patients with adenocarcinomas.

RESULTS

There were 206 patients (age, 33-88 years; 148 male/58 female; 71 ever-smokers/135 never-smokers; 135 adenocarcinoma/71 squamous cell carcinoma; 22 stage I-II/184 stage III-IV; tumor size, 1.2-15.0 cm; SUVmax, 2.9-36.4; EGFR mutations present in 47; KRAS mutations present in 20). In multivariate analysis, sex, smoking history, histology, and tumor size were significantly associated with EGFR mutation but none of the SUV-derived variables was. Likewise, no correlation was found between the SUV-derived variables and KRAS mutation.

CONCLUSIONS

Our results suggest that FDG avidity of NSCLC has no significant clinical value in predicting the EGFR or KRAS mutation status.

Prognostic impact of KRAS mutation subtypes in 677 patients with metastatic lung adenocarcinomas

BACKGROUND

We previously demonstrated that patients with metastatic KRAS mutant lung cancers have a shorter survival compared with patients with KRAS wild-type cancers. Recent reports have suggested different clinical outcomes and distinct activated signaling pathways depending on KRAS mutation subtype. To better understand the impact of KRAS mutation subtype, we analyzed data from 677 patients with KRAS mutant metastatic lung cancer.

METHODS

We reviewed all patients with metastatic or recurrent lung cancers found to have KRAS mutations over a 6-year time period. We evaluated the associations among KRAS mutation type, clinical factors, and overall survival in univariate and multivariate analyses. Any significant findings were validated in an external multi-institution patient dataset.

RESULTS

Among 677 patients with KRAS mutant lung cancers (53 at codon 13, 624 at codon 12), there was no difference in overall survival for patients when comparing KRAS transition versus transversion mutations (p = 0.99), smoking status (p = 0.33), or when comparing specific amino acid substitutions (p = 0.20). In our dataset, patients with KRAS codon 13 mutant tumors (n = 53) had shorter overall survival compared with patients with codon 12 mutant tumors (n = 624) (1.1 versus 1.3 years, respectively; p = 0.009), and the findings were confirmed in a multivariate Cox model controlling for age, sex, and smoking status (hazard ratio: 1.52, 95% confidence interval: 1.11-2.08; p = 0.008). In an independent validation set of tumors from 682 patients with stage IV KRAS mutant lung cancers, there was no difference in survival between patients with KRAS codon 13 versus codon 12 mutations (1.0 versus 1.1 years, respectively; p = 0.41).

CONCLUSIONS

Among individuals with KRAS mutant metastatic lung cancers treated with conventional therapy, there are no apparent differences in outcome based on KRAS mutation subtype.

Activation of MEK1/2-ERK1/2 signaling during NNK-induced lung carcinogenesis in female A/J mice

The extracellular signal‐regulated kinase 1/2 (ERK1/2) signaling pathway is activated by several growth factors and mitogens, and upregulation has been noted in many human cancers, including examples in the lung. In this study, to study the association of ERK1/2 activation with mutation of Kras encoding an upstream activator of ERK1/2 in lung premalignant lesions, we immunohistochemically examined expression of phosphorylated forms of ERK1/2 (pERK1/2) and MAP/ERK kinase 1/2 (pMEK1/2) proteins and correlation between ERK activation and mutation of Kras encoding an upstream activator of ERK1/2, in a mouse lung carcinogenesis model. Female 7‐week‐old A/J mice were administered a single dose of 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone (NNK), then maintained without additional treatment until sacrifice at week 52. Histopathologically, adenocarcinomas, adenomas and hyperplasias were observed in the lung. pMEK1/2 was expressed mostly in the cell cytoplasm in all three. In contrast, pERK1/2‐positive cells were also relatively rare in any histological types as compared with level of pMEK1/2 expression. However, pERK1/2‐positive cells in adenocarcinoma were still markedly more common than in hyperplasias and adenomas (~5‐fold, ~4‐fold; P < 0.01). Activating mutations of Kras gene at codons 12, 13 and 61 were detected in the majority of adenomas and adenocarcinomas, but without any significant relation to pERK1/2 expression. These results suggest that activation of ERK1/2 plays a key role in malignant transformation during lung carcinogenesis featuring Kras mutaion. Activation of ERK1/2 in lung premalignant lesions was little regardless of the mutation of Kras, and ERK1/2 activation in NNK‐induced mouse lung carcinogenesis may be regulated not only by Kras mutation but also other signaling pathway or regulatory factor.

Epidermal growth factor receptor exon 20 insertions in advanced lung adenocarcinomas: Clinical outcomes and response to erlotinib

BACKGROUND

Epidermal growth factor receptor (EGFR) exon 20 insertions (exon20ins) represent approximately 10% of EGFR-mutant lung adenocarcinomas, and are associated with resistance to EGFR tyrosine kinase inhibitors (TKIs). Clinical outcomes in comparison with patients with sensitizing EGFR mutations are not well established.

METHODS

Patients with stage IV lung adenocarcinomas with EGFR exon20ins were identified through routine molecular testing. Clinicopathologic data were collected. Overall survival (OS) was measured from the diagnosis of stage IV disease, and in patients treated with EGFR TKIs, the time to progression (TTP) on erlotinib was measured.

