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Significance of CD44 and CD24 as cancer stem cell markers: an enduring ambiguity.

Jaggupilli A, Elkord E - Clin. Dev. Immunol. (2012)

Bottom Line: Lack of universal expression of surface markers limits their usage and no best combination of markers has yet been confirmed to identify CSCs capable of initiating and metastasizing tumours.CD24, a heat stable antigen, is another surface marker expressed in many tumour types.However, their expression and prognostic value in isolating CSCs are still an enduring ambiguity.

View Article: PubMed Central - PubMed

Affiliation: Biomedical Research Centre, School of Environment & Life Sciences, University of Salford, Salford M5 4WT, UK.

ABSTRACT
Cancer stem cell population is a subset of cells capable of dictating invasion, metastasis, heterogeneity, and therapeutic resistance in tumours. Eradication of this rare population is a new insight in cancer treatment. However, prospective identification, characterization, and isolation of these CSCs have been a major challenge. Many studies were performed on surface markers for potential identification and isolation of CSCs. Lack of universal expression of surface markers limits their usage and no best combination of markers has yet been confirmed to identify CSCs capable of initiating and metastasizing tumours. CD44, a hyaluronic acid receptor, is one of the most commonly studied surface markers, which is expressed by almost every tumour cell. CD24, a heat stable antigen, is another surface marker expressed in many tumour types. However, their expression and prognostic value in isolating CSCs are still an enduring ambiguity. In this critical review, we assess the role of CD44 and CD24 in tumour initiation, development, and metastasis. We mainly focus on analysing the significance of CD44 and CD24 as CSC surface markers in combination or with other putative markers in different types of cancer.

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Related in: MedlinePlus

FACS analysis for double staining of CD44 and CD24 in selected human cancer cell lines. These cell lines are breast (MDA-MB-468), renal (CAKI2), colon (HCT116), lung (COR L23), and ovarian cancer (OVCAR3, SKOV3, CAOV3 and A2780). Each cancer cell line shows differential expression for both CD44 and CD24. It is highly variable even amongst cell lines of same cancer types indicating the heterogeneity between tumours.
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fig1: FACS analysis for double staining of CD44 and CD24 in selected human cancer cell lines. These cell lines are breast (MDA-MB-468), renal (CAKI2), colon (HCT116), lung (COR L23), and ovarian cancer (OVCAR3, SKOV3, CAOV3 and A2780). Each cancer cell line shows differential expression for both CD44 and CD24. It is highly variable even amongst cell lines of same cancer types indicating the heterogeneity between tumours.

Mentions: Many studies refer to CD44 as a commonly expressed surface marker in different cancer types. The majority of cancer cell lines express high levels of CD44. Differently and in spite of its expression in many different cancer subtypes, the ambiguity on CD24 classification and distribution is still persisting. The conclusions from several studies regarding their expression, role in tumour initiation, and metastasis, and membrane distribution appear to be different [26, 50–53]. However, including CD44 and CD24, no marker can be used universally to identify CSCs in various cancers. It is certainly acceptable that these markers are not expressed in all cancers. We found that the levels of CD44 and CD24 expression show great variation (Figure 1) between cell lines even in cells of the same cancer subtype [53]. They are engaged with distinct functionalities at different time periods during tumour progression and metastasis [18]. It strongly infers heterogeneity between and amongst cancer subtypes, which is not fully elucidated [50] and raises a question of credibility regarding their value as CSC surface markers. Despite the extensive study and emerging evidence, significance of CSC markers, their specificity, correlation, and coexistence remain elusive. Also, enormous data from literature is leaving ambiguity even for the same type of cancer subtypes and CSC markers. Collectively, CSC concept seems to be left more complicated with complex implications yet to be resolved.


Significance of CD44 and CD24 as cancer stem cell markers: an enduring ambiguity.

Jaggupilli A, Elkord E - Clin. Dev. Immunol. (2012)

FACS analysis for double staining of CD44 and CD24 in selected human cancer cell lines. These cell lines are breast (MDA-MB-468), renal (CAKI2), colon (HCT116), lung (COR L23), and ovarian cancer (OVCAR3, SKOV3, CAOV3 and A2780). Each cancer cell line shows differential expression for both CD44 and CD24. It is highly variable even amongst cell lines of same cancer types indicating the heterogeneity between tumours.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3369436&req=5

fig1: FACS analysis for double staining of CD44 and CD24 in selected human cancer cell lines. These cell lines are breast (MDA-MB-468), renal (CAKI2), colon (HCT116), lung (COR L23), and ovarian cancer (OVCAR3, SKOV3, CAOV3 and A2780). Each cancer cell line shows differential expression for both CD44 and CD24. It is highly variable even amongst cell lines of same cancer types indicating the heterogeneity between tumours.
Mentions: Many studies refer to CD44 as a commonly expressed surface marker in different cancer types. The majority of cancer cell lines express high levels of CD44. Differently and in spite of its expression in many different cancer subtypes, the ambiguity on CD24 classification and distribution is still persisting. The conclusions from several studies regarding their expression, role in tumour initiation, and metastasis, and membrane distribution appear to be different [26, 50–53]. However, including CD44 and CD24, no marker can be used universally to identify CSCs in various cancers. It is certainly acceptable that these markers are not expressed in all cancers. We found that the levels of CD44 and CD24 expression show great variation (Figure 1) between cell lines even in cells of the same cancer subtype [53]. They are engaged with distinct functionalities at different time periods during tumour progression and metastasis [18]. It strongly infers heterogeneity between and amongst cancer subtypes, which is not fully elucidated [50] and raises a question of credibility regarding their value as CSC surface markers. Despite the extensive study and emerging evidence, significance of CSC markers, their specificity, correlation, and coexistence remain elusive. Also, enormous data from literature is leaving ambiguity even for the same type of cancer subtypes and CSC markers. Collectively, CSC concept seems to be left more complicated with complex implications yet to be resolved.

Bottom Line: Lack of universal expression of surface markers limits their usage and no best combination of markers has yet been confirmed to identify CSCs capable of initiating and metastasizing tumours.CD24, a heat stable antigen, is another surface marker expressed in many tumour types.However, their expression and prognostic value in isolating CSCs are still an enduring ambiguity.

View Article: PubMed Central - PubMed

Affiliation: Biomedical Research Centre, School of Environment & Life Sciences, University of Salford, Salford M5 4WT, UK.

ABSTRACT
Cancer stem cell population is a subset of cells capable of dictating invasion, metastasis, heterogeneity, and therapeutic resistance in tumours. Eradication of this rare population is a new insight in cancer treatment. However, prospective identification, characterization, and isolation of these CSCs have been a major challenge. Many studies were performed on surface markers for potential identification and isolation of CSCs. Lack of universal expression of surface markers limits their usage and no best combination of markers has yet been confirmed to identify CSCs capable of initiating and metastasizing tumours. CD44, a hyaluronic acid receptor, is one of the most commonly studied surface markers, which is expressed by almost every tumour cell. CD24, a heat stable antigen, is another surface marker expressed in many tumour types. However, their expression and prognostic value in isolating CSCs are still an enduring ambiguity. In this critical review, we assess the role of CD44 and CD24 in tumour initiation, development, and metastasis. We mainly focus on analysing the significance of CD44 and CD24 as CSC surface markers in combination or with other putative markers in different types of cancer.

Show MeSH
Related in: MedlinePlus