The role of basement membrane in colorectal cancer invasion and liver metastasis.
BACKGROUND
Basement membrane (BM) is a specialized extracellular matrix component that plays a key role in tumor invasion and metastasis.


METHODS
Immunohistochemical staining for two major components of BM, type IV collagen (C IV), and laminin (LN), utilizing avidin-biotin-peroxidase complex detection to examine 182 primary colorectal cancers (pT2 or greater) and 20 liver metastases.


RESULTS
The distribution of C IV was the same as of LN in colorectal cancer tissue, and in normal tissue. Both C IV and LN staining were more frequently positive in the superficial zone but infrequently in the deep zone of the primary tumor. BM preservation, C IV and LN staining in both the superficial and deep zones, was seen in 18.7% of the subjects. The rate of BM preservation significantly decreased with increasing histologic grade (P < 0.01). No correlation was observed between pT number and BM preservation. The rate of BM preservation in cases of liver metastasis was 84.4%, significantly higher than the rate in cases without liver metastasis (P < 0.001). BM was observed even at the advancing front of tumor invasion and was preserved in 95.0% of the liver metastases.


CONCLUSIONS
BM is a functional substance that appears to accompany cancer rather than function as a structural barrier against cancer invasion and liver metastasis.
Hida
J
J
First Department of Surgery, Kinki University School of Medicine, Osaka, Japan.
Matsuda
T
T
Kitaoka
M
M
Machidera
N
N
Kubo
R
R
Yasutomi
M
M
D001485:Basement Membrane / Q000502:physiology*; D003094:Collagen / Q000032:analysis; D015179:Colorectal Neoplasms / Q000648:ultrastructure*; D006801:Humans; D007150:Immunohistochemistry; D007797:Laminin / Q000032:analysis; D008113:Liver Neoplasms / Q000556:secondary* / Q000648:ultrastructure*; D009361:Neoplasm Invasiveness / Q000648:ultrastructure*
D007797:Laminin; D003094:Collagen