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 a t(11:14)[3] chromosomal translocation in the DNA. Specifically, the translocation is at t(11;14)(q13;q32).[4][5]