Mantle cell lymphoma (MCL) is a type of non-Hodgkin's lymphoma (NHL), comprising about 6% of NHL cases. There are only about 15,000 patients presently[when?] in the United States with mantle cell lymphoma. It is named for the mantle zone of the lymph nodes. MCL is a subtype of B-cell lymphoma, due to CD5 positive antigen-naive pregerminal center B-cell within the mantle zone that surrounds normal germinal center follicles. MCL cells generally over-express cyclin D1 due to the t(11:14) translocation, a chromosomal translocation in the DNA. From Wikipedia