B细胞非霍奇金淋巴瘤中pRB的增殖依赖性表达和磷酸化：对RB1拷贝数的依赖性

Proliferation-dependent expression and phosphorylation of pRB in B cell non-Hodgkin's lymphomas: dependence on RB1 copy number.

作者信息

Galteland E, Smedshammer L, Suo Z, DeAngelis P, Stokke T

机构信息

Department of Biophysics, The Norwegian Radium Hospital, Oslo, Norway.

出版信息

Leukemia. 2002 Aug;16(8):1549-55. doi: 10.1038/sj.leu.2402644.

DOI:10.1038/sj.leu.2402644

PMID:12145697

Abstract

Some studies have suggested that a significant fraction of non-Hodgkin's lymphomas (NHL) do not express pRB protein, possibly due to deletions of RB1. We examined RB1/centromere 17 copy number by fluorescent in situ hybridisation, and pRB expression/phosphorylation by immunohistochemistry (IHC) and immunoblotting (IB) in 66 cases of B cell NHL. Thirteen cases had lost one RB1 copy relative to centromere 17 copy number and total DNA content. Case 458/88 had no RB1 copies. pRB levels were heterogeneous as assessed by IB (0.04-1.12 relative units), but all tumours, except for case 458/88, expressed pRB localised to the nucleus in >75% of the tumour cells by IHC. The fraction of phosphorylated pRB was correlated with pRB expression (r(2)= 0.56, P < 0.001). The 14 cases with loss of RB1 had lower pRB expression (median 0.25) than those without (median 0.48, P < 0.001), but a correlation with S phase fraction (r(2) = 0.43, P < 0.001; previously published data for tumour-specific S phase and apoptotic fractions) indicated that the variation in pRB expression was due to differences in proliferative activity. Furthermore, the regression lines for pRB expression vs S phase fraction were not different for the cases with or without loss of one RB1 copy (P = 0.5). Cases 154/88 (one RB1 copy) and 258/88 (two RB1 copies), in addition to case 458/88, had low expression of (hypophosphorylated) pRB (0.04, 0.08 and 0.04), despite their high S phase fractions (21%, 17% and 21%). There was no association between pRB expression/RB1 copy number and apoptotic fraction. Neither pRB expression nor loss of RB1 had prognostic value, but cases 154/88, 258/88, and 458/88 had short survival times (5, 3 and 46 months, respectively) compared to the others (median survival: 44 months, P = 0.03). It is suggested that pRB expression and function are normal in 63 of 66 NHL cases, including 12 of 13 lymphomas with loss of one RB1 allele.

摘要

一些研究表明，相当一部分非霍奇金淋巴瘤（NHL）不表达pRB蛋白，这可能是由于RB1基因缺失所致。我们通过荧光原位杂交检测了66例B细胞NHL中RB1/17号染色体着丝粒的拷贝数，并通过免疫组织化学（IHC）和免疫印迹（IB）检测了pRB的表达/磷酸化情况。相对于17号染色体着丝粒拷贝数和总DNA含量，有13例病例丢失了一个RB1拷贝。病例458/88没有RB1拷贝。通过IB评估，pRB水平存在异质性（相对单位为0.04 - 1.12），但除病例458/88外，所有肿瘤通过IHC检测显示，超过75%的肿瘤细胞中pRB定位于细胞核。磷酸化pRB的比例与pRB表达相关（r(2)= 0.56，P < 0.001）。14例RB1缺失的病例中pRB表达水平（中位数为0.25）低于未缺失的病例（中位数为0.48，P < 0.001），但与S期比例相关（r(2) = 0.43，P < 0.001；先前发表的肿瘤特异性S期和凋亡比例数据）表明，pRB表达的差异是由于增殖活性的不同。此外，有或没有丢失一个RB1拷贝的病例，其pRB表达与S期比例的回归线并无差异（P = 0.5）。病例154/88（一个RB1拷贝）、258/88（两个RB1拷贝）以及病例458/888，尽管它们的S期比例较高（分别为21%、17%和21%），但（低磷酸化的）pRB表达水平较低（分别为0.04、0.08和0.04）。pRB表达/RB1拷贝数与凋亡比例之间没有关联。pRB表达和RB1缺失均无预后价值，但与其他病例（中位生存期：44个月，P = 0.03）相比，病例154/88、258/88和458/88的生存期较短（分别为5、3和46个月）。研究表明，66例NHL病例中有63例的pRB表达和功能正常，包括13例丢失一个RB1等位基因的淋巴瘤中的12例。