Table 1

Characteristics of the breast basement membrane (BM) and its mimickers

ComponentBasement membraneNormal interstitial tissue stroma (ECM)Tumour-associated stromaScar tissueBM-like material in invasive carcinoma
Chemical composition (main constituents)Laminins 1, 5
Collagen IV
Anchoring fibrils XV, XVIII, VII, XIX
Fibronectin
PGs: perlecan and agrin		Fibroblasts
Laminin 1
Collagens I, III, V
Anchoring fibrils VII, VI, XXVI, XXVIII
Fibronectin
PG: hyalectans and small leucine rich
Matrix metalloproteinases
Elastic fibres		Myofibroblasts
Laminin 1
Collagens I, III, V
Anchoring fibrils VII, VI, XXVI, XXVIII
Fibronectin
PG: hyalectans and small leucine rich
Growth factors
Matrix metalloproteinases
Inflammatory cells		Collagen I
Elastic fibres
Laminin 5		Collagen IV
Laminin 5
Fibronectin
Hyaline material
Heparan sulfate proteoglycan
Entactin
Staining pattern
 Collagen IV+−−−+
 Laminin+−+++
 CD34+−++−−
 α-SMA−++−−
Special stains
 PAS+−−+
 Silver stain+++−
 Van Gieson−+++
 Masson’s trichrome++++
 Acriflavine+++
Electron microscopic featuresElectron-dense zone of lamina densa which is a network of fibrils and electron lucent area called lamina lucida, both layers called basal lamina which may be duplicated in some areas with underlying lamina reticularis of reticular fibres.89 Bundles of collagen fibres and elastin with many fibroblasts.90 Collagen fibres with more prominent elastic fibres with size and pattern variation arranged in bands with some amorphous matrix. Four cell types (fibroblasts (myofibroblasts), MECs, primitive mesenchymal cells and myelin-like bodies).91 Meshwork of thick collagen bundles with few elastic fibres which are curled or tortuous numerous large fibroblasts with long processes within and between the bundles.92 93 Narrow basal lamina area or wider hyaline (loose BM material) area, lamina densa with variable thickness fine fibrillar split into many layers, lamina lucida, bands of fine fibres.81 94
Thickness and appearance100 nm, sheet-like, homogeneous eosinophilic appearance.Wavy basket-shaped collagen bundles.Dense collagen bundles.Thick bundles of disorganised collagen fibres.Eosinophilic BM-like material, variable thickness.
Fibre arrangementsCollagen fibres packed and arranged regularly in lamellas.95 Parallel collagen fibre
Loose packing of collagen96 		Disorganised poorly aligned collagen fibres.97 Disorganised collagen bundles with no specific orientation appear as whorl-like pattern.96

  • ECM, extracellular matrix; MEC, myoepithelial cell; PAS, periodic acid-Schiff; PG, proteoglycan; SMA, smooth muscle actin.