EGFR fluorescence in situ hybridization-positive lung adenocarcinoma: incidence of coexisting KRAS and BRAF mutations

Site-specific Differences in Colonic Adenocarcinoma: KRAS Mutations and High Tumor Budding Are More Frequent in Cecal Adenocarcinoma

Recent literature indicates that adenocarcinomas of the cecum differ with respect to molecular alterations compared with noncecal proximal colon adenocarcinomas and that cecal tumor site may be a prognostically relevant variable. We compared molecular alterations, histopathologic features, and disease-specific survival in a series of 328 colonic adenocarcinomas identified over a 2-year period and stratified by tumor location (cecum, right colon, and left colon). Overall, cecal adenocarcinomas demonstrated the highest frequency of molecular abnormalities with 74% harboring either a KRAS exon 2 or 3 mutation, a BRAF mutation, or DNA mismatch repair protein deficiency. KRAS mutations were more frequently seen in the cecum compared with all other tumor sites (P=0.03). KRAS mutations were identified in 46% of cecal adenocarcinomas compared with only 25% of adenocarcinomas of the right colon (P=0.004). Cecal adenocarcinomas more frequently displayed adverse histopathologic features, in particular high tumor budding (31%), compared with tumors of the right colon (18%; P=0.04) and tumors of the left colon (17%; P=0.02). Overall stage was the most important independent predictor of disease-specific survival in the multivariable analysis; however, cecal tumor site and high tumor budding were also predictive of poor survival, particularly in patients with stage III or IV tumors. In conclusion, cecal adenocarcinomas are characterized by a high frequency of KRAS mutations compared with noncecal right colon tumors, frequently display high tumor budding, and may be a prognostically relevant variable, particularly in patients with stage III or IV disease.

Resveratrol and capsaicin used together as food complements reduce tumor growth and rescue full efficiency of low dose gemcitabine in a pancreatic cancer model

Pancreatic adenocarcinoma, highly resistant to all current anti-cancer treatments, necessitates new approaches promoting cell death. We hypothesized that combined actions of several Bioactive Food Components (BFCs) might provide specific lethal effect towards tumor cells, sparing healthy cells. Human tumor pancreatic cell lines were tested in vitro for sensitivity to resveratrol, capsaicin, piceatannol, and sulforaphane cytotoxic effects. Combination of two or three components showed striking synergetic effect with gemcitabine in vitro. Each BFC used alone did not affect pancreatic tumor growth in a preclinical in vivo model, whereas couples of BFCs had anti-tumor activity. In addition, tumor toxicity was similar using gemcitabine alone or a combination of BFCs and two thirds of gemcitabine dose. Moreover, BFCs enhanced fibrotic response as compared to gemcitabine treatment alone. Reactive oxygen species (ROS) and apoptosis increases were observed, while cell cycle was very mildly affected. This study raises the possibility to use BFCs as beneficial food complements in the therapy of pancreatic adenocarcinoma, especially for patients unable to receive full doses of chemotherapy.

Colorectal poorly differentiated neuroendocrine carcinomas frequently exhibit BRAF mutations and are associated with poor overall survival

The molecular alterations in colorectal poorly differentiated neuroendocrine carcinoma remain incompletely characterized, particularly with respect to mutations in BRAF and KRAS. We analyzed 32 colorectal poorly differentiated neuroendocrine carcinomas and 40 colorectal poorly differentiated conventional adenocarcinomas for mutations in KRAS and BRAF and for DNA mismatch repair protein abnormalities to correlate histopathology with molecular alterations and survival. Compared with poorly differentiated conventional adenocarcinoma, poorly differentiated neuroendocrine carcinoma frequently harbored BRAF mutations (59% versus 5%; P < .001) and less frequently demonstrated KRAS codon 12 or 13 mutations (17% versus 43%; P = .03). BRAF mutations were identified in both pure poorly differentiated neuroendocrine carcinoma (60%) and poorly differentiated neuroendocrine carcinoma associated with a signet ring cell adenocarcinoma component (82%). Most (93%) poorly differentiated neuroendocrine carcinomas demonstrated proficient DNA mismatch repair by either microsatellite instability polymerase chain reaction or DNA mismatch repair immunohistochemistry. Patients with poorly differentiated neuroendocrine carcinoma had a significantly worse overall survival compared with patients with poorly differentiated conventional adenocarcinoma (P < .001). There was no significant difference in overall survival between patients with pure poorly differentiated neuroendocrine carcinoma and patients with both poorly differentiated neuroendocrine carcinoma and adenocarcinoma components (P = .5). In conclusion, colorectal poorly differentiated neuroendocrine carcinomas frequently harbor BRAF mutations and are associated with poor overall survival.

