Up-regulation of Cytoplasmic CD24 Expression Is Associated with Malignant Transformation but Favorable Prognosis of Colorectal Adenocarcinoma.

Abstract

Cluster of differentiation 24 (CD24) is known to be a putative marker of stem cell and tumor metastasis. This study aimed to verify the clinicopathological value of CD24 expression in colorectal adenocarcinoma (CRAC). A total of seven whole-tissue sections of malignant polyps including the sequence non-neoplastic colorectal tissue-adenoma-CRAC, 48 adenomas and 161 CRACs arranged as tissue microarray were examined by immunohistochemistry for CD24 protein expression. Association of CD24 expression with clinicopathological parameters were also studied. CD24 was not detected in normal mucosal epithelia. Cytoplasmic CD24 expression was higher in CRAC than in adenoma (p<0.001). In CRACs, cytoplasmic CD24 expression was inversely correlated with poor differentiation (grades 1 to 3), tumor size, and pathological TNM stage (I to III versus IV) (p=0.005, p=0.034, and p=0.006, respectively). Statistical correlations between high CD24 expression and longer overall and disease-free survival were found (p=0.023 and p=0.033, respectively). Our findings suggest that up-regulation of CD24 expression in CRAC occurs at malignant transformation but is a marker of good prognosis, being down-regulated in pathological TNM stage IV. CD24 expression may be a challenging diagnostic marker in differentiating early invasive CRAC from adenoma and may serve as a prognostic marker in patients with CRAC.