树突细胞激活的肿瘤浸润性淋巴细胞抗肝癌免疫活性的研究

目的　探讨树突细胞 (DC)激活的肿瘤浸润性淋巴细胞 (TIL)体外对肝癌细胞的杀伤活性。方法　从肝癌患者外周血获取DC ,应用粒 /巨噬细胞集落刺激因子 (GM -CSF)、白细胞介素 -4 (IL -4 )和肿瘤抗原激活DC ,然后用DC激活TIL ,观察TIL在体外对自体肝癌细胞和Hep3B细胞的杀伤活性。 结果　DC激活的TIL对自体肝癌细胞具有很强的杀伤活性 ,杀伤率为89 .39%± 3.0 5 %,明显高于未经DC激活的TIL、DC激活的T淋巴细胞和未经DC激活的T淋巴细胞对自体肝癌细胞的杀伤率(分别为 5 5 .2 3%± 1.5 3%、5 4.89%± 1.48%和 3.6 5 %± 0 .2 6 %)。而它们对Hep3B细胞的杀伤活性则相对较低。 结论　肝癌患者外周血DC能诱导TIL产生高效而特异的抗肝癌免疫活性。     

树突状细胞对肿瘤浸润性淋巴细胞抗结肠癌活性影响的研究

目的:探讨树突状细胞(DC)激活的肿瘤浸润性淋巴细胞(TIL)体外对结肠癌细胞的杀伤活性。方法:从结肠癌患者外周血获取DC,应用粒/巨噬细胞集落刺激因子(GM-CSF)、白细胞介素-4(IL-4)和肿瘤抗原激活DC,然后用DC激活TIL,观察TIL在体外对自体结肠癌细胞和VoLo细胞的杀伤活性。结果:DC激活的TIL对自体结肠癌细胞具有很强的杀伤活性,杀伤率为87.62%±3.01%,明显高于未经DC激活的TIL、DC激活的T淋巴细胞和未经DC激活的T淋巴细胞对自体结肠癌细胞的杀伤率分别为53.72%±1.50%、52.23%±1.46%和3.55%±0.25%,而它们对VoLo细胞的杀伤活性则相对较低。结论:结肠癌患者外周血DC能诱导TIL产生高效而特异的抗结肠癌免疫活性。     

树突细胞对肿瘤浸润淋巴细胞抗乳腺癌免疫活性影响的研究

背景与目的:树突细胞(dendriticcell,DC)又称树突状细胞,是目前已知的功能最强的抗原呈递细胞,它可以在体内、外向T淋巴细胞呈递抗原,并诱发细胞毒T淋巴细胞(cytotoxicTlymphocyte,CTL)反应。本研究旨在探讨DC激活的肿瘤浸润淋巴细胞(tumorinfiltratinglymphocytes,TIL)体外对乳腺癌细胞的杀伤活性。方法:从乳腺癌患者外周血获取DC,应用粒/巨噬细胞集落刺激因子(granulocyte/macrophagecolonystimulatingfactor,GM-CSF)、白细胞介素-4(interleukin-4,IL-4)和肿瘤抗原激活DC,然后用DC激活TIL,观察TIL在体外对自体乳腺癌细胞和Bcap-37乳腺癌细胞的杀伤活性。结果:DC激活的TIL对自体乳腺癌细胞具有很强的杀伤活性,杀伤率为(85.76±2.93)%,明显高于未经DC激活的TIL、DC激活的T淋巴细胞和未经DC激活的T淋巴细胞对自体乳腺癌细胞的杀伤率犤分别为(52.11±1.48)%、(51.35±1.46)%和(3.59±0.25)%犦。而它们对Bcap-37乳腺癌细胞的杀伤活性则相对较低犤分别为(40.03±1.29)%、(22.09±0.87)%、(21.66±0.85)%和(1.76±0.14)%犦。结论:乳腺癌患者外周血DC能诱导TIL产生高效而特异的抗乳腺癌免疫活性。     