Significance of EGFR signaling pathway genetic alterations in radically resected non-small cell lung cancers from a Polish cohort. One institutional study

PURPOSE

We evaluated the distribution and clinical impact of EGFR, KRAS and HER2 copy number gains and EGFR, KRAS and BRAF activating mutations in resected non-small cell lung cancers (NSCLCs) from 151 Polish patients.

MATERIALS AND METHODS

Quantitative PCR and DNA sequencing were used for copy number evaluation and mutational analysis, respectively.

RESULTS

An increased EGFR CN was found in 21.2% of the tumors, more commonly of the non-squamous histology (P=0.029), larger in size (P=0.004) and those obtained from women (P=0.040). HER2 copy gain was observed in 21.8% of the patients, more frequently with lymph node metastases (P=0.048) and stage IIIA disease (P=0.061). KRAS gain was found in 29.3% of the tumors, and was not associated with patients' clinicopathological features. No BRAF mutations were found. EGFR and KRAS mutation frequency and associations with clinicopathological characteristics did not differ significantly from those previously described for the NSCLC patients of Caucasian ethnicity. Strong associations existed between most of the analyzed alterations. In the multivariate model, EGFR mutations constituted an independent prognostic factor of the disease recurrence in adenocarcinoma patients (HR 7.20; 95%CI 1.31-39.48; P=0.023), while an increased EGFR copy number tended to indicate a shorter overall survival (HR 4.85; 95%CI 0.92-25.58; P=0.062).

CONCLUSIONS

EGFR pathway genes alterations are frequent in NSCLCs from Polish patients and have a prognostic potential for patients' clinical outcome after a curative tumor resection. Gene CN evaluation by quantitative PCR provides comparable results and enables assay standardization, yet the optimal scoring system needs to be developed.

Comparison of PNA clamping and direct sequencing for detecting KRAS mutations in matched tumour tissue, cell block, pleural effusion and serum from patients with malignant pleural effusion

BACKGROUND AND OBJECTIVE

Peptide nucleic acid (PNA)-mediated real-time polymerase chain reaction clamping was recently developed to improve mutation detection sensitivity. Pleural effusion could be a good sample candidate for mutation analysis. To establish if PNA clamping could be used to detect KRAS mutation in particular in pleural effusion, we analysed its diagnostic performance.

METHODS

We studied 57 patients with malignant effusion. KRAS mutation was evaluated in samples of matched tumour tissue, cell block, pleural effusion and serum using PNA clamping and direct sequencing.

RESULTS

The detection rate of KRAS mutation using pleural effusion was 14% for PNA clamping and 10.5% for direct sequencing. The κ coefficient between the two methods was 0.76 (P value < 0.0001), 1.00 (P value < 0.0001) and 0.87 (P value < 0.0001) in pleural effusion, tissue and cell block, respectively. The diagnostic performance of KRAS mutation detection from pleural effusion compared with the results obtained for all samples combined showed that the sensitivity, specificity, positive predictive value and negative predictive value were as follows: 89, 100, 100 and 98%, respectively for PNA clamping; 67, 100, 100 and 94%, respectively for directing sequencing.

CONCLUSIONS

The current study suggests that PNA clamping had a good concordance with direct sequencing for the detection of KRAS mutation in patients with malignant effusion. Furthermore, the good diagnostic performance obtained from pleural effusion samples provides evidence that pleural effusion can be a useful source for detecting KRAS mutation in a clinical setting, in which the collection of tumour tissues is challenging.

KRAS mutational analysis and immunohistochemical studies can help distinguish pancreatic metastases from primary lung adenocarcinomas

