Extracellular matrix proteins and chemoradiotherapy: alpha5beta1 integrin as a predictive marker in rectal cancer.
OBJECTIVE
To investigate the effects of extracellular matrix (ECM) protein expression on the rates of apoptosis and proliferation in rectal cancers and subsequent response to chemoradiotherapy (CRT).


METHODS
The expression of fibronectin, collagen IV, laminin and the fibronectin receptor (FnR, alpha5beta1 integrin) were analysed in 32 pre-treatment rectal cancer biopsies by immunohistochemistry. ECM expression was correlated with tumour mitotic index (MI), apoptotic index (AI) and histopathological response to CRT.


RESULTS
18/32 cancers showed a poor response and 14/32 a good response (5/14 with complete pathological response) to CRT. Moderate to strong staining was seen in 22/32 cancers for fibronectin, 5/32 for collagen IV and 18/32 for laminin. Tumour FnR was related to stromal fibronectin content, and was significantly associated with CRT response; good responders having higher FnR expression compared to poor responders. No association was found between FnR expression and either MI or AI in pre-treatment biopsies, nor between MI or AI and CRT response.


CONCLUSIONS
Tumour FnR expression is independent of MI and AI, and may serve as a useful marker for CRT response in rectal cancer.
Jayne
D G
DG
Academic Surgical Unit, St. James's University Hospital, Leeds, UK. dgjayne@hotmail.com
Heath
R M
RM
Dewhurst
O
O
Scott
N
N
Guillou
P J
PJ
D017209:Apoptosis; D024141:Collagen Type IV / Q000378:metabolism; D003131:Combined Modality Therapy; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007797:Laminin / Q000378:metabolism; D008940:Mitotic Index; D017469:Receptors, Fibronectin / Q000378:metabolism*; D012004:Rectal Neoplasms / Q000378:metabolism / Q000473:pathology / Q000628:therapy*
D024141:Collagen Type IV; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D007797:Laminin; D017469:Receptors, Fibronectin