Centrifugal separation of cells in sputum specimens from patients with adenocarcinoma

A Ficoll density gradient centrifugation technique was used to separate fixed cells from the sputa of patients with bronchogenic adenocarcinoma. The selective enrichment of leukocytes, squamous or cancerous cells was achieved while retaining the diagnostically significant cell morphologic features. This technique is shown to typically eliminate most of the leukocytes (96.9%) macrophages (86.7%), squamous cells (70.0%) and necrotic debris from specimen fractions containing the majority of cancerous cells. The maximum purity of cancer cells (14.6%) occurs in high density (p = 1.35 g/ml) gradient fractions and results in an average 12.2-fold enrichment for cancer cells in contrast to their relative frequency of occurrence in unprocessed specimens. Differential cell count analyses of serial density centrifugation fractions show that this technique produces comparable enrichment rates for material from bronchogenic adenocarcinoma and squamous cell carcinoma.