title: Increased occurrence of caspase-dependent apoptosis in unfavorable neuroblastomas.
abstract: Neuroblastoma frequently shows spontaneous regression in which two distinct types of programmed cell death, ie, caspase-dependent apoptosis and H-Ras-mediated autophagic degeneration, have been suggested to play a key role. The current study was conducted to determine which of these cell suicide pathways predominated in this tumor regression. Periodic acid-Schiff (PAS) staining and immunostaining for H-Ras and for the full-length and cleaved forms of caspase-3, poly (ADP-ribose) polymerase (PARP), and lamin A were carried out on 55 archival tumor specimens. The incidence of caspase-dependent apoptosis in each tumor was quantified by cleaved lamin A staining and compared with clinicopathologic prognostic factors. Although a recent report has shown that neuroblastic cells undergoing autophagic degeneration were readily detectable by PAS and H-Ras staining, we could not confirm this result in any of our samples with the exception of one tumor. Instead, many of our neuroblastoma samples showed nonspecific PAS and Ras staining in areas of necrosis, suggesting that autophagic "degeneration" indeed corresponds to coagulation necrosis or oncosis. Unexpectedly, the incidence of caspase-dependent apoptosis was significantly correlated with indicators of a poor prognosis in these tumors, including Shimada's unfavorable histology, MYCN amplification, and a higher mitosis-karyorrhexis index, but not with factors related to tumor regression such as clinical stage and mass screening. These results indicate that neither caspase-dependent apoptosis nor autophagic "degeneration" may be involved in spontaneous neuroblastoma regression. This suggests that other mechanisms, perhaps such as tumor maturation, may be responsible for this phenomenon.
authors.affiliation: Department of Diagnostic Pathology, St. Marianna University School of Medicine, Miyamae, Kawasaki, Japan. koizumi@marianna-u.ac.jp
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Koizumi
authors.forename: Shiho
authors.initials: S
authors.lastname: Hamano
authors.forename: Masatomo
authors.initials: M
authors.lastname: Doi
authors.forename: Shinobu
authors.initials: S
authors.lastname: Tatsunami
authors.forename: Kounosuke
authors.initials: K
authors.lastname: Nakada
authors.forename: Toshihito
authors.initials: T
authors.lastname: Shinagawa
authors.forename: Mamoru
authors.initials: M
authors.lastname: Tadokoro
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism*; D011905:Genes, ras; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D034904:Lamin Type A / Q000378:metabolism; D018613:Microscopy, Confocal; D000071447:N-Myc Proto-Oncogene Protein; D009336:Necrosis / Q000473:pathology; D009365:Neoplasm Regression, Spontaneous / Q000503:physiopathology*; D009447:Neuroblastoma / Q000378:metabolism* / Q000473:pathology*; D009687:Nuclear Proteins / Q000235:genetics; D015513:Oncogene Proteins / Q000235:genetics; D011065:Poly(ADP-ribose) Polymerases; D011379:Prognosis
chemical_list: D034904:Lamin Type A; C459801:MYCN protein, human; D000071447:N-Myc Proto-Oncogene Protein; D009687:Nuclear Proteins; D015513:Oncogene Proteins; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases