Resistance to chemotherapy is one of the most relevant aspects of treatment failure in cancer. Cell lines are used as models to study resistance. We analyze the transcriptional profile of two multidrug resistant (MDR) cell lines (Lucena 1 and FEPS) derived from the same drug-sensitive cell K562. Microarray data identified 130 differentially expressed genes (DEG) between K562 vs Lucena, 1,932 between K562 vs FEPS, and 1,211 between Lucena 1 versus FEPS. The NOTCH pathway was affected in FEPS with overexpression of NOTCH2 and HEY1. The highly overexpressed gene in MDR cell was ABCB1, and both presented the ABCB1 promoter unmethylated.