胰腺导管腺癌和慢性胰腺炎中18q21杂合性缺失及相关性分析

目的 探讨18q21在人胰腺导管腺癌和慢性胰腺炎中杂合性缺失(LOH)的情况及其相关因素.方法 选择18q21上的位点RP11-729G3和RP11-850A17作为目的 片段,选择接近18号染色体着丝粒的位点RP11-621L6作为参照位点,利用细菌人工染色体(BAC)提取、纯化相应位点的DNA,用切口平移法分别标记生物素和地高辛后制成双色探针,应用荧光原位杂交技术(FISH)检测30例胰腺导管腺癌和10例慢性胰腺炎石蜡包埋组织切片中18q21 LOH情况,并收集、整理相应临床病理资料进行相关性分析.结果 30例胰腺导管腺癌中在RP11-729G3位点有25例(83.3%)有LOH,在RP11-850A17位点26例(86.6%)有LOH,其中25例在RP11-729G3和fuP11-850A17两个位点均有LOH,1例仅在RP11-850A17位点有LOH.10例慢性胰腺炎中均未发现18q21 LOH.经统计学分析发现,18q21 LOH在慢性胰腺炎和胰腺导管腺癌中差异有统计学意义(P<0.01),且RP11-729G3和RP11-850A17两个位点LOH有高度相关性(Phj系数=0.877),但和临床病理各因素间未发现明显相关.结论 18q21 LOH在胰腺导管腺癌中属于高频事件,并且位点RP11-729G3和RP11-850A17的LOH有高度相关性,可能在胰腺导管腺癌发生发展中起重要作用.在临床诊断中18q21LOH也能作为较特异的标记辅助诊断.

Fluorescence in-situ hybrydization detection of 18q21 LOH in human pancreatic ductal carcinoma and chronic pancreatitis

Objective To investigate 18q21 LOH in human pancreatic ductal adenocarcinomas and chronic pancreatitis by fluorescence in-situ hybrydization (FISH) technique, and to analyze the relationship between 18q21 LOH and clinicopathologic characteristics. Methods RP11-729G3 and RP11-850A17, the regions on 18q21, were selected as the target fragments, the region RP11-621L6, close to the centromere of chromosome 18, was selected as the reference fragment. The specific BAC clones were used to isolate and purify the corresponding genomic DNA, which were labeled with biotin or DIG by nick translation into dual color probes. 18q21 LOH was assessed by dual-color FISH in 30 cases of pancreatic ductal adenocarcinoma and 10 cases of chronic pancreatitis. All samples were 10% formalin fixed and paraffin embedded. The relationship between 18q21 LOH and clinicopathologic characteristics was analyzed. Results Among 30 cases of pancreatic ductal adenocarcinoma, 25 cases showed LOH at the region RP11-729G3 (83.3%), and 26 cases showed LOH at the region RP11-850A17 (86.6% ). Among these, 25 cases with LOH at both regions, 1 case showed LOH only at the region of RP11-850A17. No LOH was found in 10 cases of chronic pancreatitis. Conclusions 18q21 LOH is a high-frequency event in human pancreatic ductal adenocarcinomas. LOH at the regions RP11-729G3 and RP11-850A17 demonstrates a high concordance. 18q21 may play an important role during pancreatic carcinogenesis and tumor progression. 18q21 LOH may be used as a diagnostic marker for pancreatic ductal adenocarcinoma.