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P1.02 - Poster Session 1 - Novel Cancer Genes and Pathways (ID 144)
- Event: WCLC 2013
- Type: Poster Session
- Track: Biology
- Presentations: 1
- Coordinates: 10/28/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
P1.02-016 - Non-small cell lung cancer and EGFR mutation in Poland - preliminary results from single institution study (ID 3239)
09:30 - 16:30 | Author(s): M. Prochorec-Sobieszek
Lung cancer is the first cause of death among all cancers in the world and every year more than 1.6 million patients die from lung cancer. In Polish population morbidity and mortality from lung cancer persist in the first location and amount respectively 21.4% and 31.2% of all cancers. Over the last 30 years the development of targeted therapy significantly influenced the routine practice in pathology. The treatment based on identification of the type of tumor is still crucial information however the importance of predictive or prognostic molecular markers has become significant step in the choice of treatment. Identification of mutations in the EGFR gene in non-small cell lung cancer (NSCLC) fully illustrates the impact of molecular biology in treatment decisions. The use of one of the small molecule tyrosine kinase inhibitors, gefitinib or erlotinib depends on confirmation presence of activating somatic EGFR mutation.
The aim of the study was to evaluate the EGFR mutations in two types of material cytological and histological. 189 histological, paraffin-embedded materials as well as 12 fresh and 72 fixed cytology specimens obtained by trans-thoracic, computed tomography supported biopsy or during bronchofiberoscopy were included. Material and methods. 273 patients with confirmed NSCLC were entered into the study. Each specimen contained at least 50% of tumor cells. The macrodissecion was performed on histological specimens to maximize tumor cells content. DNA was extracted from both types of material and the EGFR mutation was analyzed in exons 18, 19 20 and 21 using the direct sequencing method
The mean age of patients was 61.5 years (range 25 – 84 years) with males predominance (151 males vs. 122 females). The histological types included: adenocarcinoma 186 (69%), squamous cell carcinoma 44 (16%), NSCLC, not-otherwise specified 30 (11%), large cell carcinoma 9 (3%) and adenosquamous carcinoma 4 (1%). Both types of material were equally sufficient to evaluate EGFR mutations. The ratio of molecularly non-diagnostic material due to DNA degradation or too scant DNA probe was respectively for cytological and histological material 1.2% vs. 4.75% (p<0.01). The percentage of EGFR somatic mutations were 10.62%. Females suffered more frequently from adenocarcinoma (females 70.49% vs. males 66.23%, p <0.01) and had significantly higher rate of EGFR mutations (females 17.21% vs. males 3.97%, p<0.01). Mutations in exons 21 and 19 together accounted for 87% of all types of mutations of the EGFR gene. Apart from these, two patients had co-existence of activating/inhibiting mutations: L858R (exon 21) with T790M (exon 20) and G719C (exon 18) with S768I (exon 20).
This study allows for the first time to estimate an EGFR mutation frequency in Polish population. Moreover the results have strengthened the importance of reusing cytological material in molecular evaluation. Cytological material recovered from fixed preparations and stained with hematoxylin and eosin showed comparable DNA quality to fresh tumor cells. The cytology especially fine needle aspirates as well as small biopsy material provide molecular biological information which is a key issue for the targeted treatment options.