KDM6A (UTX): An X-Linked Histone Demethylase Tumour Suppressor
KDM6A, also known as UTX, is an enzyme that removes methyl groups from lysine 27 of histone H3, directly opposing the polycomb complex that adds them. It is a tumour suppressor across several cancer types, and its position on the X chromosome gives it an unusual relationship with biological sex.
Quick Answer
KDM6A, also known as UTX, is an enzyme that removes methyl groups from lysine 27 of histone H3, directly opposing the polycomb complex that adds them. It is a tumour suppressor across several cancer types, and its position on the X chromosome gives it an unusual relationship with biological sex.
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Cancer Epigenetics and Chromatin Regulators
Open the complete 15-article guideErasing a Repressive Mark
KDM6A demethylates H3K27me2 and H3K27me3, the marks written by EZH2 within polycomb repressive complex 2. By removing them, KDM6A helps switch on genes that drive differentiation, and it also works within COMPASS-like complexes alongside KMT2C and KMT2D at enhancers.
Loss of KDM6A therefore tips the balance toward polycomb-mediated repression, keeping differentiation genes silenced.
The X-Chromosome Dimension
KDM6A escapes X-inactivation, so females typically express it from both X chromosomes while males have a single copy plus a partly redundant Y-linked paralogue, UTY, that lacks demethylase activity. This has been proposed to contribute to the male predominance of some KDM6A-mutant cancers, such as bladder cancer.
In practice a single inactivating hit can be sufficient to reduce KDM6A function in male cells, whereas female cells may need two.
Where Loss Is Seen
KDM6A is recurrently inactivated in bladder cancer, where it is one of the most frequently mutated genes, and in T-cell acute lymphoblastic leukaemia, multiple myeloma, pancreatic cancer and others. Germline KDM6A variants cause a form of Kabuki syndrome.
KDM6A-deficient cancer cells have shown increased sensitivity to EZH2 inhibition in laboratory models, because they depend more heavily on polycomb repression, but this is investigational.
Clinical Relevance Today
KDM6A status does not currently direct therapy. Its clearest practical use is as one of the recurrently mutated genes that build the molecular picture of bladder cancer, where chromatin-regulator loss is near-ubiquitous, and as a pointer to a possible Kabuki-syndrome diagnosis if a loss-of-function variant is germline.
The EZH2 dependency of KDM6A-deficient cells is the most actively pursued therapeutic idea, tested with EZH2 inhibitors in early-phase trials, but it has not reached routine use.
Key Takeaways
- ·KDM6A removes the repressive H3K27 methyl mark and promotes differentiation gene expression.
- ·It escapes X-inactivation, which may underlie sex differences in some KDM6A-mutant cancers.
- ·Loss is common in bladder cancer and creates a research-stage dependency on EZH2 activity.
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Frequently asked questions
Why are some KDM6A-mutant cancers more common in males?
KDM6A is on the X chromosome and escapes X-inactivation, so females usually express it from two copies while males have one plus an inactive Y-linked paralogue. A single hit can therefore reduce function more readily in male cells.
Is KDM6A loss targetable?
Only in research. KDM6A-deficient cells depend more on polycomb repression and have shown sensitivity to EZH2 inhibition in laboratory models, but this is investigational.
Which cancer most often carries KDM6A mutations?
Bladder cancer, where KDM6A is among the most frequently mutated genes; loss also occurs in T-cell acute lymphoblastic leukaemia, multiple myeloma and pancreatic cancer.
References
Continue Reading
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