肺癌细胞株中NVB和Doc药物敏感性关联基因的研究

目的:筛选小细胞肺癌(SCLC)和非小细胞肺癌(NSCLC)细胞株中与诺维苯(NVB)、泰索帝(Doc)药物感受性相关的基因.方法:采用MTT比色分析法测定4株SCLC细胞株和6株NSCLC细胞株对NVB、Doc的药物感受性,同时应用cDNA macroarray技术检测10株肺癌细胞株中1291个药物感受性关联基因的表达状态,分析二者之间的相关性.结果:与NVB和Doc药物敏感性关联(r≥±0.4)的基因共有56个.1)与NVB药物敏感性相关联的基因有36个,SCLC NSCLC组与NSCLC组共同表达的基因有20个,其中,SCLC NSCLC组表达的基因有27个,特异表达的有7个,NSCLC组为29个基因,9个基因特异表达.2)与Doc药物敏感性相关联的基因有50个,其中,SCLC NSCLC组与NSCLC组共同表达的基因有12个,SCLC NSCLC组表达的基因有24个,12个基因特异表达,NSCLC组为38个基因,26个基因特异表达.3)肺癌细胞株中与NVB、Doc药物感受性相关联基因的分类主要分布于:信号转导分子、代谢酶类及其抑制剂、细胞因子和转录因子等4类.结论:SCLC和NSCLC细胞株中NVB、Doc药物敏感性相关联基因存在明显差异,但分类基本相同.     

肺癌细胞株中顺铂药物敏感性的相关基因

目的 筛选小细胞肺癌(SCLC)和非小细胞肺癌(NSCLC)细胞株中与顺铂(DDP)药物敏感性相关的基因.方法 采用二苯基溴化四氮唑蓝(MTT)比色分析法,测定4株SCLC细胞株和6株NSCLC细胞株对DDP的药物敏感性;应用cDNA微阵列技术检测肺癌细胞株中1291个药物敏感性相关基因的表达状态,并分析基因表达与DDP敏感性之间的相关性.结果 Metallothionein、Cathepsin B、TIMP1、TNF-R1、TGFβ-induced 68000、Cathepsin L、Galectin-1、Annexin 11、PAI-1、IGFBP4、UPAR、Jagged、CD13、α1 A-AR、EphA2(Eek)、APC、RhoC、Fibromodulin、GATA-6、HSC 70共20个基因,在SCLC和NSCLC细胞株中均与DDP的药物敏感性呈负相关,只有Procoagula和MDM2与DDP的敏感性呈正相关.VHL、MMP-7、Elongin A、GSK-3β、SLC、Galectin-3、Integrinβ5、Moesin、IKKβ和ETV 1等10个基因,只在SCLC细胞株中与DDP的药物敏感性呈负相关,而AT2与DDP敏感性呈正相关.Clusterin、FG FR-2、Thrombospondin 1、HSP 32、Lactate dehydrogenase A、P300、Thymosinβ10、CD81、C/EBPγ和Rak等10个基因,只在NSCLC细胞株中与DDP的药物敏感性呈负相关,而只有CaMKK和TPA与DDP的敏感性呈正相关.结论 与DDP药物敏感性相关的基因共有45个,其中共同表达于SCLC和NSCLC细胞株中的基因有22个,在SCLC细胞株中特异表达的基因有11个,在NSCLC细胞株中特异表达的基因有12个.     

肺癌细胞株中GEM和CDDP药物敏感性相关基因的研究

背景与目的 筛选小细胞肺癌(small cell lung cancer,SCLC)和非小细胞肺癌(non-small cell lung cancer,NSCLC)细胞株中与健择(gemcitabine hydrochloride,GEM)和顺铂(cisplatin,CDDP)药物敏感性相关的基因,有助于进一步阐明抗癌药物作用机制,为克服抗癌药物的耐药性、研制开发新的抗癌药物提供新线索,同时也将为临床的个体化治疗提供理论依据.方法 采用MTT比色分析法测定4株SCLC细胞株和6株NSCLC细胞株对CDDP和GEM的药物敏感性,同时应用cDNA macroarray技术检测10株肺癌细胞株中1 291个药物敏感性相关基因的表达状态,分析二者之间的相关性.结果 与GEM药物敏感性呈明显正相关(r≥0.632,P<0.05)的基因有6个;与CDDP药物敏感性关联的基因共有45个;与GEM、CDDP敏感性关联(r≥±0.4)的基因有41个;肺癌细胞系中与GEM和CDDP两类药物敏感性呈明显相关的基因足Metallothinein(信号转导分子)、Cathepsin B(组织蛋白酶B)和TIMP1(生长因子);肺癌细胞系中与GEM、CDDP药物敏感性相关联的基因主要分布于Metallothinein、CathepsinB、牛长因子TIMP1等类别.结论 SCLC和NSCLC细胞株中GEM、CDDP存在药物敏感性相关基因,其中Metallothinein、Cathepsin B和TIMP1基因与GEM药物敏感性呈正相关,与CDDP药物敏感性呈负相关.     

