Bone marrow micrometastases and gastrointestinal cancer detection and significance

Bone marrow micrometastases in esophageal carcinoma: a 10-year follow-up study

Detection of bone marrow micrometastases (BMMs) in patients with esophageal carcinoma may indicate a metastatic phenotype. We assessed if the presence of BMMs had adverse prognostic significance in a 10-year follow-up study. Patients undergoing surgery for esophageal cancer were prospectively recruited between February 1999 and August 2000. Bone marrow aspirates were obtained from the iliac crest of patients under general anesthesia at the time of surgery. Immunocytochemical analysis using anticytokeratin antibodies CAM 5.2 and AE1/AE3 was undertaken to determine the presence of BMMs. Union International Contre le Cancer staging was recorded for all patients. Patient follow-up was completed over a 10-year period through analysis of the Northern Ireland Cancer Registry. Forty-two patients (male = 35) were included, with a mean age of 67.2 years (range 39-83). BMMs were detected in 19 patients (45.2%). International Contre le Cancer tumor staging was stage I = 6, stage II = 10, stage III = 24, and stage IV = 2. BMMs were associated with lymphovascular invasion (P= 0.02) and advanced T stage (P= 0.02). Overall, 10-year survival was 21.4% (n= 9), with a median follow-up of 877.5 days (interquartile range 391.5-2546.3). There was no statistically significant difference between the survival of patients with or without BMMs (1451.4 vs. 1431.6 days, P= 0.99). Univariate analysis demonstrated a trend toward decreased survival for patients with positive lymph nodes (P= 0.07), an increased T stage (P= 0.06), and lymphovascular invasion (P= 0.07). Multivariate analysis demonstrated that none of the variables were significant predictors of mortality. Although the presence of BMMs correlates with recognized adverse tumor characteristics in patients with esophageal cancer, micrometastases detected in the bone marrow at time of surgery does not influence long-term survival.

CK19 mRNA expression in the bone marrow of patients with esophageal squamous cell carcinoma and its clinical significance

The 5-year survival rate in resectable patients with esophageal cancer is only 20% to 36%. Regional relapse and distant metastasis are responsible for the failure of treatment and the majority of cancer-related deaths. Earlier detection of metastases, especially micrometastases, has the potential for more accurate risk stratification in subsequent therapy decisions. No effective techniques have yet been found to detect metastases in erroneously thought to have early stage disease. This study was designed to investigate the clinical significance of bone marrow micrometastases detected by reverse transcriptase-polymerase chain reaction (RT-PCR) in patients with esophageal cancer. Expression of CK19 mRNA in the bone marrow of 61 patients with esophageal squamous cell carcinoma (ESCC) and 15 benign pulmonary and esophageal disease patients was assessed via RT-PCR. Correlation of CK19 mRNA expression to the clinicopathologic features and prognosis of the 61 patients was analyzed: 21.3% (13/61) were positive for expression of CK19 mRNA in patients with ESCC. No CK19 mRNA was detected of the 15 benign pulmonary and esophageal disease patients. CK19 mRNA expression did not correlate with the clinicopathologic features of the patients with ESCC, but patients with CK19 mRNA-positive bone marrow had earlier recurrence and shorter survival after surgery. In multivariate analysis, CK19 mRNA was found to be an independent predictor of a poor outcome. CK19 mRNA may be used as a molecular maker to detect bone marrow micrometastases in patients with ESCC and may help to select the proper therapy and predict the prognosis.

Impact of disseminated tumor cells in gastrointestinal cancer

The detection of epithelial cells by sensitive immunological and molecular methods in blood, lymph nodes or bone marrow of gastrointestinal cancer patients may open a new approach to clinical metastasis research. The phenotypic and genomic characterization of these cells is of great value in the prediction of the further course of the disease and the monitoring of response to treatment. In addition, the role of ultrastaging in blood, lymph nodes and bone marrow of cancer patients for the indication of multimodal therapy is discussed in this review. The impact of prognostic or predictive factors for new treatment protocols in patients with gastrointestinal cancer was evaluated as well as the correlation with clinical factors.

