Meta-analysis of epidermal growth factor receptor and KRAS gene status between primary and corresponding metastatic tumours of non-small cell lung cancer

Genetic Concordance in Primary Cutaneous Melanoma and Matched Metastasis: A Systematic Review and Meta-Analysis

Studying primary melanoma and its corresponding metastasis has twofold benefits. Firstly, to better understand tumor biology, and secondly, to determine which sample should be examined in assessing drug targets. This study systematically analyzed all the literature on primary melanoma and its matched metastasis. Following PRISMA guidelines, we searched multiple medical databases for relevant publications from January 2000 to December 2022, assessed the quality of the primary-level studies using the QUIPS tool, and summarized the concordance rate of the most reported genes using the random-effects model. Finally, we evaluated the inter-study heterogeneity using the subgroup analysis. Thirty-one studies investigated the concordance of BRAF and NRAS in 1220 and 629 patients, respectively. The pooled concordance rate was 89.4% [95% CI: 84.5; 93.5] for BRAF and 97.8% [95% CI: 95.8; 99.4] for NRAS. When high-quality studies were considered, only BRAF mutation status consistency increased. Five studies reported the concordance status of c-KIT (93%, 44 patients) and TERT promoter (64%, 53 patients). Lastly, three studies analyzed the concordance of cancer genes involved in the signaling pathways, apoptosis, and proliferation, such as CDKN2A (25%, four patients), TP53 (44%, nine patients), and PIK3CA (20%, five patients). Our study found that the concordance of known drug targets (mainly BRAF) during melanoma progression is higher than in previous meta-analyses, likely due to advances in molecular techniques. Furthermore, significant heterogeneity exists in the genes involved in the melanoma genetic makeup; although our results are based on small patient samples, more research is necessary for validation.

Temporal genomic heterogeneity guiding individualized therapy in recurrent non-small cell lung cancer

Introduction

Despite the benefit of adjuvant systemic therapy for patients with resected non-small cell lung cancer (NSCLC), the risk of postoperative recurrence remains high. Our objective was to characterize temporal genetic heterogeneity between primary resected and recurrent tumors, and its impact on treatment outcomes.

Methods

In this study, next-generation sequencing (NGS) testing was performed on tissue specimens and circulating tumor DNA (ctDNA) collected at postoperative recurrence, and results were compared to the genotypes of initial surgical specimens.

Results

Of forty-five patients with matched primary and post-operative recurrent tumors, EGFR status switched in 17 patients (37.8%) at post-operative recurrence and 28 patients (62.2%) had no genotype change (17 mutant, 11 wild-type). Based on the changes of EGFR status, patients were divided into 4 groups. Following subsequent treatment with EGFR TKI o chemotherapy: In group A, with sustained sensitive mutation, the percentage achieving partial response (PR) was the highest, at 72.2%, the median progression-free survival (PFS) was 17 months, and the median overall survival (OS) was 44.0 months respectively; In group B, with genotype changed from wild-type to mutant, 50% achieved PR, PFS was 10 months, and OS was 35 months; In group C, in which mutant status shifted to wild-type or new co-mutation emerged, the percentage achieving PR was 30%, PFS was 9 months, and OS was 35 months. In group D, with sustained wild type, the percentage achieving PR was 27.3%, PFS was 8 months, and OS was 22 months.

Discussion

Genotypic shift between paired primary and post-operative recurrent tumors was not infrequent, and this temporal genomic heterogeneity substantially impacted subsequent treatment outcomes.

Clinical reliability of genomic data obtained from spinal metastatic tumor samples

BACKGROUND

The role of tumor genomic profiling is rapidly growing as it results in targeted, personalized, cancer therapy. Though routinely used in clinical practice, there are no data exploring the reliability of genomic data obtained from spine metastases samples often leading to multiple biopsies in clinical practice. This study compares the genomic tumor landscape between spinal metastases and the corresponding primary tumors as well as between spinal metastases and visceral metastases.

METHODS

Spine tumor samples, obtained for routine clinical care from 2013 to 2019, were analyzed using MSK-IMPACT, a next-generation sequencing assay. These samples were matched to primary or metastatic tumors from the corresponding patients. A concordance rate for genomic alterations was calculated for matching sample pairs within patients for the primary and spinal metastatic tumor samples as well as for the matching sample pairs within patients for the spinal and visceral metastases. For a more robust and clinically relevant estimate of concordance, subgroup analyses of previously established driver mutations specific to the main primary tumor histologies were performed.

