TYK2 Variants in B-Acute Lymphoblastic Leukaemia

Area of Science:

• Oncology
• Genetics
• Immunology

Background:

• B-cell precursor acute lymphoblastic leukaemia (B-ALL) is a cancer of lymphoid progenitor cells.
• The Janus kinase (JAK) gene family, including tyrosine kinase 2 (TYK2), is implicated in B-ALL.
• TYK2 plays a role in cytokine signaling via the interferon-alpha/beta receptor (IFNAR1).

Purpose of the Study:

• To identify and functionally characterize TYK2 variants associated with B-ALL.
• To investigate the role of TYK2 in B-ALL pathogenesis and immune surveillance.

Main Methods:

• Next-generation sequencing of bone marrow samples from 62 B-ALL patients.
• Site-directed mutagenesis to generate TYK2 variants (S431G, R425H, R832W).
• Functional assays including STAT1/2 and STAT3 phosphorylation, qPCR for gene expression, and molecular dynamics simulation.

Main Results:

• TYK2 variants were found in 25.8% of B-ALL patients.
• R425H and R832W variants induced STAT1/2-target genes, while S431G was kinase-dead.
• TYK2 expression was significantly lower in B-ALL patients compared to healthy donors.

Conclusions:

• Identified novel and rare TYK2 variants in B-ALL, with distinct functional consequences.
• TYK2 variants can impact STAT signaling pathways relevant to B-ALL.
• Diminished TYK2 expression in B-ALL suggests its involvement in anti-tumour immune surveillance.