The small cell lung cancer antigen cluster-4 and the leukocyte antigen CD24 are allelic isoforms of the same gene (CD24) on chromosome band 6q21

Checkpoint CD24 function on tumor and immunotherapy

CD24 is a protein found on the surface of cells that plays a crucial role in the proliferation, invasion, and spread of cancer cells. It adheres to cell membranes through glycosylphosphatidylinositol (GPI) and is associated with the prognosis and survival rate of cancer patients. CD24 interacts with the inhibitory receptor Siglec-10 that is present on immune cells like natural killer cells and macrophages, leading to the inhibition of natural killer cell cytotoxicity and macrophage-mediated phagocytosis. This interaction helps tumor cells escape immune detection and attack. Although the use of CD24 as a immune checkpoint receptor target for cancer immunotherapy is still in its early stages, clinical trials have shown promising results. Monoclonal antibodies targeting CD24 have been found to be well-tolerated and safe. Other preclinical studies are exploring the use of chimeric antigen receptor (CAR) T cells, antibody-drug conjugates, and gene therapy to target CD24 and enhance the immune response against tumors. In summary, this review focuses on the role of CD24 in the immune system and provides evidence for CD24 as a promising immune checkpoint for cancer immunotherapy.

Cluster of Differentiation 24 Polymorphism Has No Significant Association with Chronic Hepatitis B Virus Infection in the Chinese Han Population: A Family-Based Association Study

Objective

Studies have shown that cluster of differentiation (CD) 24 gene polymorphism is associated with several diseases. Among these, chronic hepatitis B (CHB) infection has not been investigated. This study aimed to assess the function of CD24 in CHB.

Methods

The study included 478 cases of CHB and 318 cases without CHB from 230 families that underwent genotyping. Polymerase chain reaction-restriction fragment length polymorphism was performed to assess the single nucleotide polymorphism (SNP) P170 of the CD24 gene. The detected genotypes were TT, CT, and CC. Then, family based-association analysis was carried out to investigate the association between CD24 gene polymorphism and susceptibility to CHB.

Results

In the 478 patients with CHB, the frequencies of CD24 P170 T and C alleles were 35.5% and 64.5%, respectively, and the frequencies of CD24 P170 CC, CT, and TT genotypes were 39.3%, 50.4% and 10.3%, respectively. In a CD24 single-locus analysis by a family-based association test of P170 polymorphisms, T and C were not significantly associated with CHB in the additive (Z = 0.169, P = 0.866; Z = −0.169, P = 0.866, respectively), dominant (Z = 0.522, P = 0.602; Z = 0.428, P = 0.669, respectively), or recessive (Z = −0.428, P = 0.669; Z = −0.522, P = 0.602, respectively) models. Transmission-disequilibrium (TD) and sib-transmission disequilibrium (STD) tests revealed no excess of T or C alleles from heterozygous parents to their children with the disease or higher frequencies of these alleles in patients compared with their normal siblings (χ² = 0.06, P = 0.897).

Conclusion

The study findings suggest that the SNP P170 of CD24 has no significant association with susceptibility to the HB virus and related phenotypes in Chinese patients.

CD24, A Review of its Role in Tumor Diagnosis, Progression and Therapy

CD24, is a mucin-like GPI-anchored molecules. By immunohistochemistry, it is widely detected in many solid tumors, such as breast cancers, genital system cancers, digestive system cancers, neural system cancers and so on. The functional roles of CD24 are either fulfilled by combination with ligands or participate in signal transduction, which mediate the initiation and progression of neoplasms. However, the character of CD24 remains to be intriguing because there are still opposite voices about the impact of CD24 on tumors. In preclinical studies, CD24 target therapies, including monoclonal antibodies, target silencing by RNA interference and immunotherapy, have shown us brighten futures on the anti-tumor application. Nevertheless, evidences based on clinical studies are urgently needed. Here, with expectancy to spark new ideas, we summarize the relevant studies about CD24 from a tumor perspective.

