Purpose: The aim of this study was to evaluate the clinical relevance of the presence of disseminated tumor cells in peripheral blood (so-called circulating tumor cells) for renal cell carcinoma patients. Methods: Two hundred thirty-three peripheral blood samples from 154 renal cell carcinoma patients were investigated for the presence of disseminated tumor cells by autoMACS technique and immunocytochemical staining of cytokeratin. The frequency of circulating tumor cells was analyzed statistically for correlation with relevant clinical data. Results: Two kinds of tumor cells were detected: those with expression of cytokeratin 8/18 (CK+) and cells without a detectable cytokeratin expression, which we called large blue-stained cells with a tumorlike morphology. After following the CD45 autoMACS depletion protocol, we identified circulating tumor cells in 96 (41%) of 233 peripheral blood samples, which originated from 81 (53%) of 154 renal cell carcinoma patients.A significant correlation between the detection of circulating tumor cells and positive lymph node status (P < 0.001; χ 2 test) and the presence of synchronous metastases at the time of primary tumor resection (P = 0.014; χ 2 test) was found. In a multivariate Cox's regression hazard model, presence of CK+ circulating tumor cells was significantly correlated with poor overall survival for renal cell carcinoma patients (relative risk, 2.3; P = 0.048). Conclusions:The presence of circulating tumor cells correlated to lymph node status and presence of synchronous metastases in renal cell carcinoma. It is important to evaluate CK+ and blue-stained tumor cells together to determine the role of circulating tumor cells in tumor behavior and disease progression. Detection of CK+ circulating tumor cells in peripheral blood is a significant and independent prognostic factor for renal cell carcinoma. (Cancer Epidemiol Biomarkers Prev 2009;18(8):2190-4)
Aberrant methylation is a main mechanism of tumor suppressor gene inactivation in carcinogenesis. In this study, the methylation status of RASSF1A, p16, MLH1, MSH2 and ER␣ was investigated in 84 primary soft tissue sarcomas (STSs), including 22 liposarcomas, 18 malignant fibrous histiocytomas (MFHs), 18 leiomyosarcomas, 6 rhabdomyosarcomas, 6 neurogenic sarcomas and several other sarcoma entities. RASSF1A hypermethylation was detected in 17 of 84 (20%) STSs; however, methylation was more frequent in leiomyosarcomas (39%) compared to MFHs (6%; p < 0.015) and liposarcomas (18%). The p16 CpG island was methylated in 22 out of 82 (27%) cases. In 7 out of 81 (9%) STS samples, the promoter of MLH1 was methylated and in liposarcoma the methylation frequency was higher (14%). For MSH2, no hypermethylation was detected. Methylation of ER␣ was detected in 48 of 63 (76%) STSs, but also in 4 of 8 (50%) normal tissue samples. Furthermore, we analyzed mutational activation of K-ras and BRAF. In 4 out of 84 (5%) of STSs, a substitution at codon 599 of BRAF was found; however, no alteration of K-ras was detected. In an univariate Cox proportional-hazards regression model, we found that the risk of a tumor-related death for STS patients with methylated RASSF1A was significantly increased (RR ؍ 2.9; p ؍ 0.037). In summary, our data indicate that inactivation of RASSF1A is a common event in STS, especially in leiomyosarcoma. Thus, the methylation status of cancer-related genes was distinct in different STS and methylation of RASSF1A promoter can serve as prognostic marker in STSs. © 2004 Wiley-Liss, Inc. Key words: soft tissue sarcoma; methylation; RASSF1; p16; tumor suppressor gene Soft tissue sarcomas (STSs) are aggressive tumors of mesodermal origin and distinct histology. They are mainly classified in liposarcomas, leiomyosarcomas, malignant fibrous histiocytomas (MFHs), rhabdomyosarcomas, neurogenic sarcomas, synovial sarcomas, fibrosarcomas and several other sarcomas according to the distinct tissues the tumor resembles. 1 STSs are malignant tumors that account for less than 1% of all malignant cancers. 2 However, 50% of STS patients will die of distant metastasis within 5 years, since soft tissue tumors are relatively resistant to chemotherapy and radiotherapy.Previously, we have analyzed the expression of DNA repair enzymes (MLH1 and MSH2) in STSs and correlated reduced expression of MSH2 with poor survival in these patients. 3 In carcinogenesis, aberrant promoter methylation is an important mechanism of cancer-related gene silencing. 4 Epigenetic inactivation of DNA repair enzymes and tumor suppressor genes is commonly reported in solid tumors. 5 However, studies on the hypermethylation of tumor suppressor genes in STSs are limited to few STS entities. In alveolar soft part sarcoma, epigenetic inactivations of MLH1 and MSH2 were undetectable. 6 In contrast, hypermethylation of p16INK4a was frequently detected in leiomyosarcoma and correlated with poor prognosis. 7 Inactivation of the RASSF1A tumor suppressor genes ...