肝癌细胞抗原致敏树突状细胞诱导的体外抗肿瘤作用

目的　探讨原发性肝癌患者外周血树突状细胞 (DC)经自体肝癌细胞抗原致敏后诱导的体外抗肿瘤作用。方法　对肝癌患者外周血采用密度梯度离心法分离 ,获得DC前体细胞 ,用重组人粒细胞 巨噬细胞集落刺激因子 (rhGM CSF)和重组人白细胞介素 4(rhIL 4)联合培养 ,诱导扩增DC。制备自体肝癌细胞抗原 ,体外脉冲DC ,检测DC诱导自体T细胞增殖能力及细胞毒性T细胞 (CTL )在体外对自体肝癌细胞的杀伤活性 ,并检测肿瘤抗原致敏DC分泌的IL 12水平。结果　经自体肝癌细胞抗原致敏的DC能分泌IL 12和诱导较强的自体T细胞增殖 ,且能诱导特异性CTL ,该CTL对自体肝癌细胞具有很强的杀伤活性 ,杀伤率显著高于DC、未经肝癌细胞抗原致敏的DC激活的CTL及T淋巴细胞的杀伤率 ,而对CT 2 6细胞、BEL 740 2细胞无明显的杀伤作用。结论　肝癌患者外周血DC经自体肝癌细胞抗原致敏后能诱导高效而特异的抗肝癌免疫 ,其机制可能与增强T细胞应答和诱导机体产生肿瘤特异CTL从而发挥特异性的抗肿瘤作用有关。     

抗原负载树突状细胞介导肝癌患者肿瘤杀伤细胞功能状态研究

目的:探讨肝癌细胞抗原负载树突状细胞激活肝癌患者外周血细胞毒性T细胞(CTL)、肿瘤浸润淋巴细胞(TI1)的抗肿瘤作用.方法:以细胞计数、间接荧光表型测定分析肝癌患者DC功能状态;MTT法测定肝癌细胞抗原负载DC介导肝癌患者外周血CTL、TIL对肝癌细胞的杀伤活性.结果:肝癌患者DC表达CD1a、CD80、CD83和HLA-DR等分子水平,DC介导的CTL、TIL对肝癌细胞的杀伤活性明显低于健康对照组(P＜0.05,P＜0.01).结论:肝癌患者存在DC功能缺陷,致使其介导的CTL、TIL对肝癌细胞的杀伤作用明显降低.     

树突状细胞对肿瘤浸润淋巴细胞抗小鼠肝癌活性影响的研究

目的探讨H22细胞全细胞性抗原致敏的DC激活的TIL体外抗小鼠肝癌活性,并将H22-DC-TIL过继免疫荷瘤小鼠,研究其对荷瘤小鼠免疫功能的影响及抑瘤作用。方法从小鼠四肢长骨骨髓中获取DC,应用粒/巨噬细胞集落刺激因子(GM-CSF)、白介素-4(IL-4)和肿瘤全细胞性抗原致敏DC,然后用DC激活TIL,观察TIL在体外对H22细胞、Hepal-6细胞和B16细胞的杀伤活性;检测应用H22-DC-TIL后荷瘤小鼠的脾淋巴细胞的NK、LAK、CTL活性、血清TNF活性、抑瘤作用以及瘤体病理改变,并与对照组相比较。结果①H22-DC-TIL具有很强的对H22细胞杀伤活性[杀伤率为(71.31±3.11)%],明显高于其对Hepal-6和B16细胞的杀伤活性[杀伤率分别为(50.11±3.03)%,(30.31±2.89)%],也明显高于未经DC激活的TIL、H22-DC-脾淋巴细胞和未经DC激活的脾淋巴细胞对H22细胞杀伤活性[杀伤率分别为(49.80±3.21)%,(48.76±3.60)%和(19.23±2.71)%]和对Hepal-6细胞杀伤活性[杀伤率分别为(39.40±3.21)%,(38.62±2.87)%和(18.73±2.40)%]以及对B16细胞杀伤活性[杀伤率分别为(26.38±2.51)%,(25.82±2.70)%和(18.34±3.01)%],同时B16-DC-TIL(TIL来源于H22瘤体)也可诱导相对较低的对B16细胞的特异性细胞杀伤活性。②H22-DC-TIL可明显诱导提高荷瘤脾淋巴细胞NK、LAK和CTL活性[活性为(30.43±1.35)%、(31.40±1.80)%、(35.30±1.20)%],并可检测到血清TNF水平明显上升[血清TNF为(40.41±1.85)U/ml],它们均达正常对照组水平,与未经DC激活的TIL组、H22-DC-脾淋巴细胞组、未经DC激活的脾淋巴细胞组、生理盐水组分别对应比较,差异均有显著性(P<0.01)。该组瘤体内淋巴细胞浸润程度也高于对照组,其瘤体生长明显受到抑制。结论①H22-DC-TIL可产生很强的体外针对H22细胞的特异性杀伤活性。②H22-DC-TIL具有很强的特异性抗小鼠肝癌作用。     

