Release of proteinases by cultures of human cell lines derived from squamous carcinomas of the tongue and larynx.

Seven human cell lines derived from squamous carcinomas of the tongue and larynx were examined for their ability to produce and secrete proteinases. All cell lines were able to release into the culture medium cysteine proteinase and plasminogen activator-like activities. All lines differed from each other in the amount of enzymes secreted, in the kinetics of the secretion, in the quality of the enzymes produced an in the intracellular pool of these activities. These features constitute potential criteria for classifying the biochemical behavior of the tumor cell lines and for explaining their different ability to invade soft tissues and bone.