KRAS and melanoma: Specifically, cytospin-prepared slides with an admixture containing a majority of Burkitt lymphoma cells (ST486, KRAS and BRAF wild-type) and either a lung carcinoma cell line (A549, KRAS+ homozygous mutation) or melanoma cell line (UACC.62, BRAF+ heterozygous mutation) in a 20:1 ratio were generated and used in all subsequent experiments.