Elevated serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1) closely reflect tumour burden in chronic B-lymphocytic leukaemia

VCAM-1 complements CA-125 in detecting recurrent ovarian cancer

BACKGROUND

Close to three-quarters of ovarian cancer cases are frequently diagnosed at an advanced stage, with more than 70% of them failing to respond to primary therapy and relapsing within 5 years. There is an urgent need to identify strategies for early detection of ovarian cancer recurrence, which may lead to earlier intervention and better outcomes.

METHODS

A customized magnetic bead-based 8-plex immunoassay was evaluated using a Bio-Plex 200 Suspension Array System. Target protein levels were analyzed in sera from 58 patients diagnosed with advanced ovarian cancer (including 34 primary and 24 recurrent tumors) and 46 healthy controls. The clinical performance of these biomarkers was evaluated individually and in combination for their ability to detect recurrent ovarian cancer.

RESULTS

An 8-plex immunoassay was evaluated with high analytical performance suitable for biomarker validation studies. Logistic regression modeling selected a two-marker panel of CA-125 and VCAM-1 that improved the performance of CA-125 alone in detecting recurrent ovarian cancer (AUC: 0.813 versus 0.700). At a fixed specificity of 83%, the two-marker panel significantly improved sensitivity in separating primary from recurrent tumors (70.8% versus 37.5%, P = 0.004), demonstrating that VCAM-1 was significantly complementary to CA-125 in detecting recurrent ovarian cancer.

CONCLUSIONS

A two-marker panel of CA-125 and VCAM-1 showed strong diagnostic performance and improvement over the use of CA-125 alone in detecting recurrent ovarian cancer. The experimental results warrant further clinical validation to determine their role in the early detection of recurrent ovarian cancer.

A New Approach for the Diagnosis of Myelodysplastic Syndrome Subtypes Based on Protein Interaction Analysis

Myelodysplastic syndromes (MDS) are a heterogeneous group of hematological malignancies with a high risk of transformation to acute myeloid leukemia (AML). MDS are associated with posttranslational modifications of proteins and variations in the protein expression levels. In this work, we present a novel interactomic diagnostic method based on both protein array and surface plasmon resonance biosensor technology, which enables monitoring of protein-protein interactions in a label-free manner. In contrast to conventional methods based on the detection of individual biomarkers, our presented method relies on measuring interactions between arrays of selected proteins and patient plasma. We apply this method to plasma samples obtained from MDS and AML patients, as well as healthy donors, and demonstrate that even a small protein array comprising six selected proteins allows the method to discriminate among different MDS subtypes and healthy donors.

Soluble intercellular adhesion molecule-1 is a prognostic marker in colorectal carcinoma

PURPOSE

Serological tumor markers are routinely used to monitor tumor onset and progression. In colorectal carcinoma (CRC), the carcinoembryonic antigen (CEA) is roughly elevated in 50% of patients at initial diagnosis. Soluble ICAM-1 (sICAM-1) is elevated in different cancers. The aim of this study was to evaluate the prognostic relevance of sICAM-1 combined with CEA in patients with CRC.

METHODS

In blood samples of 297 CRC patients, sICAM-1 was determined by ELISA and CEA by microparticle enzyme immunoassay the day before oncologic resection. Separation in patients with sICAM-1^high and sICAM-1^low was performed by minimum p value approach; separation in CEA normal and elevated was performed according to the established diagnostic cutoff. Clinical data were obtained from the prospective collected data from the Erlangen Registry for Colorectal Carcinomas.

RESULTS

Cancer-related 5-year survival rate of patients with sICAM-1^low (< 290 ng/ml, n = 208) was significantly increased (83.4%) as compared to that of patients with sICAM-1^high (≥ 290 ng/ml, n = 89) (66.2%; p < 0.001). Patients with normal CEA concentrations (n = 199; 90.8%) showed a significantly (p < 0.001) improved cancer-related 5-year survival rate compared to patients with elevated CEA concentrations (n = 98; 52.1%). Moreover, high sICAM-1 was an independent risk factor (hazard ratio 1.6) in multivariate analysis. Of note, increased sICAM-1 levels, either within normal or within elevated CEA, allowed to identify high-risk subgroups, both for overall (p < 0.001) and cancer-related survival (p < 0.001).

