 |
Vol.52 No.2 contents | Japanese/English |
 | Full Text of PDF (1033K) Article in Japanese |
- Review Article -
Morphological Characteristics of 9p21 Homozygous Deletion-Positive Malignant Pleural Mesothelioma Cells Detected by FISH
Kazuki Nabeshima1, Shinji Matsumoto1, Makoto Hamasaki1, Akiko Ohgami1, Toshiaki Kamei2, Akinori Iwasaki31Department of Pathology, Fukuoka University Hospital and School of Medicine, Japan, 2Division of Pathology, Yamaguchi Grand Medical Center, Japan, 3Department of Thoracic Surgery, Fukuoka University Hospital and School of Medicine, Japan
Background and Objective. The cytologic diagnosis of malignant pleural mesothelioma (MPM) in effusion smears is important, as most patients first present with pleural effusion. However, the lack of both well-established immunocytochemical markers and definite cytological criteria for MPM makes it difficult to discriminate MPM from reactive mesothelial cells (RMC) in effusion. Moreover, the presence of both MPM cells and RMC in effusion specimens from the same patient makes differentiation more difficult. The homozygous deletion of the CDKN2A/p16 gene in the 9p21 locus frequently occurs in MPM but has never been reported in RMC. The aim of this study was to define the cytomorphological characteristics of MPM cells in effusion by identifying them on the basis of the presence of p16 homozygous deletion by means of fluorescence in situ hybridization (FISH). Study Design. For the above purpose, cells on smear preparations were recorded using a virtual microscope system, and then analyzed by FISH. Thereafter, p16 homozygous deletion-positive cells were identified in the recorded virtual slides, followed by analysis of their morphological characteristics. Results. Compared with p16 deletion-negative RMC, p16 homozygous deletion-positive mesothelioma cells exhibited significantly more frequent cell-in-cell engulfment including hump formation, multinucleation (in particular, more than 3 nuclei), and larger multicellular clusters composed of more than 10 cells. Conclusion. The above findings were useful in the cytological differentiation of MPM from RMC cells. The combination of virtual microscopy and FISH was also shown to be useful for tumor morphological analysis.
key words: Pleural mesothelioma, Cytology, Fluorescence in situ hybridization (FISH), 9p21 homozygous deletion, p16
JJLC 52 (2): 201-208, 2012