非小细胞肺癌细胞株抗癌药物敏感性相关基因差异表达的初步研究

背景与目的为了提高晚期肺癌的化疗效果，实行个体化治疗，筛选和鉴定肺癌细胞抗癌药物敏感性基因具有重要临床意义。本研究比较了非小细胞肺癌(NSCLC)和永生化人支气管上皮细胞(BET2A)细胞株抗癌药物敏感性相关基因的差异表达，以寻找与抗癌药物敏感性相关的基因。方法应用cDNA macroarray技术，对6株NSCLC和BET2A细胞株的抗癌药物敏感性相关基因进行差异表达分析，RT-PCR技术验证滤膜杂交结果。结果在1291个候选基因中筛选出73个差异表达基因，其中45个基因表达上调，28个基因表达下调。RT-PCR验证结果与cDNA macroarray检测结果一致。结论抗癌药物敏感性相关基因的差异表达可能是药物敏感性产生不同的原因之一。本研究结果为逆转肺癌多药耐药性提供了理论基础和新靶点，并为临床新药开发及个体化治疗提供了实验依据。     

抑制Rab25基因表达的人NSCLC厄洛替尼耐药细胞PC9/ER的建立

目的 Rab25在非小细胞肺癌(non-small cell lung cancer,NSCLC)等多种肿瘤中过度表达,提示其可能在NSCLC的发生发展及耐药形成中发挥重要作用.为进一步探讨Rab25的功能及其在NSCLC酪氨酸激酶抑制剂(epidermal growth factor receptor tyrosine kinase inhibitors,EGFR-TKIs)耐药形成中的作用,建立稳定慢病毒介导的shRNA靶向干扰Rab25基因人非小细胞肺癌厄洛替尼耐药细胞PC9/ER稳定株.方法 实时定量PCR(real-time PCR,RT-PCR)检测PC9/ER及PC9细胞中Rab25基因mRNA的相对表达情况.筛选出Rab25基因的RNA干扰(RNA interference,RNAi)有效靶序列,合成靶序列的Oligo DNA并构建GV248 shRNA-Rab25慢病毒载体,酶切和测序鉴定正确后,经病毒包装,感染PC9/ER细胞,经嘌呤霉素筛选稳定表达细胞株.RT-PCR鉴定PC9/ER的表达,CCK-8检测对厄洛替尼的敏感性.结果 PC9/ER细胞中Rab25基因的mRNA表达水平显著高于PC9细胞.构建的重组慢病毒质粒经测序鉴定正确.RT-PCR证实,干扰Rab25后,PC9/ER细胞株中Rab25表达水平明显降低,抑制率为88.3％.通过传代10次后,PC9ER-Rab25i稳定细胞株中Rab25基因的mRNA表达水平显著低于阴性对照组,P＜0.05.PC9ER-Rab25i稳定细胞株的IC50为(2.133±0.222) μmol/L,显著低于阴性对照组的(6.375±0.799) μmol/L,P=0.007.结论 成功构建了Rab25-shRNA慢病毒表达载体,建立了稳定抑制Rab25基因表达的人NSCLC厄洛替尼耐药细胞PC9/ER,初步验证Rab25基因能够改善肺癌EGFR-TKIs获得性耐药,为进一步研究Rab25在NSCLCEGFR-TKIs获得性耐药的机制及逆转其获得性耐药提供了可靠的细胞模型.     