CONCLUSION

Application of a novel risk score combining CEA/sICAM-1 serum concentrations allows the identification of high-risk groups for poor survival in CRC patients.

Mesothelium expression of vascular cell adhesion molecule-1 (VCAM-1) is associated with an unfavorable prognosis in epithelial ovarian cancer (EOC)

BACKGROUND

Mesothelium vascular cell adhesion molecule-1 (VCAM-1) expression in the metastatic epithelial ovarian cancer (EOC) microenvironment is induced by tumor and mediates tumor cell invasion. VCAM-1 imaging suggests expression during treatment is an indicator of platinum resistance. Here, we assess the potential prognostic significance of mesothelium VCAM-1 expression and prospectively evaluate whether soluble VCAM-1 (sVCAM-1) is a surrogate for mesothelium expression.

METHODS

A retrospective review of EOC patients was performed to evaluate outcomes with mesothelium VCAM-1 expression determined by immunohistochemistry of peritoneum or omentum specimens. A prospective cohort of EOC patients was identified and followed through primary treatment. Serum for sVCAM-1 evaluation, which was performed via enzyme-linked immunosorbent assay, was collected before surgery or neoadjuvant chemotherapy and at each treatment cycle. Peritoneal specimens were obtained during debulking to assess mesothelial VCAM-1 expression.

RESULTS

A retrospective review identified 54 advanced-stage EOC patients. Patients expressing mesothelium VCAM-1 had shortened overall survival (44 vs 79 months, P = 0.035) and progression-free survival (18 vs 67 months, P = 0.010); the median time to platinum resistance was 36 months for VCAM-1-expressing patients and not yet determined for the VCAM-1-negative group. In our prospective observational cohort, 18 EOC patients completed primary treatment; 3 were negative for mesothelium VCAM-1 expression, and sVCAM-1 did not vary between groups.

CONCLUSIONS

Mesothelium VCAM-1 expression is negatively associated with progression-free and overall survival in EOC. This is especially compelling in light of previous data suggesting that persistent VCAM-1 expression during treatment is an indicator of platinum resistance. Our pilot study had insufficient cases to determine whether sVCAM-1 would substitute for mesothelium expression. Cancer 2017;123:977-84. © 2016 American Cancer Society.

P2Y2 receptor activation by nucleotides released from highly metastatic breast cancer cells increases tumor growth and invasion via crosstalk with endothelial cells

INTRODUCTION

Extracellular nucleotides are released and detectable in a high concentration within the tumor microenvironment. G protein-coupled P2Y2 nucleotide receptor (P2Y2R) is activated equipotently by adenosine triphosphate (ATP) and uridine 5'-triphosphate (UTP), which mediate proinflammatory responses such as cell migration and proliferation. However, the role of P2Y2R in the process of cancer metastasis remains unclear. This study aimed to determine the role of P2Y2R in the proliferation, migration and invasion of highly metastatic MDA-MB-231 breast cancer cells through crosstalk with endothelial cells (ECs).

METHODS

ATP release and P2Y2R activity between high metastatic breast cancer cell MDA-MB-231 and low metastatic breast cancer cell MCF-7 were compared. Then, the role of P2Y2R on tumor growth and invasion via crosstalk with ECs was examined in vitro, using MDA-MB-231 cells and ECs transfected with control- or P2Y2R-siRNA, and in vivo, using an animal model injected with control-shRNA- or P2Y2R-shRNA-transfected MDA-MB-231 cells.

RESULTS

We found that this highly metastatic breast cancer cell line released higher levels of ATP and showed a higher P2Y2R activity in comparison to a low metastatic breast cancer cell line, MCF-7. In MDA-MB-231 cells, P2Y2R activation by ATP or UTP increased proliferation at 24 or 72 hours, which was abolished by P2Y2R knock-down. In addition, the adhesion of MDA-MB-231 cells to ECs and cell migration were both significantly increased by ATP or UTP through the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in MDA-MB-231 or ECs but not in cells where P2Y2R was knocked down. Furthermore, ATP- or UTP-mediated activation of P2Y2R induced MDA-MB-231 invasion through ECs, increased matrix metalloproteinase-9 (MMP-9) activity and vascular endothelial growth factor (VEGF) production in MDA-MB-231 and induced the phosphorylation of vascular endothelial (VE)-cadherin in ECs. Tumor growth and metastasis to other tissues were dramatically reduced, and body weight was increased in mice injected with P2Y2R-shRNA-transfected MDA-MB-231 cells compared to mice injected with control shRNA-transfected MDA-MB-231 cells.

