胃癌患者外周血及骨髓微转移检测的临床意义

目的:探讨检测胃癌患者外周血和骨髓CK20 mRNA表达的敏感性、特异性及临床意义.方法:采用RTPCR技术,同时对照检测49例胃癌患者、5例胃良性病变患者及5例健康志愿者骨髓与外周血中的CK20 mRNA表达.结果:49例胃癌患者中,骨髓和外周血CK20阳性表达率分别为49.0%(24/49),32.7%(16/49),二者差异有统计学意义(P＜0.05).其中2例外周血CK20表达阳性,骨髓表达阴性.健康志愿者及良性病变患者外周血及骨髓中未检测到CK20表达.本实验中CK20 mRNA RT-PCR技术的灵敏度为10～-5.胃癌的微转移状况与组织分化程度和肿瘤TNM分期有关.结论:应用RT-PCR法以CK20为标志物检测胃癌微转移细胞特异性高.骨髓检测胃癌微转移较单次采血更敏感,但外周血检测仍能提供一些有价值的资料.     

检测肺癌患者外周血和骨髓微转移的临床意义

目的探讨检测肺癌患者外周血和骨髓微转移的特异性、敏感性及临床意义。方法应用巢式RT-PCR技术,检测59例肺癌患者、11例肺部良性病变患者和20例健康人外周血、骨髓中CK19 mRNA表达。结果巢式RT-PCR检测技术的敏感性达到10-6。59例肺癌患者中,20例检测出外周血微转移,13例检测出骨髓微转移,其阳性检出率分别为33.9％(20/59)和22.0％(13/59),二者有显著正相关(P<0.05)。肺癌患者外周血和骨髓微转移与肺癌组织学类型、细胞分化程度及P-TNM分期均存在密切关系(P<0.05或P<0.01)。肺良性病变患者、健康人外周血和骨髓中均未检测出CK19 mRNA表达。结论肺癌患者外周血和骨髓中均存在用常规方法检测不出的微转移;应用巢式RT-PCR技术检测肺癌患者外周血和骨髓中CK19 mRNA表达,对肺癌微转移的分子诊断具有重要的理论意义和临床应用前景。     

High percentage of false-positive results of cytokeratin 19 RT-PCR in blood: a model for the analysis of illegitimate gene expression

Cytokeratin 19 (CK19) RT-PCR is widely used in order to detect circulating tumor cells in peripheral blood and bone marrow. However, increasing amounts of information support the fact that it is also associated with a high percentage of false-positive results. In our study, we not only managed to demonstrate the significant limitations of this method, but were also able to clarify the reasons behind these limitations. We developed a completely novel RT-PCR for CK19 and sequenced an intron at nucleotide (nt) 980 of the CK19 mRNA to exclude DNA contamination. Tumor dilution experiments were performed in order to analyze the specificity and sensitivity of the method. Control experiments using the blood of healthy donors were performed. Tumor cell dilution experiments gave a detection limit of one tumor cell. If tumor cells were mixed with an equal volume of pure mononuclear cells, the detection limit was 1 tumor cell in 10(5) mononuclear cells. RT-PCR of mononuclear cells from healthy blood donors gave false-positive results in 29% of the cases. We conclude that a significant decrease in the sensitivity of CK19 RT-PCR occurs if it is performed in blood cells and that the illegitimate CK19 gene expression in normal cells can lead to false-positive results. These limitations have to be taken into account if RT-PCR is to be used for the detection of tumor cells either in blood or in bone marrow in clinical practice.     

胃肠恶性肿瘤外周血微转移的检测及其临床意义

目的研究胃癌、大肠癌患者外周血CK20 mRNA的表达,并探讨其临床意义。方法采用RT-PCR方法检测47例胃癌患者、58例大肠癌患者和6例非恶性病手术志愿者骨髓、门静脉和外周血CK20 mRNA的表达,并随访1年。结果6例健康志愿者无CK20 mRNA阳性表达;47例胃癌患者骨髓、门静脉血CK20 mRNA阳性表达率分别为87.2％(41/47)和85.1％(40/47);58例大肠癌患者骨髓、门静脉血阳性表达率分别为77.6％(45/58)和74.1％(43/58)。单次外周血采样CK20 mRNA阳性表达率胃癌患者为42.6％(20/47),大肠癌患者为44.8％(26/58);两次采样总阳性率胃癌患者为74.5％(35/47),大肠癌患者为69.0％(40/58)。外周血总阳性率略低于骨髓和门静脉血(P>0.05),外周血重复采样阳性率高于单次采样(P<0.05)。Duke C期患者CK20 mRNA阳性表达率高于DukeA、B期(P<0.05)。1年局部或远处复发率CK20 mRNA外周血阳性表达患者高于阴性者(P<0.05)。结论胃肠癌患者外周血CK20 mRNA RT-PCR检测有与骨髓、门静脉血相似的敏感性和特异性,可以作为检测胃肠癌微转移的指标并指导其治疗和预后。     

