Cytokines as tumour markers

Biochemical diagnostics of pancreatic cancer - Present and future

Pancreatic cancer is one of the deadliest cancers having an exceptionally high mortality rate. Despite a relatively low incidence (10th among cancers), it is the fourth leading cause of cancer-related deaths in most developed countries. Improving early diagnosis of pancreatic cancer and strengthening the standardised comprehensive treatment remain the main focus of pancreatic cancer research. Tumor markers are usually tumor-associated proteins of clinical relevance in these patients. Although tumor markers carbohydrate antigen (CA 19-9) and carcino-embryonic antigen (CEA) are commonly used, neither demonstrate high diagnostic accuracy. Recently, hematopoietic growth factors (HGFs) and various enzymes have been reported as potential biomarkers for pancreatic cancer. These include macrophage-colony stimulating factor (M-CSF) and granulocyte-colony stimulating factor (G-CSF), interleukin-3 (IL-3), macrophage inhibitory cytokine (MIC-1) and various enzymes (alcohol dehydrogenase, aldehyde dehydrogenase, lysosomal exoglycosidases). With the development of molecular technology, detecting K-ras mutation in serum via polymerase chain reaction (PCR) is becoming more common and efficient. Because K-ras mutation rates are high in many cancers, some regard it as a potential tumor marker. Others have shown the value of serum miRNAs in detection of pancreatic cancer. Unfortunately, there are currently no effective methods of sufficient diagnostic accuracy to detect early-stage surgically resectable pancreatic cancer. In this article we highlight these biomarkers and summarise recent developments in the diagnosis and treatment of pancreatic cancer.

Role of the hematopoietic cytokines SCF, IL-3, GM-CSF and M-CSF in the diagnosis of pancreatic and ampullary cancer

BACKGROUND

Previous studies have demonstrated altered levels of hematopoietic cytokines in the serum of patients with different types of cancer.

METHODS

We measured the serum levels of the hematopoietic cytokines stem cell factor (SCF), interleukin 3 (IL-3), macrophage-colony stimulating factor (M-CSF) and granulocyte-macrophage-colony stimulating factor (GM-CSF) in 40 pancreatic and ampullary cancer patients and 40 healthy volunteers, using ELISA. We also assessed the most widely used pancreatic tumor markers, carbohydrate antigen 19-9 (CA 19-9) and carcinoembryonic antigen (CEA), in both groups. We then correlated the concentrations of the cytokines' and the tumor markers in the patients' serum and we estimated their diagnostic ability by calculating diagnostic sensitivity and specificity, positive and negative predictive values and the receiver operating characteristic (ROC) curve.

RESULTS

The SCF and IL-3 levels were significantly lower and the M-CSF levels significantly higher in pancreatic cancer patients than in controls. There were significant positive correlations between the serum levels of CEA and M-CSF, GM-CSF and SCF, and between GM-CSF and IL-3. The area under the ROC curve and diagnostic sensitivity of M-CSF were greater than those of SCF and IL-3. The diagnostic sensitivity of the combined use of SCF and M-CSF reached 97.5%.

CONCLUSION

The diagnostic ability of M-CSF and SCF in pancreatic and ampullary cancer should stimulate further studies evaluating their clinical usefulness as tumor markers.

Serum macrophage-colony stimulating factor levels in colorectal cancer patients correlate with lymph node metastasis and poor prognosis

BACKGROUND

Elevated serum concentrations of macrophage-colony stimulating factor (M-CSF) have been found in a variety of malignant diseases. The aim of our study was to assess correlations between serum levels of M-CSF and clinicopathological features and survival rates in patients with colorectal cancer (CRC).

PATIENTS/METHODS

M-CSF and the established tumor markers (carcinoembryonic antigen - CEA and carbohydrate antigen - CA 19-9) were investigated in the sera of 116 colorectal cancer patients and correlated with the clinical parameters of the disease and with the survival of patients. We compared M-CSF serum levels in CRC with colorectal adenoma patients. M-CSF was determined using enzyme-linked immunosorbent assay (ELISA). Tumor markers were measured by microparticle enzyme immunoassays (MEIA).

RESULTS

CRC patients had significantly higher M-CSF and tumor markers levels compared to healthy controls and colorectal adenoma patients, with a significant association between M-CSF levels, disease stage and lymph node metastasis. Serum levels of M-CSF and CEA decreased significantly after radical resection of the tumor. Moreover, the multivariate analysis showed that the serum level of M-CSF in CRC patients was an independent prognostic factor.

CONCLUSION

These findings suggest the potential clinical use of circulating M-CSF measurements, particularly in estimating prognosis for patients with CRC.