RESULTS

One thousand eight hundred and eighty-two patients with stage IV lung adenocarcinomas were identified: 46 patients had EGFR exon20ins (2%), and 258 patients had an EGFR exon 19 deletion (exon19del)/L858R point mutation (14%). Among 11 patients with lung adenocarcinomas with EGFR exon20ins who received erlotinib, 3 patients (27%) had a partial response (FQEA, 1; ASV, 1; and unknown variant, 1). TTP for patients with EGFR exon20ins and patients with EGFR exon19del/L858R on erlotinib were 3 and 12 months, respectively (P < .01). Responses to chemotherapy were similar for patients with lung adenocarcinomas with EGFR exon20ins and patients with lung adenocarcinomas with EGFR exon19del/L858R. Median OS from the diagnosis of stage IV disease for patients with EGFR exon20ins and patients with EGFR exon19del/L858R was 26 months (95% confidence interval, 19 months-not reached n = 46) and 31 months (95% confidence interval, 28-33 months; n = 258), respectively (P = .53).

CONCLUSIONS

The majority of patients with advanced lung adenocarcinomas harboring EGFR exon20ins do not respond to EGFR TKI therapy. Standard chemotherapy should be used as first-line therapy. These patients have an OS similar to that of patients with sensitizing EGFR mutations. Individuals with certain variants such as FQEA and ASV may respond to erlotinib.

Differential expression of Dickkopf-1 among non-small cell lung cancer cells

Dickkopf-1 (DKK1) is a negative regulator of the Wnt/β-catenin signaling pathway, which is expressed in various human cancers. It was hypothesized that DKK1 was oncogenic and involved in invasive growth in non-small cell lung cancer (NSCLC) cells. The present study aimed to investigate whether DKK1 gene expression levels differ among various NSCLC cells. The DKK1 expression pattern was analyzed in various human NSCLC cell lines and tissues. The DKK1 protein and gene expression levels were quantified using immunoblotting, polymerase chain reaction analysis and immunohistochemistry. The majority of the lung cancer cell lines analyzed revealed increased expression levels of DKK1. Furthermore, DKK1 expression was highly transactivated in the majority of these cancer cell lines. Clinical samples were obtained from 98 NSCLC patients for immunohistochemical analysis. Of the 98 samples analyzed, 62 (63.3%) demonstrated positive staining for DKK1, whereas the remaining 36 (37%) exhibited negative staining. However, no immunohistopathological staining was detected in normal tissues. The relative effects of DKK1 were assessed in a high-expression cell line (LTEP-a-2) and a low-expression cell line (95D). The differential expression of genes involved in cell cycle, apoptosis, signaling pathway, invasion and metastasis were evaluated, relative to DKK1 levels. In conclusion, the results of the present study indicated that DKK1 functioned as a key regulator in the progression of NSCLC. The results confirmed the differential expression of DKK1 in NSCLC cells, which may present a potential therapeutic target for cancer prevention.

KRAS mutations in advanced nonsquamous non-small-cell lung cancer patients treated with first-line platinum-based chemotherapy have no predictive value

BACKGROUND

Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation is thought to be related with dismal outcome for non-small-cell lung cancer (NSCLC) patients. The role of KRAS mutation as a predictor of response to chemotherapy for patients with metastatic NSCLC is poorly understood.

METHODS

From a retrospective database of two university hospitals, all patients with advanced, nonsquamous NSCLC treated with first-line platinum-containing chemotherapy were selected. Mutation analysis for KRAS was performed and the relation with response to chemotherapy was assessed. Secondary endpoints were its relation with response to progression-free survival (PFS) and overall survival (OS).

RESULTS

A total of 161 patients, 94 men and 67 women, were included in this study. Median age was 60 years. The majority of patients (79%) had stage IV disease, of which 60 patients (37%) had a KRAS mutation. Patients with a KRAS mutation had a similar response to treatment as patients with KRAS wild-type (wt) (p = 0.77). Median PFS in KRAS-mutated patients was 4.0 months versus 4.5 months in KRAS wt patients (hazard ratio = 1.3; [95% confidence interval, 0.9-1.8]; p = 0.16). Median OS in patients with KRAS mutation was 7.0 months versus 9.3 months in patients with KRAS wt (hazard ratio = 1.2; [95% confidence interval, 0.9-1.7]; p = 0.25). Type of KRAS mutation had no influence on response or outcome.

CONCLUSION

On the basis of our multicenter data presented here, we conclude that KRAS mutation is not predictive for worse response to chemotherapy, PFS, and OS in advanced NSCLC patients treated with platinum-based chemotherapy in first-line setting.

Determinants of survival in advanced non--small-cell lung cancer in the era of targeted therapies

BACKGROUND

Molecular profiling of non-small-cell lung cancer (NSCLC) samples has a profound impact on choice of therapy. However, it is less clear whether EGFR and KRAS mutations are prognostic outside of a trial-based treatment paradigm.

METHODS

We performed a retrospective chart review of 513 patients with NSCLC undergoing EGFR and KRAS mutational analysis at the Hospital of the University of Pennsylvania between May 2008 and November 2011. Survival analysis was based on the 376 patients who received systemic treatment, and their survival was determined from the date of initiation of systemic therapy.

RESULTS

The median overall survival (OS) was 30.8 months (95% confidence interval [CI], 24.7-36.9). Neither EGFR mutational status (P = .09) nor KRAS mutational status (0.69) was associated with OS. Female sex (P < .001), never smoker status (P = .01), better performance status (PS) (P < .001), lower Charlson Comorbidity Index (P < .001), and lower age-weighted index (P < .001) were associated with prolonged survival. The presence of bone metastases (P = .001) and liver metastases (P = .004) was also associated with a shortened survival. In a multivariable regression that adjusted for stage, we demonstrated that male gender (P = .002), worse Eastern Cooperative Oncology Group PS (P = .01), metastases to bone (P = .03), and higher age-weighted comorbidity index (P = .001) were independent prognostic factors for shorter survival. EGFR mutation status was not prognostic (P = .85).

