Lack of prognostic significance of p53 and K-ras mutations in primary resected non-small-cell lung cancer on E4592: a Laboratory Ancillary Study on an Eastern Cooperative Oncology Group Prospective Randomized Trial of Postoperative Adjuvant Therapy

Clinical practice guidelines for molecular tumor markers, 2nd edition review part 1

With advances in gene and protein analysis technologies, many target molecules that may be useful in cancer diagnosis have been reported. Therefore, the "Tumor Marker Study Group" was established in 1981 with the aim of "discovering clinically" useful molecules. Later, the name was changed to "Japanese Society for Molecular Tumor Marker Research" in 2000 in response to the remarkable progress in gene-related research. Currently, the world of cancer treatment is shifting from the era of representative tumor markers of each cancer type used for tumor diagnosis and treatment evaluation to the study of companion markers for molecular-targeted therapeutics that target cancer cells. Therefore, the first edition of the Molecular Tumor Marker Guidelines, which summarizes tumor markers and companion markers in each cancer type, was published in 2016. After publication of the first edition, the gene panel testing using next-generation sequencing became available in Japan in June 2019 for insured patients. In addition, immune checkpoint inhibitors have been indicated for a wide range of cancer types. Therefore, the 2nd edition of the Molecular Tumor Marker Guidelines was published in September 2021 to address the need to revise the guidelines. Here, we present an English version of the review (Part 1) of the Molecular Tumor Marker Guidelines, Second Edition.

Benefits from Adjuvant Chemotherapy in Patients with Resected Non-Small Cell Lung Cancer: Possibility of Stratification by Gene Amplification of ACTN4 According to Evaluation of Metastatic Ability

Surgical treatment is the best curative treatment option for patients with non-small cell lung cancer (NSCLC), but some patients have recurrence beyond the surgical margin even after receiving curative surgery. Therefore, therapies with anti-cancer agents also play an important role perioperatively. In this paper, we review the current status of adjuvant chemotherapy in NSCLC and describe promising perioperative therapies, including molecularly targeted therapies and immune checkpoint inhibitors. Previously reported biomarkers of adjuvant chemotherapy for NSCLC are discussed along with their limitations. Adjuvant chemotherapy after resective surgery was most effective in patients with metastatic lesions located just outside the surgical margin; in addition, these metastatic lesions were the most sensitive to adjuvant chemotherapy. Thus, the first step in predicting patients who have sensitivity to adjuvant therapies is to perform a qualified evaluation of metastatic ability using markers such as actinin-4 (ACTN4). In this review, we discuss the potential use of biomarkers in patient stratification for effective adjuvant chemotherapy and, in particular, the use of ACTN4 as a possible biomarker for NSCLC.

Molecular Biology and Therapeutic Perspectives for K-Ras Mutant Non-Small Cell Lung Cancers

In non-small cell lung cancer (NSCLC) the most common alterations are identified in the Kirsten rat sarcoma viral oncogene homolog (KRAS) gene, accounting for approximately 30% of cases in Caucasian patients. The majority of mutations are located in exon 2, with the c.34G > T (p.G12C) change being the most prevalent. The clinical relevance of KRAS mutations in NSCLC was not recognized until a few years ago. What is now emerging is a dual key role played by KRAS mutations in the management of NSCLC patients. First, recent data report that KRAS-mutant lung AC patients generally have poorer overall survival (OS). Second, a KRAS inhibitor specifically targeting the c.34G > T (p.G12C) variant, Sotorasib, has been approved by the U.S. Food and Drug Administration (FDA) and by the European Medicines Agency. Another KRAS inhibitor targeting c.34G > T (p.G12C), Adagrasib, is currently being reviewed by the FDA for accelerated approval. From the description of the biology of KRAS-mutant NSCLC, the present review will focus on the clinical aspects of KRAS mutations in NSCLC, in particular on the emerging efficacy data of Sotorasib and other KRAS inhibitors, including mechanisms of resistance. Finally, the interaction between KRAS mutations and immune checkpoint inhibitors will be discussed.

Phase I Trial of Definitive Concurrent Chemoradiotherapy and Trametinib for KRAS-Mutated Non-Small Cell Lung Cancer

OBJECTIVE

This phase I trial (NCT01912625) evaluated the safety and pharmacokinetics of definitive concurrent chemoradiotherapy (cCRT) and the radiosensitizer trametinib (MEK1/2 inhibitor) for KRAS-mutated nonmetastatic non-small cell lung cancer (NSCLC).

METHODS

Patients received cCRT (carboplatin/paclitaxel and 60 Gy/30 fractions radiotherapy); oral trametinib (7 days/week) commenced on day 1 and completed on the final day of radiotherapy. Dose-finding of trametinib was done using the time-to-event continual reassessment method (TiTE-CRM); dose levels were 0.5mg (level -1), 1mg (initial, level 1), 1.5mg (level 2), and 2mg (level 3). Progression-free (PFS) and overall survival (OS) times were also recorded.

RESULTS

Fifteen patients (stage III, variety of KRAS mutations) were treated, with 1/5/4/5 at dose levels -1/1/2/3, respectively. Five patients received dose reductions (n=2, levels 2 and 3; n=1, level 1). Twelve patients completed the full cCRT course. One patient (following 12d trametinib) was taken off protocol for an unrelated/unresolved grade 1 event and later experienced grade 5 sepsis/respiratory failure. There was one grade 4 retinal detachment; grade 3 events included skin rash (n=2) and ventricular dysfunction, pneumonitis, pain, fatigue, and diarrhea (n=1 each). The final dose selected by the TiTE-CRM of trametinib was 1.5 mg. Pharmacokinetic profiles were elucidated and extensively described. At median follow-up of 70 months, median PFS was 11 months and median OS was 38 months.

CONCLUSIONS

The MTD for trametinib when combined with cCRT is 1.5 mg, with encouraging preliminary outcomes. This combination merits further study to combine with consolidation durvalumab in non-metastatic KRAS mutant NSCLC.

Characterization With KRAS Mutant Is a Critical Determinant in Immunotherapy and Other Multiple Therapies for Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is a frequent type of cancer, which is mainly characterized clinically by high aggressiveness and high mortality. KRAS oncoprotein is the most common molecular protein detected in NSCLC, accounting for 25% of all oncogenic mutations. Constitutive activation of the KRAS oncoprotein triggers an intracellular cascade in cancer cells, leading to uncontrolled cell proliferation of cancer cells and aberrant cell survival states. The results of multiple clinical trials have shown that different KRAS mutation subtypes exhibit different sensitivities to different chemotherapy regimens. Meanwhile, anti-angiogenic drugs have shown differential efficacy for different subtypes of KRAS mutated lung cancer. It was explored to find if the specificity of the KRAS mutation subtype would affect PD-L1 expression, so immunotherapy would be of potential clinical value for the treatment of some types of KRAS mutations. It was discovered that the specificity of the KRAS mutation affected PD-L1, which opened up immunotherapy as a potential clinical treatment option. After several breakthrough studies, the preliminary test data of many early clinical trials showed that it is possible to directly inhibit KRAS G12C mutation, which has been proved to be a targeted treatment that is suitable for about 10%-12% of patients with advanced NSCLC, having a significant impact on the prolongation of their survival and the improvement of their quality of life. This article reviews the latest progress of treatments for NSCLC with KRAS mutation, in order to gain insight into the biological diversity of lung cancer cells and their potential clinical implications, thereby enabling individualized treatment for patients with KRAS-mutant NSCLC.