肺癌组织中p16基因缺失的初步研究

目的：探讨p16基因缺失与肺癌发生的关系。方法：采用PCR方法检测48例肺癌组织标本中p16基因缺失的情况，其中包括23例原发性小细胞肺癌（SCLC）和25例原发性非小细胞肺癌（NSCLC）。结果：在23例SCLC中没发现p16基因缺失，而5例NSCLC中，7例存在p16基因缺失，缺失率达28％。结论 ：结果提示16基因的变异与原发性非小细胞肺癌的发生及发展相关。     

CyclinL2在化疗药物诱导肺癌细胞凋亡中的作用

目的：探讨cyclinL2基因在化疗药物顺铂（DDP）、长春瑞滨（NVB）和多西紫杉醇（DOC）诱导的肺癌细胞凋亡中的作用．方法：用肺腺癌A549细胞株进行培养传代，MTT试验检测DDP、NVB和DOC不同药物浓度对肺癌细胞生长的抑制作用．以及CyclinL2转染后对该细胞生长的抑制作用的影响。，同时利用流式细胞术定量检测细胞凋亡．结果：不同浓度DDP、NVB和DOC对肺癌细胞生长均有明显的抑制作用，并有浓度的依赖性。细胞凋亡率和CyclinL2基因表达率成正相关、结论：CyclinL2基因在化疗药物诱导肺癌细胞凋亡中起重要作用，     

人肺癌细胞株化疗敏感性与基因表达的关系

目的探讨人肺癌细胞株对化疗药物的敏感性与多药耐药相关基因和凋亡调控基因表达的关系。方法采用MTT法检测5株肺癌细胞SPCA1、NCI-H446、SH-77、95C和95D对阿霉素(ADM)、顺铂(DDP)、丝裂霉素(MMC)、5-氟尿嘧啶(5-Fu)、卡氮芥(BCNU)的敏感性。流式细胞术检测多药耐药基因P-糖蛋白(P-gp)、谷胱甘肽-S-转移酶-π(GST-π)、肺耐药蛋白(LRP)、多药耐药相关蛋白(MRP)和甲基鸟嘌呤甲基转移酶(MGMT)等耐药相关基因和Fas、bcl-2、p53和p16等凋亡调控基因的表达。结果不同肺癌细胞株对同一药物敏感性有较大差异。相关分析显示,肺癌细胞株对MMC的敏感性与GST-π和bcl-2的表达呈负相关,P值分别为0.040和0.030,GST-π和bcl-2的表达水平较高者,MMC的IC50较高,敏感性较低;对DDP的敏感性与p53蛋白表达水平呈负相关(P=0.036);对其余药物的敏感性与所检基因的表达水平无关(P>0.05)。结论人肺癌细胞株对不同化疗药物敏感与否有不同的机制,对MMC的敏感性与GST-π和bcl-2的表达有关,对DDP的敏感性与p53的表达有关。     

mad2检测作为小细胞肺癌早期诊断潜在指标的临床研究

  目的  探讨有丝分裂阻滞缺陷蛋白基因2（mitotic arrest deficient 2,mad2）联合抗纺锤体抗体（anti-nuclear mitotic spindle apparatus antibody,MSA）和抗着丝点抗体（anti-centromere antibody,ACA）检测对诊断小细胞肺癌（small cell lung cancer,SCLC）的临床意义。  方法  对120例SCLC、110例非小细胞肺癌（non-small cell lung cancer,NSCLC）患者和115例肺结节（pulmonary nodule,PN）患者用荧光定量PCR（qt-PCR）法检测mad2基因的表达,用间接免疫荧光法（indirect immunofluorescence assay,IFA）检测MSA,ACA的表达。  结果  mad2基因在SCLC,NSCLC患者中均有表达;和NSCLC相比,mad2在SCLC中表达量更高（P < 0.05）;mad2诊断SCLC的ROC曲线下面积为0.799,诊断价值中等;相关性分析中MSA、ACA与SCLC的OR值分别为6.94和5.60;一致性分析中mad2基因联合MSA诊断的Kappa值为0.49;mad2联合ACA诊断的Kappa值0.42;并联分析诊断的敏感性为83.31%,特异性为79.34%,约登指数为0.62;串联分析诊断的敏感性为65.32%,特异性为93.35%,约登指数为0.59。  结论  mad2在SCLC组中的表达量高于NSCLC组及肺结节组,在SCLC发生发展中起到重要作用;mad2检测联合MSA及ACA有助于提高诊断敏感性及特异性,对SCLC的早期检测、临床诊断及潜在的治疗方法有一定的应用价值。      