Polymorphisms within Immune Regulatory Pathways Predict Cetuximab Efficacy and Survival in Metastatic Colorectal Cancer Patients

Simple Summary

Cetuximab is an antibody that blocks EGFR signaling and stimulates an immune response against cancer cells. For patients with advanced colorectal cancer, tumor sidedness and RAS mutation status are the primary factors used to select systemic therapy. Additional biomarkers are needed to better predict which patients will benefit from cetuximab-based regimens. The aim of our retrospective study was to assess the predictive and prognostic value of 12 germline single nucleotide polymorphisms in five immune related genes in 924 patients with advanced colorectal cancer undergoing therapy with cetuximab. We identified a CD24 germline genetic variant which independently predicted survival in a discovery cohort and confirmed these findings in a validation cohort. If confirmed in prospective studies, CD24 and other immune related polymorphisms may guide the use of cetuximab in patients with advanced colorectal cancer.

Abstract

Cetuximab, an IgG1 EGFR-directed antibody, promotes antibody-dependent cell-mediated cytotoxicity. We hypothesized that single-nucleotide polymorphisms (SNPs) in immune regulatory pathways may predict outcomes in patients with metastatic colorectal cancer treated with cetuximab-based regimens. A total of 924 patients were included: 105 received cetuximab in IMCL-0144 and cetuximab/irinotecan in GONO-ASL608LIOM01 (training cohort), 225 FOLFIRI/cetuximab in FIRE-3 (validation cohort 1), 74 oxaliplatin/cetuximab regimens in JACCRO CC-05/06 (validation cohort 2), and 520 FOLFIRI/bevacizumab in FIRE-3 and TRIBE (control cohorts). Twelve SNPs in five genes (IDO1; PD-L1; PD-1; CTLA-4; CD24) were evaluated by PCR-based direct sequencing. We analyzed associations between genotype and clinical outcomes. In the training cohort; patients with the CD24 rs52812045 A/A genotype had a significantly shorter median PFS and OS than those with the G/G genotype (PFS 1.3 vs. 3.6 months; OS 2.3 vs. 7.8 months) in univariate (PFS HR 3.62; p = 0.001; OS HR 3.27; p = 0.0004) and multivariate (PFS HR 3.18; p = 0.009; OS HR 4.93; p = 0.001) analyses. Similarly; any A allele carriers in the JACCRO validation cohort had a significantly shorter PFS than G/G carriers (9.2 vs. 11.8 months; univariate HR 1.90; p = 0.011; multivariate HR 2.12; p = 0.018). These associations were not demonstrated in the control cohorts. CD24 genetic variants may help select patients with metastatic colorectal cancer most likely to benefit from cetuximab-based therapy.

Association between CD24 Ala/Val polymorphism and multiple sclerosis risk: A meta analysis

BACKGROUND

The aim of this study was to explore the association between CD24 Ala/Val polymorphism and susceptibility of multiple sclerosis (MS).

METHODS

A comprehensive literature search for relevant studies was performed on google scholar, PubMed, Web of science, Embase, the Chinese National Knowledge Infrastructure and the Chinese Biology Medicine. This meta-analysis was conducted using the STATA 11.0 software and the pooled odds ratio with 95% confidence interval was calculated.

RESULTS

Seven case-control studies were included in this meta-analysis. The results showed significant association between CD24 Ala/Val polymorphism and susceptibility to MS. Stratified analysis by areas also showed significant association in Asians. However, no association was found in Europeans.

CONCLUSION

This study suggested that the CD24 Val allele was associated with an increased risk of MS and larger-scale studies of populations are needed to explore the role of CD24 Ala/Val polymorphism during the pathogenesis of MS.

Ovarian cancer stem cell: A potential therapeutic target for overcoming multidrug resistance

The cancer stem cell (CSC) model encompasses an advantageous paradigm that in recent decades provides a better elucidation for many important biological aspects of cancer initiation, progression, metastasis, and, more important, development of multidrug resistance (MDR). Such several other hematological malignancies and solid tumors and the identification and isolation of ovarian cancer stem cells (OV-CSCs) show that ovarian cancer also follows this hierarchical model. Gaining a better insight into CSC-mediated resistance holds promise for improving current ovarian cancer therapies and prolonging the survival of recurrent ovarian cancer patients in the future. Therefore, in this review, we will discuss some important mechanisms by which CSCs can escape chemotherapy, and then review the recent and growing body of evidence that supports the contribution of CSCs to MDR in ovarian cancer.