Targeting KRAS in NSCLC: Old Failures and New Options for "Non-G12c" Patients

Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS) gene mutations are among the most common driver alterations in non-small cell lung cancer (NSCLC). Despite their high frequency, valid treatment options are still lacking, mainly due to an intrinsic complexity of both the protein structure and the downstream pathway. The increasing knowledge about different mutation subtypes and co-mutations has paved the way to several promising therapeutic strategies. Despite the best results so far having been obtained in patients harbouring KRAS exon 2 p.G12C mutation, even the treatment landscape of non-p.G12C KRAS mutation positive patients is predicted to change soon. This review provides a comprehensive and critical overview of ongoing studies into NSCLC patients with KRAS mutations other than p.G12C and discusses future scenarios that will hopefully change the story of this disease.

TP53 and CDKN2A mutations in patients with early-stage lung squamous cell carcinoma: an analysis of the correlations and prognostic outcomes

Background

Lung squamous cell carcinoma (LUSC) is characterized by frequent mutations of tumor protein p53 (TP53) and cyclin dependent kinase inhibitor 2A (CDKN2A). However, to date, the impact of TP53/CDKN2A status on the clinical outcome of patients with early-stage LUSC is unclear.

Methods

Tissue samples from 16 early-stage, surgically resected LUSCs were analyzed by next-generation sequencing (NGS). Information regarding TP53 and CDKN2A alterations and patient survival time was downloaded from The Cancer Genome Atlas (TCGA) database. The associations between TP53 and CDKN2A status and tumor characteristics, outcomes including overall survival (OS) and disease-free survival (DFS), and mutation counts were investigated.

Results

TP53 and CDKN2A exhibited a high frequency of somatic mutations in early-stage LUSC in our center. Data for 1,176 samples were collected from TCGA. CDKN2A mutation status was associated with TP53 mutation status (P=0.040). TP53 mutation was a favorable prognostic factor for early-stage LUSC. The OS times of patients with wild-type and mutated TP53 were 28.94 and 60.48 months, respectively (P=0.002). In contrast, CDKN2A mutations were significantly associated with a shorter survival time in early-stage LUSC. The OS times for wild-type and mutated CDKN2A patients were 62.81 and 37.55 months, respectively (P=0.026). Patients with TP53 mutations had higher total mutation counts compared to patients with wild-type TP53. Furthermore, OS was significantly shorter in patients with a low mutation count compared to patients with a median or high mutation count.

Conclusions

Early-stage LUSC patients with TP53 mutations had a longer OS, while those with CDKN2A mutations had a shorter OS. Furthermore, patients with TP53 mutation/CDKN2A wild-type status had a longer OS. CDKN2A mutation is a vital indicator for prognostic assessment according to TP53 status. The prolonged survival of patients with TP53 mutations may be due to their high mutation counts. Larger datasets are required to validate these observations.

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.

Current therapy of KRAS-mutant lung cancer

KRAS mutations are the most frequent gain-of-function alterations in patients with lung adenocarcinoma (LADC) in the Western world. Although they have been identified decades ago, prior efforts to target KRAS signaling with single-agent therapeutic approaches such as farnesyl transferase inhibitors, prenylation inhibition, impairment of KRAS downstream signaling, and synthetic lethality screens have been unsuccessful. Moreover, the role of KRAS oncogene in LADC is still not fully understood, and its prognostic and predictive impact with regards to the standard of care therapy remains controversial. Of note, KRAS-related studies that included general non-small cell lung cancer (NSCLC) population instead of LADC patients should be very carefully evaluated. Recently, however, comprehensive genomic profiling and wide-spectrum analysis of other co-occurring genetic alterations have identified unique therapeutic vulnerabilities. Novel targeted agents such as the covalent KRAS G12C inhibitors or the recently proposed combinatory approaches are some examples which may allow a tailored treatment for LADC patients harboring KRAS mutations. This review summarizes the current knowledge about the therapeutic approaches of KRAS-mutated LADC and provides an update on the most recent advances in KRAS-targeted anti-cancer strategies, with a focus on potential clinical implications.

p53-R273H promotes cancer cell migration via upregulation of neuraminidase-1

Accumulating evidence indicates that hotspot p53 mutants have gain-of-function in promoting cell migration and tumor metastasis. However, the molecular mechanisms are not completely understood. Here, we show that a hotspot mutation, p53-R273H, promotes non-small cell lung cancer (NSCLC) cell migration and upregulates the mRNA and protein expression of neuraminidase-1 (NEU1), a sialidase involved in cell proliferation, cell migration and tumorigenesis. Silencing of NEU1 leads to upregulation of integrin β4 which significantly inhibits NSCLC cell migration induced by p53-R273H. Mechanistically, p53-R273H promotes NEU1 transcription via activation of AKT signaling. Importantly, NEU1 expression is upregulated in human NSCLC samples harboring mutant p53 and is associated with poor clinical outcome. Overall, this study highlights an important role of NEU1 in p53-R273H-induced NSCLC cell migration and provides a potential target for NSCLC diagnosis and treatment.

Outcomes by EGFR, KRAS, and ALK Genotype After Combined Modality Therapy for Locally Advanced Non–Small-Cell Lung Cancer

Purpose

In 699 patients with locally advanced non–small-cell lung cancer (NSCLC) treated with radiation therapy as part of combined modality therapy, we compared outcomes among genotyped and ungenotyped patients and by tumor genotype status ( EGFR, KRAS, and ALK).

Patients and Methods

Genotyping was performed in 250 patients: EGFR+ (19%), KRAS+ (32%), ALK+ (9%), and wild type (WT−/−/−; 40%). Outcomes were analyzed using the Kaplan-Meier method and Cox regression.

Results

With a median follow-up of 48.2 months among genotyped patients, median overall survival (OS) was significantly longer for EGFR+ and ALK+ compared with KRAS+ and WT−/−/− (55.8 months v not reached v 28.0 v 33.2 months; P = .02). There was no difference in progression-free survival (median, 15.3 v 13.7 v 13.0 v 14.5 months; P = .47) or in freedom from distant metastases by genotype (3-year estimates: 42% v 49% v 27% v 25%; P = .25). There was higher freedom from locoregional recurrence (LRR) for EGFR+ tumors and lower freedom from LRR in ALK+ tumors, compared with KRAS+ and WT−/−/− tumors (3-year: 77% v 38% v 49% v 46%). In multivariable analysis, ALK+ remained associated with increased OS (HR, 0.32; 95% CI, 0.12 to 0.87; P = .03), and EGFR+ was associated with decreased LRR (HR, 0.47; 95% CI, 0.24 to 0.92; P = .03). Analysis of post-recurrence survival demonstrated that EGFR+/ ALK+ patients treated with appropriate tyrosine kinase inhibitors had higher OS compared with other groups.

Conclusion

In this series of locally advanced NSCLC treated with combined modality therapy, EGFR+ and ALK+ were associated with higher OS, whereas LRR was lower in EGFR+ patients, and the risk of distant metastases was high in all subgroups. The outcomes and patterns of failure in genotypic subgroups of NSCLC from this study can inform the design of future trials integrating targeted therapies.