Detection and clinical significance of bone marrow micrometastases in patients undergoing liver transplantation for hepatocellular carcinoma

BACKGROUND

Existing methods of selecting patients with hepatocellular carcinoma (HCC) for liver transplantation rely on computed tomography and magnetic resonance imaging, which fail to detect vascular invasion or micrometastases. Vascular invasion cannot be assessed pretransplant because of the risks of tumor biopsy. Pretransplant detection of micrometastases in bone marrow is an alternative method that may identify patients at risk of recurrence and permit better organ allocation. The authors' aim was to develop an accurate method of detecting hepatocellular carcinoma micrometastases that may have a clinical role in pretransplant assessment.

METHODS

Iliac crest bone marrow was sampled from 18 patients with HCC (before liver transplantation) and 14 controls (cirrhosis, 9; hematologic disorders, 5). Mononuclear bone marrow fractions were evaluated for the presence of micrometastases by immunocytochemistry (ICC) using Hep Par-1 (HPICC) and Glypican-3 (GPICC), and by reverse-transcriptase (RT) polymerase chain reaction using two primer pairs targeting albumin (Alb1RT and Alb2RT) and one pair targeting alpha-fetoprotein (AFPRT). Each marker was compared in terms of (1) specificity and (2) positive and negative predictive values for tumor recurrence.

RESULTS

The specificity of each marker for detecting HCC micrometastases were as follows: HPICC, 93%; GPICC, 92%; Alb1RT, 33%; Alb2RT, 59%; and AFPRT, 0%. The positive (negative) predictive values for HPICC, GPICC, and Alb2RT for posttransplant tumor recurrence were 42% (100%), 40% (73%), and 0% (43%), respectively. HPICC-positive micrometastases were identified in all patients with postoperative tumor recurrence (n=5) and in 75% of patients with microscopic vascular invasion.

CONCLUSIONS

Detection of HCC micrometastases in bone marrow of potential liver transplant candidates is a potentially useful technique that may provide important prognostic information without the need for preoperative tumor biopsy. The authors' preliminary data indicate that HPICC is a promising immunocytochemical marker for HCC micrometastases, and larger studies are needed to confirm its clinical role.

Apoptosis of circulating tumor cells in prostate cancer patients

BACKGROUND

The prescence of circulating tumor cells (CTCs) in the peripheral blood of cancer patients and their frequency has been correlated with disease status.

METHODS

In this study, CTCs were characterized by flow cytometry and fluorescence microscopy after immunomagnetic enrichment from 7.5-ml blood samples collected from patients with prostate cancer in evacuated blood-draw tubes that contained an anticoagulant and a preservative. Events were classified as tumor cell candidates if they expressed cytokeratin, lacked CD45, and stained with the nucleic acid dye 4,6-diamidino-2-phenylindole.

RESULTS

In the blood of prostate cancer patients, only few of these events were intact cells. Other CTC events appeared as damaged cells or cell fragments by microscopy. By flow cytometry, these events stained variably with 4,6-diamidino-2-phenylindole and frequently expressed the apoptosis-induced, caspase-cleaved cytokeratin 18. Similar patterns of cell disintegration were observed when cells of the prostate line LNCaP were exposed to paclitaxel before spiking the cells into normal blood samples.

CONCLUSIONS

The different observed stages of tumor cell degradation or apoptosis varied greatly between patients and were not found in blood of normal donors. Enumeration of CTCs and identification of CTCs undergoing apoptosis may provide relevant information to evaluate the response to therapy in cancer patients.

Enrichment of rare cancer cells through depletion of normal cells using density and flow-through, immunomagnetic cell separation

OBJECTIVE

To develop a reliable technique to enrich for rare cells in blood suspensions using only negative selection steps including a flow-through immunomagnetic cell separations system and by optimizing variables normally encountered during such enrichment processes.

METHODS

A human breast cancer cell line was cultivated and spiked at a ratio of 1 cancer cell to 10(5) total leukocytes in buffy coat or 1 cancer cell to 10(8) total cells in whole blood samples. The final, optimized process consisted of: a red cell lysis step, immunomagnetically staining leukocytes with an anti-CD45 PE, anti- MACS sandwich, immunomagnetic sorting using a flow-through system (QMS), and a final cell analysis step using either an automated cell counter, filtration, and visual counting or a cytospin analysis.