CONCLUSION

In our series, EGFR and KRAS do not function as prognostic determinants for NSCLC.

Mutations of the EGFR and K-ras genes in resected stage I lung adenocarcinoma and their clinical significance

PURPOSE

This study retrospectively assessed the mutations of the epidermal growth factor receptor (EGFR) and K-ras genes and their clinical significance in patients with resected stage I adenocarcinomas.

METHODS

A total of 354 patients with resected lung adenocarcinomas were included, and 256 patients with stage I disease were analyzed for the prognostic and predictive value of these mutations.

RESULTS

Mutations of EGFR and K-ras genes were detected in 149 (41.1 %) and 23 (6.4 %) of all tumors, and in 122 (47.6 %) and 14 (5.5 %) of stage I tumors, respectively. There were no significant differences in the disease-free survival (DFS) and overall survival (OS) between the EGFR-mutant and wild-type groups. However, the DFS and OS were significantly shorter in patients with K-ras mutations than in those without (5-year DFS: 50.8 vs. 76.9 %, 5-year OS: 70.0 vs. 86.6 %, p < 0.01). A multivariate analysis showed that K-ras mutations were an independent poor prognostic factor. Twenty-four of the 41 patients with recurrent disease after surgery were treated with an EGFR-TKI. Fifteen EGFR-mutant patients treated with an EGFR-TKI had a better prognosis than did the nine EGFR-wild-type patients.

CONCLUSION

The presence of an EGFR gene mutation was a predictive factor for the response to EGFR-TKI treatment in patients with resected stage I adenocarcinoma, but was not a prognostic factor. The presence of a K-ras gene mutation was a poor prognostic factor.

Prognostic value of K-RAS mutations in patients with non-small cell lung cancer: a systematic review with meta-analysis

K-RAS gene mutations have been found in 20-30% of non-small cell lung cancer and occur most commonly in adenocarcinoma, however, there was no definitive conclusion about the prognostic role of K-RAS mutations in NSCLC. Herein we performed a systematic review of the literatures with meta-analysis to assess K-RAS mutations' prognostic value in NSCLC. After a methodological assessment, survival data from published studies were aggregated. Combined hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) were calculated in terms of overall survival. 41 trials (6939 patients) were included in the analysis, the overall HR was 1.45 (95% CI: 1.29-1.62), showing that K-RAS mutations have an unfavorable impact on survival of patients with NSCLC. Then a subgroup analysis was performed about ethnicity, the combined HR was 1.97 (95% CI: 1.58-2.44) for Asians, and 1.37 (95% CI: 1.25-1.5) for non-Asians. In subgroup analysis of histology, the HR was 1.39 (95% CI: 1.24-1.55) for adenocarcinoma, suggesting that K-RAS mutations were correlated with shortened survival for adenocarcinoma. When the subgroup analysis was conducted according to disease stage, K-RAS mutations were poor prognostic factors in early stages: stage I (1.81; 95% CI: 1.36-2.39) and stage I-IIIa (1.68; 95% CI: 1.11-2.55), but not in advanced stage (IIIb-IV) (1.3; 95% CI: 0.99-1.71). At last, in subgroup analysis about test methods, all of the four methods: PCR-MSOP (1.73; 95% CI: 1.35-2.2), PCR-DGGE (1.27; 95% CI: 1.01-1.62), PCR-RFLP (1.88; 95% CI: 1.42-2.49) and PCR-seq (1.34; 95% CI: 1.14-1.58) showed statistically significant impact on survival of NSCLC patients. In conclusion, this meta-analysis suggests that K-RAS mutations are associated with a worse overall survival in patients with NSCLC, especially in patients with adenocarcinoma and early stage.

KRAS mutations in lung cancer

Epidermal growth factor receptor (EGFR) gene mutations and increased EGFR copy numbers have been associated with a favorable response to EGFR tyrosine kinase inhibitors (TKI) in patients with non-small-cell lung cancer (NSCLC), and several markers have been identified that predict response to treatment. Lung adenocarcinomas also harbor activating mutations in the downstream GTPase, v-Ki-ras2 Kirsten rat sarcoma viral oncogene (KRAS), and mutations in EGFR and KRAS appear to be mutually exclusive. Even though KRAS mutations were identified in NSCLC tumors more than 20 years ago, we have only just begun to appreciate the clinical value of determining KRAS tumor status. Recent studies indicate that patients with mutant KRAS tumors fail to benefit from adjuvant chemotherapy and do not respond to EGFR inhibitors. There is a clear need for therapies specifically developed for patients with KRAS-mutant NSCLC. In this review, we summarize the clinical and pathologic characteristics of patients with NSCLC and with KRAS mutations, describe work that explores the predictive and prognostic influence of KRAS mutations, and provide an overview of the "synthetic lethal" interactions and current approaches to targeting KRAS-mutant NSCLC.