Clinicopathologic characteristics and survival outcome in patients with advanced lung adenocarcinoma and KRAS mutation

Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations are one of the most common observed genetic events in lung adenocarcinoma. The present study aimed to characterize treatment patterns and to estimate survival for patients in China with advanced lung adenocarcinoma and KRAS mutation. We identified KRAS-mutant lung adenocarcinoma between February 2013 and June 2017 in Zhejiang Cancer Hospital. Patients' characteristics and treatment outcomes were analyzed. A total of 159 lung adenocarcinoma were included, and 26 (16.4%) patients harbored KRAS mutations. Compared to KRAS-wild patients, patients with KRAS-mutant tumors were more likely to be smokers (76.9% vs. 51.9%, P = 0.029). Median tumor mutation burden (TMB) was significantly higher in the KRAS-mutant cohort than in the KRAS-wild cohort (5.4 vs. 4.2 mutations/megabases; P=0.041). Of the 93 patients receiving first-line chemotherapy, the median progression-free survival (PFS) in the KRAS-mutant group was significantly shorter than in the KRAS-wild group (1.5 vs. 7.2 months; P<0.001). The median overall survival (OS) in the KRAS-mutant group was also significantly shorter than in the KRAS-wild group (hazard ratio for progression or death for patients with KRAS mutation, 3.260; 95% CI, 1.516 to 7.013; P=0.001). In summary, our findings have several important implications for the molecular characterization and therapeutic outcome of lung adenocarcinoma initiated by oncogenic KRAS. Since the number of KRAS-mutant lung cancer is considerable, it should be taken seriously in clinical diagnosis and treatment. KRAS-mutant lung adenocarcinoma was not sensitive to chemotherapy, new and effective drugs targeting the KRAS pathway are in urgent need.

Correlation and prognostic significance of PD-L1 and P53 expression in resected primary pulmonary lymphoepithelioma-like carcinoma

Background

Aberrant expression of programmed cell death-ligand 1 (PD-L1) and protein 53 (P53) has been observed in various malignancies, and recently, the mechanism of PD-L1 regulation by P53 has been elucidated. We aimed to explore possible correlations between PD-L1 and P53 expression and the prognosis of patients with resected pulmonary lymphoepithelioma-like carcinoma (LELC).

Methods

A total of 67 consecutive patients with primary pulmonary LELC who underwent radical resection from January 2003 to December 2014 were enrolled in our study. Membranous PD-L1 and nuclear P53 expression were detected by immunohistochemical staining (IHC).

Results

Positive expression of PD-L1 in tumor cells (TCs), PD-L1 in tumor-infiltrating lymphocytes (TILs) and P53 was investigated in 44 patients (65.7%), 37 patients (55.2%), and 34 patients (50.7%), respectively. Using univariate and multivariable analysis, both PD-L1 (+) in TCs and P53 (+) were observed to be significantly independent prognostic factors associated with longer disease-free survival (DFS, P=0.037 and 0.039, respectively), along with early stage LELC (P=0.037), but had no association with overall survival (OS) (P>0.05). In the P53 (+) group, the rate of patients with PD-L1 (+) in TCs was significantly higher than in the P53 (-) group (85.3% vs. 45.5%, P=0.001). In addition, among the 45 patients who underwent adjuvant chemotherapy, DFS was significantly longer in patients with either PD-L1 (+) in TCs or P53 (+) (P=0.036 and 0.044, respectively).

Conclusions

PD-L1 and P53 may be potential therapeutic targets for primary pulmonary LELC. PD-L1 (+) in TCs and P53 (+) were reliable predictors for longer DFS and benefits from adjuvant therapy in resected cases. Routine detection of these two indices in lung LELC may be warranted.

KRAS oncogene in non-small cell lung cancer: clinical perspectives on the treatment of an old target

Lung neoplasms are the leading cause of death by cancer worldwide. Non-small cell lung cancer (NSCLC) constitutes more than 80% of all lung malignancies and the majority of patients present advanced disease at onset. However, in the last decade, multiple oncogenic driver alterations have been discovered and each of them represents a potential therapeutic target. Although KRAS mutations are the most frequently oncogene aberrations in lung adenocarcinoma patients, effective therapies targeting KRAS have yet to be developed. Moreover, the role of KRAS oncogene in NSCLC remains unclear and its predictive and prognostic impact remains controversial. The study of the underlying biology of KRAS in NSCLC patients could help to determine potential candidates to evaluate novel targeted agents and combinations that may allow a tailored treatment for these patients. The aim of this review is to update the current knowledge about KRAS-mutated lung adenocarcinoma, including a historical overview, the biology of the molecular pathways involved, the clinical relevance of KRAS mutations as a prognostic and predictive marker and the potential therapeutic approaches for a personalized treatment of KRAS-mutated NSCLC patients.

Super enhancer associated RAI14 is a new potential biomarker in lung adenocarcinoma

Purpose

Tyrosine kinase inhibitors (TKIs) are widely used to treat lung adenocarcinoma patients with EGFR mutations or ALK-fusions. However, patients with wild-type genes or TKIs-resistant mutations lack effective therapeutic targets. Extensive studies reveal that super enhancer (SE), a large cis-regulatory element, is associated with key oncogenes in a variety of cancers. By comparing the effect of SE on lung adenocarcinoma cell lines with normal cell line, this work attempts to find new biomarkers and potential therapeutic targets for lung adenocarcinoma.

Experimental Design

Chromatin Immunoprecipitation (ChIP) followed by high-throughput DNA sequencing (ChIP-seq) of H3K27ac (acetylation on lysine 27 of histone 3) was performed in lung adenocarcinoma cell lines SPC-A1 and SCH-1153. The differences in SE distribution were then analyzed among SPC-A1, SCH-1153, A549 and normal human lung fibroblasts (NHLF) to identify SE-associated oncogenes. The expression of SE-associated oncogenes was then detected by RNA-seq and further verified in 71 patients by real-time PCR.

Results

SE associated with many new oncogenes in lung adenocarcinoma, among which, RAI14 was up-regulated in A549 and 31 of 71 patients. High expression of RAI14 could inhibit cell proliferation, indicating its potential as a new biomarker for lung adenocarcinoma.

Treating KRAS-mutant NSCLC: latest evidence and clinical consequences

KRAS mutations represent one of the most prevalent oncogenic driver mutations in non-small cell lung cancer (NSCLC). For many years we have unsuccessfully addressed KRAS mutation as a unique disease. The recent widespread use of comprehensive genomic profiling has identified different subgroups with prognostic implications. Moreover, recent data recognizing the distinct biology and therapeutic vulnerabilities of different KRAS subgroups have allowed us to explore different treatment approaches. Small molecules that selectively inhibit KRAS G12C or use of immune checkpoint inhibitors based on co-mutation status are some examples which anticipate that personalized treatment for this challenging disease is finally on the horizon.

