Table 3.

Characteristics of genes, their mutations, and pathological and therapeutic effects responsible for resistance to steroids and purine analogs.

Gene and Locus	Gene Mutation	Effects on Pathology	Effects on Treatment
NT5C2 (locus 10q24.32-q24.33)	High expression	Controls the number of purine nucleotides in the cell and their outflow	Resistance to 6-MP
PRSP1 (locus Xq22.2), PRSP2 (locus Xq22.3)	Low expression	Purine and pyrimidine biosynthesis disorder	Resistance to 6-MP and 6-TG
MSH6 (locu 2p16.3)	Hemizygous deletion, downregulation	Despite the presence of thiopurines, the loss of MSH6 produces a lack of cell apoptosis, which leads to an increase in blast survival	Resistance to 6-MP and prednisone
SETD2 (locus 3p21.3)	Loss-of-function, frameshift, nonsense mutations, low expression	Tumor suppression is absent	Resistance to 6-MP