The CD24 surface antigen in neural development and disease

A cell's surface molecular signature enables its reciprocal interactions with the associated microenvironments in development, tissue homeostasis and pathological processes. The CD24 surface antigen (heat-stable antigen, nectadrin; small cell lung cancer antigen cluster-4) represents a prime example of a neural surface molecule that has long been known, but whose diverse molecular functions in intercellular communication we have only begun to unravel. Here, we briefly summarize the molecular fundamentals of CD24 structure and provide a comprehensive review of CD24 expression and functional studies in mammalian neural developmental systems and disease models (rodent, human). Striving for an integrated view of the intracellular signaling processes involved, we discuss the most pertinent routes of CD24-mediated signaling pathways and functional networks in neurobiology (neural migration, neurite extension, neurogenesis) and pathology (tumorigenesis, multiple sclerosis).

CD24 is a genetic modifier for risk and progression of prostate cancer

CD24 plays an oncogenic role in the onset and progression of various human cancers, including prostate cancer. In the present study, we identified two linkage disequilibrium blocks with four recombination hotspot motifs in human CD24 locus. To elucidate whether genetic variants of CD24 are associated with susceptibility to prostate cancer and its disease status, we conducted a case-control association study with two P170 C/T and P-534 A/C polymorphisms of CD24 in 590 patients with prostate cancer and 590 healthy controls. A significant increased risk of prostate cancer was found in men with the P170^T/T genotype over the P170^C/C genotype (odd ratio = 1.74, 95% confidence interval = 1.16-2.63, P = 0.008), and in men with the P-534^C/C genotype over the P-534^A/A genotype (odd ratio = 1.47, 95% CI = 1.18-2.26, P = 0.003). Cochran-Armitage trend analysis showed that the P170^T allele was significantly correlated with an increased risk of prostate cancer progression (P = 0.029, trend between genotypes and stages) and this observation was also validated in an independent sample cohort. Next, we found that tumors with P170^T or P-534^C alleles had more twofold increased protein expressions of CD24 as compared to those with P170^C or P-534^A alleles, respectively. Likewise, tumors with a combination of P170^T/T and P-534^C/C genotypes were associated with a high mRNA level of CD24. Our data suggest a significant association of CD24 genetic variants with prostate cancer onset and progression, which provides new insight into molecular genetics of prostate cancer; however, these findings need to be validated in multiple independent cohorts. © 2016 Wiley Periodicals, Inc.

Association between the CD24 Ala57Val polymorphism and risk for multiple sclerosis and systemic lupus erythematosus: a meta-analysis

The cluster of differentiation 24 (CD24) Ala57Val polymorphism has been implicated as a risk factor for multiple sclerosis (MS) and systemic lupus erythematosus (SLE); however, genetic studies have produced controversial results. A meta-analysis was performed on this topic. We used odds ratio (OR) and 95% confidence interval (95% CI) to investigate the strength of association. Eleven studies from nine publications consisting of 2466 cases and 2650 controls were included. The results suggested that the CD24 Val/Val genotypes were associated with an increased risk of MS in all study subjects and Caucasians (OR = 2.28, 95% CI: 1.68–3.10, P_z < 0.001 and OR = 2.30, 95% CI: 1.66–3.20, P_z < 0.001, respectively). Sensitivity analysis showed that no individual study was found to be significantly biasing the pooled results. Although meta-analysis also suggested an association between the CD24 Val/Val genotypes and SLE risk in Caucasians (OR = 1.71, 95% CI: 1.31–2.24, P_z < 0.001), sensitivity analysis demonstrated that the association was not statistically significant after removing a Spanish study. In conclusion, this meta-analysis suggests that the CD24 Ala57Val polymorphism is associated with an increased risk of MS in Caucasians. However, the available evidence is not sufficient to support an association between the CD24 Ala57Val polymorphism and SLE risk.