CONCLUSION

This study suggests that P2Y2R may play an important role in cancer metastasis via modulation of the crosstalk between cancer cells and ECs.

Tumor-associated fibroblasts isolated from colorectal cancer tissues exhibit increased ICAM-1 expression and affinity for monocytes

Progression of colorectal cancer (CRC) is strongly associated with inflammation and other desmoplastic reactions in the tumor cell-surrounding tissue. We successfully isolated fibroblasts from the desmoplastic stroma of human CRC specimens and uninvolved colon tissue of patients treated surgically for CRC and investigated potential functional capacities. All of the isolated fibroblasts were vimentin-positive and CK-20/CD45-negative confirming the fibroblast phenotype. Differential expression patterns were detected between tumor-associated fibroblasts (TAFs) and normal tissue-associated fibroblasts (NAFs) regarding intercellular adhesion molecule-1 (ICAM-1) expression. In 11 of 12 TAF cultures, basal ICAM-1 expression was increased as compared to corresponding NAF cultures (p=0.001). After stimulation of the cultures with interleukin-1β, 8 of the 12 TAF cultures presented higher ICAM-1 levels when compared with the level in the corresponding NAF cultures (p=0.001). Moreover, the adhesive capacity of these cultures for U937 was increased in 8 out of 10 unstimulated and in 10 out of 10 stimulated cultures when TAFs and NAFs were compared. In corresponding tumor tissue sections from the same patients, the amount of ICAM-1-positive fibroblasts was significantly higher than that in the corresponding normal colon mucosa, indicating a tumor-specific effect that was maintained in the isolated cultures. These results indicate that fibroblasts from CRC tissue exhibit an increased affinity for monocytic cells. This increased intercellular interaction may contribute to elongated residence times of monocytes in CRC tissue. Therefore, these isolated fibroblasts are a useful tool for further functional investigation of desmoplastic tissue reactions in CRC.

Cell Trafficking in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is an indolent lymphoproliferative disorder characterized by both circulating peripheral disease as well as involvement of the lymph nodes and bone marrow. Increasing evidence suggests that the stromal microenvironment provides anti-apoptotic and pro-survival signals to CLL cells, and may contribute significantly to resistance to a wide variety of treatments. Our understanding of the complex interactions involved in CLL cell trafficking continues to grow. Chemokines and corresponding chemokine receptors are key factors for organizing CLL cell trafficking and homing and the complex cellular interactions between CLL and accessory cells. Important chemokines include CCL3, CCL4, and CCL22, which are released by CLL cells, and CXCL12, CXCL13, CXCL9, 10, 11, CCL 19, and CCL21, which are constitutively secreted by various stromal cells. Integrins such as VLA-4 (CD49d) as well as selectins and CD44 also likely play a role in directing CLL cell migration within the tissue microenvironments. Data are also emerging that other molecules such as MMP-9 and cytoskeletal proteins also contribute to CLL cell trafficking. Though this interplay is complex, it is critical that we improve our understanding of CLL cell trafficking to facilitate the development of novel therapies that target these pathways. Several drugs in clinical development, such as CXCR4 antagonists and PI3K, Btk, and Syk inhibitors appear to modulate CLL cell trafficking and CLL-stroma interactions. Here, we review the current understanding of the molecular interactions that underlie CLL cell trafficking and we highlight some of the promising approaches underway to target these pathways therapeutically in CLL.

Serum sICAM, sVCAM and sE-selectin levels in colorectal cancer patients

Colorectal cancer (CRC) is one of the most common cancers of the gastrointestinal tract and the fourth cause of cancers death in the world. Soluble adhesion molecules (CAMs) are thought to have an important role in host defense against carcinogenesis. They are biomarkers of inflammation and indicators of the immune response to tumors. The study included 40 CRC patients without remote metastases and 24 control subjects. Serum concentrations of sE-selectin, sICAM and sVCAM in patients with CRC were investigated by ELISA method. The level of the sCAMs decreased significantly after radical tumor resection. Preoperative serum concentrations of sICAM and sVCAM in CRC patients were significantly higher compared to the control group, whereas there were no differences regarding serum sE-selectin. Serum levels of sE-selectin, sICAM and sVCAM correlated significantly with each other. There was a significant correlation of serum levels of sICAM-1 and sVCAM-1, but not sE-selectin, with TNM stage and lymph node involvement. No significant relationship was found between serum concentrations of sICAM-1, sVCAM-1 and sE-selectin in CRC patients and patients' age or gender. Our findings suggest that an improved understanding of the mechanisms of membrane shedding of sICAM, sVCAM and sE-selectin is required to delineate their role in tumor progression.

