1304P - Diagnosis of the ALK-EML4 translocation with FISH, immunohistochemistry, and real time-polymerase chain reaction in patients with non-small-cell lu...

Date 27 September 2014
Event ESMO 2014
Session Poster Display session
Topics Diagnostics
Non-Small-Cell Lung Cancer, Metastatic
Presenter Graciela Cruz-Rico
Citation Annals of Oncology (2014) 25 (suppl_4): iv426-iv470. 10.1093/annonc/mdu349
Authors G. Cruz-Rico1, V. Morales-Oyarvide2, A. Aviles-Salas3, A.M. Espinosa-García4, V.A. Maldonado-Laguna5, C. Rojas-Enriquez6, A.F. Cardona7, O. Arrieta2
  • 1Experimental Oncology Laboratory, Instituto Nacional de Cancerologia, 14080 - Mexico City/MX
  • 2Thoracic Oncology Unit, Instituto Nacional de Cancerologia, 14000 - Mexico City/MX
  • 3Pathology, Instituto Nacional de Cancerologia, 14080 - Mexico city/MX
  • 4Genomic Medice Lab, Hospital General de México, 06726 - Mexico city/MX
  • 5Epigenetica, INMEGEN, 14610 - Mexico city/MX
  • 6Radiology, Instituto Nacional de Cancerologia, 14080 - Mexico city/MX
  • 7Clinical And Translational Oncology Group, Fundacion Sta Fe de Bogota Instituto de Oncologia, Bogota/CO

Abstract

Aim

To evaluate the value of ALK immunohistochemistry (IHC) with the 5A4 antibody and real-time polymerase chain reaction (RT-qPCR) in the diagnosis of ALK-rearranged NSCLC in the Mexican population.

Methods

170 advanced NSCLC were evaluated by FISH. Demographic and clinicopathologic characteristics were analyzed. Additional IHC and RT-qPCR (variants 1-5) was done in 63 and 48 patients, respectively. Performance characteristics of IHC and RT-qPCR were calculated.

Results

18 (10.5%) patients were positive for ALK-rearrangements (ALK+) by FISH. ALK+ patients were significantly younger at the time of diagnosis compared with ALK-negative patients (46 vs. 58 years, P = 0.02), and had a lighter smoking history. We found no significant differences in terms of sex, wood smoke exposure, histologic type, carcinoembryonic antigen, or clinical stage at presentation. When we compared IHC with FISH, using an IHC cutoff of 1+ staining, there were 15 true positive (TP) cases, 3 false positives (FP), 3 false negatives (FN), and 42 true negatives (TN), yielding a sensitivity and specificity of 83% and 93%, respectively. Compared with FISH, RT-qPCR identified 5 TP cases with variant 1, no FP, 4 FN for variants 1-5, and 39 TN, yielding a sensitivity and specificity of 55% and 100%, respectively.

Conclusions

This is the first report of ALK-rearranged NSCLC in Latin America. The high prevalence of ALK+ patients found in our study reflects a clinically enriched patient population. Our results show that ALK+ patients in Mexico are younger than ALK-negative patients and have a lighter smoking history. Our findings suggest that IHC with 5A4 clone is relatively sensitive for the detection of ALK+ NSCLC and may help select patients to undergo FISH testing.

Disclosure

All authors have declared no conflicts of interest.