Table 2.

EGFR gene copy analysis in patients with acquired resistance to gefitinib or erlotinib

SamplePrimary mutationSecondary mutationEGFR copy number
1*del L747-E749;A750PT790M5.7
2del E746-A750T790M5.1→6.3
3del L747-P753insST790M9.6→11
4L858RD761Y6.0
5*del E746-A750None2.9→6.1
6del E746-A750None8.4
7del E746-A750None5.7
8del E746-A750None7.2
  • NOTE: Tumor specimens pre- or post-EGFR TKI treatment were analyzed for EGFR copy number by chromogenic in situ hybridization (CISH) as per Materials and Methods. CISH values represent the average of signals for 30 nuclei per specimen examined. Pretreatment to posttreatment changes are indicated by an arrow; if only one value is listed, it was obtained from the posttreatment specimen.

  • * Patient previously reported [Pao et al. (6)].