Serum level of soluble vascular cell adhesion molecule 1 is a valuable prognostic marker in colorectal carcinoma

PURPOSE

Vascular cell adhesion molecule 1 plays an important role in solid tumor enlargement and/or metastasis. This study evaluated the clinical significance of measuring serum levels of soluble vascular cell adhesion molecule 1 in colorectal cancer and aimed to clarify the biologic significance of its local expression.

METHODS

Serum was collected from 161 patients with colorectal cancer and 26 healthy volunteers. Cancer tissue was collected from 128 patients. The level of soluble vascular cell adhesion molecule 1 in serum and cancer tissue was measured by enzyme-linked immunosorbent assay.

RESULTS

The mean soluble vascular cell adhesion molecule 1 level in patients was significantly higher than that in control subjects. Elevated serum soluble vascular cell adhesion molecule 1 was significantly associated with clinicopathologic parameters such as tumor size, lymph node metastasis, distant metastasis, and poor prognosis. In Cox multivariate analysis, distant metastasis and elevated serum soluble vascular cell adhesion molecule 1 level were independent risk factors predicting poor prognosis. The prognosis for Stage 2 patients positive for soluble vascular cell adhesion molecule 1 was comparable to that for Stage 3 patients. In addition, the serum level of soluble vascular cell adhesion molecule 1 level was correlated negatively with the cancer tissue level.

CONCLUSION

The preoperative level of soluble vascular cell adhesion molecule 1 level reflected disease progression and was a sensitive biomarker for colorectal cancer, especially Stage 2 disease.

Tanshinone I suppresses growth and invasion of human breast cancer cells, MDA-MB-231, through regulation of adhesion molecules

The role of cell adhesion molecules has been studied extensively in the process of inflammation, and these molecules are critical components of carcinogenesis and cancer metastasis. This study investigated the effect of tanshinone I derived from the traditional herbal medicine, Salvia miltiorrhiza Bunge, on the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in tumor necrosis factor-alpha (TNF-alpha)-stimulated endothelial cells. Furthermore, this study investigated the effect of tanshinone I on cancer growth, invasion and angiogenesis on human breast cancer cells MDA-MB-231, both in vitro and in vivo. Tanshinone I dose dependently inhibited ICAM-1 and VCAM-1 expressions in human umbilical vein endothelial cells (HUVECs) that were stimulated with TNF-alpha for 6 h. Pretreatment with tanshinone I significantly reduced adhesion of either monocyte U937 or MDA-MB-231 cells to HUVECs. Interestingly, the inhibitory effect of tanshinone I on monocyte and cancer cell adhesion to HUVECs was mimicked by transfection with ICAM-1 and VCAM-1 small interfering RNA. In addition, tanshinone I effectively inhibited TNF-alpha-induced production of vascular endothelial growth factor (VEGF) and VEGF-mediated tube formation in HUVECs. Tanshinone I also inhibited TNF-alpha-induced VEGF production in MDA-MB-231 cells and migration of MDA-MB-231 cells through extracellular matrix. Additionally, reduction of tumor mass volume and decrease of metastasis incidents by tanshinone I were observed in vivo. In conclusion, this study provides a potential mechanism for the anticancer effect of tanshinone I on breast cancer cells, suggesting that tanshinone I may serve as an effective drug for the treatment of breast cancer.

