Jens Köllermann

Heterogeneous proliferative potential of occult metastatic cells in bone marrow of patients with solid epithelial tumors

Bone marrow is a major homing site for circulating epithelial tumor cells. The present study was aimed to assess the proliferative capacity of occult metastatic cells in bone marrow of patients with operable solid tumors especially with regard to their clinical outcome. We obtained bone marrow aspirates from 153 patients with carcinomas of the prostate (n = 46), breast (n = 45), colon (n = 33), and kidney (n = 29). Most of the patients (87%) had primary disease with no clinical signs of overt metastases [tumor-node-metastasis (TNM)-stage UICC (Union Internationale Contre le Cancer) I-III]. After bone marrow was cultured for 21–102 days under special cell culture conditions, viable epithelial cells were detected by cytokeratin staining in 124 patients (81%). The cultured epithelial cells harbored Ki-ras2 mutations and numerical chromosomal aberrations. The highest median number of expanded tumor cells was observed in prostate cancer (2,619 per flask). There was a significant positive correlation between the number of expanded tumor cells and the UICC-stage of the patients (P = 0.03) or the presence of overt metastases (P = 0.04). Moreover, a strong expansion of tumor cells was correlated to an increased rate of cancer-related deaths (P = 0.007) and a reduced survival of the patients (P = 0.006). In conclusion, the majority of cancer patients have viable tumor cells in their bone marrow at primary tumor diagnosis, and the proliferative potential of these cells determines the clinical outcome.

Clinical significance of p53 alterations in surgically treated prostate cancers

Despite the high number of previous studies, the role of p53 alterations in prostate cancer is not clearly defined. To address the role of p53 alterations in prostate cancer biology, a total of 2514 cancers treated by radical prostatectomy were successfully analyzed by immunohistochemistry in a tissue microarray format. Overall a low rate of p53-positive tumors was found (2.5%). A significant underestimation of p53-positive cases was excluded by subsequent large section analyses and direct sequencing of the p53 gene in subsets of our patients. Large section analysis of 23 cases considered negative on the tissue microarray yielded only one weakly p53-positive tumor. Only 4 out of 64 (6.4%) high-grade tumors, that were considered negative for p53 by immunohistochemistry, presented exon 5–8 mutations. These data suggest a high sensitivity of our immunohistochemistry approach and confirm the overall low frequency of p53 alterations in clinically localized prostate cancer. A positive p53 immunostaining was strongly associated with presence of exon 5–8 mutations (P<0.0001), advanced pT-stage (P<0.0001), high Gleason grade (P<0.0001), positive surgical margins (P=0.03) and early biochemical tumor recurrence (P<0.0001). A higher rate of positive p53 immunostaining was detected in late-stage diseases including metastatic prostate cancer (P=0.0152) and hormone-refractory tumors (P=0.0003). Moreover, p53 expression was identified as an independent predictor of biochemical tumor recurrence in the subgroup of low- and intermediate-grade cancers. In summary, the results of this study show that p53 mutations characterize a small biologically aggressive subgroup of prostate cancers with a high risk of progression after prostatectomy. The rate of p53 alterations increases with prostate cancer progression.

Clinical Significance of Epidermal Growth Factor Receptor Protein Overexpression and Gene Copy Number Gains in Prostate Cancer

Purpose: The epidermal growth factor receptor (EGFR) is a protein involved in the tumor progression of many cancer types and is an important therapeutic target. To determine its role in prostate cancer, we analyzed 2,497 prostate cancers on the DNA and protein level. Experimental Design: Tissue samples from each tumor were brought into a tissue microarray and analyzed by immunohistochemistry and fluorescence in situ hybridization. A subset of cancers was also sequenced for EGFR exon 18 to 21 mutations. Results: Detectable EGFR expression was found in 18% of cancers and was significantly associated with high grade, advanced stage, and high risk for prostate-specific antigen recurrence in univariate analysis (P < 0.0001, each). Fluorescence in situ hybridization analysis with a dual-labeling probe for centromere 7 and EGFR showed increased EGFR copy number in 3.3% of cases. EGFR copy number gains were mostly due to an overrepresentation of the entire chromosome and were associated with EGFR protein expression (P < 0.0001), high grade (P < 0.0001), and advanced stage (P = 0.0056). Only one cancer had a high-level amplification (>20 EGFR gene copies per cell). This amplification was heterogeneous, involving only ∼30% of the cancer volume. EGFR mutations were not found in 35 of the cases analyzed. Conclusion: Increased EGFR expression is often seen in prostate cancer and is associated with poor prognosis. The significant association of EGFR copy number gains with protein expression argues for the significant role of minimal gene copy number changes for protein expression. Although EGFR expression was not an independent prognostic variable, the potential utility of anti-EGFR medications might be worth further investigation in EGFR-expressing prostate cancer.

