Cyclin D1 (bcd-1) is most commonly used diagnostically for confirming the diagnosis of mantle cell lymphoma (positivity should be diffuse, but intensity may be variable).   It has also been described to be expressed in invasive breast carcinoma.  While it is generally considered a specific marker (given the differential diagnosis usually with CLL/SLL), and can also be expressed in plasma cell neoplasms (40%) and hairy cell leukemia (25%).  One can also often see focal nuclear expression in vascular endothelial cells and other stromal cells, which should not be interpreted as focal positivity.

 

Given the small but variable expression of CD23 between CLL/SLL and Mantle cell lymphoma, including CyclinD1 in the standard IHC panel for this differential is recommended.

Recently cyclin D1 expression in proliferation centers of cases of CLL/SLL have been described, which should not be confused with diffuse expression encountered in cases of mantle cell lymphoma. 

There are several clones available, but the most sensitive marker is the rabbit monoclonal antibody from Biocare Medical.  Other clones are not recommended.

Gradowski, J. F., Sargent, R. L., Craig, F. E., Cieply, K., Fuhrer, K., Sherer, C., & Swerdlow, S. H. (2012). Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma With Cyclin D1 Positive Proliferation Centers Do Not Have CCND1 Translocations or Gains and Lack SOX11 Expression. American Journal of Clinical Pathology, 138(1), 132–139. doi:10.1309/AJCPIVKZRMPF93ET

 

Bone Marrow IHC.  Torlakovic, EE, et. al. American Society for Clinical Pathology Pathology Press © 2009.  pp. 221.