Evaluation of sICAM-1, sVCAM-1, and sE-Selectin levels in patients with metastatic breast cancer receiving high-dose chemotherapy

Soluble forms of some cell adhesion molecules (CAM), sICAM-1, sVCAM-1, and sE-selectin, are elevated in the sera and plasma of patients with inflammation, arthritis, diabetes, and cancer. Increased levels of these soluble molecules in patients with cancer have been shown to correlate with disease progression and survival. This suggests that increased expression of the soluble forms of CAMs may play an important role in cancer cell growth and metastasis and may be prognostic and/or predictive of malignant disease. In this retrospective study, we assessed the clinical significance of sICAM-1, sVCAM-1, and sE-selectin in 95 patients with metastatic breast cancer enrolled in clinical trials of high-dose chemotherapy (HDC) and autologous stem cell transplantation (ASCT). The significance of soluble HER-2 (sHER-2) and sFAS status, determined in previous studies for this group of patients, was also included in this analysis. Univariate analysis showed that sICAM-1, sVCAM-1, sFas, sHER-2 positive status, and the presence of liver metastases were significant prognostic factors for both progression-free survival (PFS) and overall survival (OS) in the total patient group. In multivariable analysis, HER-2 and sFAS were shown to be independent prognostic factors for PFS and OS. Within the various treatment groups examined, sICAM-1 was a prognostic factor for clinical outcome for patients with metastatic breast cancer enrolled in trials with cyclophosphamide- and carboplatin-based or vinblastine-based HDC, but not in trials with paclitaxeland cyclophosphamide-based HDC.

Serum levels of soluble ICAM-1 and VCAM-1 predict pre-clinical cancer

To investigate whether serum levels of soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) were related to first stage cancer before diagnosis of cancer, we compared serum levels of these adhesion molecules between pre-clinical cases and controls using a nested case-control study method. Cancer cases were recruited from a cohort database of 1465 participants who completed a baseline questionnaire and provided blood samples, and were followed up from 1989 to 2003. They consisted of 15 individuals who died of cancer and 31 individuals newly diagnosed with cancer during the follow-up period. Controls were subjects who did not suffer from cancer, cerebral apoplexy, diabetes mellitus, liver disease, or myocardial infarction during the follow-up period. Using commercially available enzyme-linked immunosorbent assay (ELISA) kits, we showed that serum levels of sVCAM-1, but not sICAM-1 were elevated in cases with pre-clinical or early cancer. We suggest that elevated serum levels of sVCAM-1 might serve as a possible marker for detecting pre-clinical or early cancer.

Specific Occlusion of Murine and Human Tumor Vasculature by VCAM-1–Targeted Recombinant Fusion Proteins

BACKGROUND

The tumor vasculature is increasingly recognized as a target for cancer therapy. We developed and evaluated recombinant fusion proteins targeting the coagulation-inducing protein soluble tissue factor (sTF) to the luminal tumor endothelial antigen vascular cell adhesion molecule 1 (VCAM-1, CD106).

METHODS

We generated fusion proteins consisting of sTF fused to antibody fragments directed against mouse or human VCAM-1 and characterized them in vitro by flow cytometry, surface plasmon resonance, and two-stage coagulation assays. Their therapeutic effects were tested in three human xenograft tumor models: L540rec Hodgkin lymphoma, Colo677 small-cell lung carcinoma, and Colo677/HDMEC small-cell lung carcinoma with human vasculature. Toxicity was analyzed by histologic examination of organs and determination of laboratory blood parameters.

RESULTS

The fusion proteins bound VCAM-1 with nanomolar affinities and had the same coagulation activity as an sTF standard. Xenograft tumor-bearing mice treated with fusion protein (FP) alone or in combination with lipopolysaccharide (FP/L) or doxorubicin (FP/D) exhibited tumor-selective necrosis (L540rec tumors: 74% tumor necrosis [95% confidence interval {CI} = 55% to 93%] with FP/L versus 13% tumor necrosis [95% CI = 4% to 22%] with vehicle; Colo677 tumors: 26% [95% CI = 16% to 36%] with FP versus 8% [95% CI = 2% to 14%] with vehicle); tumor growth delay (Colo677/HDMEC: mean tumor weights after 3 days = 42 mg in FP-treated mice versus 71 mg in vehicle-treated mice, difference = 29 mg, 95% CI = 8 to 100, Mann-Whitney P = .008); and some tumor regressions (one of seven FP-treated Colo677 tumor-bearing mice and two of seven FP/D-treated mice). The fusion protein was well tolerated.

CONCLUSIONS

Recombinant tissue factor-based fusion proteins directed against an intraluminal tumor endothelial cell marker induce tumor-selective intravascular coagulation, tumor tissue necrosis, and tumor growth delay.

