First, a PLS model in the spectral range of 1800–500 cm−1 has been established comparing leukemic cells (BCR-ABL1, TCF3-PBX1, and TEL-AML1) with normal lymphocytes (Figure 6) and cancers cells with BCR-ABL1 and TCF-PBX1 mutations (Figure 7). The gene discussed is ETV6; the disease is cancer.