负载肝癌抗原的树突状细胞瘤苗诱导的抗肿瘤作用

目的 探讨原发性肝癌患者外周血树突状细胞（DC）体外经自体肝癌细胞抗原致敏后诱导的抗肿瘤作用。方法肝癌患者外周血经梯度密度离心法分离，获得DC前体细胞，用重组人粒细胞-巨噬细胞集落刺激因子（rhGM—CSP）和重组人白细胞介素-4（rhIL-4）联合培养，诱导扩增DC。制备自体肝癌细胞抗原，体外脉冲DC，检测DC诱导自体T细胞增殖能力及细胞毒性T细胞（CTL）在体外对自体肝癌细胞的杀伤活性，并检测肿瘤抗原致敏DC分泌的IL-12水平。结果经自体肝癌细胞抗原致敏的DC能分泌IL-12和诱导较强的自体T细胞增殖，且能诱导特异性CTL，该CTL对自体肝癌细胞具有很强的杀伤活性，杀伤率明显高于DC、未经肝癌细胞抗原致敏的DC激活的CTL及T淋巴细胞的杀伤率，而对3LLLEWIS肺癌细胞、H22肝癌细胞则无明显的．杀伤作用。结论肝癌患者外周血DC经自体肝癌细胞抗原致敏后能诱导高效而特异的抗肝癌免疫，其机制可能与增强T细胞应答和诱导机体产生肿瘤特异CTL而发挥特异性的抗肿瘤作用有关。     

肝癌细胞对重组人HSP70联合肝癌组织冻融抗原修饰树突状细胞的免疫应答

目的:研究重组人热休克蛋白70(rhHSP70)联合肝癌组织冻融抗原修饰的树突状细胞(dendritic cell,DC)诱导对肝癌细胞的免疫杀伤效应.方法:外周血单个核细胞经粒-巨噬细胞集落刺激因子(GM-CSF)、白细胞介素4 (IL-4)诱导生成DC,负载冻融抗原的同时加入rhHSP70,不同分组致敏的DC激活淋巴细胞生成肿瘤抗原特异性细胞毒性T淋巴细胞(cytotoxic T cells,CTL),四甲基偶氮唑蓝(MTT)法及3H-TdR法检测DC刺激淋巴细胞增殖能力, MTT法检测CTL对肝癌细胞的体外杀伤活性,酶联免疫吸附试验(ELISA)测定细胞因子的分泌,流式细胞术(FCM)检测DC表型变化.结果:冻融抗原致敏的DC可明显促进淋巴细胞增殖,能有效呈递肝癌冻融抗原,诱导产生抗原特异性CTL,联合rhHSP70能进一步增强CTL对肝癌细胞的杀伤作用.结论:肝癌冻融抗原联合rhHSP70修饰的DC诱导CTL对肝癌细胞能产生高效杀伤作用.     

树突状细胞诱导抗人肝癌细胞系的肿瘤免疫

 目的 以树突状细胞(DC)在体外诱导抗肝癌免疫.方法 自肝癌患者外周血中分离DC;以粒/巨噬细胞集落刺激因子(GM-CSF)及白介素-4(IL-4)联合刺激DC;以人肝癌细胞系HepG2细胞和BEL-7402细胞的肿瘤相关抗原(TAA)激活DC;DC诱导自体T淋巴细胞增殖、分化为细胞毒素性T细胞(CTL);检测CTL对HepG2细胞、BEL-7402细胞、SGC-7901细胞、LOVO细胞及HOS-8603细胞的细胞毒作用.结果 肝癌患者外周血DC能够诱导自体T淋巴细胞增殖分化为CTL,该CTL对HepG2细胞和BEL-7402细胞有强大的杀伤力(杀伤率分别为90%±10%,86%±11%),对SGC-7901细胞、LOVO细胞及HOS-8603细胞则无明显的细胞毒作用(杀伤率分别为11%±6%,8%±4%,6%±4%).结论 肝癌患者外周血DC体外能够诱导高效而特异抗肝癌免疫.提示DC可能在治疗肝癌及预防肝癌术后复发和转移中发挥重要作用.     

