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MA04 - HER2, P53, KRAS and Other Targets in Advanced NSCLC (ID 380)
- Event: WCLC 2016
- Type: Mini Oral Session
- Track: Advanced NSCLC
- Presentations: 1
MA04.01 - Non-Amplification Mutation of ERBB2 in EGFR-Mutated Lung Cancer (ID 6138)
16:00 - 17:30 | Author(s): K. Gowen
Amplification of ERBB2 in EGFR-mutant lung cancers is a reported mechanism of acquired resistance to tyrosine kinase inhibitor (TKI) therapy. Comprehensive genomic profiling (CGP) of NSCLC tumors shows mutation of ERBB2, most often affecting the encoded HER2 receptor at residue S310, is also prevalent, particularly in the context of EGFR L858R.
CGP was performed on hybridization-captured, adaptor ligation-based libraries for up to 315 cancer-related genes plus select introns from 28 genes frequently rearranged in cancer on 14,887 consecutive cases of lung cancer. All classes of genomic alterations (GA) were assessed simultaneously, including base substitutions, indels, rearrangements/fusions, and copy number changes. Short variants (SV) include base substitutions or indels.
A total of 2,516 (16.9%) samples featured EGFR alterations, including amplification (amp) and SV. Of these, 2.9% (73/2,516) harbored alterations in ERBB2 (amp and/or SV). 18 samples (0.7%) harbored SV alterations in ERBB2, 14 of which were mutations at S310. ERBB2 S310 mutations were most often found with EGFR L858R. The ratio of observed to expected mutation at HER2 S310 in EGFR-mutated lung cancers was 2.12, and the ratio for HER2 S310 in combination with EGFR L858R was 5.03. The co-occurrence of HER2 S310 and EGFR L858R was highly significant (p<0.00005). The combination of EGFR and ERBB2 alterations was more common in women. The ratio of male:female patients with any lung cancer in this dataset was 1:1.1, whereas the ratio of male:female with any EGFR alteration was 1:1.7 and for both EGFR and ERBB2 alterations (amp or SV) was 1:3.4. Patients with a combination of EGFR and ERBB2 alterations have been shown to respond to treatment with the pan-ERBB inhibitor afatinib, or combinations of afatinib with the HER2-targeted therapy trastuzumab.
Short variant alterations in ERBB2 may be an additional mechanism for tumors to acquire resistance to treatment with EGFR-targeted TKIs. Mutations at residue S310, in the extracellular domain of HER2, are the most common ERBB2 SV observed in EGFR-mutant lung cancer, and are significantly associated with EGFR L858R. The co-occurence of alterations in ERBB2 and EGFR is far more common in women than in men. Treatment with the pan-ERBB inhibitor afatinib, alone or in combination with agents targeting HER2, has been shown to benefit patients with lung cancer harboring mutations in both EGFR and ERBB2.
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