RESULTS

Eighty-four patients contributed next-generation sequencing data from a spinal metastasis and at least one other site of disease: 54 from the primary tumor, 39 had genomic tumor data from another, nonspinal metastasis, 12 patients participated in both subsets. For the cohort of matched primary tumors and spinal metastases (n = 54) comprised of mixed histologies, we found an average concordance rate of 96.97% for all genetic events, 97.17% for mutations, 100% for fusions, 89.81% for deletions, and 97.01% for amplifications across all matched samples. Notably, >25% of patients harbored at least one genetic variant between samples tested, though not specifically for known driver mutations. The average concordance rate of driver mutations was 96.99% for prostate cancer, 95.69% (P = .0004513) for lung cancer, and 96.43% for breast cancer. An average concordance of 99.02% was calculated for all genetic events between spine metastases and non-spinal metastases (n = 41) and, more specifically, a concordance rate of 98.91% was calculated between spine metastases and liver metastases (n = 12) which was the largest represented group of nonspine metastases.

CONCLUSION

Sequencing data performed on spine tumor samples demonstrate a high concordance rate for genetic alterations between the primary tumor and spinal metastasis as well as between spinal metastases and other, visceral metastases, particularly for driver mutations. Spine tumor samples may be reliably used for genomic-based decision making in cancer care, particularly for prostate, NSCLC, and breast cancer.

On target: Rational approaches to KRAS inhibition for treatment of non-small cell lung carcinoma

Non-small cell lung carcinoma (NSCLC) is a leading cause of cancer death. Approximately one-third of patients with NSCLC have a KRAS mutation. KRAS^G12C, the most common mutation, is found in ~13% of patients. While KRAS was long considered 'undruggable', several novel direct KRAS^G12C inhibitors have shown encouraging signs of efficacy in phase I/II trials and one of these (sotorasib) has recently been approved by the US Food and Drug Administration. This review examines the role of KRAS mutations in NSCLC and the challenges in targeting KRAS. Based on specific KRAS biology, it reports exciting progress, exploring the use of novel direct KRAS inhibitors as monotherapy or in combination with other targeted therapies, chemotherapy, and immunotherapy.

Next-generation sequencing of tissue and circulating tumor DNA: Resistance mechanisms to EGFR targeted therapy in a cohort of patients with advanced non-small cell lung cancer

BACKGROUND

Epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) has been considered as an effective treatment in epidermal growth factor receptor-mutant (EGFR-mutant) advanced non-small cell lung cancer (NSCLC). However, most patients develop acquired resistance eventually. Here, we compared and analyzed the genetic alterations between tissue assay and circulating tumor DNA (ctDNA) and further explored the resistance mechanisms after EGFR-TKI treatment.

METHODS AND MATERIALS

Amplification refractory mutation system-polymerase chain reaction (ARMS-PCR), Cobas^® ARMS-PCR and next-generation sequencing (NGS) were performed on tissue samples after pathological diagnosis. Digital droplet PCR (ddPCR) and NGS were performed on plasma samples. The association between genetic alterations and clinical outcomes was analyzed retrospectively.

RESULTS

Thirty-seven patients were included. The success rate of re-biopsy was 91.89% (34/37). The total detection rate of EGFR T790M was 62.16% (23/37) and the consistency between tissue and ctDNA was 78.26% (18/23). Thirty-four patients were analyzed retrospectively. For tissue re-biopsy, 24 patients harbored concomitant mutations. Moreover, tissue re-biopsy at resistance showed 21 patients (21/34, 61.76%) had the concomitant somatic mutation. The three most frequent concomitant mutations were TP53 (18/34, 52.94%), MET (4/34, 11.76%), and PIK3CA (4/34, 11.76%). Meanwhile, 21 patients (21/34, 61.76%) with EGFR T790M mutation. Progression-free survival (PFS) and overall survival (OS) were better in patients with T790M mutation (p = 0.010 and p = 0.017) or third-generation EGFR-TKI treatment (p < 0.0001 and p = 0.073). Interestingly, concomitant genetic alterations were significantly associated with a worse prognosis for patients with EGFR T790M mutation receiving third-generation EGFR-TKIs (p = 0.037).