CD24 Ala57Val polymorphism is associated with spontaneous viral clearance in the HCV-infected Chinese population

BACKGROUND & AIMS

Host immune response to hepatitis C virus (HCV) is a vital factor involved in both viral clearance and liver disease pathogenesis. CD24 plays an important role in inflammation and immune response and CD24 polymorphisms are associated with risk and progression of chronic hepatitis B virus infection. Our study evaluated whether CD24 polymorphisms affect HCV clearance.

METHODS

We genotyped 544 chronic hepatitis C (CHC) patients, 78 spontaneous hepatitis C clearance (SHC) patients and 215 healthy controls for CD24 gene variants at positions -P534, P170, P1527 and IFNL3 rs12979860 by pyrosequencing. In CHC patients, 362 individuals were treated with a recombinant IFN-α2b/ribavirin combination for 48 weeks and were followed up for an additional 24 weeks. Lymphocyte CD24 expression was analysed by flow cytometry.

RESULTS

We show that P170 CT and CT/TT genotypes were over-represented in the SHC group compared to CHC patients (62.8% vs. 47.2% and 75.6% vs. 60.3%, for respective polymorphisms). In multivariate logistic analysis, P170 (CD24 Ala57Val) polymorphism was an independent predictor of SHC (adjusted OR = 2.11, 95%CI = 1.19-3.73, P = 0.010 for CT genotype; OR = 2.01, 95%CI = 1.15-3.49, P = 0.014 for CT/TT genotype). No significant associations were found between the CD24 polymorphisms and treatment-induced viral clearance in log-rank analysis and Cox regression analysis. Patients with the CT/TT genotype had greater T-cell CD24 expression than patients with the CC genotype.

CONCLUSIONS

Our findings suggest that CD24 Ala57Val polymorphism and associated variations in CD24 expression may be an important predictor for SHC, but have no effect on antiviral drug treatment response in Chinese CHC patients.

External Qi of Yan Xin Qigong induces cell death and gene expression alterations promoting apoptosis and inhibiting proliferation, migration and glucose metabolism in small-cell lung cancer cells

Small-cell lung cancer (SCLC) is a highly malignant carcinoma with poor long-term survival. Effective treatment remains highly demanded. In the present study, we demonstrated that External Qi of Yan Xin Qigong (YXQ-EQ) exerted potent cytotoxic effect towards SCLC cell line NCI-H82 via induction of apoptosis. Global gene expression profiling identified 39 genes whose expression was altered by YXQ-EQ in NCI-82 cells. Among them, semi-quantitative RT-PCR and real-time qPCR analyses confirmed that the gene expression levels of apoptotic proteins death-associated protein kinase 2 and cell death-inducing DFFA-like effector b were upregulated, whereas that of oncoproteins DEK and MYCL1, cell migration-promoting proteins CD24 and integrin-alpha 9, and glycolytic enzyme aldolase A were downregulated. These findings suggest that YXQ-EQ may exert anticancer effect through modulating gene expression in a way that facilitates cancer cell apoptosis while represses proliferation, metastasis, and glucose metabolism.

CD24 Ala57Val gene polymorphism and the risk of systemic lupus erythematosus

It was recently shown that the CD24 Ala57Val (rs 52812045) polymorphism plays a significant role in susceptibility to systemic lupus erythematosus (SLE) in a Spanish population, which has not been confirmed in other ethnic groups. We investigated the distribution of the CD24 Ala57Val polymorphism in patients with SLE (n = 250) and controls (n = 350) in Poland. The odds ratio (OR) for patients with SLE with the Ala/Val genotype compared with Ala/Ala genotype was 1.490 [95% confidence interval (CI) = 1.052-2.111, P = 0.0275], and OR for the Val/Val genotype compared with Ala/Ala genotypes was 2.001 (95% CI = 1.154-3.467, P = 0.0154). Moreover, we observed a significant association between the CD24 Val allele and the presence of anti-Scl-70 antibody (Ab) OR = 2.155 (1.438-3.229, P = 0.0002). There was also an association of Val allele with the presence of anti-snRNP Ab OR = 1.984 (1.266-3.110, P = 0.0034) in patients with SLE. We also found that the CD24 Val/Val and Ala/Val genotypes contribute to immunologic manifestations OR = 2.244 (1.323-3.806, P = 0.0037). Our observations indicate that the CD24 Ala57Val polymorphism may predispose to SLE incidence and can be linked to immunologic manifestations and production of autoantibodies in this disease.