BackgroundMembers of the urokinase-type plasminogen activator (uPA) system including uPA, its receptor uPAR and the plasminogen activator inhibitor 1 (PAI-1) play an important role in tumour invasion and progression in a variety of tumour types. Since the majority of clear cell renal cell carcinoma (ccRCC) shows distant metastasis at time of diagnosis or later, the interplay of uPA, uPAR and PAI-1 might be of importance in this process determining the patients’ outcome.MethodsCorresponding pairs of malignant and non-malignant renal tissue specimens were obtained from 112 ccRCC patients without distant metastasis who underwent tumour nephrectomy. Tissue extracts prepared from fresh-frozen tissue samples by detergent extraction were used for the determination of antigen levels of uPA, uPAR and PAI-1 by ELISA. Antigen levels were normalised to protein concentrations and expressed as ng per mg of total protein.ResultsAntigen levels of uPA, uPAR, and PAI-1 correlated with each other in the malignant tissue specimens (rs=0.51-0.65; all P<0.001). Antigen levels of uPA system components were significantly higher in tissue extracts of non-organ confined tumours (pT3+4) compared to organ-confined tumours (pT1+2; all P<0.05). Significantly elevated levels of uPAR and PAI-1 were also observed in high grade ccRCC. When using median antigen levels as cut-off points, all three uPA system factors were significant predictors for disease-specific survival (DSS) in univariate Cox’s regression analyses. High levels of uPA and uPAR remained independent predictors for DSS with HR=2.86 (95% CI 1.07-7.67, P=0.037) and HR=4.70 (95% CI 1.51-14.6, P=0.008), respectively, in multivariate Cox’s regression analyses. A combination of high antigen levels of uPA and/or uPAR further improved the prediction of DSS in multivariate analysis (HR=14.5, 95% CI 1.88-111.1, P=0.010). Moreover, high uPA and/or uPAR levels defined a patient subgroup of high risk for tumour-related death in ccRCC patients with organ-confined disease (pT1+2) (HR=9.83, 95% CI 1.21-79.6, P=0.032).ConclusionsHigh levels of uPA and uPAR in tumour tissue extracts are associated with a significantly shorter DSS of ccRCC patients without distant metastases.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2407-14-974) contains supplementary material, which is available to authorized users.
The human leukocyte antigen (HLA) system is a major part of the human immune system and has an impact on tumor initiation, tumor progression, and immunosurveillance. Renal cell carcinoma tumors are considered to be immunogenic. Therefore, we studied the allele frequencies of four gene loci (HLA-A, -B, -C, and HLA-DR) in a cohort of German renal cell carcinoma (RCC) patients and in healthy controls. HLA-A-C were determined using serological methods, whereas HLA-C12, C14, C16, C18, and HLA-DR were characterized through the use of standard molecular biological methods. The occurrence of the HLA-C*12 allele was significantly increased in German RCC patients compared with healthy controls (P < 0.005; Fisher's exact test), whereas the occurrence of the HLA-DRB1*04 allele was significantly reduced in RCC patients compared with healthy controls (P < 0.05; Fisher's exact test). However, the presence of allele HLA-C*12 was not significantly associated with 10 year overall survival. We suggest that the frequency of HLA alleles can affect development of RCC and could add knowledge as predictive marker for future immunotherapies.
Human mouse double minute 2 (Mdm2) plays an essential role in the regulation of the tumor suppressor p53. The G/G variant of SNP309 was shown to increase Mdm2 mRNA/protein expression and to be associated with an increased risk and earlier onset of different cancers in Asian populations. However, the frequency and impact of these G/G variants have not been studied in Caucasian renal cell carcinoma (RCC) patients. Therefore, we analyzed an unselected German cohort of 197 consecutive RCC patients and detected the G/G variant in 18 (9.1%) patients, the G/T variant in 116 (58.9%) patients and the T/T variant in 63 (32.0%) patients. Studying the association between age at tumor onset and SNP309 genotypes, no correlation was detected in the entire RCC cohort or among the male RCC patients. However, the female G/G patients (median age 59.5 years) were diagnosed 13.5 years earlier than the T/T females (median age 73 years). When separating all females into two groups at their median age (68 years), 7 and 1 patients with the G/G variant and 9 and 13 patients with the T/T variant were noted in these age groups (P=0.024). To study the age dependency of tumor onset further, a second, age-selected cohort of 205 RCC patients was investigated, which comprised especially young and old patients. Interestingly, the G/G type occurred more often at lower tumor stages and tumor grades compared with higher stages (P=0.039 and 0.004, respectively). In females, the percentage of the G/G variant was only slightly higher in the younger age group, whereas in males, the percentage of the G/G variant was remarkably higher in the younger age group (19.4% vs 8.0%). In summary, female Caucasian RCC patients with the MDM2 SNP309 G/G genotype showed significantly earlier tumor onset than patients with the wild-type T/T genotype.
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