Hemidesmosome morphogenesis in laryngeal carcinoma.

The ultrastructural morphology of the tumor-stromal junction of invasive squamous cell carcinoma of the human larynx is examined electron microscopically. The de novo formation of the basal lamina and hemidesmosomes in vivo is observed. The morphological sequence proceeds in four stages: (1) production of a new basal lamina; (2) extension of anchoring filaments from the plasmalemma to the basal lamina; (3) formation of the attachment plaque along the internal leaflet of the plasma membrane, and (4) development of the subbasal dense plate adjacent to and beneath the plasmalemma. This capacity in malignant keratinocytes to produce new basal lamina and hemidesmosomes is retained at certain stages of tumor invasion.