title: Impact of tissue type and content of neoplastic cells of samples on the quality of epidermal growth factor receptor mutation analysis among patients with lung adenocarcinoma.
abstract: Assessment of the epidermal growth factor receptor (EGFR) mutational status has become crucial in recent years in the molecular classification of patients with lung cancer. The impact of the type and quantity of malignant cells of the neoplastic specimen on the quality of mutation analysis remains to be elucidated, and only empirical and sporadic data are available. The aim of the present study was to investigate the impact of tissue type and content of neoplastic cells in the specimen on the quality of EGFR mutation analysis among patients with lung adenocarcinoma. A total of 515 patients with histologically-confirmed disease were included in the present study. Formalin-fixed paraffin embedded tissue samples were used for the mutation analysis and the content of the neoplastic cells was evaluated using light microscopy. Genomic DNA was isolated using a standard protocol. The coding sequences and splice junctions of exons 18, 19 and 21 in the EGFR gene were then screened for mutations by direct automated sequencing. The mean age of the patients examined was 64.9 years and 357 (69.3%) were male. A total of 429 tissue samples (83.3%) were obtained by biopsy and the remaining samples were obtained by surgery. A total of 456 samples (88.5%) were observed from primary lung adenocarcinomas, while 59 (11.5%) were from metastatic lesions. EGFR mutations occurred in 59 cases (11.5%); exon 18 mutations were detected in one case (1.7%), whereas exon 19 and 21 mutations were detected in 30 (51%) and 28 (47.3%) cases, respectively. EGFR mutations were more frequent in females and patients that had never smoked. The distribution of the mutations among primary and metastatic tissues exhibited no significant differences in the proportions of EGFR mutations detected. However, a statistically significant difference in the number of mutations detected was found between samples with at least 50% of neoplastic cells (450 cases-57 mutations; 12.7%) and those with <50% of neoplastic cells (65 cases-2 mutations; 3.1%).
authors: Department of Surgical, Microsurgical and Medical Sciences, University of Sassari, Sassari 07100, Italy.
authors: Panagiotis
authors: P
authors: Paliogiannis
authors: Department of Surgical, Microsurgical and Medical Sciences, University of Sassari, Sassari 07100, Italy.
authors: Federico
authors: F
authors: Attene
authors: Department of Surgical, Microsurgical and Medical Sciences, University of Sassari, Sassari 07100, Italy.
authors: Antonio
authors: A
authors: Cossu
authors: Pathology and Oncology Unit, Businco Oncological Hospital, Cagliari 09121, Italy.
authors: Efisio
authors: E
authors: Defraia
authors: Pathology and Oncology Unit, Businco Oncological Hospital, Cagliari 09121, Italy.
authors: Giuseppe
authors: G
authors: Porcu
authors: Pathology and Oncology Unit, Businco Oncological Hospital, Cagliari 09121, Italy.
authors: Annamaria
authors: A
authors: Carta
authors: Pathology and Oncology Unit, Businco Oncological Hospital, Cagliari 09121, Italy.
authors: Maria Ignazia
authors: MI
authors: Sotgiu
authors: Medical Oncology Unit, Local Health Unit (Azienda Sanitaria Locale), Sassari 07100, Italy.
authors: Antonio
authors: A
authors: Pazzola
authors: Clinical Pulmonology and Tisiology Unit, Hospital‑University (Azienda Ospedaliero Universitaria), Sassari 07100, Italy.
authors: Lorenzo
authors: L
authors: Cordero
authors: Medical Oncology Unit, 'Zonchello' Hospital, Nuoro 08100, Italy.
authors: Francesca
authors: F
authors: Capelli
authors: Medical Oncology Unit, 'Zonchello' Hospital, Nuoro 08100, Italy.
authors: Giovanni Maria
authors: GM
authors: Fadda
authors: Medical Oncology Unit, 'San Giovanni di Dio' Hospital, Olbia 07026, Italy.
authors: Salvatore
authors: S
authors: Ortu
authors: Epidemiology and Medical Statistics Unit, Department of Biomedical Sciences, University of Sassari, Sassari 07100, Italy.
authors: Giovanni
authors: G
authors: Sotgiu
authors: Unit of Cancer Genetics, Institute of Biomolecular Chemistry, National Research Council (Consiglio Nazionale delle Ricerche), Sassari 07100, Italy.
authors: Grazia
authors: G
authors: Palomba
authors: Unit of Cancer Genetics, Institute of Biomolecular Chemistry, National Research Council (Consiglio Nazionale delle Ricerche), Sassari 07100, Italy.
authors: Maria Cristina
authors: MC
authors: Sini
authors: Unit of Cancer Genetics, Institute of Biomolecular Chemistry, National Research Council (Consiglio Nazionale delle Ricerche), Sassari 07100, Italy.
authors: Giuseppe
authors: G
authors: Palmieri
authors: Unit of Cancer Genetics, Institute of Biomolecular Chemistry, National Research Council (Consiglio Nazionale delle Ricerche), Sassari 07100, Italy.
authors: Maria
authors: M
authors: Colombino
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology; D000077192:Adenocarcinoma of Lung; D000328:Adult; D000368:Aged; D004252:DNA Mutational Analysis; D066246:ErbB Receptors / Q000235:genetics*; D005091:Exons; D005260:Female; D015870:Gene Expression; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009154:Mutation; D015588:Observer Variation; D016366:Open Reading Frames; D016612:Paraffin Embedding; D011786:Quality Control; D012737:Sex Factors; D013048:Specimen Handling / Q000706:statistics & numerical data; D016707:Tissue Fixation
chemical_list: C512478:EGFR protein, human; D066246:ErbB Receptors