H22细胞全细胞抗原负载的树突状细胞激活肿瘤浸润性淋巴细胞抗小鼠肝癌的实验

目的探讨H22小鼠肝癌细胞（H22细胞）全细胞抗原致敏的树突状细胞激活肿瘤浸润淋巴细胞抗小鼠肝癌细胞活性。方法取得小鼠骨髓细胞并诱导生成树突状细胞,由冻融法制备的H22细胞全细胞抗原致敏,然后用已致敏的树突状细胞激活肿瘤浸润性淋巴细胞,测定致敏前后的DC表面抗原CD11c、CD80、CD86、CD40、MHCⅡ,并评估激活前后的TIL对H22细胞的杀伤活性,同时脾淋巴细胞作为杀伤对照。结果CD11c阳性细胞中CD80、CD86、CD40、MHCⅡ阳性细胞所占比例在致敏后的DC表现为明显上调。经致敏后成熟DC激活的TIL对H22细胞杀伤活性明显高于未激活的TIL,并高于激活或未激活的小鼠脾脏淋巴细胞。结论在H22细胞全抗原致敏后,小鼠成熟DC中CD80、CD86、CD40、MHCⅡ的表达率明显高于未成熟DC。经H22细胞全细胞抗原致敏的DC能诱导活化TIL,明显提高其在体外对H22细胞的杀伤活性。     

CIK、DC-CIK细胞对神经母细胞瘤细胞杀伤作用的研究

目的：研究细胞因子诱导的杀伤细胞（ CIK）与树突状细胞（ DC）共培养后对神经母细胞瘤（ neuro-blastoma,NB）细胞株的杀伤作用。方法：取健康人和肿瘤患者外周血单个核细胞（ PBMC）,加入不同的细胞因子分别诱导出DC和CIK细胞,用流式细胞术测定诱导培养前后DC和CIK细胞的表型,MTT法测定不同组CIK细胞对NB细胞株的杀伤活性。结果：流式细胞仪检测健康人PBMC培养后CD3＋CD56＋淋巴细胞百分比以及对NB细胞株的杀伤活性均显著高于肿瘤患者（ P〈0.05）。此外,与单纯CIK细胞相比,DC-CIK细胞具有更强的杀伤NB细胞株的活性（ P〈0.05）。结论：DC-CIK细胞是一种细胞毒作用高于单纯CIK细胞的免疫活性细胞。健康人和肿瘤患者的PBMC经诱导培养获得的CIK细胞有显著差别,为临床进一步提高CIK细胞的治疗效果提供了实验依据。     

Melanoma cells interfere with the interaction of dendritic cells with NK/LAK cells

Dendritic cells (DCs) and natural killer (NK) cells are key players at the interface between innate resistance and acquired immunity. NK cells can induce DC maturation, a differentiation process whereby DCs respond to a environmental stimulus and acquire the ability of eliciting adaptive immunity. Conversely, maturing DCs promote NK functions in vivo and in vitro. This interplay has important consequences on the immune response to pathogens and possibly to neoplastic cells. Here, we show that B16 melanoma cells actively modulate the interaction between DCs derived from bone marrow precursors and NK/LAK cells propagated from the spleen of C57BL/6 mice. DCs increased in a dose-dependent manner the ability of NK/LAK cells to kill melanoma cells and to produce cytokines. This activatory cross-talk entailed the production of IL-18 by DCs and of IFN-gamma by NK/LAK cells. Melanoma cells were not a passive target of NK activity; they regulated the outcome of the interaction between DCs and NK/LAK cells, inhibiting the in vitro production of cytokines as effectively as the genetic deletion of IL-18 or IFN-gamma. Interference with the NK/DC interaction possibly represents a mechanism used by growing tumors to evade the immune response.     