CD24 polymorphisms affect risk and progression of chronic hepatitis B virus infection

T-cell immunity to hepatitis B virus (HBV) is involved in both viral clearance and the pathogenesis of cirrhosis and hepatocellular carcinoma following chronic HBV infection. It is therefore of great interest to analyze whether genetic polymorphism of genes involved in the immune response may determine the outcomes of chronic HBV infection. Here we report that CD24 polymorphisms affect the risk and progression of chronic HBV infection. Thus the CD24 P170(T) allele, which is expressed at a higher level, is associated with an increased risk of chronic HBV infection. Among the chronic HBV patients this allele shows recessive association with more rapid progression to liver cirrhosis and hepatocellular carcinoma in comparison to the P170(C) allele. In contrast, a dinucleotide deletion at position 1527-1528 (P1527(del)), which reduces CD24 expression, is associated with a significantly reduced risk of chronic HBV infection. To confirm the role for CD24 in liver carcinogenesis, we compared the size of liver tumor developed in CD24(-/-) and CD24(+/-) HBV transgenic mice. Our data demonstrate that targeted mutation of CD24 drastically reduced the sizes of spontaneous liver cancer in the HBV transgenic mice.

CONCLUSION

These data demonstrate that genetic variation of CD24 may be an important determinant for the outcome of chronic HBV infection.

Expression of CD24 in clear cell renal cell carcinoma and its prognostic significance

OBJECTIVES

To evaluate the expression patterns of CD24 in clear cell renal cell carcinoma (CCRCC) and to investigate its prognostic significance. CD24 is a cell adhesion molecule that has been thought to play an important role in tumor progression and metastasis of various cancers. CD24 expression has previously been reported in RCC, although little is known about its prognostic significance.

METHODS

We immunohistochemically analyzed CD24 expression using tissue microarray in 328 cases of CCRCC. The percentage of positively stained tumor cells was evaluated and classified into four categories: 0, 0%; 1+, 1% to 10%; 2+, 11% to 50%; and 3+, more than 50%. For statistical analysis, the cases were subdivided into a CD24-low-expression group (0 and 1+) and CD24-high-expression group (2+ and 3+).

RESULTS

High CD24 expression was significantly associated with a high nuclear grade (P = 0.005) and large tumor size (P = 0.04). The survival analysis revealed no significant association between CD24 expression and disease-specific survival (P = 0.141). However, the CD24-high-expression group had a significantly shortened progression-free survival (P = 0.005). Multivariate analysis also revealed that high CD24 expression was an independent covariate for poor progression-free survival (P = 0.043).

CONCLUSIONS

We investigated CD24 expression in CCRCC and found that high CD24 expression was associated with high nuclear grade, large tumor size, and shortened progression-free survival. Although the biologic function of CD24 in CCRCC remains unknown, the expression of CD24 can provide new prognostic information about disease progression.

The novel oncogene CD24 and its arising role in the carcinogenesis of the GI tract: from research to therapy

CD24 was first described in the early 1980s and only attributed to scattered publications, referred to as a cell surface molecule in hematopoiesis. Recently, studies are accumulating to show that CD24 conveys a function in cell-to-cell interaction and regulation of proliferation and adhesion. CD24 appears to be highly expressed in a large variety of human cancers and to contribute to the acceleration of tumor growth and metastases shedding by binding to platelet (P)-selectin, L1 and by evoking--to date unknown--intracellular signal pathways. Anti-CD24 monoclonal antibodies thus act as a promising cancer treatment as was shown in the setting of gastrointestinal cancers. Recent articles also correlate CD24 expression with the identification of 'tumor stem cells'.

