Laminin-5 (LN-5) in colorectal cancer: genic expression in peritoneal lavage

Aim: Recent studies show that interaction between LN (heterotrimeric protein formed by 3/b3/g2 chains) and cancer cells plays an important role in tumor invasion, also in colorectal cancer The overall survival was significantly worse in pts with free peritoneal cancer cells(FPTCs): detection of FPTCs after curative surgery is a challenge, because could improve staging and prognosis. Peritoneal citology is the current standard procedure with very low sensivity. We aimed to study the expression of LN5 in the peritoneal lavage of colorectal cancer pts and in controls with semiquantitative reverse trancriptase-polymerase chain reaction (RT-PCR). LN-5 over-expression was evaluated observing PCR-products intensity at electrophoresis: high intensity is correlated to overexpression. Methods: Pre and post-operative peritoneal lavages of 30 pts with colorectal cancer (13M; 17F), with median age of 69 (58-84) and of 10 controls, were analyzed by conventional cytology and a semiquantitativeRT-PCR. Results: Controls showed pre/post operative negative cytology and did not express LN-5. In cancer pts. cytology was positive in 2 pts in pre/postoperative lavage. LN-5 overexpression was observed in 56, 6 9 preoperatively and in 76,6% postoperatively. LN-5 gamma 2 chain was most frequent chain. Conclusion: Our study suggests a relationship between LN-5 and FPTCs, as shown by the low expression of lamimine in controls. LN-5 could be a useful marker to identify a subgroup of early-stage patients at increased risk of recurrence. The diagnostic accuracy could be improved by using a quantitative RT-PCR or western-blot and detecting serum laminine. Finally, to validate these findings a larger number of pts with follow-up study is required.