CYB5B and anaplastic large cell lymphoma: Since there was evidence that HL cell lines KMH2 and L428 consistently showed increased expression of CYB5B mRNA regardless of the assay method used, and ALCL cell line DEL also showed an increase at even higher levels than the 2 HL cell lines, one of the possible explanations was amplification of the CYB5B gene in these cell lines.