CD24: a genetic checkpoint in T cell homeostasis and autoimmune diseases

CD24 is widely used as a marker for differentiation of multiple lineages of cells and can provide costimulation for T cells, especially in non-lymphoid target organs. Recent studies demonstrate that CD24 controls an important genetic checkpoint for homeostasis and autoimmune diseases in both mice and humans. Understanding the molecular and cellular basis of CD24 function could provide important insights into T cell biology and autoimmunity.

Overexpression of CD24: association with invasiveness in urothelial carcinoma of the bladder

CONTEXT

CD24, originally described as a B-cell marker, has gained considerable attention in tumor research. High rates of CD24 expression have been found in several types of carcinomas that are significantly associated with a more aggressive course of the disease. To our knowledge, the expression of CD24 in urothelial carcinoma (UC) of the bladder has not been previously reported.

OBJECTIVE

To determine the expression of CD24 in UCs and the association between CD24 levels and tumor grade and stage.

DESIGN

Urothelial carcinomas (48 cystectomy, 87 transurethral biopsy), including 56 pTa, 29 pT1, 19 pT2, and 31 pT3, were analyzed immunohistochemically using an anti-CD24 monoclonal antibody. The intensity of CD24 staining was semiquantitatively scored as high-level or low-level expression.

RESULTS

In normal urothelium, CD24 was localized to the cytoplasm of the luminal cell layer with very low intensity. CD24 expression was upregulated in noninvasive UCs, and a high level of expression was correlated with the tumor grade (P = .003). Invasive UCs demonstrated strong diffuse cytoplasmic overexpression of CD24 and the difference in CD24 expression between invasive and noninvasive UC was statistically significant (P < .001).

CONCLUSIONS

CD24 protein is overexpressed in a significant number of bladder UCs. The high level of CD24 expression with loss of apical localization is a marker for stromal invasion and high tumor grade in UC. This study provides the basis for future investigations of CD24 as a potential serum marker or target of antibody-based therapeutics in bladder UC.

A dinucleotide deletion in CD24 confers protection against autoimmune diseases

It is generally believed that susceptibility to both organ-specific and systemic autoimmune diseases is under polygenic control. Although multiple genes have been implicated in each type of autoimmune disease, few are known to have a significant impact on both. Here, we investigated the significance of polymorphisms in the human gene CD24 and the susceptibility to multiple sclerosis (MS) and systemic lupus erythematosus (SLE). We used cases/control studies to determine the association between CD24 polymorphism and the risk of MS and SLE. In addition, we also considered transmission disequilibrium tests using family data from two cohorts consisting of a total of 150 pedigrees of MS families and 187 pedigrees of SLE families. Our analyses revealed that a dinucleotide deletion at position 1527∼1528 (P1527^del) from the CD24 mRNA translation start site is associated with a significantly reduced risk (odds ratio = 0.54 with 95% confidence interval = 0.34–0.82) and delayed progression (p = 0.0188) of MS. Among the SLE cohort, we found a similar reduction of risk with the same polymorphism (odds ratio = 0.38, confidence interval = 0.22–0.62). More importantly, using 150 pedigrees of MS families from two independent cohorts and the TRANSMIT software, we found that the P1527^del allele was preferentially transmitted to unaffected individuals (p = 0.002). Likewise, an analysis of 187 SLE families revealed the dinucleotide-deleted allele was preferentially transmitted to unaffected individuals (p = 0.002). The mRNA levels for the dinucleotide-deletion allele were 2.5-fold less than that of the wild-type allele. The dinucleotide deletion significantly reduced the stability of CD24 mRNA. Our results demonstrate that a destabilizing dinucleotide deletion in the 3′ UTR of CD24 mRNA conveys significant protection against both MS and SLE.

When an individual's immune system attacks self tissues or organs, he/she develops autoimmune diseases. Although it is well established that multiple genes control susceptibility to autoimmune diseases, most of the genes remain unidentified. In addition, although different autoimmune diseases have a common immunological basis, a very small number of genes have been identified that affect multiple autoimmune diseases. Here we show that a variation in CD24 is a likely genetic factor for the risk and progression of two types of autoimmune diseases, including multiple sclerosis (MS), an organ-specific autoimmune disease affecting the central nervous system, and systemic lupus erythematosus, a systemic autoimmune disease. Our data indicated that if an individual's CD24 gene has a specific two-nucleotide deletion in the noncoding region of CD24 mRNA, his/her risk of developing MS or SLE is reduced by 2- to 3-fold. As a group, MS patients with the two-nucleotide deletion will likely have a slower disease progression. Biochemical analysis indicated that the deletion leads to rapid decay of CD24 mRNA, which should result in reduced synthesis of the CD24 protein. Our data may be useful for the treatment and diagnosis of autoimmune diseases.