CONCLUSIONS

Multi-platforms are feasible and highly consistent for re-biopsy after EGFR-TKI resistance. Concomitant genetic alterations may be associated with a poor prognosis for patients with EGFR T790M mutation after third-generation EGFR-TKIs.

Clinical Validation of Discordant Trunk Driver Mutations in Paired Primary and Metastatic Lung Cancer Specimens

OBJECTIVES

To propose an operating procedure for validation of discordant trunk driver mutations.

METHODS

Concordance of trunk drivers was examined by next-generation sequencing in 15 patients with two to three metastatic lung cancers and 32 paired primary and metastatic lung cancers.

RESULTS

Tissue identity was confirmed by genotyping 17 single-nucleotide polymorphisms within the panel. All except three pairs showed concordant trunk drivers. Quality assessment conducted in three primary and metastatic pairs with discordant trunk drivers indicates metastasis from a synchronous or remote lung primary in two patients. Review of literature revealed high discordant rates of EGFR and KRAS mutations, especially when Sanger sequencing was applied to examine primary and lymph node metastatic tumors.

CONCLUSIONS

Trunk driver mutations are highly concordant in primary and metastatic tumors. Discordance of trunk drivers, once confirmed, may suggest a second primary cancer. Guidelines are recommended to establish standard operating procedures for validation of discordant trunk drivers.

A Comparative Study of Genetic Profiles of Key Oncogenesis-Related Genes between Primary Lesions and Matched Lymph Nodes Metastasis in Lung Cancer

Background: The genetic heterogeneity between primary and metastatic lesions has rarely studied. Purpose: This study aims to compare the mutation profiling of key cancer-related genes in primary lung cancers and their matched lymph nodes (LN) metastasis. Methods: The gene mutation profiling of both primary cancers and their matched LN metastasis was constructed using a hybridization capture-based massively parallel sequencing assay and the sequencing of 1,408 key cancer genes in 37 NSCLC patients. Results: There are differences in the repertoire of somatic mutations and CNVs between primary lesions and metastatic lymphatic lesions in NSCLC. More mutations were discovered in the primary lesion than LN metastasis lesion, indicating that tumor mutation burden is higher in primary lesion than that in LN metastasis lesion. The copy number profiles were largely preserved through the progression of the metastasis in lung cancer individually. Regarding to the mutation context, more prevailing of signature 1 in LN metastasis lesion was observed than that of primary lesion, indicating that the spontaneous deamination of cytosine may contribute to the accumulation of mutations during tumor development and immigration. Furthermore, the LN metastasis exclusive somatic mutation (LME-SMs) genes were enriched in peptidyl-tyrosine phosphorylation, peptidyl-tyrosine modification, protein tyrosine kinase activity, and transmembrane receptor protein kinase. The KEGG pathway analysis revealed that these genes might participate in the PI3K-Akt signaling pathway, MAPK signaling pathway and Ras signaling pathway. Conclusion: Since the heterogeneity of genetic profiling exists between primary lesion and LN metastasis lesion, multi-region lesion mutation profiling is required to fully understand the progression of NSCLC, and develop an appropriate therapeutic guide. Mutations in genes involved in cell proliferation, invasion and migration may be the genetic mechanism of metastasis.

Molecular heterogeneity in lung cancer: from mechanisms of origin to clinical implications

Molecular heterogeneity is a frequent event in cancer responsible of several critical issues in diagnosis and treatment of oncologic patients. Lung tumours are characterized by high degree of molecular heterogeneity associated to different mechanisms of origin including genetic, epigenetic and non-genetic source. In this review, we provide an overview of recognized mechanisms underlying molecular heterogeneity in lung cancer, including epigenetic mechanisms, mutant allele specific imbalance, genomic instability, chromosomal aberrations, tumor mutational burden, somatic mutations. We focus on the role of spatial and temporal molecular heterogeneity involved in therapeutic implications in lung cancer patients.