Differences in inducibility of morphological differentiation of parental cells, selected variant cells and cells from spontaneous metastases of mouse neuroblastoma cells

The in vitro sensitivities to differentiating agents of a murine neuroblastoma cell line (N18) and a selected variant cell line (N18-LM5) were examined. In addition, the sensitivities to differentiating agents of cells from spontaneous metastases produced by N18 cells were examined. When N18 cells (1 X 10(5) cells/mouse) were injected into the lateral tail vein of syngeneic A/J mice, only a few metastatic nodules formed in the liver and lung, while similar injection of N18-LM5 cells produced larger numbers of metastatic nodules. Exposure of N18 cells to differentiating agents, such as dibutyryl cyclic 3':5'-AMP (db-cAMP), prostaglandin E1, and dexamethasone, resulted in induction of differentiation in terms of neurite extension. N18-LM5 cells responded to differentiating agents to a greater extent than N18 cells, and most of the cells extended neurites when they were exposed to 1 mM db-cAMP for 3 days. On the other hand, not all cell lines from spontaneous metastases produced by N18 cells responded to db-cAMP. These results suggest that the colonizing potential of neuroblastoma cells is not necessarily correlated with loss of responsiveness to differentiating agents and that various spontaneous metastases show heterogeneity in responsiveness to differentiating agents.     

Chemoresistant colorectal cancer cells and cancer stem cells mediate growth and survival of bystander cells

Background:

Recent studies suggest that cancer stem cells (CSCs) mediate chemoresistance, but interestingly, only a small percentage of cells in a resistant tumour are CSCs; this suggests that non-CSCs survive by other means. We hypothesised that chemoresistant colorectal cancer (CRC) cells generate soluble factors that enhance survival of chemonaive tumour cells.

Methods:

Chemoresistant CRC cells were generated by serial passage in oxaliplatin (Ox cells). Conditioned media (CM) was collected from parental and oxaliplatin-resistant (OxR) cells. CRC cells were treated with CM and growth and survival were assessed. Tumour growth rates were determined in nude mice after cells were treated with CM. Mass spectrometry (MS) identified proteins in CM. Reverse phase protein microarray assays determined signalling effects of CM in parental cells.

Results:

Oxaliplatin-resistant CM increased survival of chemo-naive cells. CSC CM also increased growth of parental cells. Parental and OxR mixed tumours grew larger than tumours composed of parental or OxR cells alone. Mass spectrometry detected unique survival-promoting factors in OxR CM compared with parental CM. Cells treated with OxR CM demonstrated early phosphorylation of EGFR and MEK1, with later upregulation of total Akt .We identified progranulin as a potential mediator of chemoresistance.

Conclusion:

Chemoresistant tumour cells and CSCs may promote resistance through soluble factors that mediate survival in otherwise chemosensitive tumour cells.     

α-半乳糖神经酰胺负载DC促进CIK细胞对肝癌细胞的杀伤效应

目的:研究负载α-半乳糖神经酰胺(alpha-galactosylceramide,α-GalCer)的DC功能与成熟度的改变情况,探讨α-GalCer-DC与CIK共培养对CIK细胞表型、增殖活性及杀伤肝癌细胞效率的影响.方法:采用密度梯度离心法从人外周血中分离出单个核细胞,悬浮细胞诱导培养CIK细胞,贴壁细胞诱导培养DC;流式细胞仪检测α-GalCer负载DC的表型,Real-time PCR检测DC相关基因的mRNA表达改变.将α-GalCer-DC与CIK细胞共培养,流式细胞仪检测DC与CIK细胞表面标志物;锥虫蓝染色法检测CIK细胞的增殖倍数;Real-time PCR检测CIK细胞功能相关基因的表达情况;CCK-8试剂盒检测α-GalCer-DC对CIK杀伤HepG2细胞的影响.结果:经过多种细胞因子诱导,可获得CIK细胞和成熟的DC;α-GalCer负载可促进DC成熟,DC表面标志物CD80、CD86、CD83和CD11c的阳性率均升高(P＜0.05或P＜0.01),表面趋化因子受体CCR-7、IL-12、IL-10的mRNA水平升高(P＜0.05).α-GalCer-DC与CIK共培养,可显著提高CIK细胞CD3+ CD56+的表达和增殖活性(P＜0.05或P＜0.01),并显著提高INF-γ、IL-12、穿孔素和颗粒酶素B的mRNA表达水平(P＜0.05或P＜0.01);CIK、DC-CIK、α-GalCer-DC-CIK细胞对HepG2细胞的杀伤作用随效靶比的升高而增强,在同一效靶比时α-GalCer-DC-CIK细胞对靶细胞的杀伤作用最强(P＜0.05).结论:α-GalCer负载可促进DC成熟,α-GalCer-DC与CIK共培养能促进后者增殖和成熟,能显著增强其对肝癌细胞的杀伤活性,为DC-CIK在肿瘤免疫治疗中的应用提供了实验依据.     