CD24 Ala/Val polymorphism and multiple sclerosis

CD24 is expressed on a broad range of cells in the immune and central nervous systems and appears to be required for development of experimental autoimmune encephalomyelitis in mice. Association of a CD24 Ala/Val coding polymorphism with susceptibility to and progression of multiple sclerosis was recently reported. We typed this coding polymorphism in a combined cohort of 1,180 cases and 1,168 unrelated and family-based controls from Belgium and the UK, but were unable to confirm either association. Since the CD24 gene is part of a segmental duplication, special care is required for the identification and genotyping of single nucleotide polymorphisms.

Cytoplasmic CD24 expression in advanced ovarian serous borderline tumors

OBJECTIVES

CD24, originally described as a B-cell marker, has been revealed as one of the candidate molecular markers of epithelial ovarian cancer. We aimed to determine the pattern and extent of CD24 expression in ovarian serous tumors and to clarify its relationship with pathological parameters, especially those associated with the early events of tumor progression in serous tumors of borderline malignancy.

METHODS

A total of 114 ovarian serous tumors, including 9 adenomas, 34 borderline, and 71 carcinomas, were analyzed immunohistochemically using a CD24 monoclonal antibody on paraffin blocks.

RESULTS

In normal epithelium and serous cystadenomas, the CD24 expression was localized to the apical membranous portion. In some of borderline tumors (26.4%), additional cytoplasmic expression was observed. The cytoplasmic expression of CD24 in borderline tumors was associated with microinvasion (P = 0.001) and omental implants (P = 0.033) with statistical significance. Serous adenocarcinomas showed strong diffuse cytoplasmic expression of CD24, which was significantly associated with shortened survival rate both in univariate (P = 0.011) and multivariate (P = 0.009) analysis.

CONCLUSION

The loss of apical localization with the acquisition of the cytoplasmic staining of CD24 protein is a surrogate marker of stromal invasion in ovarian serous tumors of borderline malignancy. Furthermore, the increase in the cytoplasmic expression of CD24 protein is a strong independent molecular marker for shortened survival rate of patients with ovarian serous adenocarcinomas.

Tumour biological aspects of CD24, a mucin-like adhesion molecule

CD24 is a molecule that recently has raised considerable attention in tumour biology. It is involved in cell adhesion and metastatic tumour spread. It has also been described as a new diagnostic marker of tumours, of neuroendocrine differentiation and, possibly most intriguing of all, of patient prognosis. High rates of CD24 expression detected by immunohistochemistry have been found in epithelial ovarian cancer (83%), breast cancer (85%), non-small cell lung cancer (45%), prostate cancer (48%) and pancreatic cancer (72%). With the exception of pancreatic cancer, high rates of CD24 are significantly associated with a more aggressive course of the disease, a finding that remains significant in a multivariate analysis. The aim of this review is to summarize relevant work covering these aspects of CD24.

Tumour biological aspects of CD24, a mucin-like adhesion molecule

CD24 is a molecule that recently has raised considerable attention in tumour biology. It is involved in cell adhesion and metastatic tumour spread. It has also been described as a new diagnostic marker of tumours, of neuroendocrine differentiation and, possibly most intriguing of all, of patient prognosis. High rates of CD24 expression detected by immunohistochemistry have been found in epithelial ovarian cancer (83%), breast cancer (85%), non-small cell lung cancer (45%), prostate cancer (48%) and pancreatic cancer (72%). With the exception of pancreatic cancer, high rates of CD24 are significantly associated with a more aggressive course of the disease, a finding that remains significant in a multivariate analysis. The aim of this review is to summarize relevant work covering these aspects of CD24.

