Histone Deacetylase 8 (HDAC8)

Histone deacetylases (HDACs) are a large family of enzymes originally identified as key regulators of nucleosomal histone acetylation, thereby controlling gene transcription. Specific HDACs have also been shown to deacetylate non-histone proteins (including tumor suppressor p53 and the cytoskeletal protein a-tubulin), indicating that these enzymes may be involved in the regulation of other processes. HDAC8, a class I HDAC, has a mainly cytosolic distribution and is exclusively expressed by cells showing smooth muscle differentiation, including visceral and vascular smooth muscle cells, myoepithelial cells, and myofibroblasts. HDAC8 associates with SMA and may regulate smooth muscle cytoskeleton dynamics2.

Immunohistochemical expression (cytoplasmic)

Non-neoplastic tissues:

• Smooth muscle:

  • Small intestinal and colonic muscularis mucosae and muscularis propria2

  • Muscular layer of renal pelvis, ureter and bladder, vas deferens and epididymis periductal layer2

  • Myometrium, cervical stroma and Fallopian tube muscle2

  • Vascular smooth muscle1,2

  • Skin erector pili smooth muscle2

• Myofibroblasts2

  • Lung alveolar septal myofibroblasts2

  • Subepithelial myofibroblasts in lamina propria of the gastrointestinal tract2

  • Prostatic stromal cells2

  • Testis peritubular myoid cells2

  • Ovarian external theca cells2

• Myoepithelial cells2

  • Tracheal, bronchial and bronchiolar myoepithelial cells from mucous glands2

  • Salivary glands myoepithelial cells2

  • Myoepithelial cells of sweat glands2

  • Mammary gland myoepithelial cells of lobules and ducts 2

It is not expressed by:

• Myocardium2

• Skeletal muscle2

• Endometrial stroma1

• Nervous system (spinal cord, peripheral nerves and brain)2

• Bone2

In uterine tumours:

Diagnostic utility

• Differentiation of uterine smooth muscle tumours from endometrial stromal tumours. HDAC8 may be a more sensitive marker than desmin and h-caldesmon in epithelioid smooth muscle tumours1.

References

1 de Leval L, Waltregny D, Boniver J, et al. Use of histone deacetylase 8 (HDAC8), a new marker of smooth muscle differentiation, in the classification of mesenchymal tumors of the uterus. Am J Surg Pathol 2006; 30:319-27

2 Waltregny D, De Leval L, Glenisson W, et al. Expression of histone deacetylase 8, a class I histone deacetylase, is restricted to cells showing smooth muscle differentiation in normal human tissues. Am J Pathol 2004; 165:553-64 FULL TEXT

This page last revised 10.4.2006.

©SMUHT/PW Bishop