p14ARF、p15INK4b 和 p16INK4a 失活在恶性外周神经鞘瘤中的预后意义。

Prognostic significance of p14ARF, p15INK4b, and p16INK4a inactivation in malignant peripheral nerve sheath tumors.

机构信息

Departments of Anatomic Pathology and Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka Sanno Hospital, Fukuoka, Japan.

出版信息

Clin Cancer Res. 2011 Jun 1;17(11):3771-82. doi: 10.1158/1078-0432.CCR-10-2393. Epub 2011 Jan 24.

DOI:10.1158/1078-0432.CCR-10-2393

PMID:21262917

Abstract

PURPOSE

p14(ARF), p15(INK4b), and p16(INK4a) are tumor suppressor genes that are located closely at 9p21 and are often coinactivated by genetic or epigenetic alterations. Malignant peripheral nerve sheath tumor (MPNST) is a rare sarcoma with poor prognosis. However, the prognostic implications of inactivation of p14(ARF), p15(INK4b), and p16(INK4a) in MPNSTs have not been adequately investigated. Here we carried out a genetic, epigenetic, and expression analysis of p14(ARF), p15(INK4b), and p16(INK4a), and clarified the prognostic significance of their inactivation in MPNSTs.

EXPERIMENTAL DESIGN

p14(ARF), p15(INK4b), and p16(INK4a) protein expressions were assessed by immunohistochemistry in 129 formalin-fixed samples of MPNST including 85 primary tumors. Thirty-nine samples, for which frozen material was available, were also investigated by Western blotting and quantitative reverse transcription PCR (RT-PCR) to detect p14(ARF), p15(INK4b), and p16(INK4a) protein and mRNA expression, and by multiplex real-time PCR, PCR single strand conformation polymorphism and methylation-specific PCR to detect p14(ARF), p15(INK4b), and p16(INK4a) gene alterations.

RESULTS

Immunohistochemically decreased expressions of p14(ARF), p15(INK4b), and p16(INK4a) were observed in 48%, 54%, and 49% of primary MPNSTs, respectively, and were significantly correlated with their concordant mRNA levels. As for gene alterations, homozygous deletion of CDKN2A was detected in one third of the cases. Inactivation of p14(ARF) and p16(INK4a) was associated with poor prognosis by both univariate and multivariate analyses. Furthermore, cases with inactivation of all p14(ARF), p15(INK4b), and p16(INK4a) genes showed the worst prognosis in a combined prognostic assessment.

CONCLUSION

A comprehensive analysis of p14(ARF), p15(INK4b), and p16(INK4a) inactivation status provides useful prognostic information in MPNSTs.

摘要

目的

p14（ARF）、p15（INK4b）和 p16（INK4a）是位于 9p21 附近的肿瘤抑制基因，它们经常因遗传或表观遗传改变而共同失活。恶性外周神经鞘瘤（MPNST）是一种预后不良的罕见肉瘤。然而，p14（ARF）、p15（INK4b）和 p16（INK4a）失活对 MPNST 的预后意义尚未得到充分研究。在这里，我们对 p14（ARF）、p15（INK4b）和 p16（INK4a）进行了遗传、表观遗传和表达分析，并阐明了它们在 MPNST 中的失活的预后意义。

实验设计

通过免疫组织化学法检测了 129 例福尔马林固定的 MPNST 标本中的 p14（ARF）、p15（INK4b）和 p16（INK4a）蛋白表达，包括 85 例原发性肿瘤。对于 39 例有冷冻组织的样本，我们还通过 Western blot 和定量逆转录 PCR（RT-PCR）检测 p14（ARF）、p15（INK4b）和 p16（INK4a）蛋白和 mRNA 表达，通过多重实时 PCR、PCR 单链构象多态性和甲基化特异性 PCR 检测 p14（ARF）、p15（INK4b）和 p16（INK4a）基因改变。

结果

免疫组化显示，48%、54%和 49%的原发性 MPNST 中 p14（ARF）、p15（INK4b）和 p16（INK4a）的表达降低，且与相应的 mRNA 水平显著相关。至于基因改变，三分之一的病例检测到 CDKN2A 纯合缺失。p14（ARF）和 p16（INK4a）失活与单因素和多因素分析的不良预后相关。此外，在综合预后评估中，所有 p14（ARF）、p15（INK4b）和 p16（INK4a）基因失活的病例预后最差。