Low Level Her2 Overexpression Is Associated with Rapid Tumor Cell Proliferation and Poor Prognosis in Prostate Cancer

Purpose: The HER2 oncogene is involved in the biology of many different tumor types and serves as a prognostic marker and a therapeutic target in breast cancer. In contrast to breast cancer, studies on Her2 overexpression and gene amplification in prostate cancer have yielded different results. The purpose of this study was to learn more on the prevalence and clinical significance of HER2 amplification and overexpression in prostate cancer. Experimental Design: A tissue microarray containing >2,000 prostate cancers with follow-up data was used. Tissue microarray sections were analyzed on protein and DNA level using two different antibodies (HercepTest, DAKO; Novocastra NCL-CB11) and fluorescence in situ hybridization. Results: Immunohistochemical analyses showed highly similar results for both antibodies. Detectable Her2 immunostaining was observed in 17.2% for the HercepTest and in 22.5% for the Novocastra antibody with the vast majority of cases showing 1+ or 2+ staining. For both antibodies (HercepTest/Novocastra), significant associations were found between positive staining and high Gleason grade (P < 0.0001, both), advanced pT stage (P < 0.0001/P = 0.0015), rapid tumor cell proliferation (P = 0.0004/P = 0.0071), and tumor recurrence (P < 0.0001, both). HER2 amplification was only found in 1 of 2,525 analyzable cases (0.04%). Conclusions: Low-level Her2 overexpression occurs at relevant frequency in prostate cancer and in the absence of gene amplification. Increased Her2 expression may potentially lead to an aggressive behavior of tumor cells through the stimulation of tumor cell proliferation because Her2 staining was shown to be significantly associated with Ki67 labeling index. These data argue for reconsidering anti-Her2 therapy, possibly with modified approaches. Clin Cancer Res; 16(5); 1553–60

Chromosome 8p deletions and 8q gains are associated with tumor progression and poor prognosis in prostate cancer.

Purpose: Deletions of 8p and gains of 8q belong to the most frequent cytogenetic alterations in prostate cancer. The target genes of these alterations and their biological significance are unknown. Experimental Design: To determine the relationship between chromosome 8 changes, and prostate cancer phenotype and prognosis, a set of 1.954 fully annotated prostate cancers were analyzed in a tissue microarray format by fluorescence in situ hybridization. Results: Both 8p deletions and 8q gains increased in number during different stages of prostate cancer progression. 8p deletions/8q gains were found in 26.1%/4.8% of 1,239 pT2 cancers, 38.5%/9.8% of 379 pT3a cancers, 43.5%/8.9% of 237 pT3b cancers, 40.7%/14.8% of 27 pT4 cancers, 39.1%/34.8% of 23 nodal metastases, 51.9%/33.3% of 27 bone metastases, and 45.5%/59.9% of 22 hormone refractory cancers (P < 0.0001 each). Both 8p deletions and 8q gains were also significantly associated with high Gleason grade and with each other (P < 0.0001 each). In primary tumors, 8p deletions were seen in only 27.3% of 1,882 cancers without 8q gain but in 57.4% of 122 tumors with 8q gain (P < 0.0001). Among cancers treated with radical prostatectomy, 8p deletions (P = 0.003) and 8q gains (P = 0.02) were associated with biochemical tumor recurrence. However, multivariate analysis (including prostate-specific antigen, pT/pN stage, Gleason score, and surgical margin status) did not reveal any statistically independent effect of 8p or 8q alterations on biochemical tumor recurrence. Conclusions: 8p deletions and 8q gains are relatively rare in early stage prostate cancer but often develop during tumor progression. The prognostic effect does not seem to be strong enough to warrant clinical application. Clin Cancer Res; 16(1); 56–64

Expression and prognostic relevance of annexin A3 in prostate cancer.

