胃癌细胞凋亡与增殖的平衡与相关基因的关系

Balance of cell apoptosis and proliferation and its association with related genes in gastric cancer

目的: 探讨在肿瘤细胞中凋亡与增殖平衡的变化(apoptotic index/proliferative index,AI/PI)以及与相关基因的关系. 方法:取普外科手术切除的标本68例,其中胃正常组10例,癌旁组10例,胃癌标本48例.术前均未接受过化疗或放疗.男32例,女16例.年龄24-74(平均54.4)岁. 术前内镜活检病检诊断,术后病理诊断证实.标本均经中性甲醛(40 g/L)固定,常规石蜡包埋,作4μm厚连续切片.应用流式细胞仪,分别定量分析细胞的凋亡群体和增殖群体;免疫组化方法检测survivin,Fas与FasL基因表达的变化;共聚焦显微镜对细胞增殖进行形态学观察. 结果:在从胃正常组,癌旁组到肿瘤组细胞的演进过程中,AI/PI分别为0.46±0.14,0.35±0.12,0.23±0.11. 胃正常组,癌旁组和肿瘤组细胞相互之间,差异有显著性(F=19.453,P=0.000<0.01).胃癌细胞的AI/PI经频数分布表分析和检验均服从正态分布.胃癌细胞AI/PI 范围0.05-0.46.中位数和均数±标准差分别为0.245和0.23±0.11.Skewness的值为0.067,Kurtosis的值为-0.868. 胃癌细胞随着恶性进展,AI/PI总体呈下降的趋势, 与淋巴转移和远处转移相关(P<0.05).survivin,Fas与Fasl,基因表达阳性染色主要定位于肿瘤细胞胞质或胞膜中,为粗细不一的棕黄色颗粒.在48例胃癌中survivin,Fas与FasL的阳性表达率分别为56.2%,43.8% 和60.4%.AI/PI的中位数为0.245,将胃癌分为>0.245 组和<0.245组.结果显示相应的两组组织切片中survivin 阳性表达率增加(X2=6.857,P<0.01),而Fas的阳性表达率降低(x2=4.148,P<0.05)和FasL的阳性表达率增加(x2=4.269,P<0.05),.共聚焦显微镜显示肿瘤组织中Ki- 67高表达. 结论:AI/PI总体呈下降的趋势,可能与survivin基因表达上调,Fas基因表达下调有关.

AIM: To investigate the balance between cell proliferation and apoptosis in gastric cancer and their association with related genes. METHODS: Sixty-eight surgically resected samples were collected between 2000 and 2001, including 10 normal gastric tissues, 10 para-cancerous tissues, and 48 gastric carcinoma tissues from pathologically confirmed pa-tients(32 males and 16 females, aged 24-74 years with mean age 54.4 years). The patients did not receive chemotherapy or radiotherapy. All of the samples were fixed in 40 g/L formalin, embedded in paraffin, and sliced into 4 μm thick sections. The apoptotic cells and proiiferative cells were quantitatively analyzed by flow cytometry. Immuno-histochemical assay (SP method) was used to detect the expression of survivin, Fas and FasL. The morphology of proliferating cells was identified by confocal microscope. RESULTS: In the normal, para-cancerous and tumor groups, the ratio of apoptosis and proliferation indexes (Al/ PI) were 0.46±0.14, 0.35±0.12, and 0.23±0.11, respectively. The difference was significant (F=19.453, P <0.01). Normal distribution was observed by frequency distribution of AI/PI in gastric carcinoma cells. Tumors exhibited a wide range of AI/PI from 0.05 to 0.46. Overall, the median and mean±SD of AI/PI were 0.245 and 0.23±0.11, respectively. The value of Skewness and Kurtosis were 0.067 and -0.868, respectively. A stepwise decreasing trend in AI/PI was noted in clinicopathological variables, including lymph node metastasis and beyond metastasis (P<0.05 for each). Granular staining was observed in both the cytoplasm and cell membrane of survivin, Fas and FasL positive cells. The expression rates of survivin, Fas and FasL in 48 gastric cancer were 56.2%, 43.8% and 60.4%, respectively. Using the median AI/PI of 0.245, we divided the cells into two groups(greater than and less than the median AI/PI). The expression of survivin and FasL in >0.245 were significantly lower than that of <0.245.On the contrary, the expression of Fas in >0.245 was significantly higher than that of <0.245. The high expression of ki-67 in tumor was found by confocal microscope. CONCLUSION: A stepwise decreasing trend in AI/PI may exist in tumor progression, which might be correlated with the up-regulation of survivin gene and the down-regulation of Fas gene.