Molecular biomarkers for lung adenocarcinoma

The identification of oncogenic driver alterations that underlie sensitivity to small inhibitors has led to growing interest in identifying additional targetable oncogenes in nonsmall cell lung cancer. Although the therapeutic impact of the discovery of these alterations has now been widely demonstrated, the epidemiological data associated with each of these biomarkers remain insufficiently studied. In this review, we discuss the techniques used to discover each of these candidate oncogenes, their prevalence in nonsmall cell lung cancer, and briefly outline the epidemiological features of the major oncogenes and ways in which their identification can determine therapeutic strategies.

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.

Prognostic and Predictive Effect of TP53 Mutations in Patients with Non-Small Cell Lung Cancer from Adjuvant Cisplatin-Based Therapy Randomized Trials: A LACE-Bio Pooled Analysis

INTRODUCTION

Tumor protein p53 gene (TP53) mutations are common in stage I through III non-small cell lung cancer, but clinical trials have shown inconsistent results regarding their relationship to the effects of adjuvant therapy. The objective is to clarify their putative prognostic and predictive effects.

METHODS

A pooled analysis of TP53 mutations (exons 5-8) was conducted in four randomized trials (the International Adjuvant Lung Cancer Trial, J BRonchus 10, Cancer and Leukemia Group B-9633, and Adjuvant Navelbine International Trialist Association trial) of platinum-based adjuvant chemotherapy (ACT) versus observation (OBS). Hazard ratios (HRs) and 95% confidence intervals (CIs) of mutant versus wild-type (WT) TP53 for overall survival (OS) and disease-free survival (DFS) were estimated using a multivariable Cox model stratified on trial and adjusted on sex, age, and clinicopathological variables. Predictive value was evaluated with an interaction between treatment and TP53.

RESULTS

A total of 1209 patients (median follow-up 5.5 years) were included. There were 573 deaths (47%) and 653 DFS events (54%). Mutations (434 [36%]) had no prognostic effect (OBS HROS = 0.99, 95% CI: 0.77-1.28, p = 0.95; HRDFS = 0.99, 95% CI: 0.78-1.25, p = 0.92) but were marginally predictive of benefit from ACT for OS (test for interaction: OS, p = 0.06; DFS, p = 0.11). Patients with WT TP53 had a tendency toward better outcomes with ACT than did those in the OBS group (HROS = 0.77, 95% CI: 0.62-0.95, p = 0.02; HRDFS = 0.75, 95% CI: 0.62-0.92, p = 0.005). In the ACT arm, a deleterious effect of mutant versus WT TP53 was observed (HROS = 1.40, 95% CI: 1.10-1.78, p = 0.006; HRDFS = 1.31, 95% CI: 1.04-1.64, p = 0.02).

CONCLUSIONS

TP53 mutation had no prognostic effect but was marginally predictive for survival from ACT. In patients who received ACT, TP53 mutation tended to be associated with shorter survival than wild-type TP53.

KRAS-Mutant Lung Cancers in the Era of Targeted Therapy

KRAS-mutant lung cancers account for approximately 25% of non-small cell lung carcinomas, thus representing an enormous burden of cancer worldwide. KRAS mutations are clear drivers of tumor growth and are characterized by a complex biology involving the interaction between mutant KRAS, various growth factor pathways, and tumor suppressor genes. While KRAS mutations are classically associated with a significant smoking history, they are also identified in a substantial proportion of never-smokers. These mutations are found largely in lung adenocarcinomas with solid growth patterns and tumor-infiltrating lymphocytes. A variety of tools are available for diagnosis including Sanger sequencing, multiplex mutational hotspot profiling, and next-generation sequencing. The prognostic and predictive roles of KRAS status remain controversial. It has become increasingly clear, however, that KRAS mutations drive primary resistance to EGFR tyrosine kinase inhibition. Until recently, mutant KRAS was not thought of as a clinically-targetable driver in lung cancers. With the expansion of our knowledge regarding the biology of KRAS-mutant lung cancers and the role of MEK and PI3K/mTOR inhibition, the face of targeted therapeutics for this genomic subset of patients is slowly beginning to change.

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.

KRAS Mutation as a Biomarker for Survival in Patients with Non-Small Cell Lung Cancer, A Meta-Analysis of 12 Randomized Trials

BACKGROUND

Because there is no clear consensus for the prognostic implication of KRAS mutations in patients with non-small cell lung cancer (NSCLC), we conducted a meta-analysis based on 12 randomized trials to draw a more accurate conclusion.

MATERIALS AND METHODS

A systematic computer search of articles from inception to May 1, 2014 using the PubMed, EMBASE, and Cochrane databases was conducted. The enrollment of articles and extraction of data were independently performed by two authors.

RESULTS

Our analysis was based on the endpoints overall survival (OS) and progression-free survival (PFS). Nine records (All for OS, 7 for PFS) comprising 12 randomized trials were identified with 3701 patients who underwent a test for KRAS mutations. In the analysis of the pooled hazard ratios (HRs) for OS (HR: 1.39; 95% confidence interval [CI] 1.23-1.56) and PFS (HR: 1.33; 95% CI 1.17-1.51), we found that KRAS mutations are related to poor survival benefit for NSCLC. According to a subgroup analysis stratified by disease stage and line of therapy, the combined HRs for OS and PFS coincided with the finding that the presence of a KRAS mutation is a dismal prognostic factor. However, the prognostic role of KRAS mutations are not statistically significant in a subgroup analysis of patients treated with chemotherapy in combination with cetuximab based on the endpoints OS (P=0.141) and PFS (P=0.643).

CONCLUSIONS

Our results indicate that KRAS mutations are associated with inferior survival benefits for NSCLC but not for those treated with chemotherapies integrating cetuximab.

High expression of cellular retinol binding protein-1 in lung adenocarcinoma is associated with poor prognosis

Purpose

Adenocarcinoma, the most common non-small cell lung cancer is a leading cause of death worldwide, with a low overall survival (OS) despite increasing attempts to achieve an early diagnosis and accomplish surgical and multimodality treatment strategies. Cellular retinol binding protein-1 (CRBP-1) regulates retinol bioavailability and cell differentiation, but its role in lung cancerogenesis remains uncertain.

Experimental design

CRBP-1 expression, clinical outcome and other prognostic factors were investigated in 167 lung adenocarcinoma patients. CRBP-1 expression was evaluated by immunohistochemistry of tissue microarray sections, gene copy number analysis and tumor methylation specific PCR. Effects of CRBP-1 expression on proliferation/apoptosis gene array, protein and transcripts were investigated in transfected A549 lung adenocarcinoma cells.

Results

CRBP-1^High expression was observed in 62.3% of adenocarcinomas and correlated with increased tumor grade and reduced OS as an independent prognostic factor. CRBP-1 gene copy gain also associated with tumor CRBP-1^High status and dedifferentiation. CRBP-1-transfected (CRBP-1⁺) A549 grew more than CRBP-1⁻ A549 cells. At >1μM concentrations, all trans-retinoic acid and retinol reduced viability more in CRBP-1⁺ than in CRBP-1⁻ A549 cells. CRBP-1⁺ A549 cells showed up-regulated RARα/ RXRα and proliferative and transcriptional genes including pAkt, pEGFR, pErk1/2, creb1 and c-jun, whereas RARβ and p53 were strongly down-regulated; pAkt/pErk/ pEGFR inhibitors counteracted proliferative advantage and increased RARα/RXRα, c-jun and CD44 expression in CRBP-1⁺ A549 cells.