Risk factors for brain metastases in patients with non-small-cell lung cancer

Brain metastases (BM) are severe incidents in patients with non-small-cell lung cancer (NSCLC). The controversial value of prophylactic cranial irradiation (PCI) in NSCLC in terms of survival benefit prompted us to explore the possible risk factors for BM in NSCLC and identify the potential population most likely to benefit from PCI. Risk factors for brain metastases in NSCLC are reviewed in this article. Identifying patients with a higher risk of BM could possibly increase the benefit of PCI while reducing the discomfort and risks caused by unnecessary invasive procedures in the NSCLC patient population. Future studies might focus on finding a solid basis for the prediction of the occurrence of brain metastases and for the therapeutic decision on the use of PCI.

Development and validation of a model to predict tyrosine kinase inhibitor-sensitive EGFR mutations of non-small cell lung cancer based on multi-institutional data

BACKGROUND

Non-small cell lung cancer (NSCLC) with different EGFR mutation types shows distinct sensitivity to tyrosine kinase inhibitors (TKIs). This study developed a patho-clinical profile-based prediction model of TKI-sensitive EGFR mutations.

METHODS

The records of 1121 Chinese patients diagnosed with NSCLC from November 2008 to October 2014 (the development set) were reviewed. Multivariate logistic regression was conducted to identify any association between potential predictors and the classic sensitive EGFR mutations (exon 19 deletion and exon 21 L858R point mutation). A prediction index was created by assigning weighted scores to each factor proportional to a regression coefficient. Validation was made in an independent cohort consisting of 864 patients who were consecutively enrolled between November 2014 and January 2017 (the validation set).

RESULTS

Seven independent predictors were identified: gender (female vs. male), adenocarcinoma (yes vs. no), smoking history (no vs. yes), N stage (N+ vs. N0), M stage (M1 vs. M0), brain metastasis (yes vs. no), and elevated Cyfra 21-1 (no vs. yes). Each was assigned a number of points. In the validation set, the area under curve of the prediction index appeared as 0.698 (95% confidence interval 0.663-0.733). The sensitivity, specificity, positive and negative predictive values, and concordance were 95.0%, 32.3%, 61.4%, 85.1%, and 65.6%, respectively.

CONCLUSION

We developed a patho-clinical profile-based model for predicting TKI-sensitive EGFR mutations. Our model may represent a noninvasive, economical choice for clinicians to inform TKI therapy.

Comparison of genetic profiles among primary lung tumor, metastatic lymph nodes and circulating tumor DNA in treatment-naïve advanced non-squamous non-small cell lung cancer patients

OBJECTIVES

Genetic profiles of primary and metastatic lung tumor have been investigated by previous studies. However, whether they can be replaced by each other to guide treatment remains controversial. Moreover, it is unclear that whether genetic profiles of plasma can reflect genetic divergence between primary and metastatic lesions.

MATERIALS AND METHODS

In this prospective study, we collected 35 pairs of matched primary tumor tissue, metastatic lymph nodes and plasma from treatment-naïve patients with advanced non-squamous non-small cell lung cancer (NSCLC) and applied to capture-based sequencing using a panel consisting 56 NSCLC-related genes to interrogate the heterogeneity and similarity among the 3 sites.

RESULTS

We observed 62.0% (67/108) by-variant concordance rate among primary tumor, metastatic lymph nodes and plasma as well as 76.4% (81/106) by-variant concordance rate between primary tumor and metastatic lymph nodes. When the analysis restricted to driver genes, we achieved 60.9% (28/46) and 77.3% (34/44) concordance, respectively. Furthermore, there is no statistically significant difference in progression-free survival (PFS) of 17 patients who used matched targeted therapy between patients having 100% concordance rate between primary tumor and metastatic lymph nodes and patients having partially matched mutational profiles.

CONCLUSION

Collectively, our study revealed a similar genetic profile shared between primary tumor and metastatic lymph nodes. The limited discordance observed can be partially reflected by plasma. Sequencing results obtained from either site can be utilized for providing treatment guidance.