RNA干扰c-Met基因表达对非小细胞肺癌侵袭和迁移及顺铂敏感性的影响

[目的]研究c-Met基因干扰后对肺癌细胞株95D侵袭、迁移能力和化疗药物敏感性的影响。[方法]分别采用免疫组化SP法和WesternBlot技术检测肺癌组织及不同肺癌细胞株中Met蛋白的表达情况。将c-MetshRNA质粒转染人肺癌细胞株95D．通过WestemBlot检测转染效率;Transwell小室和划痕愈合实验测定细胞体外侵袭和迁移能力：四甲基偶氮唑法（Mar法）检测细胞的增殖情况及顺铂敏感性。[结果]Met蛋白在NSCLC组织中的表达明显高于癌旁正常组织,同时高侵袭性的肺癌细胞株（95D、801D）中Met蛋白的表达也较高。c-Met基因干扰能明显降低95D细胞的侵袭和迁移能力,并显著提高其对顺铂的敏感性。[结论]c-Met基因可作为一个重要的靶点应用于非小细胞肺癌治疗。     

Loss of YAP1 defines neuroendocrine differentiation of lung tumors

YAP1, the main Hippo pathway effector, is a potent oncogene and is overexpressed in non‐small‐cell lung cancer (NSCLC); however, the YAP1 expression pattern in small‐cell lung cancer (SCLC) has not yet been elucidated in detail. We report that the loss of YAP1 is a special feature of high‐grade neuroendocrine lung tumors. A hierarchical cluster analysis of 15 high‐grade neuroendocrine tumor cell lines containing 14 SCLC cell lines that depended on the genes of Hippo pathway molecules and neuroendocrine markers clearly classified these lines into two groups: the YAP1‐negative and neuroendocrine marker‐positive group (n = 11), and the YAP1‐positive and neuroendocrine marker‐negative group (n = 4). Among the 41 NSCLC cell lines examined, the loss of YAP1 was only observed in one cell line showing the strong expression of neuroendocrine markers. Immunostaining for YAP1, using the sections of 189 NSCLC, 41 SCLC, and 30 large cell neuroendocrine carcinoma (LCNEC) cases, revealed that the loss of YAP1 was common in SCLC (40/41, 98%) and LCNEC (18/30, 60%), but was rare in NSCLC (6/189, 3%). Among the SCLC and LCNEC cases tested, the loss of YAP1 correlated with the expression of neuroendocrine markers, and a survival analysis revealed that YAP1‐negative cases were more chemosensitive than YAP1‐positive cases. Chemosensitivity test for cisplatin using YAP1‐positive/YAP1‐negative SCLC cell lines also showed compatible results. YAP1‐sh‐mediated knockdown induced the neuroendocrine marker RAB3a, which suggested the possible involvement of YAP1 in the regulation of neuroendocrine differentiation. Thus, we showed that the loss of YAP1 has potential as a clinical marker for predicting neuroendocrine features and chemosensitivity.     

The small GTPase RhoA has greater expression in small cell lung carcinoma than in non-small cell lung carcinoma and contributes to their unique morphologies

The two major forms of lung carcinoma, small cell lung carcinoma (SCLC) and non-small cell lung carcinoma (NSCLC), are clinically distinct, and are also differentiated by morphology and behavior in culture. SCLC cells have a greater metastatic potential than NSCLC cells in vivo, and exhibit a unique spherical morphology in culture due to their inability to adhere and spread on the substratum. Because the small GTPase RhoA affects metastatic properties and regulates cell morphology, we examined whether differences in RhoA expression and activity contribute to the distinct SCLC and NSCLC phenotypes. We found that the expression and GTPgammaS-dependent activation of RhoA are generally greater in SCLC cell lines (SCC-9, NCI-H69, NCI-H146, and NCI-H345) than in NSCLC cell lines (NCI-H23, NCI-H157, NCI-H520, and NCI-H522). The effects of inhibiting Rho-mediated signaling in these cells were investigated by transfecting the cells with cDNA coding for C3 exoenzyme, which ADP-ribosylates and inactivates Rho. Expression of C3 exoenzyme in SCLC cells induces cell-cell compaction, and causes NCI-H345 cells to adhere and spread on collagen IV. In contrast, expression of C3 exoenzyme in NSCLC cells does not induce detectable compaction, but induces cell spreading of NCI-H23 and NCI-H157 cells. Cell proliferation is diminished by Rho inactivation in the majority of the NSCLC cell lines, but not the SCLC cell lines. Expression of p21Cip1/WAF1 is also diminished by Rho inactivation in two of the SCLC cell lines, but is not significantly altered in the NSCLC lines. These results indicate that Rho-mediated signaling may regulate different events in SCLC and NSCLC cells, including adhesion of SCLC cells and proliferation of NSCLC cells.     

