In this work , we try to investigate anew marker for early detection and diagnosis of malignant tumor .also, we can used it to classified the different type of malignancy. Lactate dehydrogenase enzyme was found in animal and human and play important role in gluconeogenesis process. Lactate dehydrogenases represented as supplementary enzymatic tool can be used as differentiation marker between the different types of leukemia not only but also, follow up the patients during treatment period.