Lung metastases from primary pancreatic adenocarcinomas often have mucinous features, which makes them difficult to distinguish from the primary lung adenocarcinoma. We explored the potential utility of KRAS mutational status and immunohistochemical studies in the evaluation of adenocarcinomas in the lungs of patients with known pancreatic cancer. Metastatic pancreatic cancer cases had fewer solitary lung lesions (5 (15%) versus 37 (95%) for lung primaries; P=0.0001), more tumors with pure (100%) mucinous morphology (16 (50%) versus 9 (23%) for lung primaries; P=0.0037), and more frequent KRAS mutations (24 (75%) versus 18 (46%) for lung primaries; P=0.0093). Presence of the KRAS G12C mutation had 96% specificity and positive predictive value for lung adenocarcinoma, whereas G12R was 99% specific for pancreatic cancer with a positive predictive value of 86%. Of the 18 KRAS mutated mucinous lung tumors, only 3 (16%) occurred in nonsmokers. Conversely, of the 19 KRAS mutated pancreatic cancer metastases, 11 (58%) occurred in nonsmokers. The median overall survival was significantly shorter for patients with metastatic tumors when compared with patients with primary mucinous tumors (19 months, 95% confidence interval, 10-28 months versus 55 months, 95% confidence interval, 39-70 months, P=0.005). CK20 and CDX2 positivity supported metastatic pancreatic cancer, whereas TTF-1 positivity supported primary lung adenocarcinoma. In summary, KRAS G12C mutations, TTF-1, and napsin A were associated with primary lung adenocarcinoma, whereas KRAS G12R mutations, CK20, and CDX2 favored pancreatic adenocarcinoma. We showed survival differences for patients whose pancreatic metastases were synchronous versus metachronous to their primary tumors, and for patients with mucinous pancreatic cancer metastases versus primary mucinous lung adenocarcinomas. Differences in KRAS mutations reflect differences in exposure to tobacco smoking and highlight biological differences between two KRAS oncogene-driven cancers.

Immunohistochemical detection of BRAF V600E mutant protein using the VE1 antibody in colorectal carcinoma is highly concordant with molecular testing but requires rigorous antibody optimization

The BRAF V600E mutation occurs in 15% of colorectal carcinomas (CRCs) and has important genetic, prognostic, and therapeutic implications. A monoclonal antibody (VE1) targeting the BRAF V600E mutant protein has become available with variable efficacy in literature reports. We investigated the utility of the VE1 antibody in detecting BRAF V600E mutant protein in two cohorts: (1) a retrospectively accrued series of 103 resected CRCs with (N = 57) and without (N = 46) known BRAF V600E mutation status by PCR and (2) a prospective series of 25 CRCs requiring BRAF analysis during routine screening for Lynch syndrome. All 74 cases with positive BRAF V600E mutation demonstrated cytoplasmic positivity with the VE1 antibody with most tumors (70/74, 95%) demonstrating moderate to strong staining. Of the 54 BRAF V600E-negative cases, 51/54 CRCs (94%) were negative with the VE1 antibody while 3 CRCs (6%) demonstrated weak cytoplasmic staining. The sensitivity and specificity of VE1 was 100% and 94%, respectively. Ten BRAF V600E-mutated CRCs had adjacent precursor lesions including 7 sessile serrated adenomas associated with CRCs with high-level microsatellite instability (MSI-H). All 10 precursor adenomas were positive for VE1 staining with the 7 sessile serrated adenomas maintaining preserved MLH1 expression. Our results indicate that VE1 immunohistochemistry is a useful surrogate for the detection of the BRAF V600E mutation in CRC, although weak staining must be evaluated by BRAF PCR analysis to exclude a false positive result. In addition, the BRAF V600E mutation appears to be an early event before the divergent development into MSS and MSI-H pathways.

MUC2 expression is an adverse prognostic factor in superficial gastroesophageal adenocarcinomas

Mucin core proteins (MUCs) are expressed in tissue-specific patterns in the gastrointestinal tract and expression is deregulated in Barrett's metaplasia. Based on differential expression, MUCs have been used to classify adenocarcinomas into distinct phenotypes (eg, intestinal, gastric, pancreaticobiliary, etc). Because MUC expression patterns carry prognostic significance in other tumors, we evaluated MUC expression in superficial adenocarcinomas of the gastroesophageal junction and esophagus (EAC) to determine whether there are differences in outcome associated with MUC subtype in this potentially curable subset of EAC. We classified 142 resected, superficial (T1) EAC based on their pattern of expression of MUC2, MUC5AC, MUC6 and MUC1. The association between survival and MUC expression pattern was determined in univariate and multivariate analyses. The MUC2 positive "intestinal" phenotype was associated with significantly worse prognosis in submucosal EAC (hazard ratio 2.2, 95% confidence interval 1.2-4.2), independent of node stage and other prognostic factors. MUC2 expression in submucosal EAC also showed significantly accelerated time to recurrence (hazard ratio 2.8, 95% confidence interval 1.2-6.8) after adjusting for node stage. The classification of superficial EAC by MUC protein expression has prognostic significance. MUC2 expression is an adverse prognostic indicator in submucosal EAC, independent of node stage and other prognostic factors.