Conclusion

CRBP-1^High expression in lung adenocarcinoma correlated with increased tumor grade and reduced OS, likely through increased Akt/Erk/EGFR-mediated cell proliferation and differentiation. CRBP-1^High expression can be considered an additional marker of poor prognosis in lung adenocarcinoma patients.

Adjuvant therapy following surgery in non-small cell lung cancer (NSCLC)

Non-small cell lung cancer (NSCLC) accounts for 80-90 % of cases of primary lung cancer. Although surgery is recommended as the primary treatment for early-stage NSCLC, the prognosis is unsatisfactory even when complete resection is achieved. Recent clinical trials have shown that postoperative adjuvant chemotherapy with cytotoxic agents, namely uracil-tegafur (UFT) for stage IA (>2 cm in diameter)-IB patients or cisplatin-based regimens for stage II-IIIA patients, improves the prognosis, and adjuvant chemotherapy is recommended as the "standard treatment of care." However, adjuvant chemotherapy provides only a modest 5-year survival benefit of 4 % and may sometimes be fatal. To improve the risk-benefit balance of adjuvant chemotherapy, targeting agents such as antibodies against vascular endothelial growth factor (VEGF) and tyrosine-kinase inhibitors of epidermal growth factor receptor (EGFR-TKIs) are being evaluated in ongoing adjuvant trials. Another promising approach may be the individualization of adjuvant chemotherapy based on biomarkers that may predict the prognosis or benefits associated with adjuvant chemotherapy. The current status and future perspectives of adjuvant chemotherapy for NSCLC are reviewed and discussed.

KRAS mutant lung cancer: progress thus far on an elusive therapeutic target

The KRAS mutation remains the most common driver mutation in patients with non-small cell lung cancer (NSCLC) and confers a poor prognosis. Thus far, efforts to target this mutation over the last two decades have been unsuccessful. Over the past 5 years, many efforts to develop drugs that target the RAS-RAF-MEK-ERK (MAPK) pathway have resulted in enhanced understanding of the KRAS mutant NSCLC and have provided optimism that this disease can be targeted.

Targeting the KRAS variant for treatment of non-small cell lung cancer: potential therapeutic applications

Lung cancer is the leading cause of cancer deaths worldwide, with non-small cell lung cancer (NSCLC) accounting for 80% of all lung cancers. Kirsten rat sarcoma viral oncogene homolog (KRAS) is one of the deadliest cancer-related proteins and plays a pivotal role in the most aggressive and lethal human cancers, including lung adenocarcinoma where it represents one of the most frequently mutated oncogene. Although therapeutic progresses have made an impact over the last decade, median survival for patients with advanced lung cancer remains disappointing, with a 5-year worldwide survival rate of <15%. For more than 20 years it has been recognized that constitutively active signaling downstream of KRAS is a fundamental driver of lung tumorigenesis. However, years of pursuit have failed to yield a drug that can safely curb KRAS activity; up to now no approved therapies exist for KRAS-mutant NSCLC. The aim of this review is to discuss the current knowledge of KRAS-mutated NSCLC, touching upon KRAS clinical relevance as a prognostic and predictive biomarker, with an emphasis on novel therapeutic approaches for the treatment of KRAS-variant NSCLC.

Impact of KRAS mutation on response and outcome of patients with stage III non-squamous non-small cell lung cancer

The frequency and clinical profile of patients with stage III non-small cell lung cancer harboring KRAS mutations have not yet been well documented. Here, we analyzed hotspot KRAS mutations using high-resolution melting analyses in tumor specimens from patients who received chemoradiotherapy between January 2001 and December 2010 at the National Cancer Center Hospital. The associations between the presence of KRAS mutations and the response rate, relapse-free survival, first relapse sites, survival post-progression and overall survival were investigated. A total of 274 non-squamous non-small cell lung cancer patients received chemoradiotherapy at our hospital. After excluding 121 patients for whom tumor specimens were not available and 34 patients with EGFR mutations, the remaining 119 patients were included in the analysis. KRAS mutations were found at a frequency of 13%. Patients with KRAS mutations had a shorter median relapse-free survival (6.1 vs 10.9 months) and a lower response rate (63% vs 81%). As for the first relapse site, patients with KRAS mutations had fewer local relapses (8% vs 23%) and more brain metastases (46% vs 12%). After disease progression, patients with KRAS mutations had a significantly shorter median survival post-progression (2.5 vs 7.3 months, P = 0.028) and median overall survival (15.1 vs 29.1 months, P = 0.022). Our results suggested that KRAS mutation could be associated with a reduced efficacy of chemoradiotherapy and a shortened survival time.

Prognostic and predictive biomarkers in early stage non-small cell lung cancer: tumor based approaches including gene signatures

In early stage non-small cell lung cancer (NSCLC) large randomized trials have demonstrated that in patients with radically resected disease adjuvant chemotherapy improves 5-year survival rates. However, a customization of systemic treatment is needed to avoid treatments in patients cured by surgery alone or to justify the use of adjuvant chemotherapy in high risk patients, including those in stage IA. Recently, the possibility of identifying prognostic and predictive factors related to the genetic signatures of the tumor that could affect adjuvant and neo-adjuvant treatment choices for resectable non-small cell lung cancer (NSCLC) has been of interest. This review summarizes the current status and future opportunities for clinical application of genotyping and genomic tests in early NSCLC.

Are we ready to use biomarkers for staging, prognosis and treatment selection in early-stage non-small-cell lung cancer?

Lung cancer accounts for the majority of cancer-related deaths worldwide. At present, platinum-based therapy represents the standard of care in fit stage II and IIIA non-small cell lung cancer (NSCLC) patients following surgical resection. In advanced disease, personalized chemotherapy and targeted biologic therapy based on histological and molecular tumor profiling have already shown promise in terms of optimizing treatment efficacy. While disease stage is associated with outcome and is commonly used to determine adjuvant treatment eligibility, it is known that a subset of patients with early stage disease experience shorter survival than others with the same clinicopathological characteristics. Improved methods for identifying these individuals, at or near the time of initial diagnosis, may inform the decision to pursue adjuvant therapy options. Among the numerous candidate molecular biomarkers, only few gene-expression profiling signatures provide clinically relevant information, while real-time quantitative polymerase-chain reaction (RT-qPCR) strategy involving relatively small numbers of genes offers a practical alternative with high cross-platform performance. mRNA and/or protein expression levels of excision repair cross-complementation group 1 (ERCC1), ribonucleotide reductase M subunit 1 (RRM1) and breast cancer susceptibility gene 1 (BRCA1) are among the most promising potential biomarkers for early disease and their clinical utility is currently being evaluated in randomized phase II and III clinical trials. This review describes the most promising clinicopathological and molecular biomarkers with predictive and prognostic significance in lung cancer that have been identified through advanced research and which could influence adjuvant and neoadjuvant chemotherapy decisions for operable NSCLC in routine clinical practice.

Integrating RAS status into prognostic signatures for adenocarcinomas of the lung

PURPOSE

While the dysregulation of specific pathways in cancer influences both treatment response and outcome, few current prognostic markers explicitly consider differential pathway activation. Here we explore this concept, focusing on K-Ras mutations in lung adenocarcinoma (present in 25%-35% of patients).

