Abstract: The invention relates to an in vitro analysis method for predicting resistance to azacitidine treatment in a patient, using the BCL2L10 protein contained in a sample of biological fluid taken from said patient, and also biological molecules which specifically bind the BCL2L10 protein. It is characterized in that a sample of biological fluid is recovered from a patient; the percentage of total cells in said biological fluid expressing the BCL2L10 protein is calculated; this calculated percentage is compared with a reference threshold value, this threshold value being between 20% and 60%; and resistance to azacitidine treatment is diagnosed in a patient who has a percentage of cells expressing the BCL2L10 protein in said biological fluid which is greater than said reference value.