title: Expression of Cell Cycle Regulating Proteins in an Unusual Transformation of Mantle Cell Lymphoma.
abstract: We describe here two patients with mantle cell lymphoma (MCL) who after a few years, developed to the diffuse large cell lymphoma (DLCL)( anaplastic centrocytic lymphoma) growing in a diffuse sheets without the classical MCL component. In both the initial and second biopsy specimens, in each case, tumor cells were positive for cyclin D1, sIgM, sIgD, and CD5, but were negative for CD10 and CD23. In a study of immunoglobulin heavy chain (IgH) gene rearrangement, using the polymerase chain reaction (PCR) method, the products obtained from each paired biopsy tissue sample were the same size, and in one case had an identical sequence to the non-mutated VH gene. Immunohistochemistry was used to examine the expression of p53, p27(Kip1) and cyclin E. Interestingly, there was clear overexpression of p53 protein in case 1 but not in case 2, compared with other typical MCL cases. The expression of p27(Kip1) in the second biopsies of each case was decreased compared with those in the initial biopsies. In case 2, however, p27(Kip1) was clearly expressed in the first and second biopsies, in contrast to other typical MCL cases. Thus these 2 cases demonstrate not only that the variant form of MCL may arise de novo, but also that MCL may transform to DLCL at the time of relapse. Although the mechanism of tumor progression/transformation is still poorly understood, the overexpression of p53 or p27(Kip1) may be linked to a cellular mechanism involved in the development of the variant form of MCL.
authors.affiliation: First Department of Pathology; University School of Medicine, Chiba, Japan.
authors.initials: JI
authors.lastname: Tamaru
authors.initials: H
authors.lastname: Kawana
authors.initials: Y
authors.lastname: Takahashi
authors.initials: N
authors.lastname: Takahashi
authors.initials: K
authors.lastname: Isobe
authors.initials: A
authors.lastname: Hirai
authors.initials: Y
authors.lastname: Saito
authors.initials: K
authors.lastname: Harigaya
authors.initials: S
authors.lastname: Itoyama
authors.initials: A
authors.lastname: Mikata