Identification of EGFR mutation, KRAS mutation, and ALK gene rearrangement in cytological specimens of primary and metastatic lung adenocarcinoma

Abstract

BACKGROUND:The identification of molecular alterations has an important therapeutic implication in patients with lung adenocarcinomas. In the current study, the authors evaluated their experience with the identification of epidermal growth factor receptor (EGFR), Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation, and anaplastic lymphoma kinase (ALK) gene rearrangement using cytological specimens of primary and metastatic lung adenocarcinoma. METHODS: A total of 54 cases of lung adenocarcinomas (11 primary and 43 metastatic tumors) in which molecular tests were performed were retrieved. Molecular tests were performed on the cell block material of 19 effusions and 35 fine-needle aspirates. EGFR mutation was evaluated by polymerase chain reaction sequencing analysis of exons 18, 19, 20, and 21. KRAS mutation was tested using polymerase chain reaction-single-strand conformational polymorphism analysis of codons 12 and 13. ALK gene rearrangement was evaluated by fluorescence in situ hybridization using an ALK break apart probe. RESULTS: Molecular tests were successful in 49 of 54 cases (91%). Evaluation of EGFR mutation, KRAS mutation, and ALK gene rearrangement were performed in 49 cases, 14 cases, and 22 cases, respectively. EGFR mutations were found in 14 of 49 cases (29%), including 5 primary and 9 metastatic tumors. Three metastatic/recurrent adenocarcinomas demonstrated an additional EGFR T790M mutation that was not identified in the original specimens. KRAS mutation was detected in 3 of 14 cases (21%) including 1 primary and 2 metastatic tumors. ALK gene rearrangement was evident in 3 of 22 cases (14%), all of which were metastatic tumors. CONCLUSIONS:The results of the current study have demonstrated the feasibility of using cytological specimens for EGFR mutation, KRAS mutation, and ALK gene rearrangement analysis. Repeating molecular testing in metastatic/ recurrent lung adenocarcinomas may uncover newly acquired molecular alterations. Cancer (Cancer Cytopathol) 2013;121:500-7.

Molecular Spectrum of Somatic EGFR and KRAS Gene Mutations in non Small Cell Lung Carcinoma: Determination of Frequency, Distribution Pattern and Identification of Novel Variations in Indian Patients

“…The frequency of EGFR mutation in the current study is comparable to those published from Korea, Japan, Italy and USA (25-29 %) [41,48,56,59] higher than those from Canada, France, Brazil and Japan (5-21 %) [38, 47, 51, 53], while lower in comparison to Taiwan, China and Mexico (33-54 %) [43,54,57]. In comparison to recent Indian studies, our frequency was pretty much similar to some studies 23-32 % [27, 65,66], though few studies even reported a much higher mutation rate varying between 39-52 % [28, 64,67] which could be attributed to small sample size, and or clinically selected patients.…”

Preparation of Cell Blocks for Lung Cancer Diagnosis and Prediction: Protocol and Experience of a High-Volume Center

“…Furthermore, changes to the original slide due to molecular analyses (microdissection) can be avoided. Molecular analyses can even be repeated or complemented by other methods using the available serial sections [23]. Disadvantages of cell blocks compared to conventional cytology approaches refer to the sometimes reduced morphological quality (due to the spin down during processing), although others have even reported cell blocks to be helpful for a better demonstration of architectural patterns compared to ThinPrep specimens [24].…”

Molecular Testing of Non–Small Cell Lung Carcinoma Diagnosed by Endobronchial Ultrasound–Guided Transbronchial Fine-Needle Aspiration: The Cleveland Clinic Experience

“…Given the diversity of cytopathologic specimen types and the different methods of fixation and processing available, options for procuring DNA from cytologic specimens for molecular analysis vary; material can be successfully obtained from cell blocks, smears, cytospins, and liquid-based preparations. 7,9,11,12,14,[19][20][21][22][23][24][25] Most commonly, cell blocks are used for molecular testing on cytopathologic specimens. 21 The cell block closely approximates surgical pathology material; tissue fragments from cytopathologic specimens are embedded in paraffin and are sectioned akin to surgical specimens.…”