TY - JOUR
T1 - Evaluation of 7q31 region improves the accuracy of EGFR FISH assay in non small cell lung cancer
AU - Casorzo, Laura
AU - Corigliano, Mara
AU - Ferrero, Paolo
AU - Venesio, Tiziana
AU - Risio, Mauro
PY - 2009
Y1 - 2009
N2 - Background. Increase of EGFR gene copy number consequent to gene amplification and/or polysomy of chromosome 7 has been significantly associated with better clinical outcome in Non Small Cell Lung Cancer (NSCLC) patients treated with Tyrosin-Kinase Inhibitors (TKIs). The primary method to detect EGFR copy number is FISH (Fluorescence in Situ Hybridization), that in lung cancer requires a precise standardization due to the presence of intratumor heterogeneity and high frequency of chromosome 7 polysomy. Recommendations and interpretative guidelines to discriminate NSCLC patients into FISH positive (gene amplification and high chromosome 7 polysomy) and FISH negative have been proposed by the University of Colorado Cancer Center (UCCC). However, in a subset of cases the distinction between EGFR amplification and chromosome 7 polysomy can be controversial because of a complex pattern of multiple EGFR and centromere signals. Methods. In order to distinguish more accurately these two genetic events, 20 NSCLC FISH positive patients, showing a controversial pattern of EGFR and centromere specific signals, were further evaluated for the status of 7q31 distal region. Results. A discrepancy between FISH results obtained with UCCC scoring system and 7q31 control was evidenced in 2 patients (10%). Conclusion. Our data strengthen the usefulness of 7q31 region evaluation to discriminate EGFR amplification from chromosome 7 polysomy in controversial EGFR FISH positive cases. Since it has been reported a possible different contribution of amplification and polysomy to TKIs susceptibility in NSCLC, the clear distinction between these two genetic events may be important to identify a subset of patients more responsive to the therapy.
AB - Background. Increase of EGFR gene copy number consequent to gene amplification and/or polysomy of chromosome 7 has been significantly associated with better clinical outcome in Non Small Cell Lung Cancer (NSCLC) patients treated with Tyrosin-Kinase Inhibitors (TKIs). The primary method to detect EGFR copy number is FISH (Fluorescence in Situ Hybridization), that in lung cancer requires a precise standardization due to the presence of intratumor heterogeneity and high frequency of chromosome 7 polysomy. Recommendations and interpretative guidelines to discriminate NSCLC patients into FISH positive (gene amplification and high chromosome 7 polysomy) and FISH negative have been proposed by the University of Colorado Cancer Center (UCCC). However, in a subset of cases the distinction between EGFR amplification and chromosome 7 polysomy can be controversial because of a complex pattern of multiple EGFR and centromere signals. Methods. In order to distinguish more accurately these two genetic events, 20 NSCLC FISH positive patients, showing a controversial pattern of EGFR and centromere specific signals, were further evaluated for the status of 7q31 distal region. Results. A discrepancy between FISH results obtained with UCCC scoring system and 7q31 control was evidenced in 2 patients (10%). Conclusion. Our data strengthen the usefulness of 7q31 region evaluation to discriminate EGFR amplification from chromosome 7 polysomy in controversial EGFR FISH positive cases. Since it has been reported a possible different contribution of amplification and polysomy to TKIs susceptibility in NSCLC, the clear distinction between these two genetic events may be important to identify a subset of patients more responsive to the therapy.
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U2 - 10.1186/1746-1596-4-36
DO - 10.1186/1746-1596-4-36
M3 - Article
C2 - 19889201
AN - SCOPUS:73249140354
VL - 4
JO - Diagnostic Pathology
JF - Diagnostic Pathology
SN - 1746-1596
IS - 1
M1 - 36
ER -