In silico analysis of the differential expression of the LEF1 gene in APL identified 9 differentially expressed, up-modulated genes (ETS1, FAIM3, CCR7, IL7R, LCK, IL2RB, ITK, RASGRP1, TRBC1), associated with a high expression of LEF1 (Figure 4); GO analysis revealed that the majority of these genes is involved in the regulation of apoptosis (FAIM3, IL2RB, LCK, ETS1). The gene discussed is LCK; the disease is acute promyelocytic leukemia.