To demonstrate that microFTIR combined with unsupervised multi-parametric analysis in spectra is a robust method to achieve rapid and accurate information on drug-sensitivity and drug-resistance in leukemic cells. The FTIR absorbance spectra of single Ba/F3 cells expressing the drug-sensitive p210BCR-ABL or the drug-resistant p210T315IBCR-ABL mutant exposed to drugs, and of blast cells isolated from patients with Chronic Myeloid Leukemia (CML) responsive and non responsive to common anti-leukemic treatment protocols will be obtained. To identify drug-sensitive and drug-resistant cells, we will apply cluster analysis (CA) to selected intervals of frequencies where signatures of interference with BCR-ABL are expected in the IR spectrum of cells exposed to different drugs. Cross-validation will be obtained by complementary analyses in samples and correlation studies will be carried out.