KRAS gene amplification and overexpression but not mutation associates with aggressive and metastatic endometrial cancer

BACKGROUND

Three quarter of endometrial carcinomas are treated at early stage. Still, 15 to 20% of these patients experience recurrence, with little effect from systemic therapies. Homo sapiens v-Ki-ras2 Kirsten rat sarcoma viral oncogenes homologue (KRAS) mutations have been reported to have an important role in tumorigenesis for human cancers, but there is limited knowledge regarding clinical relevance of KRAS status in endometrial carcinomas.

METHODS

We have performed a comprehensive and integrated characterisation of genome-wide expression related to KRAS mutations and copy-number alterations in primary- and metastatic endometrial carcinoma lesions in relation to clinical and histopathological data. A primary investigation set and clinical validation set was applied, consisting of 414 primary tumours and 61 metastatic lesions totally.

RESULTS

Amplification and gain of KRAS present in 3% of the primary lesions and 18% of metastatic lesions correlated significantly with poor outcome, high International Federation of Gynaecology and Obstetrics stage, non-endometrioid subtype, high grade, aneuploidy, receptor loss and high KRAS mRNA levels, also found to be associated with aggressive phenotype. In contrast, KRAS mutations were present in 14.7% of primary lesions with no increase in metastatic lesions, and did not influence outcome, but was significantly associated with endometrioid subtype, low grade and obesity.

CONCLUSION

These results support that KRAS amplification and KRAS mRNA expression, both increasing from primary to metastatic lesions, are relevant for endometrial carcinoma disease progression.

K-Ras Mutations in Non-Small-Cell Lung Cancer: Prognostic and Predictive Value

Non-small-cell lung cancer (NSCLC) is a heterogeneous disease due to the presence of different clinically relevant molecular subtypes. Until today, several biological events have been identified in lung adenocarcinoma, including epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) translocations, offering new hopes to patients with metastatic disease. Unfortunately, in approximately 50% of adenocarcinoma and for those harbouring K-RAS mutations, the most frequent mutation in Caucasian lung adenocarcinoma, so far no specific drug demonstrated efficacy. The rat sarcoma (RAS) genes, including H-RAS, K-RAS, and N-RAS, encode a family of proteins regulating cell growth, differentiation, and apoptosis. K-RAS mutations are present in 20-30% of NSCLC and occur most commonly, but not exclusively, in adenocarcinoma histology and life-long smokers. Although in colorectal cancer patients K-RAS mutations represent a validated negative predictive biomarker for treatment with anti-EGFR monoclonal antibodies, their role in selecting specific treatment for NSCLC patients remains undefined. Aim of the present paper is to critically analyze the prognostic and predictive value of K-RAS mutations in NSCLC.

Molecular changes in smoking-related lung cancer

To elucidate the effect of cigarette smoke on developing lung cancer among individuals, numerous genetic and epigenetic factors related to cigarette smoke-induced lung cancers have been widely investigated and a various genes, loci and pathways have been identified as candidates to date. However, the importance of these molecular alterations in the initiation and progression of lung cancer still remains imprecise and different molecules altered in lung cancer are being used for stratification of patients for targeted therapy. There are a number of molecular pathways involved in the development of lung cancer, and environmental factors related to these alterations are still unclear. Furthermore, various genetic alterations determined by candidate gene approach have not been re-evaluated for their functional significance together with epigenetic alterations in the same population. Accumulated evidence suggested that lung cancer in ever smokers and never smokers follow distinct molecular pathways and may therefore respond to distinct therapy. Therefore, additional studies will be essential to re-evaluate the individual risk of developing lung cancer based on the combination of genetic and epigenetic alterations and to set up a guideline to assess the individual risk for lung cancer and for its prevention.

Do all lung adenocarcinomas follow a stepwise progression?

Similar to the adenoma-carcinoma sequence of colorectal cancer, lung adenocarcinoma is thought to follow a linear multistep progression, in which a precursor lesion progresses to adenocarcinoma in situ, which is followed by invasive adenocarcinoma. However, lung adenocarcinoma can no longer be considered as a single type of tumor but rather a group of distinct subsets of tumors that arise from different molecular pathways. Consistent with this concept, recent findings revealed that this linear progression might not occur in all lung adenocarcinomas. First, according to the molecular classification based on expression profiling, lung cancer can be divided into at least two subsets; precancerous and in situ lesions share characteristics of molecular expression and clinical features with only one of the two subsets, suggesting that the linear progression is only applicable to the subset in the molecular classification. Second, when EGFR and KRAS were examined based on the progression steps, the mutation rate of KRAS was disproportionally distributed; however, according to the progression schema, gene alterations should be evenly accumulated along the entire progression. Third, by means of comparative genomic hybridization analysis, some adenocarcinoma in situ revealed gene alterations discontinuous to invasive adenocarcinoma. Finally, there were some clinical observations that support that some lesions escape from the progression. In this review, we hypothesize a novel scenario for the progression of lung adenocarcinoma, which does not support a linear progression schema.

Prognostic implications of miR-16 expression levels in resected non-small-cell lung cancer

BACKGROUND

MicroRNAs are novel regulators of gene expression that are linked to the main oncogene networks, including the p53 pathway. p53 regulates the maturation process of miR-16 and miR-143. We analyzed the role as prognostic markers of miR-16 and miR-143 in 70 non-small-cell lung cancer (NSCLC) patients.

METHODS

MicroRNAs were analyzed by TaqMan MicroRNA assays. Disease-free survival (DFS) and overall survival (OS) were examined using Kaplan-Meier curves with log-rank tests and the Cox proportional hazard model.

