BCL2 and mantle cell lymphoma: The overexpression of Cyclin D1, which occurs in more than 90% of mantle cell lymphoma patients,5, 36 is correlated with higher rates of tumor cell growth and decreased survival.48 We also examined two anti‐apoptotic proteins in the Bcl‐2 family: Bcl‐2, which is commonly overexpressed in mantle cell lymphoma, and Mcl‐1.