RESULTS

The final, optimized process produced a final enrichment of the rare cancer cells of 5.17 log(10) and an average, final recovery of 46%. It should be noted that a negative depletion protocol was used (i.e., no labeling of the rare cancer cells was used).

CONCLUSIONS

To the authors' knowledge, no examples in the literature exist of a 5.17 log(10) enrichment of cancer cells in human blood using a negative depletion protocol. The closest example is a 4 log(10) enrichment in which two positive magnetic cell separation steps were used (none were used in this study). Ongoing studies are investigating further modifications of the precommercial, prototype flow-through immunmagnetic separation system to increase both the enrichment and recovery rate. However, even at current performance levels, the presented process could significantly improve visual and molecular analysis of rare cells in blood.

Clinical significance of bone marrow micrometastases in esophageal cancer

Using the reverse transcriptase-polymerase chain reaction (RT-PCR), we investigated the clinical significance of bone marrow micrometastases in patients with esophageal cancer. Bone marrow samples from 57 patients with esophageal cancer, who underwent esophagotomy, were investigated by specific RT-PCR for carcinoembryonic antigens (CEA). A total of 40 out of 57 patients (70.1%) were positive for CEA mRNA in the bone marrow. Among curatively resected cases, 34 of 50 patients (68.0%) were positive for CEA. Ten of 13 T1 patients (76.9%) were positive for CEA. Although the CEA-positive rate was high, there was no significant correlation between CEA positivity and any clinical characteristics. Among the 40 CEA-positive patients, 50% have shown recurrence so far. Detection of cancer cells in the bone marrow by RT-PCR may not always correspond to the malignant potential or other characteristics of the tumor. CEA-positive 'micrometastases' might actually represent isolated circulating tumor cells without much biological significance.

Bone Marrow Micrometastases and Markers of Angiogenesis in Esophageal Cancer

BACKGROUND

Tumor angiogenesis is critical for metastasis development. The detection of bone marrow micrometastases may indicate a metastatic phenotype. We aim to establish if the detection of bone marrow micrometastases associates with elevated markers of angiogenesis and adverse histopathologic features of esophageal cancer.

METHODS

Bone marrow aspirates from 49 patients with esophageal cancer were assessed and assigned to be positive or negative for micrometastases. Routine histologic assessment of the primary tumor was also undertaken. Circulating and tumor levels of the angiogenic cytokine vascular endothelial growth factor were determined in plasma and tumor homogenate. Intratumor microvessel density was evaluated by counting anti-CD34 positive neovessels.

RESULTS

Twenty-two patients were positive for bone marrow micrometastases (44.9%). The detection of micrometastases was associated with advanced T stage (T3/4 vs T1/2; p = 0.023), circumferential margin involvement (p = 0.002) and lymphovascular invasion (p = 0.024). Plasma vascular endothelial growth factor was significantly more elevated in micrometastatic-positive patients than in those without micrometastases (p = 0.018). No difference was noted in tumor vascular endothelial growth factor expression. For adenocarcinomas alone, intratumor microvessel density was significantly higher in micrometastatic positive cases (p = 0.03). This was not the case for squamous cell carcinomas.

CONCLUSIONS

The detection of bone marrow micrometastases is associated with esophageal tumors of advanced T stage and specifically for adenocarcinomas with tumor vascularity. Plasma vascular endothelial growth factor is elevated in micrometastatic positive cases and might be derived from sources other than the primary tumor.

Prevalence of bone marrow micrometastases in esophagogastric cancer patients with and without neoadjuvant chemoradiotherapy

BACKGROUND

Bone marrow micrometastases are present in a high proportion of patients undergoing curative resection for esophagogastric cancer. The incorporation of preoperative systemic therapies into these patients' treatment is widely practiced. This study investigates the effect of neoadjuvant chemoradiotherapy (CRT) on the incidence of micrometastases and the viability of detected tumor cells.

MATERIALS AND METHODS

Rib bone marrow was obtained from patients (n = 106) in three centers, who were selected for potentially curative resection. Patients received neoadjuvant CRT plus surgery (n = 55), or surgery alone (n = 51). To detect micrometastases, mononuclear cells were isolated from fresh marrow and immediately stained immunohistochemically with an anti-cytokeratin-18 antibody using the APAAP technique. Tumor cell viability was assessed by immunohistochemical staining of marrow cell cultures for cytokeratin-positive cells.

