To investigate if human tumours display altered CD44 expression we performed reverse transcriptase a polymerase chain reaction (PCR) analysis of CD44 in 49 specimens from normal colonic mucosa, primary colon and rectal tumours, normal liver, and metastases of 20 patients.
CD44 expression, observed in only 49% of primary tumours, was associated with distant metastases at time of diagnosis and, among 31 curatively resected patients, with tumour recurrence (p = 0.0014) and increased mortality (p = 0.001) during follow-up averaging 17 months.
In human colorectal neoplasia CD44 variant proteins, including homologues of those which confer metastatic ability to rat tumors, were found on all invasive carcinomas and carcinoma metastases.
Recently, it was noted that CD44 participates in a wide variety of cell-cell or cell-matrix interactions including tumor metastasis and the altered expression of CD44 splice variants is helpful in the diagnosis of colon and breast cancer.
In all normal brain and tumor samples, with the exception ofmetastases from colon carcinoma, PCR analysis demonstrated one prominent product that corresponded to the CD44H hematopoietic form of CD44.
To examine whether renal cell carcinoma displays altered CD44 expression we performed reverse transcription-polymerase chain reaction (RT-PCR) analysis of CD44 in 38 specimens from renal cancer, normal kidney and metastases of 19 patients and 6 renal cancer cell lines.
Recently expression of some alternatively-spliced variants of CD44 transcripts (CD44v) has been suggested to play a potential role in tumor metastasis and the detection of CD44v containing exon 6 to 11 may be helpful for the diagnosis of cancers.
CD44 is a polymorphic family of immunologically related cell surface proteoglycans and glycoproteins implicated in cell-cell and cell-matrix adhesion interactions, lymphocyte activation and homing, cell migration, and tumor metastasis.
The relation between expression of several splicing variants of the CD 44 glycoprotein by tumor cells and the increased risk of metastases was discussed recently.
Recent studies have shown that some variant forms of CD44, a transmembrane glycoprotein expressed on various cell surfaces, might be involved in tumor progression or tumor metastasis.
The factors which lead to the formation of metastases are generally poorly understood; however the expression of a particular variant of the cell adhesion molecule CD44 may be important in facilitating metastasis formation in colon cancer.
CD44 is a polymorphic family of cell surface proteoglycans and glycoproteins implicated in cell-cell and cell-matrix adhesion interactions, cell migration, and tumor metastasis.
Expression of none of the CD44 variant epitopes was found to be positively correlated with tumour progression or with colorectal tumour metastasis to the liver, results which are inconsistent with a role for CD44 variants as indicators of colonic cancer progression.
In animal models, isoforms of CD44 (CD44v) containing sequences encoded by one or several of ten different exons (v1-v10) contribute to tumour metastasis.