ALK rearranged cancer cell lines are sensitive to heat-shock protein 90 (Hsp90) inhibitors. (A) Cancer cell lines with epidermal growth factor receptor (EGFR) mutations (H1975, L858R/T790M, and HCC827 exon 19 deletion) or ALK gene rearrangement (H3122 and MGH-006) were treated with increasing doses of the Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) for 24 hours.