KRAS mutant allele-specific imbalance is associated with worse prognosis in pancreatic cancer and progression to undifferentiated carcinoma of the pancreas

KRAS codon 12 mutations are present in about 90% of ductal adenocarcinomas and in undifferentiated carcinomas of the pancreas. The role of KRAS copy number changes and resulting KRAS mutant allele-specific imbalance (MASI) in ductal adenocarcinoma (n=94), and its progression into undifferentiated carcinoma of the pancreas (n=25) was studied by direct sequencing and KRAS fluorescence in situ hybridization (FISH). Semi-quantitative evaluation of sequencing electropherograms showed KRAS MASI (ie, mutant allele peak higher than or equal to the wild-type allele peak) in 22 (18.4%) cases. KRAS FISH (performed on 45 cases) revealed a trend for more frequent KRAS amplification among cases with KRAS MASI (7/20, 35% vs 3/25, 12%, P=0.08). KRAS amplification by FISH was seen only in undifferentiated carcinomas (10/24, 42% vs 0/21 pancreatic ductal adenocarcinoma, 0%, P=0.0007). In 6 of 11 cases with both undifferentiated and well-differentiated components, transition to undifferentiated carcinoma was associated with an increase in KRAS copy number, due to amplification and/or chromosome 12 hyperploidy. Pancreatic carcinomas with KRAS MASI (compared to those without MASI) were predominantly undifferentiated (16/22, 73% vs 9/97, 9%, P<0.001), more likely to present at clinical stage IV (5/22, 23% vs 7/97, 7%, P=0.009), and were associated with shorter overall survival (9 months, 95% confidence interval, 5-13, vs 22 months, 95% confidence interval, 17-27; P=0.015) and shorter disease-free survival (5 months, 95% confidence interval, 2-8 vs 13 months, 95% confidence interval, 10-16; P=0.02). Our findings suggest that in a subset of ductal adenocarcinomas, KRAS MASI correlates with the progression to undifferentiated carcinoma of the pancreas.

The prognostic and predictive value of KRAS oncogene substitutions in lung adenocarcinoma

BACKGROUND

The prognostic and therapeutic implications of the spectrum of v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) oncogene substitutions in lung cancer remain poorly understood. The objective of this study was to determine whether KRAS oncogene substitutions differed with regard to prognosis or predictive value in lung adenocarcinoma.

METHODS

KRAS oncogene substitutions and mutant allele-specific imbalance (MASI) were determined in patients with lung adenocarcinoma, and the associations with overall survival (OS), recurrence-free survival (RFS), and chemotherapy interactions were assessed.

RESULTS

KRAS mutational analysis was performed on 988 lung adenocarcinomas, and 318 KRAS mutations were identified. In this predominantly early stage cohort (78.6% of patients had stage I-III disease), OS and RFS did not differ according to the type of KRAS substitution (OS, P = .612; RFS, P = .089). There was a trend toward better OS in the subset of patients with KRAS codon 13 mutations (P = .052), but that trend was not significant in multivariate analysis (P = .076). RFS did not differ according to codon type in univariate analysis (P = .322). There was a marked difference in RFS based on the presence of MASI in univariate analysis (P = .004) and multivariate analysis (P = .009). A test for interaction was performed to determine whether the effect of chemotherapy on OS and RFS differed based on KRAS substitution type, codon type, or the presence of MASI. That test indicated that there were no differences in the effects of chemotherapy for any of variables examined.

CONCLUSIONS

KRAS codon 13 mutations and MASI were identified as candidate biomarkers for prognosis, and it may be useful to incorporate them into prospective studies evaluating novel therapies in KRAS-mutant lung adenocarcinoma.

EGFR and KRAS mutations in lung carcinomas in the Dutch population: increased EGFR mutation frequency in malignant pleural effusion of lung adenocarcinoma

Background

Frequencies of EGFR and KRAS mutations in non-small cell lung cancer (NSCLC) have predominantly been determined in East Asian and North American populations, showing large differences between these populations. The aim of the present study was to determine the frequency of EGFR and KRAS mutations in NSCLC in the West European Dutch population in primary carcinomas and different metastatic locations.

