Interestingly, although a CD44 splice variant contributes to MPNST cell invasion and interacts with c-Met and HGF in ST8814 cells, it is not required for c-Met activation.
Analysis of variance showed that lymphatic invasion alone was associated significantly with tumor budding (P = 0.02), and there was a significant interaction effect for tumor budding between CD44 variant 6 expression and nuclear beta-catenin expression (P = 0.01).
The expression of particular splice variants of CD44 as well as the simultaneous presence of hyaluronan is important for motility, invasion, and the metastatic spread of some tumors.
Expression of CD44 variant exons 8-10 did not significantly correlate with histological type, depth of tumor invasion, lymphatic invasion, venous invasion, or lymph node metastasis.
As a conclusion, a decrease in CDH1, CDH13, and TIMP3 expression levels with an increase in CD44 can be used as an indicator for invasion in both ER-positive and -negative breast tumors.
The results suggest that (i) serumfree suspension cultivation is non-toxic and a convenient way for isolating the ECSCs, and is not limited to specific surface markers; (ii) Ishikawa cells can be used as an effective source of ECSCs, and the obtained ECSCs expressing the pluripotent stem cells markers CD44, CD133, Oct4, Sox2, and Nanog; (iii) ECSCs originated from Ishikawa cells showed an increased ability to invasion and metastasis in vitro, and exhibited a high proliferative capacity and pluripotency in vivo and vitro.
This study suggests that CD44 and CD147 together improve the prognostic efficacy of tumor differentiation; in vitro results further point out that these markers might be determinant of differentiation characteristics, imparting properties of increased self-renewal, migration, and invasion.
The ability of TM to inhibit cell migration and invasion was enhanced or reversed in CD44s knockdown cells and cells overexpressing CD44s, respectively.
Several adhesion factors, including cadherin 6 (CDH6), cadherin 11 (CDH11) and cluster of differentiation 44 (CD44), have been reported to be involved in the invasion and metastasis of multiple types of cancer.