Immunogenic reactivity of CTLs induced by electrofusion cells of human dendritic cells and gastric cancer cells

In tumor immunotherapy, there were several reports of attempts to induce anti-tumor immunity by fusion hybrid cells generated with dendritic and tumor cells. One of them reported that vaccination of hybrid cells resulted in a remarkable reduction of tumor cells in a lab mouse experiment. In our study, fusion cells were generated successfully with human matured dendritic and human gastric cancer cells by electrofusion technique and employed to induce CTLs. The evaluated fusion rate was 47.8% by FACS analysis. We tried to induce CTLs by co culture of effector and stimulator cells in the presence of IL-2, IL-7 and IL-12 for 4 weeks. Although it was not statistically significant in tumor cytotoxic assay, effector cells induced by the fusion cells as stimulator cells showed a few cytotoxic responses in an immunological tumor specific manner. Our data suggest that fusion hybrid cells may facilitate stimulation and expansion of tumor-specific T cells, but further investigation is required for clinical application of fusion cells in adoptive immunotherapy.     

Marker profile of mesothelial cells versus ovarian carcinoma cells

We investigated the marker profile of human ascitic and cultured mesothelial cells, and compared it to that of ovarian carcinoma cells which are related in terms of their histogenesis, unrelated colon carcinomas being used as reference. Mesothelial and ovarian carcinoma cells could not be distinguished by (intermediate) filament typing, using monoclonal antibodies (MAbs) to keratins, vimentins and desmins. Colon carcinomas differed from mesothelial cells and ovarian carcinomas by the absence of keratin-7 filaments. The epithelial marker BW 495/36 was completely negative on mesothelial cells and positive on all ovarian and colon carcinoma cells. While CEA was found on about 85% of all colon carcinomas, CEA expression on mesothelial cells and ovarian carcinoma cells was below 20%. The ovarian carcinoma markers (OV-TL 3, OV-TL 10, OC 125, MOV 18) were strongly positive on ovarian carcinomas and negative on colon carcinomas (or limited to traces of immunofluorescence on some samples). Although the mesothelial cells showed weak or negative reactivity with these markers, OC 125 antigen was found by immunoelectron microscopy on the surface of cultured mesothelial cells, and was shed in the culture supernatant at concentrations of 50, 28, and 25 CA 125 U/ml/10(4) positive cells. This suggests that mesothelial cells may be responsible for the synthesis of CA 125 in ascitic fluid. The data indicate that ovarian carcinomas, mesothelial cells and colon carcinomas can be distinguished using a combination of anti-keratin antibodies with BW 495/36 and anti-ovarian carcinoma markers.     

Radial glia cells are candidate stem cells of ependymoma

Tumors of the same histologic type often comprise clinically and molecularly distinct subgroups; however, the etiology of these subgroups is unknown. Here, we report that histologically identical, but genetically distinct, ependymomas exhibit patterns of gene expression that recapitulate those of radial glia cells in the corresponding region of the central nervous system. Cancer stem cells isolated from ependymomas displayed a radial glia phenotype and formed tumors when orthotopically transplanted in mice. These findings identify restricted populations of radial glia cells as candidate stem cells of the different subgroups of ependymoma, and they support a general hypothesis that subgroups of the same histologic tumor type are generated by different populations of progenitor cells in the tissues of origin.     

Can cancer cells transform normal host cells into malignant cells?

A human prostate tumour cell line, LNCaP C4-2, when injected into athymic male nude mice, produced tumours containing: (1) only human cancer cells similar to those injected; (2) only murine stromal cells containing abnormal chromosome constitutions; or (3) both human prostate cancer cells similar to those injected and the transformed murine stromal cells with altered chromosome constitutions. Karyotypic analysis of murine metaphases from all the host-derived tumours showed mostly pseudodiploid chromosome constitutions, with multiple copies (amplification) of mouse chromosome 15 and the absence of a typical Y chromosome. Fluorescence in situ hybridization analysis of these murine cells, using a biotin-labelled total human DNA painting probe, further demonstrated the absence of human DNA and the presence of only mouse metaphase and interphase cells in these transformed stromal cells. These results suggest that cancer cells are capable of inducing neoplastic transformation in stromal cells of the host organ by some, as yet unknown, epigenetic mechanism(s).