Factors that emerge as crucial participants in tumour invasion and metastases are matrix metalloproteinases (MMPs), tissue inhibitor of metalloproteinase (TIMP) inhibitors and cellular adhesion molecules (CD44 and similar molecules).
Alternative splicing of CD44 and aberrant levels of soluble CD44 variants in the serum of cancer patients have been correlated to tumor progression and metastasis in different tumors including breast cancer.
The present study demonstrated that CD44 expression in primary lesions is related to a higher frequency of extrahepatic metastasis, suggesting that this is a clinicopathologically useful parameter in predicting the occurrence of distant metastasis.