Stem cell factor and macrophage-colony stimulating factor in patients with pancreatic cancer

Stem cell factor (SCF) and macrophage-colony stimulating factor (M-CSF) have assumed an increasing importance in cancer biology. In the present study we investigated the serum levels of these cytokines in pancreatic cancer patients in relation to controls and to patients with benign lesions of the pancreas (chronic pancreatitis group). The classical tumor markers, such as carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA 19-9) were also tested. We compared the serum levels of cytokines with tumor stage. We also defined the receiver-operating characteristics (ROC) curve for cytokines and classical tumor markers. The cytokines were measured in 47 patients with pancreatic cancer, in 27 patients with chronic pancreatitis and in 35 healthy subjects. SCF and M-CSF were determined using enzyme-linked immunosorbent assay (ELISA). CEA and CA 19-9 were measured by microparticle enzyme immunoassay. There were significant differences in the levels of circulating SCF, M-CSF, CEA and CA 19-9 in the pancreatic cancer patients compared to the control group, but only the serum levels of M-CSF, CEA and CA 19-9 were significantly higher in pancreatic cancer patients compared to the pancreatitis group. The levels of cytokines and tumor markers were higher in patients with a more advanced tumor stage. The M-CSF serum levels correlated positively with the tested tumor markers. The M-CSF area under the ROC curve was higher than the SCF area. These results suggest that M-CSF is a better candidate for a pancreatic cancer tumor marker than SCF.

Hematopoietic cytokines as tumor markers

Stem cell factor (SCF), interleukin 3 (IL-3), granulocyte-macrophage-colony stimulating factor (GM-CSF), granulocyte-colony stimulating factor (G-CSF) and macrophage-colony stimulating factor (M-CSF) are members of a group of glycoproteins called hematopoietic cytokines (HCs). These cytokines regulate the growth and differentiation of hematopoietic progenitor cells and functionally activate mature neutrophils or macrophages. The effect of HCs is not limited to bone marrow cells. Some studies have shown that HCs can also stimulate the proliferation of non-hematopoietic cells. The receptors for HCs have been detected in cancer cell lines, and stimulation of HCs receptors induced proliferation of tumor cells. Moreover, some investigations have shown HC mRNA expression in these cell lines and recent studies have demonstrated that HCs can stimulate tumor progression. Several cells of malignant tumors have been observed to secrete large amounts of HCs and increased concentrations of HCs have been found in the sera of cancer patients. There are a number of situations in which the measurement of HCs may provide clinically useful information, particularly regarding prognosis and response to treatment. In this paper we discuss the results of studies that have examined the potential use of HCs as tumor markers.

Hematopoietic growth factors in colorectal cancer patients

Hematopoietic growth factors (HGFs) are involved in the regulation of growth and spread of cancer. Therefore, in the present study, we have investigated in colorectal cancer patients the serum levels of selected HGFs, such as stem cell factor (SCF), interleukin 3 (IL-3), granulocyte-macrophage-colony stimulating factor (GM-CSF), and M-CSF in relation to controls and to the classical tumor markers, such as carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA 19-9) in colorectal cancer. Additionally, we have compared the serum levels of cytokines with tumor site and stage and other clinical characteristics such as age and sex. We also defined the receiver-operating characteristics (ROC) curve for HGFs and classical tumor markers. The tested cytokines were measured in 70 patients with colorectal cancer and in 40 healthy subjects. HGFs were determined using enzyme-linked immunosorbent assay (ELISA). CEA and CA 19-9 were measured by microparticle enzyme immunoassay. There were significant differences in the levels of circulating SCF, IL-3, M-CSF, GM-CSF, and CEA and CA 19-9 in the colorectal cancer patients compared to the control group. The levels of M-CSF and CEA were significantly higher in patients with a more advanced tumor stage. The significant positive correlation was observed between the CEA and CA 19-9 concentrations. The M-CSF serum levels correlated positively with the tested tumor markers. The M-CSF area under the ROC curve was the largest. These results suggest that M-CSF is, among the tested HGFs, the best candidate for a colorectal cancer tumor marker.

Serum adhesion molecules and interleukin-2 receptor as markers of tumour load and prognosis in advanced cutaneous melanoma

