Complex assessment of tumor cell proliferation in various forms of lung cancer.

Mitotic regime, labelling index and DNA distribution in malignant lung tumours of different histological types (47 cases) were investigated. The most pronounced proliferative activity in combination with high incidence of three-group metaphases and multipolar mitoses in bi- and polyclonal cases of small cell carcinoma and poorly differentiated squamous cell carcinoma were established. Well-differentiated tumours were monoclonal and usually had a low labelling index. The high incidence of C-mitoses in well-differentiated squamous cell carcinomas is, probably, an evidence for a more pronounced damage of their cell multiplication.