Abstract: The present disclosure concerns a method for the identification of the presence or absence of cancer cells in a biological sample, more particularly a method for the identification of the susceptibility or resistance to a treatment with CD20 agonists of cancer cells in a biological sample, the methods including determining the level of expression of the gene Cyclon in the cells and comparing the level of expression to the level of expression in a non-cancer cell, wherein a level of expression higher than the level of expression in a non-cancer cell is an indication of the presence of a cancer cell, more particularly an indication of cancer cells with a resistance to treatment with antagonists. Kits for the determination of a level of expression of the Cyclon gene in a biological sample, a method for the identification of Cyclon expression antagonists, and methods for treating patients are provided.