The basement membranes are a specialized extracellular matrix underlying all epithelia, endothelia and surrounding muscle, adipose and Schwann cells. Im the embryo, the basal membrane is the first organized extracellular matrix to appear, underlying the trophodermal epithelia in the blastocyst.
Major constituents
laminins
collagen IV
perlecan
nidogen
Basement membranes and cancer
Basement membranes can be a barrier to tumour growth, but basement membrane molecules, including laminins, are also important autocrine factors produced by cancers to promote tumorigenesis.
References
Kalluri R. Basement membranes: structure, assembly and role in tumour angiogenesis. Nat Rev Cancer. 2003 Jun;3(6):422-33. PMID: 12778132