EXPERIMENTAL DESIGN

The effect of K-Ras mutation status on prognostic accuracy of existing signatures was evaluated in 404 patients. Genes associated with K-Ras mutation status were identified and used to create a RAS pathway activation classifier to provide a more accurate measure of RAS pathway status. Next, 8 million random signatures were evaluated to assess differences in prognosing patients with or without RAS activation. Finally, a prognostic signature was created to target patients with RAS pathway activation.

RESULTS

We first show that K-Ras status influences the accuracy of existing prognostic signatures, which are effective in K-Ras-wild-type patients but fail in patients with K-Ras mutations. Next, we show that it is fundamentally more difficult to predict the outcome of patients with RAS activation (RAS(mt)) than that of those without (RAS(wt)). More importantly, we demonstrate that different signatures are prognostic in RAS(wt) and RAS(mt). Finally, to exploit this discovery, we create separate prognostic signatures for RAS(wt) and RAS(mt) patients and show that combining them significantly improves predictions of patient outcome.

CONCLUSIONS

We present a nested model for integrated genomic and transcriptomic data. This model is general and is not limited to lung adenocarcinomas but can be expanded to other tumor types and oncogenes.

Selumetinib for the treatment of cancer

Introduction: The MAPK pathway is essential for regulation of cellular proliferation, differentiation and survival. Multiple human cancers have demonstrated activation of Raf-mitogen-activated kinase kinase (MEK)-extracellular signal-related kinase signaling, a hallmark of these tumors. Efforts to inhibit various protein kinases in this pathway have led to the development of MEK inhibitors. Selumetinib is one such drug, functioning as an oral, selective non-ATP-competitive MEK1/2 inhibitor. Areas covered: In this article, the authors discuss the underlying biology of MEK inhibition and its rationale in cancer treatment. Furthermore, the authors summarize the clinical development of selumetinib in various tumor types, from initial Phase I studies to randomized Phase II studies, both as monotherapy or in combination with other chemotherapeutics. Expert opinion: Given the frequency of activated MAPK signaling in multiple tumor types, the potent MEK inhibitor selumetinib had strong preclinical and early clinical rationale, particularly in those tumors harboring KRAS or BRAF mutations. While efficacy signals have been seen in various tumor types treated with selumetinib, better biomarkers are needed to select patients most likely to respond favorably to this agent. Furthermore, combinatorial therapy with selumetinib and other targeted agents can likely be optimized to maximize the antitumor effect of inhibiting RAS/MAPK signaling.

Outcomes by tumor histology and KRAS mutation status after lung stereotactic body radiation therapy for early-stage non-small-cell lung cancer

BACKGROUND

We analyzed outcomes after lung stereotactic body radiotherapy (SBRT) for early-stage non-small cell lung-carcinoma (NSCLC) by histology and KRAS genotype.

PATIENTS AND METHODS

We included 75 patients with 79 peripheral tumors treated with SBRT (18 Gy × 3 or 10 to 12 Gy × 5) at our institution from 2009 to 2012. Genotyping for KRAS mutations was performed in 10 patients. Outcomes were analyzed by the Kaplan-Meier method/Cox regression, or cumulative incidence method/Fine-Gray analysis.

RESULTS

The median patient age was 74 (range, 46 to 93) years, and Eastern Cooperative Oncology Group performance status was 0 to 1 in 63%. Tumor histology included adenocarcinoma (44%), squamous cell carcinoma (25%), and NSCLC (18%). Most tumors were T1a (54%). Seven patients had KRAS-mutant tumors (9%). With a median follow-up of 18.8 months among survivors, the 1-year estimate of overall survival was 88%, cancer-specific survival (CSS) 92%, primary tumor control 94%, and freedom from recurrence (FFR) 67%. In patients with KRAS-mutant tumors, there was a significantly lower tumor control (67% vs. 96%; P = .04), FFR (48% vs. 69%; P = .03), and CSS (75% vs. 93%; P = .05). On multivariable analysis, histology was not associated with outcomes, but KRAS mutation (hazard ratio, 10.3; 95% confidence interval, 2.3-45.6; P = .0022) was associated with decreased CSS after adjusting for age.

CONCLUSION

In this SBRT series, histology was not associated with outcomes, but KRAS mutation was associated with lower FFR on univariable analysis and decreased CSS on multivariable analysis. Because of the small sample size, these hypothesis-generating results need to be studied in larger data sets.

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.

KRAS mutations as prognostic and predictive markers in non-small cell lung cancer

A greater understanding of non-small-cell lung cancer at a molecular level has led to the identification of an increasing number of driver mutations. Extensive research of the KRAS gene as well as specific mutations has established its role in tumorigenesis. Nevertheless, the role of KRAS oncogene in non-small-cell lung cancer remains unclear. Recent studies indicated that mutant KRAS could be predictive of lack of response to chemotherapy, but large pooled analysis failed to confirm this result. The predictive value of KRAS mutation and EGFR-TKI treatment is more ambiguous with some recent evidence suggesting that it may be a negative predictive biomarker. This review provides an overview of RAS biology, assesses the utility of KRAS as a prognostic marker, and evaluates its role as a predictive marker for response to chemotherapy and EGFR-TKIs. In addition, we review some current studies that are targeting the KRAS pathway.

Molecular Targeted Drugs and Biomarkers in NSCLC, the Evolving Role of Individualized Therapy

Lung cancer first line treatment has been directed from the non-specific cytotoxic doublet chemotherapy to the molecular targeted. The major limitation of the targeted therapies still remains the small number of patients positive to gene mutations. Furthermore, the differentiation between second line and maintenance therapy has not been fully clarified and differs in the clinical practice between cancer centers. The authors present a segregation between maintenance treatment and second line and present a possible definition for the term “maintenance” treatment. In addition, cancer cell evolution induces mutations and therefore either targeted therapies or non-specific chemotherapy drugs in many patients become ineffective. In the present work pathways such as epidermal growth factor, anaplastic lymphoma kinase, met proto-oncogene and PI3K are extensively presented and correlated with current chemotherapy treatment. Future, perspectives for targeted treatment are presented based on the current publications and ongoing clinical trials.

KRAS mutations in non-small-cell lung cancer and colorectal cancer: implications for EGFR-targeted therapies

BACKGROUND

KRAS mutations are associated with diverse biologic functions as well as prognostic and predictive impact in non-small cell-lung cancer (NSCLC) and colorectal cancer (CRC). In CRC, benefit from monoclonal antibody therapies targeting EGFR is generally limited to patients whose tumors have wild-type (WT) KRAS, whereas data suggest that this association is not present for NSCLC. We hypothesized that the unique tobacco-related carcinogenesis of NSCLC results in a divergence of KRAS MT genotype compared with CRC, contributing to differences in outcomes from EGFR-targeted therapies.

MATERIAL AND METHODS

Tumor from 2603 patients (838 CRC and 1765 NSCLC) was analyzed for KRAS mutations. DNA was extracted from microdissected formalin-fixed-paraffin-embedded specimens (FFPE) and 7 different base substitutions in codons 12 and 13 of KRAS were determined.