RESULTS

Micrometastases were detected in fresh marrow in 42% (23/55) of patients who received neoadjuvant CRT plus surgery, and in 67% (34/51) of patients treated with surgery alone. Viable tumor cells were demonstrated in 10 of 18 marrow cultures from CRT plus surgery cases. In this patient subset, combination of results of staining fresh and cultured marrow significantly increased micromet detection to 78%.

CONCLUSIONS

A significant proportion of patients with esophagogastric cancer have disseminated viable tumor cells at time of surgery, irrespective of pre-operative treatment. The use of marrow culture in parallel with fresh marrow staining may increase the detection of micrometastases. The persistence of tumor cells resistant to systemic therapy may explain why these regimens fail in a majority of patients.

Management of neuroendocrine liver metastases

BACKGROUND

The optimum management of neuroendocrine liver metastases, particularly the role of liver transplantation is ill-defined. Current strategies are based on anecdotal reports and small retrospective studies, rather than prospective data. This, as well as the failure to standardize treatment, has probably contributed to the reported variations in outcome.

DATA SOURCES

To formulate a putative management protocol and to reevaluate the role of liver transplantation in patients with neuroendocrine liver metastases, a review of the published literature (Medline search) was conducted.

CONCLUSIONS

Isolated hepatic metastases should be resected when suitable. Chemoembolization of liver metastases should precede resection of bulky disease and be used to palliate those with unresectable disease. Radiofrequency ablation is suitable for smaller metastatic lesions (<3 cm diameter) in the liver. Systemic treatment with somatostatin analogues or radioactive metaiodobenzylguanidine (MIBG) is appropriate to reduce symptoms and slow disease progression, but prospective data is required to define their exact roles as adjuvant and therapeutic agents. Although current systemic chemotherapy, applied in isolation, may have a role in patients in whom other therapies have failed, its efficacy remains unproven. Restriction of liver transplantation to the treatment of patients with carcinoid metastases with biologically favorable features, limited tumor bulk and without systemic disease may make transplantation a curative rather than a palliative treatment option in selected patients.

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Orthotopic transplantation model of human gastrointestinal cancer and detection of micrometastases

AIM: To establish a relevant animal model of human gastrointestinal cancer, which can be used for repetitive investigations, so as to improve our understanding and management of carcinogenesis and cancer metastasis.

METHODS: Intact tissues of human colorectal and pancreatic cancers were transplanted in nude mice. The biological characteristics of the original and the corresponding transplanted tumors were investigated by HE staining, PAS staining and immunostaining. The metastases in the livers and lungs of nude mice were investigated by immunostaining with biotinylated mab KL-1 and by RT-PCR using CK20 specific primers.

RESULTS: There were totally 9 of 16 surgical specimens growing in nude mice subcutaneously and/or orthotopically (4 of 6 colorectal and 5 of 10 pancreatic cancer). Tumor cell content of the specimens and freezing of tissue specimens are important factors influencing the growth of transplanted tumor. In the group of fresh tumor tissues with greater than 50% tumor cell content, the success rate of the transplantation was 100% (3 cases of pancreatic cancer and 3 cases of colorectal cancer). The orthotopically transplanted tumors resemble the original tumor morphologically and biologically, including TAA expression such as CEA by immunohistochemistry, and CEA level in the serum of mice. Ki-67 labeling index and the expression of TAA especially K-ras, 17-1A and RA-96, are associated with the potential of tumor growth in nude mice. Micrometastases in the lungs and livers of tumor bearing mice can be detected by immunostaining with biotinylated mab KL-1 and CK20-specific RT-PCR.

CONCLUSION: An orthotopic transplantation model for human colon and pancreatic cancer in nude mice has been set up. We have also established sensitive detection methods with CK-immunohistochemistry and CK20-RT-PCR to study xenotransplanted human cancer and its metastatic cancer cells in the liver and lung of nude mice. This study may be helpful in understanding the mechanism of cancer metastasis and in developing new diagnostic methods and therapeutic strategies for metastases including micrometastases.