Histologic, immunophenotypic, and cytogenetic findings in 2 cyclin D1–negative/cyclin D2–positive MCLs withIGK-CCND2fusion. (A,D) Hematoxylin and eosin (H&E)–stained lymph node biopsies of cases 1 (A) and 2 (D) showing the typical morphology of MCL. (B) Chromosome R-banding analysis of case 1 revealing the karyotype 48,XX,t(2;12)(p12;p13),+3,+21. (C insert, E) Interphase FISH analysis using double-color, double-fusion probes spanning the IGK (green) and CCND2 (red) loci.1,2 Both cells in case 1 (C insert) and several cells in case 2 (E) show 2 fusion (yellow, arrows) signals indicating IGK-CCND2 juxtaposition in addition to isolated red and green signals indicating intact CCND2 and IGK loci. (C,F) Cyclin D2 nuclear expression in the tumor cells detected by immunohistochemistry using a polyclonal anti–cyclin D2 antibody, as described recently.1 H&E images were visualized under a Zeiss Axioskop 40 microscope (Carl Zeiss, Jena, Germany) equipped with a 40 ×/0.75 objective lens and an RT Slider camera (Diagnostic Instruments, Sterling Heights, MI). Images were processed with MetaVue software (Diagnostic Instruments) and Adobe Photoshop (Adobe Systems, San Jose, CA). FISH images were acquired with a 63 ×/1.40 oil-immersion objective in a Zeiss Axioskop2 fluorescence microscope (Zeiss, Göttingen, Germany) equipped with the appropriate filter sets (AHF, Tübingen, Germany), and were documented and processed using the ISIS imaging system (MetaSystems, Altlussheim, Germany).