RESULTS

KRAS mutation genotype differed significantly between NSCLC and CRC in frequency (25% vs. 39%; p<0.001), smoking-associated G>T transversions (73% versus 27%; p<0.001), and ratio of transversions to transitions (3.5 vs. 0.79; p<0.001). In NSCLC GLY12Cys mutations, resulting from a codon 12 GGT>TGT substitution, were observed in 44% compared to 10% for CRC. In contrast, codon 12 or 13 GLY>ASP substitutions (resulting in a G>A transition) were more frequent in CRC (42%) compared with NSCLC (21%).

CONCLUSION

In this large dataset, KRAS mutation patterns are quantitatively and qualitatively distinct between NSCLC and CRC, reflecting in part differences in tobacco-related carcinogenesis. In light of differences in predictive value for EGFR-directed monoclonal antibody therapy and prognosis for specific KRAS mutations between NSCLC and CRC, these data provide an underlying biologic rationale.

The influence of TP53 mutations on the prognosis of patients with early stage non-small cell lung cancer may depend on the intratumor heterogeneity of the mutations

A large number of studies have evaluated the impact of TP53 mutations on the prognosis of patients with non-small cell lung cancer (NSCLC); however, the results of these studies are still controversial. Recently, considerable intratumor heterogeneity for genetic alterations has been demonstrated in various human cancers, including lung cancer. In the present study, we evaluated TP53 mutations in NSCLCs by direct sequencing and observed remarkable variation in the values of relative intensity (RI, the height of the peak of mutated allele/the height of the peak of non-mutated allele) of the mutations. We also examined whether the RI values were associated with intratumor heterogeneity of TP53 mutations. In addition, we evaluated the relationship between TP53 mutations and survival outcome. The patients with a TP53 mutation did not have significantly worse survival compared to those without the mutation. However, when tumors with a TP53 mutation were categorized into two groups, those with a low and those with a high RI, the latter group had significantly worse survival compared to those with wild-type TP53 (adjusted hazard ratio = 2.58, 95% confidence interval = 1.21-5.48, P = 0.01), whereas the former group did not. These results suggest that intratumor genetic heterogeneity may be an important factor in determining the role of TP53 mutations on the prognosis of NSCLC patients.

Targeted therapy and new anticancer drugs in advanced disease

The development of targeted therapies in lung cancer (mainly non-small cell lung cancer) has led to improvement in clinical outcomes and a more personalized approach to the management of these patients. This article discusses the main categories of novel targeted agents and the evidence behind their use.

Markers of response to platinum-based chemotherapy in lung cancer

SUMMARY Non-small-cell lung cancer (NSCLC) is the most common cause of cancer-related deaths among men and women worldwide. Despite the development of molecular targeted therapies, platinum-based combination chemotherapy remains the most effective systemic chemotherapy for NSCLC patients. Unfortunately, the outcomes of platinum-based therapies, in particular those containing cisplatin, have reached a plateau due to the development of both intrinsic and acquired resistance. While significant variations in response to platinum-based chemotherapeutic regimens exist, defining molecular features that may determine resistance or response to chemotherapy is critical. This review will focus on some of the emerging biomarkers that are predictive of response to such treatments that may offer potential in the future management of NSCLC patients.

Prognostic and predictive value of KRAS mutations in advanced non-small cell lung cancer

Clinical implications of KRAS mutations in advanced non-small cell lung cancer remain unclear. We retrospectively evaluated the prognostic and predictive value of KRAS mutations in patients with advanced NSCLC. Among 484 patients with available results for both KRAS and EGFR mutations, 39 (8%) had KRAS and 182 (38%) EGFR mutations, with two cases having both mutations. The median overall survivals for patients with KRAS mutations, EGFR mutations, or both wild types were 7.7, 38.0, and 15.0 months, respectively (P<0.001). The KRAS mutation was an independent poor prognostic factor in the multivariate analysis (hazard ratio = 2.6, 95% CI: 1.8–3.7). Response rates and progression-free survival (PFS) for the pemetrexed-based regimen in the KRAS mutation group were 14% and 2.1 months, inferior to those (28% and 3.9 months) in the KRAS wild type group. KRAS mutation tended to be associated with inferior treatment outcomes after gemcitabine-based chemotherapy, while there was no difference regarding taxane-based regimen. Although the clinical outcomes to EGFR tyrosine kinase inhibitors (TKIs) seemed to be better in patients with KRAS wild type than those with KRAS mutations, there was no statistical difference in response rates and PFS according to KRAS mutation status when EGFR mutation status was considered. Two patients with both KRAS and EGFR mutations showed partial response to EGFR TKIs. Although G12D mutation appeared more frequently in never smokers, there was no difference in clinical outcomes according to KRAS genotypes. These results suggested KRAS mutations have an independent prognostic value but a limited predictive role for EGFR TKIs or cytotoxic chemotherapy in advanced NSCLC.

Developments in the treatment of early NSCLC: when to use chemotherapy

approximately 30% of lung carcinomas are resected and these cases are candidates for adjuvant treatments. The PORT meta-analysis reported in 1999 that postoperative radiotherapy had a detrimental effect for pathological N0 and N1 patients, and a debatable effect for N2 patients. Following the results of the 1995 meta-analysis on the role of chemotherapy (CT) in non-small-cell lung cancer (NSCLC), many randomized, controlled trials were launched to evaluate the effect of adjuvant cisplatin-based CT after the complete resection of NSCLC. The Lung adjuvant Ciplatin Evaluation pooled analysis included a total of 4584 patients recruited in five recent cisplatin-based adjuvant trials. It confirmed that adjuvant CT was associated with an absolute 5-year survival benefit of 5.3% (P = 0.0043). In addition, it showed that adjuvant cisplatin-based CT is detrimental in cases of stage Ia resected NSCLC; it also suggested that the combination of vinorelbine and cisplatin was of more benefit than older two and three drug combinations. The individual data-based meta-analysis was also updated with a total of over 10 000 patients. It confirmed the substantial effect of postoperative CT, with or without postoperative radiotherapy, with a substantial overall benefit of 4% at 5 years. Recent results of biological programs suggest that evaluating the expression of various tumor markers, including excision repair cross-complementation group 1, may allow the identification of patients most likely to benefit from CT. If these results are confirmed, tailored therapy might be the next step forward for resected NSCLC.

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.

Wnt pathway activation predicts increased risk of tumor recurrence in patients with stage I nonsmall cell lung cancer

OBJECTIVE

To determine the incidence of Wnt pathway activation in patients with stage I NSCLC and its influence on lung cancer recurrence.

BACKGROUND

Despite resection, the 5-year recurrence with localized stage I nonsmall cell lung cancer (NSCLC) is 18.4%-24%. Aberrant Wnt signaling activation plays an important role in a wide variety of tumor types. However, there is not much known about the role the Wnt pathway plays in patients with stage I lung cancer.

METHODS

Tumor and normal lung tissues from 55 patients following resection for stage I NSCLC were subjected to glutathione S-transferase (GST) E-cadherin pulldown and immunoblot analysis to assess levels of uncomplexed β-catenin, a reliable measure of Wnt signaling activation. The β-catenin gene was also screened for oncogenic mutations in tumors with activated Wnt signaling. Cancer recurrence rates were correlated in a blinded manner in patients with Wnt pathway-positive and -negative tumors.

