title: Frequent alteration of p16(INK4a)/p14(ARF) and p53 pathways in the round cell component of myxoid/round cell liposarcoma: p53 gene alterations and reduced p14(ARF) expression both correlate with poor prognosis.
abstract: In myxoid/round cell liposarcoma (MLS/RCLS), the presence of a round cell (RC) component has been reported to correlate with a worse prognosis for the patients. However, little is known about the molecular genetic differences between conventional myxoid (MX) components and RC components in this tumour. The aim of this study was to investigate the possible implications of molecular alterations of G1 to S-phase check-point genes, especially in the RC component. We evaluated the immunohistochemical expression of p53, MDM2, p14 and p16 protein and assessed proliferative activities using MIB-1 in 29 RC components and 81 MX components from 90 cases. Mutation of the p53 gene, amplification of the MDM2 gene, homozygous deletion, methylation status and mutation of the p16(INK4a)/p14(ARF) genes were also investigated, using concordant paraffin-embedded and frozen material. The data were analysed together with clinicopathological factors to assess their prognostic implications in MLS/RCLS. Immunohistochemically, the over-expression of p53 protein (p = 0.01366) and the reduced expression of p14 (p < 0.0001) and p16 (p < 0.0001) proteins were significantly more frequently observed in RC components than in MX components. Reduced expression of p14 protein correlated significantly with hypermethylation of the p14(ARF) gene promoter (p = 0.0176) and over-expression of p53 protein (p = 0.00837). By univariate analysis, reduced expression of p14 and p53 missense mutation were found to reduce the rate of survival significantly (p < 0.05). Multivariate analysis, including clinicopathological factors, revealed that tumour site (p = 0.0251), the presence of an RC component (p = 0.0113), high MIB-1 labelling index (p = 0.0005) and p53 missense mutation (p = 0.0036) were adverse prognostic factors. In MLS/RCLS, reduction of p14 protein expression and p53 mutation were related to poor prognosis. Accordingly, the p14(ARF)/p53 pathway may contribute to the presence of an RC component and malignant progression in this tumour.
authors.affiliation: Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. oda@surgpath.med.kyushu-u.ac.jp
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Oda
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Tomonari
authors.initials: T
authors.lastname: Takahira
authors.forename: Chikashi
authors.initials: C
authors.lastname: Kobayashi
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kawaguchi
authors.forename: Naomi
authors.initials: N
authors.lastname: Tateishi
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nozuka
authors.forename: Sadafumi
authors.initials: S
authors.lastname: Tamiya
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tanaka
authors.forename: Shuichi
authors.initials: S
authors.lastname: Matsuda
authors.forename: Ryohei
authors.initials: R
authors.lastname: Yokoyama
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Iwamoto
authors.forename: Masazumi
authors.initials: M
authors.lastname: Tsuneyoshi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics* / Q000378:metabolism; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D016158:Genes, p53; D006801:Humans; D007124:Immunoenzyme Techniques; D018208:Liposarcoma, Myxoid / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods; D018807:Polymorphism, Single-Stranded Conformational; D011379:Prognosis; D012983:Soft Tissue Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D016019:Survival Analysis; D025803:Tumor Suppressor Protein p14ARF / Q000235:genetics* / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004273:DNA, Neoplasm; D025803:Tumor Suppressor Protein p14ARF