RESULTS

When patients were classified in three groups according to their miR-16 expression levels, those with normal levels had the best outcome while those with high levels had the worst. DFS was 22.4 months for patients with high levels, 71.8 months for those with normal levels, and 55.8 months for those with low levels (P = 0.05). OS was 23.9 months for patients with high levels, 97.6 months for those with normal levels, and 63.5 months for those with low levels (P < 0.001). In the multivariate analyses, high miR-16 levels emerged as an independent prognostic factor for poor DFS (P = 0.001) and OS (<0.001).

CONCLUSIONS

Our results provide the first hints that miR-16 levels in tumor samples may be a prognostic marker in NSCLC.

Prognostic implications of epidermal growth factor receptor and KRAS gene mutations and epidermal growth factor receptor gene copy numbers in patients with surgically resectable non-small cell lung cancer in Taiwan

INTRODUCTION

The prognostic role of epidermal growth factor receptor (EGFR) mutations in patients with surgically resectable non-small cell lung cancer (NSCLC) without EGFR tyrosine kinase inhibitor treatment has not been well established, because the reports are still few.

MATERIALS AND METHODS

We analyzed the survival data of 164 patients with surgically resectable (stages I to IIIA) NSCLC of two year groups (1996-1998 and 2002-2004), and compared with EGFR mutations, KRAS mutations, and EGFR gene copy numbers.

RESULTS

Comparing the survival of wild-type patients and patients having L858R mutations or exon 19 deletion, the median survival was much longer for patient with EGFR mutations (54.7 months) than wild type (34.9 months). The difference was not statistically significant by univariate analysis (p = 0.1981) but had borderline significance by multivariate analyses (p = 0.0506). In addition, the 3-year survival rates of patients with EGFR mutations were also significantly higher than wild type (p = 0.0232). After exclusion of 18 patients treated by EGFR-tyrosine kinase inhibitor for tumor recurrence, the trends were still the same. Patients with KRAS mutations had shorter median survival (21 months) than wild type (44.4 months). Patients with EGFR polysomy (>==copies) also had longer median survival (56.2 months) than wild type (53.4 months). But the survival differences of these two genetic markers were all not significant statistically.

CONCLUSION

It is intriguing that patients with NSCLC with EGFR mutations had better survival than wild type. Such a tumor biology may confound the survival data in a study without the stratification by EGFR mutation.

The identification of KRAS mutations at codon 12 in plasma DNA is not a prognostic factor in advanced non-small cell lung cancer patients

BACKGROUND

Qualitative analysis of circulating DNA in the blood is a promising non-invasive diagnostic and prognostic tool. Our aim was to study the association between the presence of KRAS mutations at codon 12 and several clinical variables in advanced non-small cell lung cancer (NSCLC) patients.

METHODS

We examined 308 stage IIIB and IV NSCLC patients who were treated with cisplatin and docetaxel. Blood samples were collected before chemotherapy, and circulating DNA was extracted from the plasma using commercial adsorption columns. The KRAS mutational status was determined by an RT-PCR method that is based on allelic discrimination.

RESULTS

The median age of the patients was 60 years [31-80], 84% were male, 98% had a performance status of 0-1 and 84% of the patients were in stage IV. The histological subtypes were as follows: 30% squamous cell carcinoma (SCC), 51% adenocarcinoma (ADC) and 19% others. Of the 277 response-evaluated patients, 1% achieved a complete response (CR), 26% achieved a partial response (PR), 34% had stable disease (SD) and 39% had progressive disease (PD). Additionally, 27 (8.8%) patients had KRAS mutations; 26 had a KRAS codon 12 TGT mutation, and 1 had a codon 12 GTT mutation. Plasmatic KRAS mutations were found in patients presenting SCC or ADC. Patients with KRAS mutations in plasma DNA had a median progression free survival (PFS) of 5.77 months [3.39-8.14], whereas for patients with wild-type (wt) KRAS, the PFS was 5.43 months [4.65-6.22] (p=0.277). The median overall survival (OS) in KRAS-mutated patients was 9.07 months [4.43-13.70] vs 10.03 months [8.80-11.26] in wt patients (p=0.514).

CONCLUSIONS

In advanced NSCLC patients, there were no significant differences between patients with or without KRAS mutations in plasma-free DNA with respect to the baseline characteristics, response rates, PFS or OS.

Predictive advantage of a cell type classification for pulmonary adenocarcinoma coupled with data for p53, K-ras and EGFR alterations

We analyzed relationships between histological subtypes of pulmonary adenocarcinomas and three gene alterations (p53, K-ras, and epidermal growth factor receptor gene), or thyroid transcription factor-1 (TTF-1) expression, and also studied prognoses by the subtypes, with or without combined multiple gene mutation status. Our purpose was to clearly determine pathogenesis, along with the best predictive value for biology and therapy-related traits. A total of 223 consecutively resected pulmonary adenocarcinomas were sub-classified using either the World Health Organization (WHO) or our five-cell type (FCT) classification system (hobnail, columnar/cuboidal, mixed, polygonal/oval, and goblet cell types). DNAs extracted from frozen samples of the adenocarcinomas were examined for gene alterations, and TTF-1 expressions were determined using immunohistochemistry. Next, relationships among the various data and clinicopathological factors were analyzed. The most striking result was: while almost 70% of adenocarcinomas were sub-classified as a mixed subtype by WHO, the FCT classified many of them as other cell subtypes. The FCT closely reflected differences in etiological factors, cellular lineages, and frequencies of gene mutations; and whether the data from combined gene mutations were used or not, differences among the cell types in postoperative survivals appeared. In contrast, subtypes of WHO did not show any association with the gene alteration or prognosis, and the FCT more suitably indicated sensitivity to gefitinib therapy than did WHO. The FCT combined with multiple gene mutation status appears to be useful in indicating pathogenesis and predicting the biological nature of pulmonary adenocarcinomas, and it could facilitate development of new therapies for each subtype.

Dickkopf-1 autoantibody is a novel serological biomarker for non-small cell lung cancer

OBJECTIVE

We investigated whether or not there are autoantibodies for DKK1 (Dickkopf-1) in patients with non-small cell lung cancer (NSCLC) and whether this autoantibody can be used for cancer detection.

METHODS

The levels of DKK1 autoantibodies were determined in 93 NSCLC patients and 87 healthy controls.

RESULTS

We found that, in the sera, the presence of autoantibody against DKK1 was highly correlated with NSCLC. High anti-DKK1 autoantibody titres were found in the sera of NSCLC patients, whereas low or negative titres were found in the control group. The ROC curve results showed that autoantibody immunoassay exhibited 62% sensitivity and 84% specificity. The sensitivity for the detection of NSCLC in stage I also reach 64.3%. Furthermore, a combined ELISA assays for both DKK1 and autoantibody DKK1 increased sensitivity and classified 81.7% (76/93) of the NSCLC patients as positive, whereas only 13.8 % (12/87) of healthy volunteers were falsely diagnosed as positive.

CONCLUSIONS

Our results suggest that the detection of circulating DKK1 autoantibody could potentially serve as a useful non-invasive marker for determining lung cancer status.

miR-34a as a prognostic marker of relapse in surgically resected non-small-cell lung cancer

MicroRNAs (miRNAs) have been identified as promising prognostic markers in non-small-cell lung cancer (NSCLC) since they play an important role in oncogenesis. The miR-34 family is composed of three miRNAs (miR-34a, miR-34b and miR-34c) that are part of the p53 network and whose expression is directly induced by p53 in response to DNA damage or oncogenic stress. We have analyzed the impact of miR-34 expression on relapse and overall survival in surgically resected NSCLC patients. For this purpose, we used stem-loop reverse transcription-polymerase chain reaction to analyze the expression of the miR-34 family in paired tumor and normal tissue from 70 surgically resected NSCLC patients who received no postsurgical treatment until relapse. In addition, in patients with sufficient tumor tissue, we assessed p53 mutations and the methylation status of the MIRN34A gene promoter region and correlated these findings with miR-34a expression. Molecular findings were correlated with relapse and overall survival. The miR-34 family was downregulated in tumor compared with normal tissue, and low levels of miR-34a expression were correlated with a high probability of relapse (P = 0.04). A relation was also found between MIRN34A methylation and miR-34a expression (P = 0.008). Patients with both p53 mutations and low miR-34a levels had the highest probability of relapse (P = 0.001). In the multivariate analysis, miR-34a expression emerged as an independent prognostic marker for relapse. In summary, we have identified miR-34a as a novel prognostic marker in NSCLC patients, providing a potential mechanism for estimating a patient's risk of disease recurrence and a useful tool to help guide treatment decisions.

Type I insulin-like growth factor receptor induces pulmonary tumorigenesis

Despite the type I insulin-like growth factor receptor (IGF-IR) being highly expressed in more than 80% of human lung tumors, a transgenic model of IGF-IR overexpression in the lung has not been created. We produced two novel transgenic mouse models in which IGF-IR is overexpressed in either lung type II alveolar cells (surfactant protein C [SPC]-IGFIR) or Clara cells (CCSP-IGFIR) in a doxycycline-inducible manner. Overexpression of IGF-IR in either cell type caused multifocal adenomatous alveolar hyperplasia with papillary and solid adenomas. These tumors expressed thyroid transcription factor 1 and Kruppel-like factor 5 in most tumor cells. Similar to our previous work with lung tumors that developed in the mouse mammary tumor virus-IGF-II transgenic mice, the lung tumors that develop in the SPC-IGFIR and CCSP-IGFIR transgenic mice expressed high levels of the cyclic adenosine monophosphate response element binding protein that was localized primarily to the nucleus. Although elevated IGF-IR expression can initiate lung tumor development, tumors can become independent of IGF-IR signaling as IGF-IR down-regulation in established tumors produced tumor regression in some, but not all, of the tumors. These findings implicate IGF-IR as an important initiator of lung tumorigenesis and suggest that the SPC-IGFIR and CCSP-IGFIR transgenic mice can be used to further our understanding of human lung cancer and the role IGF-IR plays in this disease.

Detection of K-Ras mutations in tumour samples of patients with non-small cell lung cancer using PNA-mediated PCR clamping

Non-small cell lung cancers (NSCLC), in particular adenocarcinoma, are often mixed with normal cells. Therefore, low sensitivity of direct sequencing used for K-Ras mutation analysis could be inadequate in some cases. Our study focused on the possibility to increase the detection of K-Ras mutations in cases of low tumour cellularity. Besides direct sequencing, we used wild-type hybridisation probes and peptide-nucleic-acid (PNA)-mediated PCR clamping to detect mutations at codons 12 and 13, in 114 routine consecutive NSCLC frozen surgical tumours untreated by targeted drugs. The sensitivity of the analysis without or with PNA was 10 and 1% of tumour DNA, respectively. Direct sequencing revealed K-Ras mutations in 11 out of 114 tumours (10%). Using PNA-mediated PCR clamping, 10 additional cases of K-Ras mutations were detected (21 out of 114, 18%, P<0.005), among which five in samples with low tumour cellularity. In adenocarcinoma, K-Ras mutation frequency increased from 7 out of 55 (13%) by direct sequencing to 15 out of 55 (27%) by clamped-PCR (P<0.005). K-Ras mutations detected by these sensitive techniques lost its prognostic value. In conclusion, a rapid and sensitive PCR-clamping test avoiding macro or micro dissection could be proposed in routine analysis especially for NSCLC samples with low percentage of tumour cells such as bronchial biopsies or after neoadjuvant chemotherapy.