OBJECTIVES By differential quantitative protein expression, it has previously been shown that annexin A3 (ANXA3) expression is associated with prostate cancer. However little is known about the role and biology of ANXA3 in the human prostate. The aim of this study was to thoroughly analyze ANXA3 expression patterns and its potential as a prognostic marker in a large set of benign, preneoplastic, and neoplastic prostate tissue samples. METHODS Immunohistochemistry-based ANXA3 protein expression was analyzed for 1589 prostate cancers as well as smaller subsets of benign epithelium and high-grade prostatic intraepithelial neoplasia (PIN) in a tissue microarray format. RESULTS All samples of benign prostatic epithelium and PIN showed ANXA3 protein expression, with PIN lesions showing a decreased staining intensity compared with benign epithelium (p<0.0001). In cancer, ANXA3 protein expression was essentially reduced, resulting in a negative staining rate of 27.2%, which correlated with increasing pT stage and Gleason score (p<0.0001). ANXA3 status in cancer was shown to be an independent adverse prognostic factor and enabled substratification of the large group of intermediate-risk patients (n=969) into high- and low-risk subgroups. CONCLUSIONS ANXA3 represents a promising candidate tissue marker, and when combined with the standard prognostic parameters, is suggested to provide a more precise prediction of prognosis in the individual patient, therefore harboring the potential to contribute to future patient management.

Immunological microenvironment in prostate cancer: High mast cell densities are associated with favorable tumor characteristics and good prognosis

Number of intratumoral mast cells predicts survival in various cancers. The prognostic significance of such mast cells in surgically treated prostate cancer is unknown.

Expression of Vascular Endothelial Growth Factor (VEGF) and VEGF Receptor Flk-1 in Benign, Premalignant, and Malignant Prostate Tissue

Vascular endothelial growth factor (VEGF) is one of the most potent mitogenic, highly specific tumor angiogenic factors, which acts via binding to 2 specific tyrosine kinase receptors. There are few studies analyzing VEGF receptor expression in prostate cancer cells, and results are contradictory. In an immunohistochemical study, we analyzed VEGF and VEGF receptor fetal liver kinase (Flk)-1 expression in benign glands, high-grade prostatic intraepithelial neoplasia (HGPIN), and prostatic carcinomas of different Gleason scores, obtained from 21 radical prostatectomy specimens. In all benign glands, VEGF and Flk-1 expression was confined almost exclusively to the basal cell layer (proliferative cell compartment). In HGPIN, labeling was no longer confined to the basal cell layer, but also was seen in all neoplastic secretory cells. All carcinomas stained positive for both markers. There was a trend for increasing labeling intensity with increasing cellular dedifferentiation. We concluded that tumor growth stimulated by the VEGF-Flk-1 system is promoted not only by neoangiogenesis, but also by tumor cell autostimulation. The VEGF-Flk-1 system may have an important role in the process of malignant transformation and tumor progression.

Biochemical recurrence after radical prostatectomy: multiplicative interaction between surgical margin status and pathological stage.

PURPOSE A positive surgical margin after radical prostatectomy is considered an adverse prognostic feature. However, few groups have explored the potential interaction between surgical margin status and other cancer characteristics, specifically pathological stage. We addressed the first degree of interaction between positive surgical margins and other established adverse predictors of biochemical recurrence after radical prostatectomy. MATERIALS AND METHODS We used univariate and multivariate analysis to test the effect of surgical margin status on biochemical recurrence in 4,490 patients treated at a single institution between 1992 and 2008. We systematically tested all first-degree interactions between surgical margin status, and pretreatment prostate specific antigen, pT and pN stage, and radical prostatectomy Gleason sum. If interactions were significant, we quantified the effect on the biochemical recurrence rate. RESULTS Overall 850 patients (18.9%) had positive surgical margins. In those with negative vs positive surgical margins the 5-year biochemical recurrence-free survival rate was 95% vs 83%, 74% vs 62% and 47% vs 29% for pT2, pT3a and pT3b disease, respectively. In multivariate models only the pT stage-surgical margin status interaction achieved independent predictor status (p = 0.003). Negative vs positive surgical margin multivariate HRs were 1 vs 2.9, 2.3 vs 4.3 and 4.1 vs 5.6 in pT2, pT3a and pT3b cases, respectively. CONCLUSIONS Compared to negative surgical margins, positive surgical margins increase the absolute biochemical recurrence 5-year rate by 12% to 18%. More importantly, positive surgical margins may substantially worsen the prognosis beyond that of the original pathological disease stage.

Long-term data on the survival of patients with prostate cancer treated with radical prostatectomy in the prostate-specific antigen era.

Study Type – Therapy (case series)
Level of Evidence 4