[1510] FISH Analysis of Blastic Plasmacytoid Dendritic Cell Neoplasm for 9p21.3 Deletion

Reza Setoodeh, Haipeng Shao, Dahui Qin, Lynn Moscinski, Maryam Tahmasbi, Mojdeh Naghashpour, Ling Zhang, Kenian Liu. University of South Florida, Tampa, FL; Moffitt Cancer Center, Tampa, FL

Background: Blastic plasmacytoid dendritic cell neoplasm (BPDCN), a malignant proliferation of precursors of professional type-1 interferon-producing plasmacytoid dendritic cells, is a rare but well-recognized hematopoietic malignancy with an aggressive clinical course. The tumor usually presents as skin lesions in the elderly men with a diffuse dermal infiltrate of medium-sized blast cells. Genetic data is limited for this entity due to rarity of cases. Six recurrent chromosomal abnormalities are reported in the literature with the deletion 9p21.3 being the most common, identified in 28-66% of cases. This genetic change is reportedly related with a poor prognosis. 9p21.3 contains cyclin-dependent kinase inhibitor 2A gene (CDKN2A), a tumor suppressor gene with an important role in regulating the cell cycle. CDKN2A loss of function caused by chromosome 9p deletion is associated with increased risk of developing a variety of cancers.
Design: From Moffitt Cancer Center database slides were retrieved and deparaffinized. Tissues was treated in pepsin solution at 37 °C for 20 min, followed by serial dehydration in 70%, 85%, and 100% ethanol for 2 min each. After air dry, 10 µl of diluted Vysis LSI CDKN2A Spectrum Orange/CEP 9 Spectrum Green was applied to tissue area. Slides were subjected to processes of denaturation at 80 °C for 10min and hybridization at 37 °C overnight. The slides were washed and counterstained with DAPI. Results were analyzed under a fluorescence microscope. In a selected area, total 400 signals were recorded, among these, ratio of orange to green signal is less than 70% is considered to be positive for deletion of CDKN2A gene in the specimen.
Results: In 6 male patients with mean age of 71 years, presenting with skin lesions; FISH analysis revealed 9p21 deletion in two out of six cases (33%).

Survival rate in patients with 9p21.3 deletion is 30 months compare to 29 months in cases without deletion.
Conclusions: Our study corroborates previous reports of 9p21.3 deletion in some BPDCN cases. Presence of high percentage of chromosome 9p deletion encompassing CDKN2A gene indicates that loss of this gene is related to BPDCN oncogenesis. However we didn't observe any significant prognostic effect of 9p21.3 gene status on the survival rate.
Category: Hematopathology

Tuesday, March 5, 2013 9:30 AM

Poster Session III # 176, Tuesday Morning

 

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