Frequency and clinicopathologic correlates of KRAS amplification in non-small cell lung carcinoma.
ABSTRACT Characterization of the non-small cell lung cancer (NSCLC) genome has suggested that KRAS amplification is one of the commonest molecular abnormalities in NSCLC. However, the prevalence and clinicopathologic significance of KRAS amplification, and its relationship with KRAS activating mutations have not been well-defined. The purpose of this study was to establish the prevalence of KRAS amplification in two separate, large NSCLC cohorts, to define the clinicopathologic features of KRAS-amplified NSCLC in a single uniformly treated cohort, and to investigate the interplay between KRAS amplification and KRAS mutation.
Fluorescence in situ hybridization was utilized to detect KRAS amplification on tissue microarrays constructed from a Swiss cohort of 538 NSCLCs and a series of 402 patients with NSCLC treated in a single institution in New York. DNA sequencing to detect KRAS codon 12 activating mutations was performed on a subset of tumors. Amplification and mutation status were compared with patient baseline characteristics, tumor characteristics, and overall- and disease-free survival.
The prevalence of KRAS amplification was 13.7% in the Swiss cohort and 15.1% in the New York cohort. Among adenocarcinomas, KRAS amplification was associated with larger (mean size 2.8±1.8 cm vs. 2.1±1.3 cm, p=0.003), less well-differentiated tumors (18% vs. 42%, p=0.004) that were more likely to be invasive (95% vs. 77%, p=0.004) and to exhibit angiolymphatic invasion (24% vs. 12%, p=0.04). These differences were statistically significant within the subset of adenocarcinomas harboring activating KRAS mutations, suggesting a synergistic relationship between amplification and mutation. No significant association between KRAS amplification and nodal metastasis or survival was seen.
KRAS amplification is a common molecular alteration in NSCLC, characterizing ∼15% of tumors. This alteration is associated with indicators of local aggressiveness, and may act synergistically with KRAS mutations to promote tumor progression.
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ABSTRACT: KRAS mutations are the most common oncogenic event in colorectal (CRC) cancer progression and their occurrence is associated with lack of response to anti EGFR targeted therapies. Using preclinical models and patients' samples we recently reported that the emergence of KRAS mutations but also KRAS amplification is associated with acquired resistance to the EGFR inhibitors cetuximab or panitumumab. We reasoned that KRAS amplification may also be responsible for primary resistance to these agents. Furthermore, while the prevalence of KRAS mutations has been well established in CRC, little is known about the frequency of KRAS amplification in large CRC series. We performed a screening of 1039 CRC samples to assess the prevalence of KRAS amplification in this tumour type and further evaluated the role of this genetic alteration on the sensitivity to anti EGFR therapies. We detected KRAS amplification in 7/1039 (0.67%) and 1/102 evaluable CRC specimens and cell lines, respectively. KRAS amplification was mutually exclusive with KRAS mutations. Tumours or cell lines harbouring this genetic lesion are not responsive to anti-EGFR inhibitors. Although KRAS amplification is an infrequent event in CRC, it might be responsible for precluding response to anti-EGFR treatment in a small proportion of patients. © 2013 Wiley Periodicals, Inc.International Journal of Cancer 09/2013; 133(5):1259-65.. · 6.20 Impact Factor
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ABSTRACT: Anaplastic lymphoma kinase (ALK) rearrangement is a validated predictive marker to define patients with non-small cell lung cancer (NSCLC) who can benefit from selective ALK inhibitors. Therefore, accurate assessment of its prevalence and clinical characteristics is increasingly important in the treatment of NSCLC. Also, this ALK rearrangement was previously reported to be more common in patients with no smoking history or those with adenocarcinoma. Never-smokers with completely resected pulmonary adenocarcinoma were screened for ALK rearrangements using Nanostring's gene expression platform. Clinicopathologic data, such as information about epidermal growth factor receptor (EGFR) and KRAS mutation status were retrospectively reviewed. Of 231 tumors screened, 20 (9%) had an ALK rearrangement and all were confirmed to be positive with immunohistochemical and fluorescent in situ hybridization analysis. Of the tumors with available data on the EGFR/KRAS mutation status, EGFR and KRAS mutation rates were 64% (69/108) and 5% (5/102), respectively. Amongst the tumors that were free of EGFR and KRAS mutations, the proportion of ALK rearrangements reached up to 33%. At the time of data cut-off, total of 68 tumors were recurred. Although the recurrence rate was similar between the ALK-positive and negative groups (30% vs. 29%), there was a tendency for ALK-positive tumors to recur more frequently in the pleural space (15% vs. 5%). The five-year disease-free survival (61%) and overall survival rates (79%) in the ALK-positive group were similar to those in the ALK-negative group (51% and 83%, respectively). Even after excluding two patients treated with crizotinib after disease recurrence, overall survival was similar between the two groups. In an NSCLC subpopulation based on smoking history, histology, and EGFR and KRAS mutation status, the prevalence of ALK rearrangements is considerably high. However, ALK rearrangement status itself has no prognostic relevance in patients with completely resected NSCLC.Lung cancer (Amsterdam, Netherlands) 11/2013; · 3.14 Impact Factor
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ABSTRACT: Lymphovascular invasion (LVI) is considered a high-risk pathologic feature in resected non-small cell carcinoma (NSCLC). The ability to stratify stage I patients into risk groups may permit refinement of adjuvant treatment recommendations. We performed a systematic review and meta-analysis to evaluate whether the presence of LVI is associated with disease outcome in stage I NSCLC patients. A systematic search of the literature was performed (1990 to December 2012 in MEDLINE/EMBASE). Two reviewers independently assessed the quality of the articles and extracted data. Pooled hazard ratios (HRs) and 95% confidence intervals (CI) were estimated with a random effects model. Two end points were independently analyzed: recurrence-free survival (RFS) and overall survival (OS). We analyzed unadjusted and adjusted effect estimates, resulting in four separate meta-analyses. We identified 20 published studies that reported the comparative survival of stage I patients with and without LVI. The unadjusted pooled effect of LVI was significantly associated with worse RFS (HR, 3.63; 95% CI, 1.62 to 8.14) and OS (HR, 2.38; 95% CI, 1.72 to 3.30). Adjusting for potential confounders yielded similar results, with RFS (HR, 2.52; 95% CI, 1.73 to 3.65) and OS (HR, 1.81; 95% CI, 1.53 to 2.14) both significantly worse for patients exhibiting LVI. The present study indicates that LVI is a strong prognostic indicator for poor outcome for patients with surgically managed stage I lung cancer. Future prospective lung cancer trials with well-defined methods for evaluating LVI are necessary to validate these results.The Annals of thoracic surgery 01/2014; · 3.45 Impact Factor