Basement membrane changes in human breast tissue in explant culture: a morphometric and ultrastructural study.

Basement membrane has been studied in vitro using human mammary lobules maintained in explant culture for periods up to 4 weeks. Morphologic similarities with basal lamina in malignant tumors in vivo have been observed, such as decrease in numbers of hemidesmosomes as determined by morphometry, reduplication and multilayering of the basal lamina, and failure to produce basal lamina after migration to the surface of the explant. Light microscopy using special stains for basement membrane has shown increasing fragmentation and loss with time in culture. These findings suggest that basement membrane changes seen in malignant tumors in vivo may not be limited to malignancy, per se, but may also be the result of other conditions.