Gene polymorphisms of SOCS1 and SOCS2 and acute lymphoblastic leukemia.

OBJECTIVE

Acute lymphoblastic leukemia (ALL) causes the dysfunction of the systemic blood system and immune system. The etiology and predisposing factors of ALL are unknown. The suppressor of cytokine signaling 1 (SOCS1) and SOCS2 are inhibitors of cytokine signal transduction. Gene polymorphisms of SOCS1 and SOCS2 and their expressions may be related to ALL.

PATIENTS AND METHODS

A total of 200 ALL patients in our hospital and 200 healthy people were enrolled in ALL group and control group, respectively. Genomic deoxyribonucleic acids (DNAs) and total RNAs were extracted from the peripheral blood of each subject. Gene polymorphisms of SOCS1 at rs33977706, rs243327, and rs33932899 and those of SOCS2 at rs3816997 were amplified by polymerase chain reaction (PCR) and sequenced. Besides, the expression levels of SOCS1 and SOCS2 in ALL patients were detected by real-time fluorescence quantitative PCR.

RESULTS

The frequency of the allele C of SOCS1 rs33977706 in ALL group was lower than that in the control group, displaying a significant difference between the two groups (p=0.015). The frequency of allele A of SOCS2 rs3816997 was notably higher in ALL group than that of the control group (p=0.000). In addition, the frequency of CA genotype of SOCS1 rs33977706 in ALL group was markedly lower than that in the control group, showing a significant difference (p=0.000). ALL group had remarkably higher frequencies of AA genotype of SOCS2 rs3816997 (p=0.000) and ACC haplotype of SOCS gene (p=0.000), and lower frequencies of ATG (p=0.026) and CCC (p=0.006) haplotypes. The two loci, SOCS1 rs33932899 and SOCS1 rs243327, were linked to each other (D'=0.781). Moreover, the expression level of SOCS1 in ALL group was lower than that in the control group, in which the expression of the CT genotype of SOCS1 rs243327 was relatively higher (p=0.021). SOCS2 level was lower in ALL group. Particularly, SOCS2 level in ALL patients carrying AC genotype was lower than those carrying AA and CC genotypes (p=0.000). ALL patients carrying CT genotype of SOCS1 rs243327 had shorter period of agranulocytosis (p=0.000), a lower ratio of bone marrow primitive/immature cells (p=0.001), and a higher hemoglobin (Hb) level in blood (p=0.000). The ratio of bone marrow primordial/immature cells was lower in ALL patients with AC genotype of SOCS2 rs3816997 (p=0.038).

CONCLUSIONS

The expression levels of SOCS1 and SOCS2 are prominently related to ALL, and their polymorphisms are associated with the susceptibility to ALL.