Mortality association of enhanced CD44v6 expression is not mediated through occult lymphatic spread in stage II colorectal cancer

Background and Aims: In the absence of other metastatic disease, the presen ce of lymph node metastasis remains the most important determinant of survi val in colorectal cancer (CRC). Cluster designation 44 variant 6 (CD44v6) o ver-expression is associated with worse outcome in all stages of CRC. The C D44v6 is believed to confer metastatic potential through its facilitation o f migration, extravasation and proliferation, although the specific means b y which it conveys an adverse prognosis in CRC is unknown. The aim of the p resent study was to determine if CD44v6 over-expression in Stage II CRC sub jects was associated with the presence of lymph node micrometastases. Methods: We assessed tumour CD44v6 expression in 43 randomly sampled subjec ts who had resections for Stage II CRC between 1984 and 1991 by using immun ohistochemistry. Micrometastases were sought in corresponding lymph node (L N) sections using keratin immunohistochemistry. Results: There was a statistical trend between tumour CD44v6 over-expressio n and mortality (P = 0.09) and a significant relationship between LN cytoke ratins and mortality (P = 0.01). There was no association between the detec tion of LN cytokeratins and tumour CD44v6 over-expression. Conclusion: We conclude that the adverse survival effect of CD44v6 over-exp ression is not mediated though lymphatic spread and postulate that it may t herefore facilitate haematogenous metastasis. (C) 2000 Blackwell Science As ia Pty Ltd.