SHP1 is a non-receptor protein tyrosine phosphatase primarily encoded by the gene PTPN6.
Immune Checkpoint Brake, Tumor Suppressor Signaling, and Immune Evasion
– In blood cancers such as leukemia and lymphoma, altered SHP1 expression (often downregulation) is frequently observed.
– Downregulation or loss of SHP1 is often associated with more aggressive disease phenotypes and poorer prognosis.
Direction of Regulation in Cancer
Two distinct, context-specific directions:
A. Tumor Cells (especially hematologic malignancies): DOWNREGULATED
-Frequently silenced epigenetically (promoter methylation)
-Rarely mutated; loss is regulatory
-Results in unchecked growth and survival signaling
B. Immune Cells within the Tumor Microenvironment: FUNCTIONALLY UPREGULATED
-Actively recruited by inhibitory receptors
-Suppresses T-cell, NK-cell, and myeloid anti-tumor responses
-Promotes immune evasion
This duality is critical to interpret SHP1 correctly.
When SHP1 is lost in tumor cells:
-JAK–STAT signaling becomes hyperactive
-Growth and survival pathways escape negative feedback
-Cells gain a proliferative and survival advantage
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