Methods

EGFR (exons 19, 20 and 21) and KRAS (exons 2 and 3) mutation test results of NSCLC samples of patients in 13 hospitals were collected. The tests were performed on paraffin-embedded tissue or cytological material of primary and metastatic lung carcinomas.

Results

EGFR mutations were detected in 71/778 (9.1 %) tested patients; in 66/620 (10.6 %) adenocarcinomas. EGFR mutations were significantly more often detected in female than in male patients (13.4 % vs. 5.5 %, p < 0.001). KRAS mutations were found in 277 out of 832 (33.3 %) tested patients; in 244/662 (36.9 %) adenocarcinomas. A significantly increased frequency of EGFR mutations was observed in patients with malignant pleural/pericardial effusions (26.5 %; odds ratio (OR) 2.80, 95 % confidence interval (CI) 1.22–6.41), whereas the frequency of KRAS mutations was significantly decreased (18.8 %; OR 0.35, 95 % CI 0.14–0.86).

Conclusions

In the investigated Dutch cohort, patients with malignant pleural/pericardial effusion of lung adenocarcinoma have an increased frequency of EGFR mutations. The overall frequency of EGFR mutations in lung adenocarcinomas in this West European population is within the frequency range of North American and South European populations, whereas KRAS mutation frequency is higher than in any population described to date.

Mutant allele-specific imbalance modulates prognostic impact of KRAS mutations in colorectal adenocarcinoma and is associated with worse overall survival

The prognostic impact of distinct KRAS mutations in colorectal carcinomas is not fully characterized. We hypothesized that the prognostic impact of KRAS mutations is modulated by KRAS mutant allele-specific imbalance (MASI). KRAS MASI was assessed by sequencing electropherograms in KRAS-mutated colorectal carcinomas (N = 394, prospectively tested). The mechanism of KRAS MASI was studied by fluorescence in situ hybridization (FISH; N = 50). FISH showed that KRAS MASI developed by chromosome 12 hyperploidy (9/18, 50%) or KRAS amplification (1/18, 5.5%). KRAS MASI was more common in tumors with KRAS codon 13 than with codon 12 mutations [24/81, 30% vs. 54/313, 17%; odds ratio (OR), 2.0, 95% confidence interval (CI), 1.2-3.5; p = 0.01]. KRAS MASI was correlated with overall survival (N = 358, median follow-up = 21 months). In a multivariate analysis, KRAS codon 13 MASI was an independent adverse prognostic factor (compared to codon 13 mutants without MASI combined with all codon 12 mutants; adjusted hazard ratio, 2.2, 95% CI: 1.2-3.9; p = 0.01). KRAS MASI arises through chromosome 12 hyperploidy or KRAS amplification and, when affects KRAS codon 13, is associated with worse overall survival.

KRAS mutant allele-specific imbalance in lung adenocarcinoma

The significance of KRAS mutant allele-specific imbalance (MASI) in lung adenocarcinomas is unknown. KRAS MASI was defined as predominance of the mutant allele over the wild-type allele. We assessed the frequency of KRAS MASI by comparing peak heights of mutant and wild-type alleles on sequencing electropherograms and by KRAS fluorescence in situ hybridization (FISH). A review of sequencing electropherograms of 207 KRAS-mutated lung adenocarcinomas demonstrated 23 (11%) cases with the mutant allele peak higher than the wild-type allele peak and 15 (7%) cases with the mutant allele peak equal to the wild-type allele peak. Of 17 cases with the mutant allele peak higher or equal to the wild-type allele peak, 8 (47%) showed KRAS amplification by FISH. KRAS FISH analysis of 36 KRAS-mutated lung adenocarcinomas with the mutant allele peak lower than the wild-type allele peak, 21 KRAS and EGFR wild-type and 16 EGFR-mutated adenocarcinomas showed no KRAS amplification. KRAS MASI was associated with selective amplification of the KRAS mutant allele (P<0.001). Patients with KRAS MASI showed worse overall survival. The cumulative proportion surviving at 17 months for KRAS MASI group was 35% compared with 84.1% for patients with KRAS mutant allele peak lower than wild-type allele peak (P=0.012). The adverse prognostic significance of KRAS MASI was independent of clinical stage and was maintained among stage I patients. The detection of KRAS MASI in lung adenocarcinomas by sequencing electropherograms may identify patients with more aggressive disease.

