Six of the seven patients harbored a known sensitizing mutation in their tumor EGFR (five exon 19 deletions, 1 L858R mutation); a seventh patient had insufficient tissue for EGFR mutation analysis but was eligible for enrollment based on a radiographic response to prior therapy with an EGFR-TKI; she had received a total of 20 months of vandetanib before developing leptomeningeal metastases as her primary site of metastasis. This evidence concerns the gene EGFR and neoplasm.