Cytokeratin 20 and guanylyl cyclase C mRNA is largely present in lymph node and liver specimens of colorectal cancer patients

The aim of our prospective study was to detect circulating epithelial cells (CEC) indicating the presence of disseminated tumor cells (DTC) in tissues affected by lymphatic and hematogenic colorectal cancer metastasis. DTC were tracked in lymph node, liver or bone marrow samples of 245 colorectal cancer patients using 2 independent RT-PCR assays for cytokeratin 20 (CK20) and guanylylcyclase C (GCC) that demonstrated a sensitivity of 1 colorectal cancer cell in 10(6) nucleated hematopoietic cells. CK20 mRNA was detected in 79% of lymph nodes, 35% of both liver lobes and 11% of bone marrow samples. GCC mRNA was found in 68% of lymph nodes, 60% of both liver lobes and 6% of bone marrow specimens. Both markers were recorded in 63% of lymph nodes, 45% of at least 1 liver lobe and 1% of bone marrow samples. There was no significant difference when comparing lymph node samples tested positive for both markers in patients with (N1/2; 65%) and without (N0; 56%) nodal involvement. The same was true when comparing the percentages of patients with and without clinically overt distant metastasis who were positive for both markers in at least 1 liver lobe (62% vs. 41%) or in bone marrow (4% vs. 0%). A score denoting the cumulative sum of tests indicating presence of CK20 and GCC mRNA in the liver was significantly related with UICC classification (p = 0.039). However, addition of lymph node results to this score decreased the correlation. The high incidence of clinically inconspicuous lymph node and liver samples tested positive for both markers emphasizes the function of these organs as primary filters for epithelial cells possibly shed from colorectal carcinomas. The potential prognostic significance of these findings warrants verification, especially regarding the importance of CEC or DTC resident in the liver of colorectal cancer patients.     

Differential expression of carcinoembryonic antigen (CEA) splice variants in whole blood of colon cancer patients and healthy volunteers: implication for the detection of circulating colon cancer cells

Quantification of circulating cancer cells in whole blood samples by real time quantitative RT-PCR might be of clinical value for monitoring therapeutic effectiveness. In colon cancer patients, carcinoembrynic antigen (CEA) and cytokeratin 20 (CK20) have been frequently used for RT-PCR based tumor cell detection, but the specificity in particular for CEA has been questioned. In this study, we compared real-time RT-PCR for CEA and CK20 and analysed patients with metastatic disease (n=32) and healthy volunteers (n=17). CK20 mean values were elevated in cancer patients (P<0.001) and defined a subgroup (38%) who showed CK20 levels at least 100-fold above the highest value of the healthy control group. In contrast, only two cancer patients (6%) showed elevated CEA levels. Samples of the healthy control group showed exclusively a CEA-PCR product of 79 degrees C melting temperature. Thirty per cent of the colon cancer patients showed an additional product of 82 degrees C melting temperature. The 82 degrees C product was identical with the amplification product of CEA-cDNA and cDNA from different colon cancer cell lines. Colon cancer cells were spiked into normal blood in 10-fold dilutions that resulted in a dose dependent shift of the melt curve from 79 degrees C to the 82 degrees C. Sequencing of the PCR products showed that white blood cells express a splice variant of CEA, which hinders detection of tumor cell cDNA in whole blood samples. Our findings have implications for the use of CEA as a diagnostic molecule (e.g. by RT-PCR). The discovery of a physiologically expressed CEA splice variant might lead to a better understanding of the biological function of CEA and its family members.     

