cDNA sequencing of ALK kinase domain revealed activating mutations—I1171T in Karpas299CR and F1174C in Karpas299CHR...everolimus, an inhibitor of mammalian target of rapamycin (mTOR), suppressed growth of parental and resistant cells at low nanomolar concentrations, albeit it demonstrated a little weaker efficacy against Karpas299CHR cells (p < 0.0001).