Makoto Hamasaki1, Shinji Matsumoto1, Sousei Abe2, Daisuke Hamatake2, Toshiaki Kamei3, Kenzo Hiroshima4, Kunimitsu Kawahara5, Ayuko Sato6, Tohru Tsujimura6, Yukio Nakatani7, Yasuhiro Yoshida2, Akinori Iwasaki2, Kazuki Nabeshima8. 1. Departments of Pathology, Fukuoka University Hospital and School of Medicine, Fukuoka, Japan. 2. Departments of Thoracic Surgery, Fukuoka University Hospital and School of Medicine, Fukuoka, Japan. 3. Pathology and Cytology Center of the PCL Fukuoka, Fukuoka, Japan. 4. Department of Pathology, Tokyo Women's Medical University Yachiyo Medical Center, Yachiyo, Japan. 5. Department of Pathology, Osaka Prefectural Hospital Organization, Osaka Prefectural Medical Center for Respiratory and Allergic Disease, Habikino, Japan. 6. Department of Pathology, Hyogo College of Medicine, Hyogo, Japan. 7. Department of Diagnostic Pathology, Graduate School of Medicine, Chiba University, Chiba, Japan. 8. Departments of Pathology, Fukuoka University Hospital and School of Medicine, Fukuoka, Japan. Electronic address: kaznabes@fukuoka-u.ac.jp.
Abstract
OBJECTIVES: Homozygous deletion (homo-d) of the p16 (CDKN2A) gene, as determined by fluorescence in situ hybridization (FISH), helps differentiate malignant pleural mesothelioma (MPM) from reactive mesothelial hyperplasia (RMH). Heterozygous deletion (hetero-d) has also been identified variably in p16 FISH. This study aimed to investigate the significance of homo-d and hetero-d of p16 in the diagnosis and prognosis of MPM. MATERIALS AND METHODS: p16 FISH was performed in 93 MPMs and 47 RMHs. Real-time polymerase chain reaction (PCR) and methylation specific PCR (MSP) were also performed for cases in which DNA was available. Overall survival (OS) was assessed via the Kaplan-Meier method and logrank test. RESULTS: Cutoff values for homo-d and hetero-d were set at 10% and 47%, respectively, based on p16 FISH results in RMH. In MPM, 80/93 (86.0%) were homo-d positive, and 15/93 (16.1%) were hetero-d positive. No RMH was homo/hetero-d positive. In nine cases of MPM with the low homo-d (<30%)/high hetero-d (>47%) pattern, FISH with a shorter probe caused a slight increase (from 20.1% to 26.5%) in the mean percentage of homo-d and a decrease in that of hetero-d (from 59.6% to 55.6%). Four cases in which the low homo-d/high hetero-d pattern was maintained with the shorter probe were further analyzed by real-time PCR, which separated them into a two (n=2) or one allele deletion group (n=2). MSP revealed no promoter methylation in the two cases with one allele deletion. The OS was significantly shorter in homo-d positive cases (n=24) than homo-d negative cases (n=5, p=0.0002) in the 29 MPM cases with follow-up data. Also, low homo-d/high hetero-d cases (n=5) had a significantly better prognosis than high homo-d (≥30%) cases (n=17, p=0.011). CONCLUSIONS: Within p16 homo-d positive MPMs with poorer prognosis, the low homo-d/high hetero-d pattern may belong to a better prognostic subgroup in homo-d positive MPMs.
OBJECTIVES: Homozygous deletion (homo-d) of the p16 (CDKN2A) gene, as determined by fluorescence in situ hybridization (FISH), helps differentiate malignant pleural mesothelioma (MPM) from reactive mesothelial hyperplasia (RMH). Heterozygous deletion (hetero-d) has also been identified variably in p16 FISH. This study aimed to investigate the significance of homo-d and hetero-d of p16 in the diagnosis and prognosis of MPM. MATERIALS AND METHODS: p16 FISH was performed in 93 MPMs and 47 RMHs. Real-time polymerase chain reaction (PCR) and methylation specific PCR (MSP) were also performed for cases in which DNA was available. Overall survival (OS) was assessed via the Kaplan-Meier method and logrank test. RESULTS: Cutoff values for homo-d and hetero-d were set at 10% and 47%, respectively, based on p16 FISH results in RMH. In MPM, 80/93 (86.0%) were homo-d positive, and 15/93 (16.1%) were hetero-d positive. No RMH was homo/hetero-d positive. In nine cases of MPM with the low homo-d (<30%)/high hetero-d (>47%) pattern, FISH with a shorter probe caused a slight increase (from 20.1% to 26.5%) in the mean percentage of homo-d and a decrease in that of hetero-d (from 59.6% to 55.6%). Four cases in which the low homo-d/high hetero-d pattern was maintained with the shorter probe were further analyzed by real-time PCR, which separated them into a two (n=2) or one allele deletion group (n=2). MSP revealed no promoter methylation in the two cases with one allele deletion. The OS was significantly shorter in homo-d positive cases (n=24) than homo-d negative cases (n=5, p=0.0002) in the 29 MPM cases with follow-up data. Also, low homo-d/high hetero-d cases (n=5) had a significantly better prognosis than high homo-d (≥30%) cases (n=17, p=0.011). CONCLUSIONS: Within p16 homo-d positive MPMs with poorer prognosis, the low homo-d/high hetero-d pattern may belong to a better prognostic subgroup in homo-d positive MPMs.
Authors: Marieke Hylebos; Guy Van Camp; Geert Vandeweyer; Erik Fransen; Matthias Beyens; Robin Cornelissen; Arvid Suls; Patrick Pauwels; Jan P van Meerbeeck; Ken Op de Beeck Journal: Oncotarget Date: 2017-12-01