Serum angiogenin is not elevated in patients with early B-cell chronic lymphocytic leukemia but is prognostic factor for disease progression

The association between angiogenin and cancer progression and poor outcome in solid tumors has been documented, but its significance in leukemias has not been evaluated. Using an ELISA technique (Quantikine Human Angiogenin Immunoassay; R&D Systems), we measured serum angiogenin levels in 77 previously untreated Binet stage A B-cell chronic lymphocytic leukemia (CLL) patients. No difference in angiogenin serum levels could be found between patients (median: 295 ng/mL; range: 74-1700) and 15 age- and sex-matched healthy controls (median: 264 ng/mL; range: 29-1835) (P = NS; Mann-Whitney test). Increased angiogenin serum level was associated with higher LDH (P = 0.03) and beta2-m (P = 0.007) concentrations. However, angiogenin did not reflect the extent of bone marrow (BM) angiogenesis as evaluated by microvessel area (P = 0.611), circulating levels of vascular endothelial growth factor (VEGF) (P = 0.873) and basic fibroblastic growth factor (FGF-2) (P = 0.421). When the 25 patients with available data were stratified into the four major cytogenetic categories (normal karyotype, 13q as a sole aberration, 12q trisomy, 11q or 17p deletion) and aberrations were compared with angiogenin serum levels, no correlation was found (P = 0.651; Kruskall-Wallis test). A cut-off of angiogenin serum level corresponding to median (i.e. 330 ng/mL) or higher identified later upstaging and longer progression-free survival (PFS). The 5-yr PFS was 51.5% for patients with angiogenin levels lower than median and 85% for patients with higher values [P = 0.03; hazard ratio (HR) = 2.86; 95% CI: 1.08-6.72]. Although in multivariate analysis only Rai substages (P = 0.00001) and peripheral blood lymphocytosis (P = 0.009) retained their prognostic significance, angiogenin could be incorporated into the Rai substages thus leading to the identification of the following risk categories: (i) stage 0 (angionenin >330 ng/mL); (ii) stage 0 (angiogenin <330 ng/mL) + stage I-II (angiogenin >330 ng/mL); and (iii) stage I-II (angiogenin <330 ng/mL). The 40-month PFS were as follows: 85%, 65%, 25% (chi(2) for trend = 6.33; d.f. = 1; P = 0.01). In conclusion, serum angiogenin levels although not increased in comparison with healthy controls, may predict clinical outcome of patients with early CLL and help to refine Rai's stratification.

Pregnancy and successful labor in the course of chronic lymphocytic leukemia

Pregnancy and leukemia are difficult to manage. Protecting the mother from hemorrhage and infection and the fetus from developmental failure are the main aims. Chronic lymphocytic leukemia (CLL) has been seen very rarely with pregnancy. In this article, the successful labor of a 43-year-old woman with CLL is reported. She was not a candidate for chemotherapy at that time. She was without symptoms when she got pregnant. In the 30th gestational week she was found to have urinary tract infection and preterm labor and she was stabilized. Gestational diabetes and preeclampsia were also determined after that period and managed. The patient was delivered by cesarean section in the 39th gestational week. Cord blood was collected and preserved. No postpartum complication was seen in either the patient or the infant. This is one of the rare cases presenting CLL with pregnancy in the literature.

The role of soluble CD23 in distinguishing stable and progressive forms of B-chronic lymphocytic leukemia

Soluble CD23 (sCD23) has been recognized as an important prognostic parameter in patients with chronic lymphocytic leukemia (B-CLL) at early clinical stages. There is, however, no clear information on its prognostic significance in advanced stages and on its role as an indicator for aggressive or indolent courses of disease. Therefore, sCD23 was measured in the serum of 145 patients at diagnosis and serial determinations were carried out for 8 years in 38 patients. The results indicate that in patients with identical clinical stages at first presentation the disease could take different courses depending on initial sCD23 concentrations below or above specific threshold levels (860 and 5900U/ml). sCD23 higher than these thresholds was associated with faster progression into upper clinical stages. Furthermore, sCD23-doubling time (sCD23-DT) indicated that patients with long DT progressed slowly, while those with short DT had more aggressive disease. Particularly in patients with advanced disease stages, long sCD23-DT indicated development of smoldering disease. Since sCD23 levels reflect total tumor mass, determination of sCD23-DT has probably a better predictive value than lymphocyte doubling time. It appears that B-CLL patients can be divided into different risk categories according to initial determinations of sCD23 and that sCD23-DT is an additional important parameter in predicting disease progression.