Cell adhesion molecules are cell surface glycoproteins that may act as mediators in the metastatic process. Soluble interleukin-2 receptor (sIL-2R) is an immunological marker that may also serve as an indicator of tumour progression. Normal and neoplastic cells are capable of releasing these molecules into circulation. We evaluated the association between pretreatment serum levels of soluble intercellular adhesion molecule 1 (sICAM-1), vascular cell adhesion molecule 1 (sVCAM-1) and sIL-2R and metastases and survival in 50 patients with advanced melanoma. The patients with liver and/or bone metastases had significantly higher sICAM-1 levels than those with soft tissue and/or lung involvement (P=0.002). In addition, there was a trend towards higher sIL-2R levels in patients with more metastatic sites (P=0.07). In univariate analysis, the number of metastatic sites (P=0.0001, odds ratio (OR) 3.0, 95% confidence interval (CI): 1.7-5.3), the metastatic site (P=0.01, OR 2.3, 95% CI: 1.2-4.4) and the levels of sICAM-1 (P=0.011, OR 2.5, 95% CI: 1.2-5.0), sVCAM-1 (P=0.036, OR 2.1, 95% CI: 1.0-4.3) and sIL-2R (P=0.0016, OR 3.0, 95% CI: 1.5-6.0) were found to be statistically significant prognostic factors for survival. In multivariate analysis, the number of metastatic sites was the dominant prognostic indicator. After it was excluded from the analysis, the sIL-2R level and the metastatic site were found to be significant. It can be concluded, that high sICAM-1 levels suggest liver metastases and sIL-2R seems to serve as a marker of tumour load in metastatic melanoma. Furthermore, the sIL-2R level appears to add to clinical data predicting the patient's outcome.

The clinical usefulness of the measurement of cytokines

The utilization of accurate and sensitive methods for the measurement of cytokines in body fluids is prerequisite for the proper use of these mediators in clinical practice. Many factors contribute to the complexity of cytokine quantitation. Bioassays historically preceded immunoassays, which are now very popular, but there is a need for standardization. Nevertheless, due to the local effects of cytokines, the study of their blood levels is of limited value for an understanding of the pathophysiology of these mediators. This explains the development of alternative approaches to assess the ability of cells to produce cytokines. These include the Enzyme-Linked Immuno Spot Assay (ELISPOT), the measurement of cell-associated cytokines by flow cytometry, and the study of cytokine secretion by isolated peripheral blood mononuclear cells or by whole blood test. All these techniques, associated with a local detection of cytokines by immunohistochemistry or in situ hybridization and reverse transcriptase polymerase chain reaction, appear to be complementary tools for a better understanding of the biology of cytokines. Selected examples of possible clinical applications related to infectious diseases, cancer, autoimmune diseases, allergy, transplantation and preclinical evaluation of drugs and biotechnology products are given.

The tumor necrosis factor family and and correlation with disease activity and response to treatment in hairy cell leukemia

Hairy cell leukemia (HCL) is a well recognized indolent B-cell lymphoproliferative disorder. HCL cell proliferation is regulated by growth factors and cytokines, of which tumor necrosis factor-alpha (TNF-alpha) may be one of the most important. The mechanism of TNF-alpha-induced HCL cell growth is mediated via 2 receptors, which are present in both cellular and soluble forms. In this study we determined the serum levels of TNF-alpha and their soluble receptors - sTNF-R60 and sTNF-R80 - in 23 HCL patients and correlated them with clinical parameters before and after therapy. Patients were classified according to their clinical status as either "active" at diagnosis or during relapse and "non-active" (responding to therapy with partial and complete remission). Most patients were treated with 2-CDA, following which serum levels of TNF-alpha, sTNF-R60 and sTNF-R80 were significantly decreased, particularly in CR. Significant differences in paired observation values were noted for TNF-alpha and sTNF-R80, indicating a good correlation with the clinical status of disease, but this was not the case for sTNF-R60 (coefficients of correlation between levels of TNF-alpha and sTNF-R80 and of TNF-alpha and sTNF-R60 were r = 0.85 and r= 0.64, respectively). These results suggest that decreases in both TNF-alpha and sTNF-R80 are indicative of response to treatment, while increased levels accompany active disease. Accordingly, we conclude that serum levels of the TNF family, as for the sIL-2R and IL-1 family, may also be used as sensitive markers for monitoring HCL status. Levels may be indicative of the clinical efficacy of therapy and can be used as an indicator of the presence of residual disease.

Preanalytical factors and the measurement of cytokines in human subjects

Cytokines are widely measured in research. However, cytokine analyses are influenced by a myriad of factors. For instance, a delay in the separation of plasma from cells may lead to a 50% decrease in the concentration of tumor necrosis factor in plasma. Another example is the secretion of interleukin-1 beta in women which can be twice as high during the follicular phase as in the luteal phase. The factors influencing the outcome of these tests can be divided into in vivo preanalytical factors (e.g., aging, chronobiological rhythms, diet, etc), in vitro preanalytical factors (e.g., specimen collection, equipment, transport, storage, etc), and analytical factors. To improve the value of the cytokine tests, factors strongly influencing the results have to be controlled. This can be done by using standardized assays and specimen collection procedures. In general, sufficient attention is not given to the preanalytical factors, especially in the measurement of cytokines. This article reviews the preanalytical factors which may influence the outcome of these tests in human subjects.