CD24 is a genetic modifier for risk and progression of multiple sclerosis

Multiple sclerosis (MS) is a chronic neurological disease of unknown etiology, but a genetic basis for the disease is undisputed. We have reported that CD24 is required for the pathogenicity of autoreactive T cells in experimental autoimmune encephalomyelitis, the mouse model of MS. Here we investigate the contribution of CD24 to MS by studying single-nucleotide polymorphism in the ORF among 242 MS patients and 207 population controls. This single-nucleotide polymorphism results in replacement of alanine (CD24a) with valine (CD24v) in the mature protein. We found that the CD24v/v renders a >2-fold increase in the relative risk of MS in the general population (P = 0.023). Among familial MS, the CD24v allele is preferentially transmitted into affected individuals (P = 0.017). Furthermore, 50% of CD24v/v patients with expanded disability status scale 6.0 reached the milestone in 5 years, whereas the CD24a/v (P = 0.00037) and CD24a/a (P = 0.0016) patients did so in 16 and 13 years, respectively. Moreover, our data suggest that the CD24v/v patients expressed higher levels of CD24 on peripheral blood T cells than did the CD24a/a patients. Transfection with CD24a and CD24v cDNA demonstrated that the CD24v allele can be expressed at higher efficiency than the CD24a alleles. Thus, CD24 polymorphism is a genetic modifier for susceptibility and progression of MS in the central Ohio cohort that we studied, perhaps by affecting the efficiency of CD24 expression on the cell surface.

The 5'-flanking region of human CD24 gene has cell-type-specific promoter activity in small-cell lung cancer

The human surface antigen CD24 is over-expressed in small-cell lung cancer. Here we describe the isolation, sequencing and functional characterization of the 5'-flanking region of the human CD24 gene. A sequence (accession number: Y14692) of 3.4 kb regulates the activity of a luciferase reporter gene in CD24-expressing small-cell-lung-cancer cell lines up to 1.6-fold more than the control SV40 promoter and enhancer. In contrast, little or no luciferase activity was detected in 4 non-small-cell-lung-cancer cell lines. A deletion fragment of 269 bp had maximal activity in small-cell-lung-cancer cell lines (15- to 20-fold higher than control), while activity remained 2- to 10-fold below control in non-small-cell-lung-cancer cell lines. We conclude that the CD24 promoter has a strong and cell-type-specific activity, and propose its exploitation to drive the expression of therapeutic genes in small-cell lung cancer.

Potent anti-tumor effects of an anti-CD24 ricin A-chain immunotoxin in vitro and in a disseminated human Burkitt's lymphoma model in SCID mice

A new anti-CD24 immunotoxin (IT), SWA11.dgA, was constructed by coupling the MAb SWA11 via the bivalent linker SMPT to deglycosylated ricin A-chain (dgA). The effects of SWA11.dgA were evaluated in vitro against the B-precursor leukemia cell line REH, the non-B-non-T acute lymphoblastic leukemia cell line NALM-6 and the Burkitt's lymphoma cell lines BL-2 and BL-38. Binding of SWA11 to the CD24 antigen was assessed by flow cytometry demonstrating high affinity of the MAb for all cell lines tested. SWA11.dgA inhibited the protein synthesis of BL-38, NALM-6, REH and BL-2 cells by 50% at concentrations (IC50) of 4.0 x 10(-11) M, 6.0 x 10(-11) M, 8.0 x 10(-11) M and 3.0 x 10(-9) M, respectively. SWA11.dgA was subsequently used for the treatment of disseminated human BL-38 Burkitt's lymphoma in a newly developed SCID mouse model. The mean survival time (MST) of BL-38-bearing SCID mice was extended from 23 days in untreated controls to more than 230 days when 6 microg SWA11.dgA was applied intraperitoneally one day after tumor challenge. All of the animals achieved continuous complete remissions. SCID mice treated with SWA11.dgA 4 days after tumor cell challenge or a reduced dose of SWA11.dgA (67%) also had a significantly extended MST (45.0 and 51.4 days, respectively, as compared to 22.7 and 23.1 days in the controls). We conclude that SWA11.dgA might be of potential use for the treatment of lymphoma in man.