RESULTS

Tumors in 20 patients (36.4%) scored as Wnt positive, with only 1 exhibiting a β-catenin oncogenic mutation. Patients with Wnt-positive tumors experienced a significantly higher rate of overall cancer recurrence than those with Wnt-negative tumors (30.0% vs. 5.7%, P = 0.02), with 25.0% exhibiting distal tumor recurrence compared with 2.9% in the Wnt-negative group (P = 0.02).

CONCLUSIONS

Wnt pathway activation occurred in a substantial fraction of Stage I NSCLCs, which was rarely due to mutations. Moreover, Wnt pathway activation was associated with a significantly higher rate of tumor recurrence. These findings suggest that Wnt pathway activation reflects a more aggressive tumor phenotype and identifies patients who may benefit from more aggressive therapy in addition to resection.

New and potential clinical applications of KRAS as a cancer biomarker

IMPORTANCE OF THE FIELD

KRAS mutation is the most common oncogenic alteration in various human cancers. Recently, KRAS has emerged as an important predictive biomarker in common malignancies such as metastatic colorectal cancer (mCRC) and non-small cell lung cancer (NSCLC). This work aims to discuss the clinical impact of the KRAS mutation status on state-of-the-art treatment approaches, including epidermal growth factor receptor (EGFR)-targeted therapies.

AREAS COVERED IN THIS REVIEW

This review considers the potential of KRAS to serve as a diagnostic, prognostic or predictive biomarker in various cancers, including those of the lung, colon/rectum, pancreas, ovary and endometrium.

WHAT THE READER WILL GAIN

KRAS mutations in mCRC and NSCLC primary tumors predict resistance to EGFR-targeted therapy. In pancreatic cancer, KRAS may prove useful as a diagnostic biomarker to screen for early neoplasia. Furthermore, quantitative KRAS mutation analysis could have the potential to distinguish pancreatic cancer from other conditions such as chronic pancreatitis. With respect to ovarian and endometrial cancer, further studies should focus on determining reliable biomarkers for predicting response to EGFR-targeted therapy. Besides EGFR inhibition, KRAS may also serve as a diagnostic and predictive biomarker for evolving therapies directed against mutant RAS proteins.

TAKE HOME MESSAGE

KRAS has been recognized as an outstanding predictive biomarker to select mCRC and NSCLC patients for EGFR-targeted therapies; however, multi-determinant approaches including other molecular markers should facilitate the identification of patients likely to respond to such therapies.

KRAS mutation: should we test for it, and does it matter?

Lung cancer is the leading cause of cancer mortality in the United States and worldwide. Previously, lung cancer was simplistically divided into non-small-cell lung cancer (NSCLC) and small-cell lung cancer. However, in the last decade, we have gone from a simplistic binary system of classifying lung cancer to defining NSCLC on the basis of molecular subsets. KRAS mutations represent the most common molecular change in NSCLC. The presence of KRAS mutation has been shown to be associated with a poor prognosis in NSCLC, but this is of little clinical utility. More important is determining the clinical utility of KRAS mutational analysis for predicting benefit of chemotherapy, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), anti-EGFR monoclonal antibodies, or other novel therapeutics. Current data does not support the routine use of KRAS mutational analysis for predicting chemotherapy benefit. Additionally, there was significant interest in using KRAS status to select patients for EGFR TKI and anti-EGFR monoclonal antibodies. However, the EGFR mutational status has demonstrated significant predictive value in the selection of patients for EGFR TKI therapy and is now the preferred test. An association between KRAS mutational status and benefit of anti-EGFR monoclonal antibodies has not been demonstrated in NSCLC. Here we review, in the context of NSCLC, the underlying biology of KRAS mutations, the predictive value of KRAS mutations for therapeutic intervention, and the integration of KRAS mutational testing into our current clinical paradigms.

Personalized medicine and treatment approaches in non-small-cell lung carcinoma

Chemotherapy has been the traditional backbone for the management of metastatic lung cancer. Multiple trials have shown the benefits of treatment with platinum doublets in lung cancer. This "one treatment fits all" approach was further refined by the introduction of targeted agents and discovery of subpopulations of patients who benefited from treatment with these agents. It has also become evident that certain histologic subtypes of non-small-cell lung cancer respond better to one cytotoxic chemotherapy versus others. This has led to the concept of using histology to guide therapy. With the introduction of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors and the discovery of activating mutations in the EGFR gene, further personalization of treatment for subgroups of patients has become a reality. More recently, the presence of a fusion gene, echinoderm microtubule-associated protein-like 4 - anaplastic lymphoma kinase (EML4-ALK), was identified as the driver mutation in yet another subgroup of patients, and subsequent studies have led to approval of crizotinib in this group of patients. In this article, efforts in personalizing delivery of care based on the histological subtypes of lung cancer and the role of K-RAS and EGFR mutations, EML4/ALK translocation, and ERCC1 (excision repair cross-complementing 1) and EGFR expression in choosing appropriate treatments for patients with advanced lung cancer are discussed. This article also reviews the problem of resistance to EGFR tyrosine kinase inhibitors and the ongoing trials that target novel pathways and mechanisms that are implicated in resistance.

A pooled exploratory analysis of the effect of tumor size and KRAS mutations on survival benefit from adjuvant platinum-based chemotherapy in node-negative non-small cell lung cancer

INTRODUCTION

The staging of node-negative non-small-cell lung cancer is modified in the 7th edition TNM classification. Here, we pool data from the National Cancer Institute of Canada Clinical Trials Group JBR.10 trial and the Cancer and Leukemia Group B-9633 trial to explore the prognostic and predictive effects of the new T-size descriptors and KRAS mutation status.

METHODS

Node-negative patients were reclassified as T2a (>3-≤5 cm), T2b (>5-≤7 cm), T3 (>7 cm) or T ≤ 3 cm (≤3 cm, but other T2 characteristics).

RESULTS

Of 538 eligible patients, 288 (53.5%) were T2a, 111 (21%) T2b, 62 (11.5%) T3, whereas 77 (14%) T≤3 cm were excluded to avoid confounding. KRAS mutations were detected in 104 of 390 patients (27%). T-size was prognostic for disease-free survival (p = 0.03), but borderline for overall survival (OS; p = 0.10), on multivariable analysis. Significant interaction between the prognostic value of KRAS and tumor size was observed for OS (p = 0.01), but not disease-free survival (p = 0.10). There was a nonsignificant trend (p = 0.24) for increased chemotherapy effect on OS with advancing T-size (hazard ratio [HR] T2a 0.90, [0.63-1.30]; T2b 0.69, [0.38-1.24]; and T3 0.57, [0.28-1.17]). The HR for chemotherapy effect on OS in T2a patients with KRAS wild-type tumors was 0.81 (p = 0.36), whereas a trend for detrimental effect was observed in those with mutant tumors (HR 2.11; p = 0.09; interaction p = 0.05). Similar trends were observed in T2b to T3 patients with wild-type (HR 0.86; p = 0.62), and KRAS mutant tumors (HR 1.16; p = 0.74; interaction p = 0.58).

CONCLUSION

Chemotherapy effect seems to increase with tumor size. However, this small study could not identify subgroups of patients who did or did not derive significant benefit from adjuvant chemotherapy based on T-size or KRAS status.

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.