Reversed mutation rates of KRAS and EGFR genes in adenocarcinoma of the lung in Taiwan and their implications

BACKGROUND

In western countries, the Kirsten ras oncogene homolog gene (KRAS) mutation rate is high in patients with nonsmall cell lung cancer (NSCLC), especially in those with adenocarcinoma (30%-50%), but the epidermal growth factor receptor gene (EGFR) mutation rate is very low (3%-8%). In addition, KRAS mutations reportedly were associated with EGFR tyrosine kinase inhibitor (EGFR-TKI) resistance. In Taiwan, high EGFR mutation rates associated with high EGFR-TKI response rates in patients with NSCLC have been reported; however, KRAS mutation data are limited and have not been correlated with TKI response.

METHODS

KRAS mutation analysis was performed on 237 NSCLC specimens, and the results were correlated with clinicopathologic features. All but 2 tumors also underwent EGFR mutation analysis.

RESULTS

KRAS mutations were identified in only 9 of 237 patients (3.80%). Five patients were women who were nonsmokers, and 4 patients were men who were ever-smokers. The mutation rate was 5.03% in patients with adenocarcinoma (8 of 159 patients) and 1.56% in patients with squamous cell carcinoma (1 of 64 patients). Four mutations were G12V, 3 mutations were G12D, 1 mutation was L19F, and 1 was the duplication insertion mutation dupT50_M72. In contrast, EGFR mutations were detected in 96 of 235 patients (40.8%) and in 90 of 157 adenocarcinomas (57.3%). None of the KRAS mutations coexisted with EGFR mutations. KRAS mutations were not associated significantly with any clinicopathologic characteristics, including smoking status. Among the 53 patients who had received TKI monotreatment, only 1 patient had a KRAS mutation and had progressive disease.

CONCLUSIONS

The KRAS mutation rate was too low to play a significant role in TKI resistance or tumorigenesis among Taiwanese patients with NSCLC, which was the complete reverse of the results reported in western countries.

Role of DMP1 and its future in lung cancer diagnostics

Lung cancer is the most lethal carcinoma worldwide. Mutations of p53, inactivation of p16(INK4a), and overexpression of cyclins E, A and B are independently associated with poor prognoses of patients, while the prognostic value of cyclin D1 or RB expression is inconclusive. Cyclin D binding myb-like protein 1 (Dmp1) encodes a DNA binding protein that receives signals from oncogenic Ras and functions as a tumor suppressor by activating the Arf-p53 [corrected] pathway. Dmp1 has been shown to be haplo-insufficient for tumor suppression in mouse models including K-ras-mediated lung carcinogenesis. The human DMP1 gene is located on chromosome 7q21, and our recent results revealed that the hDMP1 gene is deleted, but not mutated or silenced, in approximately 40 % of human non-small-cell lung carcinomas. These cases typically retained wild-type ARF and p53 and expressed very low levels of the hDMP1 protein. Thus, hDMP1 loss could be a novel diagnostic marker for non-small-cell lung carcinomas.

Molecular predictors of EGFR-TKI sensitivity in advanced non-small cell lung cancer

The epidermal growth factor receptor (EGFR) is overexpressed in the majority of non-small cell lung cancers (NSCLC) and is a major target for new therapies. Specific EGFR tyrosine kinase inhibitors (TKIs) have been developed and used for the treatment of advanced NSCLC. The clinical response, however, varies dramatically among different patient cohorts. Females, East Asians, non-smokers, and patients with adenocarcinoma usually show higher response rates. Meanwhile, a number of biological factors are also associated with EGFR-TKIs responsiveness. In order to better understand the predictive value of these biomarkers and their significance in clinical application we prepared this brief review. Here we mainly focused on EGFR somatic mutations, MET amplification, K-ras mutations, EGFRvIII mutation, EGFR gene dosage and expression, HER2 gene dosage and expression, and Akt phosphorylation. We think EGFR somatic mutation probably is the most effective molecular predictor for EGFR-TKIs responsiveness and efficacy. Mutation screening test can provide the most direct and valuable guidance for clinicians to make decision on EGFR-TKIs therapy.

Sequential molecular changes during multistage pathogenesis of small peripheral adenocarcinomas of the lung

INTRODUCTION

We investigated EGFR and KRAS alterations among atypical adenomatous hyperplasia and small lung adenocarcinomas with bronchioloalveolar features to understand their role during multistage pathogenesis.

METHODS

Sixty lesions measuring 2 cm or less were studied, including 38 noninvasive lesions (4 atypical adenomatous hyperplasias, 19 Noguchi type A and 15 type B) and 22 invasive lesions (type C) based on the World Health Organization classification and Noguchi's criteria. EGFR and KRAS mutations were examined using PCR-based assays. EGFR copy number was evaluated using fluorescence in situ hybridization.

