CD133 expression is a putative cancer stem cell marker and a proposed prognostic marker in CRC, whereas the predictive value of CD133 expression for effect of adjuvant chemotherapy in CRC is unclear.
Together, these data show that ABCG2 expression correlates with the presence of CD133-positive cancer cells, and thus is a possible therapeutic target for colorectal cancer.
In order to identify other CRC stem cell-specific genes, we performed a comparative expression profiling of CD133(+) and CD133(-) cell populations in primary and metastatic tumors from four patients with CRC.
Using microarray-based comparative genomic hybridization (aCGH) platform and CD133 immunostaining, we characterized colon polyps according to their association with CRC that developed in the same individual.
The CC genotype of rs3130 polymorphism in the CD133 gene can predict poorer overall survival in patients with metastatic CRC on bevacizumab which cannot be attributed to increased treatment toxicity.
Moreover, in contrast to individual CD133 or B7-H3 expression, the coexpression of B7-H3 and CD133 was evidently associated with the depth of tumor invasion, lymphatic metastasis, distant metastasis, and Dukes' stage, suggesting it is a valuable biomarker for the progression of CRC.
In light of the recent discovery of tumor-initiating cancer stem cells (CSCs) in various tumor types, we developed an in vitro CSC model from xenograft tumors established in mice from a colorectal cancer patient tumor in which the CD133+/EpCAM+ population represented tumor-initiating cells.
The current study was performed to examine the prognostic role of 53 messenger ribonucleic acid (mRNA) expression in patients with colorectal cancer and analyze its relationship with the expression of CD44 and CD133 mRNA levels.
Thymosin β4 (Tβ4), a small acidic actin binding peptide, is overexpressed in a side population of cancer stem cells and CD133-positive colorectal cancer stem cells.
In a random-effects model, the results showed that CD133-high expression in colorectal cancer was an independent prognostic marker correlating with both OS rate (RR = 0.67, 95%CI 0.54-0.82, P<0.01) and disease free survival (DFS) rate (RR = 0.71, 95%CI 0.52-0.96, P = 0.03).
By Cox progression analysis, it was shown that CEA/CK/CD133 mRNA in tumor drainage blood was an independent prognostic factor for DFS and OS in patients with Dukes' stage B and C. These results suggest that detecting CEA/CK/CD133 mRNA in tumor drainage blood by the real-time RT-PCR method would have a prognostic value in CRC patients with Dukes' stage B and C.
Expression levels of CD133, a cancer stem cell marker, and of the α-subunit of the dystroglycan (α-DG) complex, have been previously reported to be altered in colorectal cancers.
After Cox regression, age, Duck's stage, lymph node metastasis, and CD133 and CD44 proteins co-expression were shown to be the independent prognostic factors of colorectal cancers.
Therefore, definite conclusions can not be drawn yet, but it is strongly suggestive that CD133 should not be used as a single CSC marker of colorectal cancer.