Efficacy and safety of immune checkpoint inhibitors in non-small cell lung cancer

Immune checkpoint inhibitors (ICIs) are new therapeutic strategies for non-small cell lung cancer (NSCLC). We aimed to quantitatively evaluate the efficacy and safety of ICIs in NSCLC. Pubmed, Embase, Cochrane Library, and Web of Science were searched for randomized clinical trials comparing ICIs with control therapies in NSCLC. Data were pooled according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. A total of 12 trails comprising 6,919 NSCLC patients were included in this meta-analysis. ICIs therapies significantly improved progression-free survival (PFS) (HR, 0.838; P < 0.001), overall survival (OS) (HR, 0.747; P < 0.001) and objective response rates (ORR) (RR, 1.311; P < 0.001) in NSCLC. Prognostic benefit was observed irrespective of age, sex, treatment line, performance status and histology. Survival improvement of ICIs was limited for NSCLC patients with non-smoker (PFS, P = 0.468; OS, P = 0.317) or central nervous system (CNS) metastasis (PFS, P = 0.209; OS, P = 0.090), or positive EGFR mutation (PFS, P = 0.083; OS, P = 0.522) or PD-L1 expression level less than 5% (PFS, P = 0.370; OS, P = 0.047). The relative risks of all-grade and high-grade (≥3) anemia, neutropenia, leukopenia, thrombocytopenia, stomatitis, nausea, pyrexia, asthenia and neuropathy were all decreased in patients received ICIs compared with control therapies. This meta-analysis provides clinical evidence that ICIs improve PFS, OS, and ORR in NSCLC with fewer adverse effects. Our data establish ICIs as a prefer treatment option for NSCLC patients with smoker, no CNS metastasis, wild type EGFR, and high PD-L1 expression.

EGFR copy number alterations in primary tumors, metastatic lymph nodes, and recurrent and multiple primary tumors in oral cavity squamous cell carcinoma

Background

The EGFR and downstream signaling pathways play an important role in tumorigenesis in oral squamous cell carcinoma (OSCC). Gene copy number alteration is one mechanism for overexpressing the EGFR protein and was also demonstrated to be related to lymph node metastasis, tumor invasiveness and perineural invasion. Therefore, we hypothesized that EGFR gene copy number alteration in the primary tumor could predict amplification in recurrent tumors, lymph node metastatic foci or secondary primary tumors.

Methods

We recruited a group of newly diagnosed OSCC patients (n = 170) between Mar 1997 and Jul 2004. Metastatic lymph nodes were identified from neck dissection specimens (n = 57). During follow-up, recurrent lesions (n = 41) and secondary primary tumors (SPTs, n = 17) were identified and biopsied. The EGFR gene amplifications were evaluated by fluorescence in situ hybridization (FISH) assay in primary tumors, metastatic lymph nodes, recurrences and SPTs.

Results

Of the 170 primary OSCCs, FISH showed low EGFR amplification/polysomy in 19 (11.4%) patients and amplification in 33 (19.8%) patients. EGFR gene amplification was related to lymph node metastasis (χ2 trend test: p = 0.018). Of 57 metastatic lymph nodes, nine (15.8%) had EGFR polysomy and 14 (24.6%) had EGFR gene amplification. The concordance rate of EGFR gene copy number in primary tumors and lymph node metastasis was 68.4% (McNemar test: p = 0.389). Of 41 recurrent tumors, five (12.2%) had EGFR polysomy and five (12.2%) had gene amplification. The concordance rate of EGFR gene copy number between primary tumors and recurring tumors was 65.9% (McNemar test: p = 0.510). The concordance rate between primary tumors and SPTs was 70.6%. EGFR amplification in either primary tumors, metastatic lymph nodes or recurrent tumors had no influence on patient survival.

Conclusion

We can predict two-thirds of the EGFR gene copy number alterations in lymph node metastasis or recurrent tumors from the analysis of primary tumors. For OSCC patients who are unable to provide lymph node or recurrent tumor samples for EGFR gene copy number analysis, examining primary tumors could provide EGFR clonal information in metastatic, recurrent or SPT lesions.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3586-9) contains supplementary material, which is available to authorized users.

