In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 24, No. 18_suppl ( 2006-06-20), p. 7171-7171
Abstract:
7171 Background: EGFR, the presumed target of gefitinib and erlotinib, has been studied (expression, gene copy number, & mutations) for predicting response to these tyrosine kinase inhibitors (TKI), in non-small cell lung cancer (NSCLC). ’High polysomy’ and ’amplification’ of the EGFR gene, as defined by Cappuzzo et al. JNCI 97:643, using fluorescence in situ hybridization (FISH), showed significant association with objective response (Resp) and survival. We also measured EGFR and chromosome 7 (C7) copy numbers by FISH in 81 gefitinib-treated NSCLC patients (12 Resp). Using Cappuzzo’s FISH± parameter alone we saw similar trends but no statistical significance in the 81 patient group. Therefore we sought to optimize FISH parameters for these patients. Methods: FISH was performed (paraffin sections) using a 2-color probe set (Vysis LSI EGFR/CEP 7), median 80 cells per specimen. 〉 50 parameters were derived from the data (e.g. mean EGFR/cell, C7/cell etc) and compared, using different threshold values, to Resp and survival. Results: The best single parameter associated with survival was the average C7/cell. Applying upper and lower thresholds of 3.6 and 2.0 C7/cell to delineate moderate from extreme ratios yielded median survival of 177 and 465 d, respectively (Kaplan-Meier, p 〈 .002). A single threshold of 3.6, separating low from high, yielded survival of 201 and 522 d, respectively (p 〈 .01). For these thresholds C7/cell was not associated with Resp, however, thresholds could be found for which both survival and Resp were significant. The best single parameter associated with Resp was average EGFR/cell. Of the 70 patients with EGFR/cell≤6.0, 63 (90%) did not respond while 5 of 11 patients (45%) with EGFR/cell 〉 6.0 responded (p 〈 .01). No EGFR/cell threshold could be found for which both survival and Resp were significant. Many 2-parameter combinations provided significant associations with both survival and Resp. Conclusions: Several FISH-derived parameters were significantly associated with either survival or Resp to gefitinib and a subset were associated with both. These parameters must be tested on independent data sets to determine their value in directing TKI therapy. [Table: see text]
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/jco.2006.24.18_suppl.7171
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2006
detail.hit.zdb_id:
2005181-5
detail.hit.zdb_id:
604914-X
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