Elevated serum levels of soluble CD44 can identify a subgroup of patients with early B-cell chronic lymphocytic leukemia who are at high risk of disease progression

BACKGROUND

Although soluble CD44 (sCD44) is considered a reliable marker of both tumor burden and disease activity, to the authors' knowledge, its predictive and prognostic value in B-cell chronic lymphocytic leukemia (CLL) has not been addressed to date.

METHODS

The authors studied 94 previously untreated CD5-positive B-cell CLL patients whose sera was taken at the time of diagnosis, stored at - 70 degrees C, and analyzed for the presence of standard sCD44 (sCD44(std)) using a commercial enzyme-linked-immunoadsorbent-assay. The impact of the sCD44 level on the clinical outcome of the disease was assessed in 74 patients with early CLL (61 Binet Stage A patients and 13 asymptomatic Stage B patients). Because the time to disease progression appears to predict the survival time of patients with CLL, it was used as a surrogate endpoint in the current study.

RESULTS

Patients with higher than median sCD44 levels (i.e., 642 ng/mL) had a more advanced clinical disease stage (P = 0.04), higher peripheral blood lymphocytosis (P = 0.006), and increased circulating levels of either lactate dehydrogenase (P = 0.01) or beta(2)-microglobulin (P < 0.0001). In univariate analysis, seven of the nine parameters investigated predicted progression-free survival (PFS). In a stepwise multiple regression analysis, only 2 parameters provided independent prognostic information regarding PFS: Rai substages (0 vs. I-II) (P = 0.002) and serum sCD44 levels > 642 ng/mL (P = 0.01). When added to the classification of smoldering CLL versus nonsmoldering CLL, the sCD44 level distinguished two groups within the group of nonsmoldering Stage A patients; patients with a sCD44 level > 642 ng/mL had a median PFS of 36 months, whereas patients with a sCD44 level < 642 ng/mL experienced a longer PFS (median had not been reached at 8 years of follow-up). Furthermore, serum levels of sCD44 defined two different patterns of PFS within the group of patients with Rai disease Stages I-II (P = 0.01).

CONCLUSIONS

An increased serum level of sCD44 can be considered to be a promising parameter for predicting the risk of disease progression in patients with early CLL. Furthermore, sCD44 helps to refine the prognostic stratification of patients with either nonsmoldering CLL or Rai Stage I-II disease, thus enabling the identification of different prognostic subgroups in patients with early CLL.

Production of soluble CD34 by human myeloid cells

CD34, a glycophosphoprotein present in lymphohaematopoietic stem and progenitor cells, as well as in other cell types, exists in both transmembrane and intracytoplasmic forms. Transmembrane CD34 expression, which is high in the earliest haematopoietic precursors, decreases as cells mature. However, to our knowledge, there is no information on whether a decrease in transmembrane CD34 can also predict a release of the molecule from the cell membrane into the extracellular fluid. To investigate the above possibility, we studied conditions (incubation time, cell density and proliferative status) in human myeloid cells (lines KG-1a, KG-1 and cord blood-derived cells) that may cause a decrease in surface CD34 and the generation of a soluble form of the molecule. The latter, as demonstrated by Western blot analysis, adds more complexity to the proposed structural features and functional properties of CD34 in myeloid cells.

Update on the biology of chronic lymphocytic leukemia

An understanding of the molecular biology of B-cell chronic lymphocytic leukemia (B-CLL) has led to the appreciation that several different B-cell diseases are represented under this name. Variability in the bcl-2 family of proteins, p53 mutation, or the presence of various chromosomal abnormalities corresponds to variability of the clinical course of disease and response to therapy. Differential expression of cell surface adhesion molecules by B-CLL cells have also been shown to influence clinical outcome, as have the expression of immune regulatory molecules (eg, CD80, CD40R, CD27 and CD79b). Recent work studying immunoglobulin-heavy chain gene rearrangement postulates at least two subsets of B-CLL originating from different stages of B-cell development and following different clinical courses. The knowledge that B-CLL is the final consequence of many different molecular perturbations may allow the development of chemotherapies, immunotherapies, and gene therapies that target the specific molecular defect in a given case of B-CLL.