Study of gene polymorphisms in Toll-like receptor 2 in patients with acute lymphoblastic leukemia

Acute Lymphoblastic Leukemia (ALL) is a multifactorial disease that results from the interaction between multiple genetic factors. ALL is characterized by uncontrolled production of hematopoietic precursor cells of the lymphoid progenitors within the bone marrow. The development of hematological malignancies has been associated with malignant-like cells that express low levels of immunogenic surface molecules, thus, facilitating their escape from cellular antineoplastic immune responses. This risk may be partly influenced by variations in polymorphic genes that control immune function and regulation. Toll-like receptors (TLRs) are well known pattern recognition receptors playing key role in innate immune response. Abnormal expression and dysregulation of TLRs will provide an opportunity for cancer cells to escape from the immune system and enhance their proliferation and angiogenesis. Toll-like receptor 2 (TLR2) play an essential role in innate immunity. Single nucleotide polymorphisms (SNPs) are present in a number of TLR genes and have been associated with various disorders.

In this study, 265 subjects have been divided into two groups included 150 patients with ALL and115 healthy volunteers. All subjects were genotyped using TaqMan PCR techniques. In total, Five SNPs were statistically evaluated in the TLR2 (rs1898830 A/G, rs3804099 T/C, rs3804100 T/C, rs1339 T/C, and rs1337 C/G), which may influence the susceptibility of ALL. Minor allele frequency and genotype distribution were compared across the study groups, and the relative risk and differences between patients and controls were estimated. Moreover, the mRNA expression level was evaluated in patients with ALL and the matched healthy individuals by Real-Time Quantitative Reverse Transcription PCR (qRT-PCR).

TLR2 rs1898830 A/G; rs3804099 T/C; rs3804100 T/C; rs1339 T/C, were significantly decrease the risk in our population, overall and for certain subtypes and ALL samples exhibited significant increase in the mRNA levels of TLR2.

This study shows that TLR2 could be an independent prognostic factor of ALL risks in the Saudi population. Suggesting that genetic variation in genes associated with an immune response may be important in the etiology of ALL. In addition, the results herein revealed that TLR2 overexpression is associated with ALL and has diverse biological significance in the context of the complex relationship between inflammation and cancer development. Therefore, these data could open further studies to explore the possible clinical relevance of TLRs as pathological markers for Leukemia and enhance the strategies regarding hematological malignancies prevention based on their gene expression.