Heterogeneity of EGFR Aberrations and Correlation with Histological Structures: Analyses of Therapy-Naive Isogenic Lung Cancer Lesions with EGFR Mutation.

These data indicate that expression of EGFR mutant protein and EGFR gene copy number do not change as a consequence of tumor progression. This also justifies using the biopsy specimens from metastases as a surrogate for primary tumors.