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P1.06 - Poster Session 1 - Prognostic and Predictive Biomarkers (ID 161)
- Event: WCLC 2013
- Type: Poster Session
- Track: Biology
- Presentations: 1
- Coordinates: 10/28/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
P1.06-016 - Anaplastic Lymphoma kinase (ALK) alterations by FISH in a cohort of Spanish Non-Small Cell Lung Cancer (NSCLC) patients analysed in a certified centre of reference (ID 1626)
09:30 - 16:30 | Author(s): M. Magem
Patients with NSCLC harbouring an ALK translocation exquisitely respond to ALK inhibitors. It is therefore important to know ALK status for newly diagnosed NSCLC patients. Our institution has become centre of reference in Spain for ALK determination by FISH for other hospitals. The aim of this work was to report the clinical and pathological characteristics of the samples with ALK results evaluated in our institution.
We entered clinical-pathological characteristics of external and in-house samples into a database. ALK was evaluated by FISH with the FDA approved test (Abbot Molecular Inc, Des Plaines, IL). Whole sections were analysed evaluating a minimum of 50 nuclei per case. The case was considered typically rearranged when separated green and orange/red signals (at least by three times the signal diameter) were identified and atypically rearranged when a single orange signal was observed. Gain (including both low or high genomic gain) was defined as a mean copy number of 3 to 5 fusion signals in >=10% of cells and amplification as the presence of >=6 copies of ALK per cell in >=10% of analysed cells (Salido et al, JTO 2010). To analyse correlations between ALK status and clinical-pathologic variables, we used the Chi-square test or Fisher’s exact test with a significance at p<0.05.
A total of 471 cases were included in the database. Patients’ clinical characteristics are summarized in Table 1. ALK translocation was found in 15 of 471 patients (3.2%). Within the ALK translocated cases 8 were female, 11 were adenocarcinomas, 2 squamous cell histology, 1 large cell neuroendocrine carcinoma, and 1 not otherwise specified. There was a significant association between smoking status and ALK translocation (6.6% of translocations among non-smokers and 2% among smokers, p=0.042). Fourteen patients (3%) showed ALK amplification, 366 (77.7%) gain in ALK copy number, 50 (10.6%) were disomic and 5 (1%) monosomic for ALK and 20 cases were not evaluable (4.2%). EGFR mutation was found in 23 of 252 patients (9.1%) and non of these was observed in cases with ALK translocation. We observed an association between the type of sample and the ability to obtain an evaluable result for ALK with 97.5% assessable biopsies vs 84.4% citologies, (p<0.0001).
N (%) Median age (range) 62.46 (32-91) Gender Male 330 (70.1) Female 141 (29.9) Smoking status Never 121 (25.7) Current/Former 350 (74.3) Sample origen Lung 425 (90.2) Pleura 15 (3.2) Lymph node 15 (3.2) Other 16 (3.3) Type of sample Citology 66 (14) Biopsy 405 (86) Stage I 104 (22) II 40 (8.5) III 87 (18.5) IV 240 (51) Histology Adenocarcinoma 363 (77.1) Squamous cell carcinoma 44 (9.3) Large cell carcinoma 11 (2.3) Other 43 (11.3)
ALK translocation is present in about 3% in Spanish NSCLC patients and is associated with adenocarcinoma histology and non-smoking status. The performance of ALK FISH in biopsy specimens is significantly better than in citologies.