Rab1A对NSCLC细胞迁移和JAK1磷酸化的影响

目的:观察Rab1A(Ras-related protein Rab-1A)对非小细胞肺癌(non-small cell lung cancer,NSCLC)细胞系迁移的影响及其分子机制.方法:应用siRNA干扰Rab1A基因表达;应用RTCA(real-time cell analysis)法分析干扰Rab1A基因表达对NSCLC细胞迁移速率的影响;应用免疫印迹观察干扰Rab1A基因表达对JAK1(Janus Kinase 1)磷酸化水平的影响.结果:与阴性对照组相比,Rab1A siRNA转染组NSCLC细胞系的Rab1A蛋白表达水平显著下调(P＜0.01);干扰Rab1A基因表达抑制NSCLC细胞迁移(P＜0.01);干扰Rab1A基因表达可下调NSCLC细胞迁移相关蛋白JAK1磷酸化水平(P＜0.01).结论:Rab1A通过调节JAK1磷酸化水平影响NSCLC细胞迁移.     

Fragile histidine triad-mediated tumor suppression of lung cancer by targeting multiple components of the Ras/Rho GTPase molecular switch

The fragile histidine triad (FHIT) gene has been shown to function as a tumor suppressor gene in vitro and in vivo. However, the mechanism of its action is still largely unknown. To elucidate the molecular mechanism and biological pathway in FHIT-mediated tumor suppression, we used a complementary gene and protein expression profiling with DNA microarray and ProteinChip technologies to quantitatively monitor cellular changes in gene and protein expression and discover the molecular targets of FHIT in non-small cell lung carcinoma (NSCLC) cells. The Ras/Rho signaling pathway was identified as one of the unique biological pathways associated with FHIT activity. A significantly down-regulated expression of genes and proteins of multiple key components in the Ras/Rho GTPases molecular switch, including Ran, Rab, Rac, Rap, and Ral, was observed on gene and protein expression profiles and further validated by Western blot analysis. Ectopic activation of FHIT in FHIT-deficient H1299 cells also significantly reduced the invasive potential of tumor cells by down-regulating expression of RhoC, a potential marker of tumor cell invasion and metastases. A simultaneous knockdown of the expression of several key Ras/Rho signaling molecules using gene-specific small interfering RNAs (RHO-siRNA) targeting selected Rab11, Rac1, and Rap1 genes significantly inhibited tumor cell growth and induced apoptosis in NSCLC cells in vitro, and a local injection of RHO-siRNAs complexed with N-[1-(2,3-dioleoyloxyl)propyl]-N,N,N-trimethylammoniummethyl sulfate:cholesterol nanoparticles inhibited tumor growth in A549 tumor xenografts in mice, mimicking the AdFHIT-mediated tumor-suppressing effect. These results suggest a new role of FHIT in down-regulating the Ras/Rho GTPase-associated oncogenic signaling pathway.     