Discrepancy in BRAF status among patients with metastatic malignant melanoma: A meta-analysis

The incidence of malignant melanoma is growing rapidly. Approximately half of the cases are BRAF mutated, making treatment with kinase inhibitors a (MEK and BRAF inhibitors) preferred choice in the advanced setting. The vast majority of these patients will benefit from the treatment. It is therefore of vital importance that the BRAF analysis is reliable and reflects the true nature of the tumour. Intraindividual tumour BRAF heterogeneity may exist, and changes of BRAF status over time might occur. We reviewed the literature by searching the PubMed database and 630 potentially relevant studies were identified. Thereafter, studies that investigated intralesional heterogeneity only, studies with ≤10 patients and studies that did not include adequate data to calculate discrepancy rates were excluded. Twenty-two studies met our inclusion criteria and were included in the meta-analysis. The pooled discrepancy rate between primary and metastatic lesions was 13.4% (95% confidence interval [CI]: 9.2-18.2%) while it was 7.3% (95% CI: 3.3-12.6) between two metastatic lesions. The number of patients whose tumoural BRAF status was changed from mutation to wild type and from wild type to mutation, respectively, was comparable. We conclude that a clinically meaningful discrepancy rate in BRAF status both between primary-metastatic and metastatic-metastatic melanoma lesions exists. Our results support the polyclonal model of melanomas in which subclones with different BRAF status co-exist in the same melanoma lesion. In addition, the results indicate a need for biopsy of a metastatic lesion for subsequent BRAF analysis when treatment with kinase inhibitors is considered.

CTLA-4 expression in the non-small cell lung cancer patient tumor microenvironment: diverging prognostic impact in primary tumors and lymph node metastases

The immune checkpoint receptor CTLA-4 plays a crucial part in negatively regulating T cell activation and maintaining self-tolerance. It is frequently overexpressed in a variety of malignancies, yet its prognostic impact in non-small cell lung cancer (NSCLC) remains unclear. We constructed tissue microarrays from tumor tissue samples and evaluated the immunohistochemical expression of CTLA-4 in 536 patients with primary resected stage I-IIIA NSCLC. Expression of CTLA-4 was analyzed in tumor and stromal primary tumor tissue and in locoregional metastatic lymph nodes. CTLA-4 expression in neither tumor epithelial cells (T-CTLA-4) nor stromal cells (S-CTLA-4) of primary tumors was significantly associated with disease-specific survival (DSS) in all patients. However, high S-CTLA-4 expression independently predicted significantly improved DSS in the squamous cell carcinoma subgroup (HR 0.62, 95% CI 0.41-0.93, P = 0.021). In contrast, there was an independent negative prognostic impact of T-CTLA-4 expression in metastatic lymph nodes (HR 1.65, 95% CI 1.03-2.65, P = 0.039). Our results indicate that the expression of CTLA-4 has diverging prognostic impacts in metastatic NSCLC lymph nodes versus primary tumors. The presented results highlight important differences in the tumor microenvironments of primary and metastatic NSCLC tissues, and have potential to guide treatment and clinical sampling strategies.

EGFR and KRAS Mutations Predict the Incidence and Outcome of Brain Metastases in Non-Small Cell Lung Cancer

Background: Lung cancer is the leading cause of brain metastases (BM). The identification of driver oncogenes and matched targeted therapies has improved outcome in non-small cell lung cancer (NSCLC) patients; however, a better understanding of BM molecular biology is needed to further drive the process in this field. Methods: In this observational study, stage IV NSCLC patients tested for EGFR and KRAS mutations were selected, and BM incidence, recurrence and patients’ outcome were assessed. Results: A total of 144 patients (142 Caucasian and two Asian) were selected, including 11.27% with EGFR-mutant and 33.10% with KRAS-mutant tumors, and 57.04% patients had developed BM. BM incidence was more frequent in patients with EGFR mutation according to multivariate analyses (MVA) (Odds ratio OR = 8.745 [1.743–43.881], p = 0.008). Among patients with treated BM, recurrence after local treatment was less frequent in patients with KRAS mutation (OR = 0.234 [0.078–0.699], p = 0.009). Among patients with untreated BM, overall survival (OS) was shorter for patients with KRAS mutation according to univariate analysis (OR = 7.130 [1.240–41.012], p = 0.028), but not MVA. Conclusions: EGFR and KRAS mutations have a predictive role on BM incidence, recurrence and outcome in Caucasian NSCLC patients. These results may impact the routine management of disease in these patients. Further studies are required to assess the influence of other biomarkers on NSCLC BM.