K-ras codon 12 and 13 mutations are correlated with differential patterns of tumor cell dissemination in colorectal cancer patients

The aim of this prospective study was to relate the incidences of cytokeratin 20 (CK20) and guanylylcyclase C (GCC) in lymph node, liver, and bone marrow specimens of 245 colorectal cancer (CRC) patients with the K-ras oncogene status of the corresponding primary tumor. Qualitative RT-PCR detection of CK20 and GCC mRNA was used as marker of circulating epithelial cells (CEC). Samples were considered positive for CEC only when both markers were detected concomitantly. For the detection of K-ras mutations, a PCR-RFLP assay was used. In the group with K-ras mutated primary carcinomas (n=92), CEC were detected in 62% of lymph node-, 43% of liver-, and 2% of bone marrow samples. No statistical significance was found when comparing these results with those from patients with K-ras wild-type carcinoma (59%, 46%, and 0%, respectively). In contrast to this combined evaluation, separate analysis of K-ras codons 12 (n=75, 82%) and 13 (n=17, 18%) revealed significantly differing CEC incidences. Lymph node specimens from corresponding K-ras codon 13 mutated carcinomas showed a significantly higher CEC incidence (82%) than the groups with codon 12 mutation (57%, p<0.05) or K-ras wild-type sequence (59%, p<0.05). Unlike these findings in lymph nodes, liver biopsies from corresponding carcinomas with K-ras codon 12 mutation or wild-type sequence were significantly more often positive for CEC (31% and 29%) than specimens from K-ras codon 13 mutated primary CRC (12%, p<0.04, respectively). In conclusion, colorectal carcinomas with K-ras codon 12 mutation showed the same pattern of tumor cell dissemination as their K-ras wild-type counterparts. Since K-ras codon 12 mutations prevailed 4-fold over codon 13 mutations, combined analysis of the two codons showed the same result. However, sub-analysis of patients with K-ras codon 13 mutation revealed that the respective CEC incidence was significantly increased in lymph nodes, but decreased in liver biopsies.     

胃肠道癌患者外周血和骨髓中微转移检测的意义

目的：探讨胃道肠癌患者外周血和骨髓中微转移的检测及其意义。方法：以CK19作指标，用巢式RT－PCR方法检测75例胃、结肠癌患者术前外周血中癌细胞，同时对其中33例患者骨髓进行检测。结果：75例中，24例（32.0％）外周血中检测出CK19mRNA的表达，其中60例胃癌患者的检出率为30.0%(18/60)，15例结肠癌的检出率为40.0%(6/15)。外周血阳性率随着肿瘤分期的增加而增加。其中33例的骨髓阳性率为48.5%，高于这些患者的血液中阳性率（33.3%)。结论：检测外周血和骨髓中微 转移可提高胃结肠癌患者临床分期的准确性，帮助判断患者的预后。     

Clinical significance of immunocytochemical detection of tumor cells using digital microscopy in peripheral blood and bone marrow of breast cancer patients.

PURPOSE: The presence of tumor cells in bone marrow has been reported to represent an important prognostic indicator in breast cancer, but the clinical significance of circulating cells in peripheral blood is less well known. The aim of this study was to evaluate the feasibility of identifying cytokeratin (CK)-expressing cells in peripheral blood with an automat-assisted immunohistochemical detection system and to compare it with detection of tumor cells in bone marrow samples. EXPERIMENTAL DESIGN: Cytospun Ficoll fractions of peripheral blood and bone marrow were obtained simultaneously in 114 breast cancer patients at different stages of the disease (I to IV) before treatment with chemotherapy. The pancytokeratin (CK) monoclonal antibody A45-B/B3 (anti-CKs 8, 18, and 19) was used for epithelial cell detection. Immunostained cells were detected by an automated cellular imaging system (ChromaVision Medical System). RESULTS: CK+ cells were detected in 28 (24.5%) patients in blood and in 67 (59%) patients in bone marrow. Twenty-six (93%) patients with CK-positive cells in blood also had positive bone marrow (P < 0.001). Positive cells were detected in peripheral blood in 3/39 (7.5%) operable breast cancers (stage I/II), 9 of 36 (25%) locally advanced breast cancers (stage III), and 16 of 39 (41%) patients with metastatic disease (stage IV; P = 0.017). In the subgroup of nonmetastatic patients (n = 75), prognostic factors for poor disease-free survival were: absence of estrogen receptor; presence of CK+ cells in bone marrow (P = 0.012); clinical nodal involvement; large tumor size (T4); and presence of tumor emboli. Presence of circulating CK+ cells in the peripheral blood was not statistically correlated with disease-free survival. On multivariate analysis, independent indicators for disease-free survival were: absence of estrogen receptor (P = 0.043) and presence of CK+ cells in bone marrow (P = 0.076). CONCLUSIONS: The clinical relevance of circulating epithelial cells as a prognostic factor is not supported by the present data, especially in comparison with tumor cells in the bone marrow. However, this method of detection may be useful to monitor the efficacy of treatment in advanced or metastatic breast cancer.     