Epidermal growth factor receptor expression in human lung cancer cell lines

Non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) cell lines were studied for epidermal growth factor (EGF) receptor expression. All NSCLC cell lines tested (eight of eight) had specific EGF binding sites, whereas only five of 11 SCLC cell lines bound EGF. NSCLC and SCLC cell lines expressed the same type of high affinity EGF binding sites with a Kd of 0.5 to 4.5 nM; however, NSCLC cells bound significantly more EGF than SCLC cell lines. The amount of binding sites in NSCLC cells ranged between 71 and 1,000 fmol/mg of protein and in SCLC cells, between 26 and 143 fmol/mg of protein. The two SCLC cell lines with EGF binding values within the range of NSCLC belonged to the variant subtype of SCLC. By means of an anti-erbB serum and indirect radioimmunoprecipitation, a strong Mr approximately 170,000 protein band could be detected in the NSCLC cell lines. This protein corresponds to the EGF receptor molecule. Its identity was proven by competition with excess erbB antigen for the antibody during the radioimmunoprecipitation. Furthermore, this Mr 170,000 protein exhibited protein kinase activity as evidenced by in vitro autophosphorylation. The radioactivity incorporated into the Mr 170,000 band in radioimmunoprecipitation and protein kinase assays was 10 to 100 times lower in these SCLC cell lines which were positive in the EGF binding assay compared to the NSCLC cell lines. We conclude that NSCLC in contrast to SCLC expresses high levels of EGF receptors which may be used to facilitate the differential diagnosis in some cases of lung cancer. These data suggest that EGF may play a role in growth and differentiation of NSCLC.     

Elevated DT-diaphorase activity and messenger RNA content in human non-small cell lung carcinoma: relationship to the response of lung tumor xenografts to mitomycin C?.

The enzyme DT-diaphorase (DTD; NAD(P)H:quinone oxidoreductase, EC 1.6.99.2), is an obligate two electron reductase which catalyzes reduction of a broad range of substrates, including quinones. We report here variations in DTD concentrations among different classes of lung tumors known also to vary in their responsiveness to cytotoxic agents. Small cell lung carcinomas (SCLCs) and cell lines derived from them have the low DTD activities and mRNA content characteristic of normal human lung, whereas non-small cell lung carcinomas (NSCLCs) have greatly elevated levels. DTD activity was increased up to 80-fold in NSCLC tumors relative to normal lung and 20-35-fold in NSCLC relative to SCLC cell lines. Increased DTD activity appeared to be a function of the NSCLC phenotype rather than a result of derivation from a cell type rich in DTD, since all histological classes of NSCLC showed this phenotype. In addition, where transfection of SCLC cell lines with the v-Ha-ras protooncogene caused a transition to a NSCLC phenotype, DTD activity was also elevated. Neuroendocrine-positive cells (SCLC, carcinoids, and a few NSCLC lines) typically had far lower DTD activities than did cell lines which lacked neuroendocrine markers (most NSCLC cells and mesotheliomas). High DTD activity may be exploited in the design of drugs which undergo bioreductive activation by this enzyme. Consistent with this, xenografts derived from NSCLC cell lines with high DTD that were grown in athymic nude mice were more susceptible to the antitumor quinone, mitomycin C, than were xenografts derived from SCLC cells containing low DTD. These data provide a mechanistic basis for the rational design of more effective bioreductive antitumor agents for use against NSCLC.     

Expression of placental growth factor gene in lung cancer.

Differences in the gene expression profiles in small cell lung cancers (SCLC) and non-small cell lung cancers (NSCLC) may explain their different clinical characteristics. The aims of this study were (1) to identify genes differentially expressed in SCLC and NSCLC using mRNA differential display, and (2) to determine the clinical relevance of such genes in lung cancer. RNA differential display using three SCLC and six non-SCLC cell lines was used to identify a differentially expressed gene. Differential expression of the gene was confirmed in additional lung cancer cell lines using RT-PCR. Immunohistochemical staining for the gene product was performed on paraffin-embedded tissue from lung cancer patients. We examined the relationship between the expression of the gene and clinical parameters, including disease stage, response to treatment and survival time. The placental growth factor (PGF) gene was identified as preferentially expressed in SCLC compared with NSCLC cell lines using mRNA differential display. Further analysis of 45 lung cancer cell lines using RT-PCR showed that the placental growth factor (PGF) gene was expressed in nine of 13 SCLC cell lines (69%) and five of 32 NSCLC cell lines (15.6%) (p < 0.001, Fisher's exact test). Immunohistochemistry using anti-PGF antibody on the paraffin blocks from lung cancer patients showed that PGF expression was significantly higher in SCLC than NSCLC tissue sections (32 vs. 5.6%, p = 0.041, Fisher's exact test). Expression of PGF protein did not correlate with disease stage, response to treatment or survival time in SCLC patients. The present study suggests there is higher expression of PGF in SCLC compared to NSCLC. It may be that higher expression of the angiogenic factor PGF contributes to differences between the progression of SCLC and NSCLC, especially in regard to the nature of SCLC metastasis.