Increased contraenvironmental-pressure cell division capability: a decisive force in metastasis and invasion of mouse lung adenocarcinoma cell lines.

The correlation between the growth of ML2, ML3 and ML4 cell lines in 1% agar cultures and their metastatic potential (mouse lung adenocarcinoma) was investigated. The growth ability in 1% agar cultures of ML2, ML3 and ML4 correlated far better with growth rates at lung metastatic sites than with the period required for the cells to reach the lungs following transplantation into the subcutaneum. Clones from 1% agar cultures of ML2, ML3 and ML4 show more conspicuous invasive and destructive growth than their monolayer counterparts in the muscle organ culture assay. We discuss the possible significance of 1% agar cultures to the investigation of 'contraenvironmental-pressure cell division capability', an important factor in the invasive and metastatic potential of cancer.