The B-Raf status of tumor cells may be a significant determinant of both antitumor and anti-angiogenic effects of pazopanib in xenograft tumor models

Pazopanib is an FDA approved Vascular Endothelial Growth Factor Receptor inhibitor. We previously reported that it also inhibits tumor cell B-Raf activity in an experimental brain metastatic setting. Here, we determine the effects of different B-Raf genotypes on pazopanib efficacy, in terms of primary tumor growth and anti-angiogenesis. A panel of seven human breast cancer and melanoma cell lines harboring different mutations in the Ras-Raf pathway was implanted orthotopically in mice, and tumor growth, ERK1/2, MEK1/2 and AKT activation, and blood vessel density and permeability were analyzed. Pazopanib was significantly inhibitory to xenografts expressing either exon 11 mutations of B-Raf, or HER2 activated wild type B-Raf; no significant inhibition of a xenograft expressing the common V600E B-Raf mutation was observed. Decreased pMEK staining in the responsive tumors confirmed that B-Raf was targeted by pazopanib. Interestingly, pazopanib inhibition of tumor cell B-Raf also correlated with its anti-angiogenic activity, as quantified by vessel density and area. In conclusion, using pazopanib, tumor B-Raf status was identified as a significant determinant of both tumor growth and angiogenesis.

RASOnD-a comprehensive resource and search tool for RAS superfamily oncogenes from various species

Background

The Ras superfamily plays an important role in the control of cell signalling and division. Mutations in the Ras genes convert them into active oncogenes. The Ras oncogenes form a major thrust of global cancer research as they are involved in the development and progression of tumors. This has resulted in the exponential growth of data on Ras superfamily across different public databases and in literature. However, no dedicated public resource is currently available for data mining and analysis on this family. The present database was developed to facilitate straightforward accession, retrieval and analysis of information available on Ras oncogenes from one particular site.

Description

We have developed the RAS Oncogene Database (RASOnD) as a comprehensive knowledgebase that provides integrated and curated information on a single platform for oncogenes of Ras superfamily. RASOnD encompasses exhaustive genomics and proteomics data existing across diverse publicly accessible databases. This resource presently includes overall 199,046 entries from 101 different species. It provides a search tool to generate information about their nucleotide and amino acid sequences, single nucleotide polymorphisms, chromosome positions, orthologies, motifs, structures, related pathways and associated diseases. We have implemented a number of user-friendly search interfaces and sequence analysis tools. At present the user can (i) browse the data (ii) search any field through a simple or advance search interface and (iii) perform a BLAST search and subsequently CLUSTALW multiple sequence alignment by selecting sequences of Ras oncogenes. The Generic gene browser, GBrowse, JMOL for structural visualization and TREEVIEW for phylograms have been integrated for clear perception of retrieved data. External links to related databases have been included in RASOnD.

Conclusions

This database is a resource and search tool dedicated to Ras oncogenes. It has utility to cancer biologists and cell molecular biologists as it is a ready source for research, identification and elucidation of the role of these oncogenes. The data generated can be used for understanding the relationship between the Ras oncogenes and their association with cancer. The database updated monthly is freely accessible online at http://202.141.47.181/rasond/ and http://www.aiims.edu/RAS.html.

Adenosquamous carcinoma of the lung: a microdissection study of KRAS and EGFR mutational and amplification status in a western patient population

Molecular testing of pulmonary adenocarcinomas for EGFR and KRAS mutations is becoming more common as tyrosine kinase inhibitor therapy is used for EGFR-mutated adenocarcinomas. Adenosquamous carcinomas represent a hybrid carcinoma, and there is no literature addressing the frequency of EGFR and KRAS mutations in this subset of lung carcinomas in Western populations. For this study, 23 adenosquamous carcinomas were microdissected with the glandular and squamous components analyzed for EGFR and KRAS mutations and EGFR amplification. In 3 cases (13%), there were EGFR mutations, with 2 having the identical mutation in the glandular and squamous elements. In 3 cases (13%), there were KRAS mutations in both histologic elements. Great heterogeneity existed in the rates of EGFR amplification in the 2 histologic components. Amplification was most common in both glandular and squamous components (11/23 [48%]). EGFR mutations occur in adenosquamous carcinoma in the same percentages as in conventional adenocarcinoma in the Western population. KRAS mutations are less common.

ASCO Provisional Clinical Opinion: Epidermal Growth Factor Receptor Mutation Testing in Practice

ASCO has recently provided guidance on emerging data on EGFR testing for the purpose of selecting first-line therapy for persons with advanced NSCLC through its Provisional Clinical Opinion.