EGFR gene copy number as a predictive/biomarker for patients with non-small-cell lung cancer receiving tyrosine kinase inhibitor treatment: a systematic review and meta-analysis

Epidermal growth factor receptor (EGFR) gene copy number has been proposed as a candidate biomarker for predicting treatment response to EGFR tyrosine kinase inhibitors (EGFR-TKIs) in patients with advanced non-small-cell lung cancer (NSCLC). MEDLINE, PubMed, Cochrane, and Google Scholar databases were searched until October 21, 2015 using the following search terms: lung neoplasms/lung cancer/non-small cell lung cancer/NSCLC, EGFR, gene amplification, copy number, erlotinib, gefitinib, tyrosine-kinase inhibitor/TKI, predictor. 17 studies were included in the analysis with a total of 2047 patients. The overall analysis found that increased EGFR gene copy number was associated with higher overall response rate (ORR), overall survival (OS) and progression-free survival (PFS; p values ≤0.008) compared with patients without a high EGFR gene copy number. Subgroup analysis found that in a population of patients who were primarily Caucasian, a higher EGFR gene copy number was also associated with increased ORR, OS, and PFS (p values ≤0.018). The results were similar in a population of Asian patients, except that a higher EGFR gene copy number was not associated with improved OS (p=0.248). Sensitivity analysis indicated that no one study overly influenced the results and that the findings are robust. The result of the analysis found that EGFR gene copy number was associated with increased OS and PFS, supporting the idea that EGFR gene copy number is a biomarker for response to EGFR-TKI therapy in patients with advanced NSCLC.

Detecting Tumor Metastases: The Road to Therapy Starts Here

Metastasis is the complex process by which primary tumor cells migrate and establish secondary tumors in an adjacent or distant location in the body. Early detection of metastatic disease and effective therapeutic options for targeting these detected metastases remain impediments to effectively treating patients with advanced cancers. If metastatic lesions are identified early, patients might maximally benefit from effective early therapeutic interventions. Further, monitoring patients whose primary tumors are effectively treated for potential metastatic disease onset is also highly valuable. Finally, patients with metastatic disease can be monitored for efficacy of specific therapeutic interventions through effective metastatic detection techniques. Thus, being able to detect and visualize metastatic lesions is key and provides potential to greatly improve overall patient outcomes. In order to achieve these objectives, researchers have endeavored to mechanistically define the steps involved in the metastatic process as well as ways to effectively detect metastatic progression. We presently overview various preclinical and clinical in vitro and in vivo assays developed to more efficiently detect tumor metastases, which provides the foundation for developing more effective therapies for this invariably fatal component of the cancerous process.

Genetic heterogeneity of actionable genes between primary and metastatic tumor in lung adenocarcinoma

BACKGROUND

Biopsy for lung cancer diagnosis is usually done at a single site. But it is unclear that genetic information at one biopsy site represents that of other lesions and is sufficient for therapeutic decision making.

METHODS

Non-synonymous mutations and insertions/deletions of 16 genes containing actionable mutations, and intron 2 deletion polymorphism of Bcl2-like11 were analyzed in 41 primary tumor and metastatic lymph node (L/N) matched, pStage IIA ~ IIIA non-small cell lung cancer (NSCLC) samples using a next generation sequencing based technique.

RESULTS

A total of 249 mutations, including 213 non-synonymous mutations, 32 deletions, and four insertions were discovered. There was a higher chance of discovering non-synonymous mutations in the primary tumors than in the metastatic L/N (138 (64.8%) vs. 75 (35.2%)). In the primary tumors, 106 G > A:C > T transitions (76.8%) of 138 non-synonymous mutations were detected, whereas in the metastatic L/N, 44 (58.7%) of 75 were discovered. A total 24 (11.3%) out of 213 non-synonymous mutations were developed in the context of APOBEC signature. Of those, 21 (87.5%) was detected in the primary tumors and 4 (16.7%) was detected in the metastatic L/N. When the mutation profiles between primary tumor and metastatic L/N were compared, 13 (31.7%) of 41 cases showed discrepant mutation profile. There were no statistically significant differences in disease free survival and overall survival between groups showing identical mutation profiles and those with discrepancy between primary and metastatic L/N.

CONCLUSIONS

Genetic heterogeneity between the primary and L/N metastatic lesions is not infrequent finding to consider when interpreting genomic data based on the result of one site inspection. A large prospective study may be needed to evaluate the impact of genetic heterogeneity on the clinical outcomes of NSCLC patients.