We used the prior information of the Chronic myeloid leukemia pathway to estimate the block-precision matrix using samples of first condition (i.e., patients without ABL/BCR genomic rearrangement) and we performed gene-wise likelihood ratio tests in order to ascertain which gene was the most likely perturbation candidate. This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.