RESULTS

EGFR and KRAS mutations were found in 26 (43.3%) and 5 (8.3%) lesions, respectively. Increased EGFR copy number status was identified in 10 lesions (16.7%), both mutant and wild type. EGFR or KRAS mutations were present in 39.5% and 7.9% (respectively) of noninvasive lesions and 50% or 9.1% (respectively) of invasive lesions. EGFR copy number was increased in 7.9% and 31.8% of noninvasive and invasive lesions (P = 0.029). Multivariate analysis revealed that increased EGFR copy number was the only significant factor to associate with invasive lesions (P = 0.035).

CONCLUSIONS

EGFR and KRAS mutations occur early during the multistage pathogenesis of peripheral lung adenocarcinomas. By contrast, increased EGFR copy number is a late event during tumor development and plays a role in the progression of lung adenocarcinoma independent of the initiating molecular events.

Pathologic and molecular features of screening low-dose computed tomography (LDCT)-detected lung cancer: a baseline and 2-year repeat study

Detailed studies on the pathologic and molecular features of low-dose computed tomography (LDCT)-detected carcinomas and comparison with unscreened tumors are still lacking. We evaluated the histopathologic features of 89 LDCT-detected lung cancers resected between 2004 and 2006. These tumors occurred within a cohort of 5202 volunteers undergoing annual LDCT, aged > or =50 years, and with a minimum 20 pack-year index. In adenocarcinomas, central scar diameter, invasion foci size and K-ras mutations were also assessed. The results were compared with those of 89 consecutive lung carcinomas matched for confounding factors (sex, smoking habit), selected from group of 363 consecutive clinically worked-up lung cancer, surgically resected in the same period and at the same Institution. The tumors were diagnosed in 63 males and 26 females (range 50-79 years), 55 of which diagnosed at the baseline (1.05%) and 34 (including 10 repeat cancers) operated after work-up during the second year (0.72%). LDCT-detected tumors showed high resectability rate (89%), earlier stage (63%) and prevalence of adenocarcinoma nodules (72%), most often of the mixed subtype, in comparison with unscreened tumors. A similar prevalence of K-ras mutations was found in both screened and unscreened adenocarcinomas. Repeat cancers were found in 10 screened patients, and were predominantly stage I adenocarcinomas of mixed subtype exhibiting smaller dimension but greater central scar diameter and stromal invasion size in comparison with the other second-year, slower-growing adenocarcinomas. Multiple tumor nodules were identified in 10 patients exclusively at the baseline, were mostly mixed adenocarcinomas and differed in their K-ras mutation profile. Screening-detected lung cancers shared most of the histologic features of fully malignant tumors, in addition to a similar prevalence of K-ras mutations, despite their earlier detection and less advanced clinical stage. Repeat cancers are potentially aggressive tumors. K-ras mutation analysis supports the impression that multifocal tumors at baseline are separate synchronous primaries.

Impact of smoking status on the biological behavior of lung cancer

Cigarette smoking is the most established risk factor for lung carcinogenesis; however, its effects on the progression of lung cancer are still unclear. We reviewed the clinical investigations on this issue, which imply that smoking status is a treatment predictor and prognostic factor for several subtypes of lung cancer. Moreover, gene alterations and various protein expressions of tumor progression were recognized more frequently in the tumor tissues of smokers than in those of the never smokers. A cellular analysis revealed that tobacco-specific chemical compounds cause genetic or epigenetic alterations, modulate expressions of large numbers of genes that include molecules related to proliferation, invasion and metastasis, and deteriorate anti-tumor immunity. Our findings suggest that smoking promotes the progression of lung cancer, and that elucidating the molecular mechanisms may help to clarify the therapeutic targets.

The impact of epidermal growth factor receptor gene status on gefitinib-treated Japanese patients with non-small-cell lung cancer

We investigated the relationships between genetic factors and clinical outcome in Japanese non-small-cell lung cancer (NSCLC) patients treated with gefitinib. Ninety-eight NSCLC patients who had been treated with gefitinib, were screened for mutations in epidermal growth factor receptor (EGFR) exons 18-21, KRAS exon2, and polymorphisms including the CA simple sequence repeat in intron1 (CA-SSR1) and single nucleotide polymorphisms in the promoter region (-216G/T and -191C/A), using a PCR-based assay and direct sequencing. The EGFR copy number status was also evaluated using a fluorescence in situ hybridization assay. EGFR and KRAS mutations were found in 38 (38.8%) and 8 (8.2%) of the 98 patients, respectively. A high EGFR copy number status was identified in 31 (41.3%) of the 75 assessable patients. Drug-sensitive EGFR mutations limited to exon19 deletions and L858R were independent predictive factors of a stronger sensitivity to gefitinib (p = 0.0002), the overall survival (OS) (p = 0.0036), and prolonged progression-free survival (PFS) (p < 0.0001). The EGFR copy number status was not related to a sensitivity to gefitinib and prolonged OS and PFS. Regarding polymorphisms, patients with a short CA-SSR1 showed a prolonged OS as compared with those with a long length in patients with a drug-sensitive EGFR mutation, although this difference was not significant (p = 0.13). Thus, drug-sensitive EGFR mutations predict a favorable clinical outcome and a high EGFR copy number may not be related to clinical benefits in gefitinib-treated Japanese patients with NSCLC. Our findings also suggest that the CA-SSR1 length may influence the clinical outcome in patients with a drug-sensitive EGFR mutation.