Bone marrow cytokeratin 19 mRNA level is an independent predictor of relapse-free survival in operable breast cancer patients

Purpose To study the prognostic significance of elevated cytokeratin 19 (CK19) mRNA levels in the bone marrow (BM) of operable breast cancer patients. Patients and Methods From 1998 to 2000, BM was collected from 195 consecutive breast cancer patients immediately prior to surgery and from 34 healthy volunteers. The patients received surgical and adjuvant treatment according to national guidelines at the time. We analyzed the level of CK19 mRNA in the BM samples from patients and normal controls using a real-time RT-PCR assay. The associations with known prognostic factors and the impact of pathological CK19 mRNA levels on patients’ prognosis were investigated. Results Using the 99 percentile of the normal control group as a cut-off, 24 (12%) of the 195 patients and 1 (3%) of the 34 volunteers were diagnosed as CK19 mRNA positive. There was no correlation between CK19 BM status and the clinicopathological factors tested. During a median follow-up of 72 months, 7 (29%) of the 24 CK19 mRNA BM positive patients experienced systemic relapse compared to 20 (12%) of the 171 in the CK19 mRNA negative group. The patients with CK19 mRNA-positive BM had significantly shorter systemic recurrence-free survival (P = 0.01) and overall recurrence-free survival (P = 0.005). Multivariate Cox regression showed CK19 mRNA BM status to be an independent predictor of relapse. Conclusion Detection of CK19 mRNA in the BM of breast cancer patients by real-time RT-PCR is an independent predictor of relapse-free survival in operable breast cancer patients. This work was supported by the Norwegian Cancer Society.     

检测乳腺癌患者骨髓中CK19的表达及其临床意义

背景与目的:乳腺癌早期即可发生播散和转移,远处转移尤其骨转移是影响患者预后的主要因素之一,而骨髓微转移用常规方法又难以检测出来。本研究旨在探讨检测乳腺癌患者骨髓中CK19mRNA的表达及其临床意义。方法:应用RT鄄PCR技术,同时对照检测65例乳腺癌患者、15例乳腺良性病变患者和8例健康人骨髓中的CK19mRNA表达,并分析CK19mRNA表达与临床病理因素的关系。结果:65例乳腺癌患者中,22例CK19mRNA阳性,阳性率为33.8%;乳腺良性病变患者和健康人骨髓中未检测到CK19mRNA表达。CK19mRNA表达与乳腺癌肿瘤大小和分期有关(P<0.05),与年龄和淋巴结转移状况无显著性相关(P>0.05);与外周血中CEA异常增高呈正相关(r=0.372,P=0.002)。结论:CK19mRNA可作为检测乳腺癌患者骨髓微转移的分子指标之一,可为乳腺癌患者的治疗和预后判断提供帮助。     

Detection of isolated tumour cells in the blood and bone marrow of patients with gastric cancer by combined sorting, isolation and determination of MAGE-1, -2 mRNA expression

The detection of isolated (circulating or disseminated) tumour cells (ITC) in patients with cancer requires very sensitive methods, as such cells are very rare. In the present study, the method that combines the negative isolation of CD45- leukocytes from the blood and bone marrow of patients with gastric cancer by flow cytometry, followed by the positive isolation of single cytokeratin-positive (CK+) cells by a Laser Capture Microdissection System for the determination of MAGE-1, -2 mRNA expression was used to detect ITC. This study shows that this method is highly sensitive as it allows to determine beta-actin-mRNA expression in a single CK+ cell. Using > or =5 CK+ cells as a cut-off level, the MAGE-1 mRNA expression was detected in 100% of CK+ cells in the peripheral blood and in 75% of bone marrow samples of patients with gastric cancer. The MAGE-2 mRNA expression was observed in 40 and 58% of samples, respectively. Furthermore, an analysis of primary tumours and locoreginal lymph nodes with respect to the mRNA expression of the two genes showed that MAGE-1 mRNA expression was detected in 88% of the primary tumours and in 67% of the lymph node samples, whereas the MAGE-2 mRNA expression was observed in 72 and 67% of the cases, respectively. Thus, the method described here allows the precise and sensitive determination of tumour-associated gene expression in single ITC present in the blood and bone marrow of patients with gastric cancer.