Clinical significance of circulating CD44 in non-Hodgkin's lymphoma

Elevated levels of soluble CD44 are associated with advanced disease and in vitro proliferation of neoplastic lymphocytes in B-cell chronic lymphocytic leukaemia

PURPOSE

Increased expression of the adhesion molecule CD44 has been associated with an unfavourable clinical outcome in lymphomas. We evaluated the prognostic value of soluble CD44 in B-cell chronic lymphocytic leukaemia (B-CLL) and analysed the source and regulation of CD44 secretion in B-CLL clones in vitro.

PATIENTS AND METHODS

Levels of soluble CD44 standard (sCD44s) and of the soluble variant isoform CD44v6 (sCD44v6) were analysed by enzyme linked immuno sorbent assay. Highly purified B-CLL cells (98% CD19 + CD3 - cells) were stimulated in vitro by different combinations of thioredoxin (Trx), Staphylococcus aureus Cowan strain 1 (SAC), IL-2, IL-4, IL-10, 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and by anti-CD40 mAbs presented on irradiated CD32L cells.

RESULTS

Serum levels of sCD44s and of sCD44v6 are significantly elevated in B-CLL patients (n = 90) in comparison with normal persons (n = 44) (P < 0.001). Elevated levels of sCD44s and sCD44v6 are associated with an advanced disease as reflected by an extended lymph node involvement (P < 0.02), an advanced Binet (P < 0.03) and Rai stage (P < 0.04) and chemotherapy requirement (P < 0.02). High levels of sCD44s are associated with high leukocyte counts (P < 0.04) and increased sCD44v6 is significantly associated with splenomegaly (P < 0.002). In B-CLL sCD44s as well as sCD44v6 is shed from leukaemia cells as shown by in vitro cultures. Stimulation of B-CLL clones results in a proliferation-associated increased secretion of sCD44s (rho = 0.7; P = 0.0001) and of sCD44v6 (rho = 0.5; P = 0.005). B-CLL clones from advanced stage patients are characterised by an increased capacity for proliferation and CD44 production in comparison with early stage patients.

CONCLUSIONS

Both sCD44s and sCD44v6 represent a reliable prognostic marker in B-CLL and may be involved in the pathogenesis of B-CLL.

High serum soluble CD44 is correlated with a poor outcome of aggressive non-Hodgkin's lymphoma

We measured soluble CD44 (sCD44) by enzyme-linked immunosorbent assay in 216 patients with non-Hodgkin's lymphoma (NHL). The sCD44 level was significantly elevated in patients with NHL. A sCD44 level of > or =500 ng/ml showed a significantly decreased overall survival (OS) rate and progression free survival (PFS) rate. In the high-intermediate+high risk group (international prognostic index (IPI)), both the OS rate and the PFS rate were significantly decreased when the sCD44 level was > or =1000 ng/ml. Moreover, the results of a multivariate analysis showed that the five IPI prognostic factors and the sCD44 level were independent prognostic factors, thus suggesting that sCD44 levels could be a useful prognostic marker for aggressive lymphoma

CD44 variant exons in leukemia and lymphoma

CD44 is a cell surface glycoprotein expressed on different cell types that functions in lymphocyte activation and homing, extracellular matrix adhesion and cellular migration. CD44 is encoded by a single gene composed of at least 20 exons. The standard CD44 protein (CD44S or CD44H) is the hematopoietic form of CD44 in lymphoid cells. Variant isoforms (designated from v1 to v10) are formed by addition of new exons to the extracellular domain. High levels of CD44v6 expression has been observed in some tumors and are associated with metastatic spread. The aim of the present study was to investigate and evaluate expression of the CD44v6 and v6-containing variants as a possible marker in chronic myeloid leukemia and lymphoma by reverse transcription-polymerase chain reaction. CD44 exon v6 was detected in all patients and all individuals in the control group. CD44v6-v10 mRNA was observed in 25 patients but in none of the subjects in the control group. CD44v6/v9-10, CD44v6-v7, CD44v6/v10 transcripts were detected in 11, 6, and 2 patients, respectively. CD44v6-7/v9-10 transcripts were not observed in either the patients or the healthy individuals. We conclude that CD44v6-v10 expression may be associated with hematologic malignancies.

Soluble CD44 in human ovarian follicular fluid

PURPOSE

In the present study, we investigated the existence of soluble CD44 (sCD44) in human follicular fluid, the relationship between the concentration of sCD44 and that of other hormonal parameters, and the prognostic value of sCD44 in follicular fluid in in vitro fertilization (IVF) programs.

METHODS

A total of 63 follicular fluid specimens from patients (n = 30) participating in our IVF programs was analyzed by RIA and enzyme-linked immunosorbent assay (ELISA).

RESULTS

The mean concentration (+/- SE) of sCD44 in follicular fluid was 265.4 +/- 7.8 ng/ml. The variation of the follicular fluid concentration of sCD44 was strictly associated with that of human chorionic gonadotropin (hCG) (r = 0.572, P < 0.0001). The mean concentration of sCD44 in follicular fluid was significantly higher in follicles containing subsequently unfertilized oocytes than that in those containing oocytes that had undergone fertilization (P = 0.0428). In the analysis of each follicle that contained an oocyte subsequently fertilized, the mean concentration of sCD44 was significantly higher in follicular fluid with the subsequently good-quality embryos than in that with the subsequently poor-quality embryos (P < 0.05).

CONCLUSIONS

These results indicated that the concentration of sCD44 in follicular fluid reflects the development of embryos derived from the same follicle, so the sCD44 in human follicular fluid may be useful in the assessment of the prognostic value of IVF programs.

Soluble CD44: quantification and molecular repartition in plasma of patients with colorectal cancer

Based on the important role of CD44 in tumour progression and metastasis, we evaluated, in a prospective study, plasma-soluble CD44 (sCD44) as a serum marker in colorectal cancer. Blood plasma specimens from 89 patients with colorectal neoplasm, 22 patients with a gastrointestinal disease and 23 healthy donors were analysed for quantitation (ELISA assay) and purification of sCD44. The concentration of sCD44, indicating the concentration of all isoforms, was significantly higher in patients with colorectal cancer and intestinal disease than in normal individuals, but no significant differences were found between the two groups. We found no association between plasma levels and staging of the colorectal cancer patients according to Astler and Coller. A two-step batch purification combining ion exchange and immunoaffinity chromatography, followed by Western blot analysis, revealed a complex pattern with a major band corresponding to the standard form of CD44 and minor bands that may correspond to larger variant forms. No particular sCD44 isoform was clearly associated with anatomopathological or biological information.

Serum CD44 in non-Hodgkin's lymphoma

CD44 molecule is a cell surface glycoprotein involved in several cell-cell and cell-matrix interactions. It has been linked to the growth and spread of malignancies. The majority of non-Hodgkin's lymphomas (NHL) express CD44 reflecting the CD44 expression of the normal lymphocytic counterparts. Cell surface CD44 has been suggested to be involved in hematogenous distribution of NHL, and elevated levels of serum CD44 (s-CD44) have been detected in various malignant diseases. Circulating s-CD44 has been found to be functionally active according to several functional studies. In patients with NHL increased s-CD44 levels have been detected at the time of diagnosis and at progression of the disease and s-CD44 levels change in parallel with response to therapy. Moreover, a high s-CD44 level at diagnosis is associated with a high tumor burden, poor response to treatment and unfavorable outcome in NHL.