目的　研究小细胞肺癌 (SCLC)与非小细胞肺癌 (NSCLC)中p53与Bcl- 2基因表达的差异及意义 ,探讨SCLC与NSCLC凋亡基因调控的异同。方法　免疫组化方法检测 87例NSCLC与 2 0例SCLC中p53、Bcl- 2蛋白的表达 ,TUNEL法检测凋亡指数 (AI)。结果　SCLC的AI=5 .6± 4 .8,NSCLC的AI=3 .3± 4 .5 ,腺癌AI=2 .3± 1 .7,腺鳞癌AI=2 .7± 2 .8,SCLC的AI值与NSCLC无显著差异 (P >0 .0 5) ,但显著高于腺癌和腺鳞癌 (P <0 0 5)。SCLC与NSCLC中Bcl- 2表达率分别为 80 .0 % (1 6 2 0 )和 2 8.7% (2 5 87) ,有显著差异 (P <0 .0 1 ) ;SCLC与NSCLC中p53表达率分别为 60 .0 % (1 2 2 0 )和 63 .2 % (55 87) ,差异无显著性 (P >0 .0 5)。SCLC中Bcl- 2阳性组AI=3 .6± 3 .5 ,阴性组AI =8.6± 4 .2 ,差异有显著性 (P <0 .0 5)。结论　SCLC细胞凋亡率与NSCLC无显著差异 ,但显著高于腺癌和腺鳞癌。SCLC与NSCLC凋亡基因调控存在显著不同 :Bcl- 2在SCLC中高表达 ,是SCLC凋亡调控的关键蛋白质 ,但在NSCLC中表达率低下 ,在其凋亡调控中不起主要作用 ;p53参与SCLC与NSCLC的凋亡调控 ,其异常表达在肺癌发生中是保守过程 Objective To study the difference and significance of p53 and Bcl-2 gene expression in small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) and to explore the similarities and differences in the regulation of apoptosis genes between SCLC and NSCLC. Methods The expressions of p53 and Bcl-2 proteins in 87 cases of NSCLC and 20 cases of SCLC were detected by immunohistochemistry. The apoptosis index (AI) was detected by TUNEL method. Results The AI ​​of SCLC was 5.6 ± 4.8, the AI ​​of NSCLC was 3.3 ± 4.5, AI of adenocarcinoma was 2.3 ± 1.7, AI of adenosquamous carcinoma was 2.7 ± 2.8, The AI ​​value of SCLC was not significantly different from that of NSCLC (P> 0.05), but significantly higher than that of adenocarcinoma and adenosquamous carcinoma (P <0.05). The expression rates of Bcl-2 in SCLC and NSCLC were 80.0% (1620) and 27.7% (2587) respectively, there was significant difference (P <0.01). The positive rate of p53 in SCLC and NSCLC 60.0% (122%) and 63.2% (5587), respectively, with no significant difference (P> 0.05). The Bcl-2-positive group in SCLC was 3.6 ± 3.5, the AI ​​in the negative group was 8.6 ± 4. 2, the difference was significant (P <0.05). Conclusion The apoptosis rate of SCLC is not significantly different from that of NSCLC, but significantly higher than that of adenocarcinoma and adenosquamous carcinoma. There are significant differences in the regulation of apoptosis genes between SCLC and NSCLC: Bcl-2 is overexpressed in SCLC and is a key protein in the regulation of apoptosis in SCLC. However, it is poorly expressed in NSCLC and plays a major role in the regulation of apoptosis. P53 is involved in SCLC With the regulation of apoptosis of NSCLC, its abnormal expression is a conservative process in the development of lung cancer